TIAs and Strokes

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Chapter 11 TIAs and Strokes

Transient ischemic attacks (TIAs) and strokes (or cerebrovascular accidents [CVAs]) cause readily recognizable constellations of transient or permanent neurologic deficits. Well-informed psychiatrists should be able to recognize their physical manifestations and anticipate their most common accompanying neuropsychologic manifestations, including amnesia, dementia, depression, and altered levels of consciousness. Psychiatrists should also be able to distinguish TIAs and strokes from conditions that produce similar clinical manifestations, such as seizures and brain tumors.

Transient Ischemic Attacks

As their name suggests, TIAs are temporary interruptions in cerebral circulation that give rise to neurologic deficits. Although the maximum allowable duration of a TIA is 24 hours, only 10% last longer than 4 hours and most resolve in 30–60 minutes. During that first hour of a neurologic deficit, neurologists who witness it cannot predict whether the deficit will completely resolve or become permanent. In other words, if the deficit resolves, it constitutes a TIA, but if the deficit persists, it constitutes a stroke. Most of the time neurologists diagnose TIAs only in retrospect.

The majority of TIAs result from platelet emboli that have formed on the surface of atherosclerotic plaques that have built up on the inner wall of the extracranial arteries: the carotid and vertebral arteries and the aortic arch. The plaques are usually ulcerated and cause some degree of stenosis. When platelet emboli leave their surface, they course through a cerebral artery, temporarily interrupt a portion of the cerebral circulation, and induce a brief period of ischemia. Alternatively, cardiac arrhythmias and other causes of hypotension produce TIAs.

Not only do TIAs cause temporary neurologic deficits, they also reflect underlying atherosclerotic cerebrovascular disease and represent a risk factor for stroke. TIAs lead to strokes when either an atherosclerotic plaque grows large enough to occlude an extracerebral vessel or it throws off an embolus that permanently blocks a “downstream” cerebral artery. Within the first year following a TIA, approximately 12% of patients develop a stroke. Each year thereafter, an additional 5% develop one.

TIAs mimic other transient neurologic conditions, particularly partial seizures, postictal confusion and (Todd’s) hemiparesis, hemiplegic migraine, metabolic aberrations, adverse reactions to medicines, and, rarely, effects of cerebral mass lesions. In addition, when TIAs produce aphasia, amnesia, or another neuropsychologic deficit, but no physical deficit, they mimic psychogenic episodes.

Carotid Artery TIAs

Platelet emboli that form on plaques at the common carotid artery bifurcation (Fig. 11-1) can lead to cerebral-hemisphere TIAs. Contralateral hemiparesis, hemisensory loss, paresthesias, or homonymous hemianopsia characterize carotid artery TIAs. Depending on whether the dominant or nondominant carotid artery gives rise to the problem, a TIA may induce neuropsychologic aberrations accompanied or unaccompanied by hemiparesis and other physical deficits. For example, dominant-hemisphere TIAs may suddenly, but briefly, cause aphasia with or without hemiparesis or homonymous hemianopsia. Similarly, nondominant-hemisphere TIAs may cause brief neglect or hemi-inattention with or without homonymous hemiparesis.

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FIGURE 11-1 Top, At its bifurcation in the neck, the common carotid artery divides to form the external and internal carotid arteries. Giving off no branches until it is within the skull, the internal carotid artery immediately sends off the ophthalmic artery. The internal carotid artery then divides into the anterior and middle cerebral arteries. It also gives rise to the posterior communicating artery – not the posterior cerebral artery. Thus, each internal carotid artery perfuses the ipsilateral eye and anterior and middle portions of the ipsilateral cerebral hemisphere. The middle cerebral artery, a major branch of the internal carotid artery, supplies the deep and mid-section of the hemisphere. This region contains most of the motor cortex, sensory cortex, and, in the dominant hemisphere, the perisylvian language arc (see Fig. 8-1). Each anterior cerebral artery, another branch of the internal carotid artery, supplies the frontal lobe, including the medial surface of the motor cortex, which contains the motor innervation for the leg. The posterior cerebral artery (see Fig. 11-2), terminal branches of the basilar artery, supplies the occipital lobe, which houses the visual cortex, and most of the temporal lobe. Bottom left, An arteriogram of the carotid artery and its branches prominently displays the bifurcation (black arrow), the typical “candelabra” of branches that comprise the middle cerebral artery, and a faint anterior cerebral artery that sweeps from anterior to posterior (white arrow). Bottom right, A magnification of the bifurcation reveals an extensive circumferential plaque constricting the internal carotid artery. The remaining blood flow appears as an “apple core.” The rough interior surface of the artery gives rise to retinal and cerebral emboli.

Sometimes a TIA causes only brief visual loss in one eye, i.e., monocular blindness. Neurologists call this distinctive symptom amaurosis fugax (Greek, fleeting darkness). The underlying mechanism consists of emboli from the internal carotid artery flying into the ophthalmic artery, the carotid artery’s first branch, to induce several minutes of ischemia in the retina and optic nerve (Box 11-1). Unlike migraines, which can also cause transient visual loss, TIAs rarely cause headache or scintillations.

Between each TIA, patients have no lasting neurologic deficits. However, occasionally auscultation over the carotid artery bifurcation reveals a harsh systolic sound (bruit) that suggests carotid artery stenosis or at least atherosclerotic cerebrovascular disease. Retinal emboli (Hollenhorst plaques) of atheromatous material, which neurologists see on fundoscopy, strongly suggest carotid artery atherosclerotic plaque with stenosis.

In patients with mild cognitive impairment, TIAs may produce a brief but marked confusional state. A similar disturbance may occur after atherosclerosis slowly occludes one carotid artery, forcing the other carotid artery to supply both cerebral hemispheres through the circle of Willis (Fig. 11-2, top right). In this case, the cerebral blood supply is tenuous and emboli from the patent artery produce bilateral cerebral ischemia.

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FIGURE 11-2 Top left, After ascending, encased in the cervical vertebrae, the two vertebral arteries enter the skull. They join to form the basilar artery at the base of the brain. Small, delicate branches of the basilar artery supply the brainstem and its contents. (The Roman numerals refer to cranial nerve nuclei.) Large branches, as if wrapping their arms around the brainstem, supply the cerebellum and posterior portion of the cerebrum (i.e., the occipital lobes and inferomedial portions of the temporal lobes). The posterior cerebral arteries are, for practical purposes, the terminal branches of the basilar artery. They supply the occipital cortex and the posterior, inferior aspect of the temporal lobes. Top right, Belying its name, the circle of Willis, the “great anastomoses,” is completely patent in only about 20% of people. Connections between the basilar and internal carotid arteries ideally form the circle, which should give off the anterior, middle, and posterior cerebral arteries. The circle should provide anastomoses between anterior–posterior and right–left cerebral circulations. Despite the advantages that the circle confers, junctions of the arteries are weak spots. Defects at the junctions may balloon outward to form berry aneurysms that rupture and produce subarachnoid hemorrhages. Bottom left, This axial magnetic resonance angiogram (MRA) shows the major cerebral arteries that form the circle of Willis and anterior and posterior circulations. Bottom right, This MRA highlights the major cerebral arteries and shows the anterior and posterior circulations. The anterior circulation consists of the middle cerebral arteries (MCA), anterior cerebral arteries (ACA), and the anterior communicating artery (∧), which joins the ACAs. The posterior circulation consists of the basilar (Bas.) artery and two vertebral (Vert.), posterior cerebral (PCA), and posterior communicating arteries (*), which connect the PCAs and the basilar artery.

Preventive Measures

The goal of treatment is not merely to prevent recurrences of TIAs, but to prevent a stroke. In conjunction with the patient’s internist, neurologists generally suggest stroke risk reduction measures, such as smoking cessation, weight reduction, and treatment of hypertension, diabetes, and elevated cholesterol. In addition, neurologists usually suggest inhibiting platelet aggregation with aspirin (81 mg daily), clopidogrel (Plavix), or a dipyridamole–aspirin combination (Aggrenox). They usually suggest warfarin (Coumadin) or other anticoagulants to prevent cardioembolic embolization in patients with atrial fibrillation, left ventricular thrombus, and certain other cardiac conditions.

For TIA patients with atherosclerotic plaque causing at least 70% stenosis of the common or internal carotid artery, neurologists often recommend a carotid endarterectomy. This is invasive, delicate surgery in which surgeons briefly open the artery to remove the plaque. Although effective, carotid endarterectomy carries substantial risk because it briefly interrupts the cerebral blood supply and potentially allows pieces of the plaque to enter the cerebral circulation that, like emboli, may cause a stroke. Carotid endarterectomy for asymptomatic individuals with comparably severe carotid stenosis may also be indicated to prevent a stroke; however, the criteria remain uncertain. No procedure is feasible for a completely occluded artery.

For patients who cannot undergo carotid endarterectomy, an alternative is intravascular insertion of stents. These devices are essentially expandable tubes that neuroradiologists insert intravascularly into the carotid artery to widen atherosclerotic stenoses (see Fig. 20-28). They also trap underlying atheromatous debris against the inner surface of the arterial wall to reduce the likelihood of emboli. In contrast to the benefits of inserting stents into the extracranial carotid arteries, inserting stents into intracerebral arteries, such as the basilar or middle cerebral artery, carries too much risk to justify its use.

Basilar Artery TIAs

The vertebrobasilar system, basilar artery system, or simply the posterior circulation supplies the brainstem, cerebellum, and the posterior inferior portion of the cerebrum (the occipital and medial inferior portion of the temporal lobes [see Fig. 11-2]). Emboli-generating plaques tend to develop at both the origin of the vertebral arteries (in the chest) and their junction at the base of the brain.

Symptoms and signs of basilar artery TIAs, which usually result from patchy brainstem ischemia, differ greatly from those of carotid artery TIAs (Box 11-2). Typical basilar artery TIA symptoms include tingling around the mouth (circumoral paresthesias), dysarthria, nystagmus, diplopia, ataxia, and vertigo. On rare occasions, when all blood flow through the basilar artery momentarily stops, almost the entire brainstem suffers from ischemia. The brainstem ischemia interrupts consciousness and body tone, which causes patients to collapse. This TIA, termed a drop attack, strikes suddenly and unexpectedly. (It appears similar to cataplexy [see Chapter 17].)

Vertigo represents one of the most characteristic – but perplexing – symptoms of basilar artery TIAs. As a medical symptom, vertigo means a sensation of the patient or the surroundings revolving or otherwise moving. The thoughtful physician should accept no other descriptions. In particular, the common complaint of “dizziness” has no clinical value because, depending on the patient, it may mean imbalance, lightheadedness, anxiety, confusion, or impending trouble.

The evaluation of basilar artery symptoms typically includes – as with the evaluation of carotid artery symptoms – MRI, MRA, and evaluation for cardiac and systemic illness. In addition, a transcranial Doppler examination, which harmlessly penetrates the skull, may portray the vertebrobasilar system’s architecture. Neurologists rely on the same medications used for carotid artery TIAs. Because the usual sites of vertebrobasilar stenosis remain shielded by the chest, vertebrae, and skull, an endarterectomy would not be feasible.

Transient Global Amnesia

TIAs sometimes impair the circulation of the basilar artery’s terminal branches, the posterior cerebral arteries, which supply the temporal lobes (see Fig. 11-2). Because the temporal lobes contain portions of the limbic system, particularly the hippocampi (see Fig. 16-5), posterior circulation TIAs may induce episodes of temporary amnesia and personality change – called transient global amnesia (TGA).

The fundamental feature of TGA is an acutely developing period of amnesia. During an attack, patients cannot memorize or learn new information, such as a sequence of digits, i.e., they have anterograde amnesia. They also cannot recall recently acquired information, such as the events of the last several hours or days, i.e., they have retrograde amnesia. Although patients suffer both antero- and retrograde amnesia, the anterograde amnesia is more profound, has a greater duration, causes the greater impediment, and creates more distress. As examples of their anterograde amnesia, patients typically do not know how they came to the physician’s office or the emergency room. Once there, they lose track of their responses during their examination by a physician, who may require reintroduction several times during the examination.

In the midst of TGA, individuals may perform rote but relatively complex activities, such as driving a well-known route or preparing dinner for a large family. However, unable to comprehend their situation, some individuals become distraught, agitated, or panicked. Some, as if recoiling, appear apathetic and immobile. Most, however, seem calm but bewildered.

TGAs typically occur in middle-aged and older individuals who are apt to have cerebrovascular disease. These attacks typically develop in the midst of frightening events or physical exertion, particularly sexual activity – a coincidence that might lead to misinterpretation.

In contrast to their amnesia for new facts, TGA patients characteristically retain their general knowledge and fundamental personal information. For example, they remain able to recite their name, address, telephone number, and occupation. (All this preserved memory contradicts the adjective global in TGA.)

After their abrupt onset, TGAs last for 3–24 hours, but their intensity is most pronounced during the initial 1–2 hours. By definition, the total duration must not exceed 24 hours. The recurrence rate is approximately 10% and they do not represent a risk factor for stroke. Neurologists have proposed various etiologies for TGA, including migraine, complex partial seizures, metabolic aberrations, use of certain medicines, and congestion of cerebral veins, as well as posterior-circulation TIAs. Although the posterior-circulation TIA theory remains the most popular, TGAs do not behave like TIAs. For instance, TGA rarely if ever recurs, develops in conjunction with TIAs in other arterial distributions, shows TIA-like MRI changes, or precedes a stroke.

Even in the absence of a confirmatory laboratory test for TGA, its clinical features differentiate it from other neurologic conditions. TGA patients’ preserved intellect and general knowledge, as well as their remaining fully conscious, distinguishes them from patients in delirium. TGA patients, despite their amnesia, also do not confabulate in the manner of Wernicke–Korsakoff patients. Complex partial seizures differ by producing dulling of the sensorium, simple repetitive actions, paroxysmal or other epileptiform EEG changes, and a high rate of recurrence (see Chapter 10).

Physicians using the preliminary version of the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5) might be tempted to diagnose a patient with no recall of recent events as having Dissociative Amnesia, which it defines primarily as “inability to recall important autobiographical information, usually of a traumatic or stressful nature” and requires that, presumably over time, patients experience “significant distress or impairment in social, occupational, or other important areas of functioning.” However, that diagnosis would exclude TGA patients because they retain fundamental personal information. The preliminary version of DSM-5 also notes a subtype of Dissociative Amnesia, Dissociative Fugue, previously called Psychogenic Fugue, in which individuals purposefully travel or show “bewildered wandering.” Presumably, after establishing a new location, these individuals function within it and do not recall their previous life’s crucial aspects, such as a spouse, debts, or crimes. In other words, unlike TGA patients, these patients’ anterograde memory remains normal, but their retrograde amnesia persists, and the disorder lasts for months, years, or possibly indefinitely.

Strokes

Strokes cause permanent physical and neuropsychologic deficits. Most result from an arterial thrombosis, embolus, or hemorrhage. Feeling that there is nothing accidental about strokes, neurologists have largely abandoned the term “cerebrovascular accident.”

Risk Factors

Reflecting the necessity of preventing strokes, epidemiologic studies constantly search for stroke risk factors (Box 11-3). Although physicians customarily list stroke risk factors as individual threats, the factors actually tend to cluster. For example, obesity, elevated low-density lipoprotein cholesterol, and hypertension frequently occur together in the metabolic syndrome. Some factors, by themselves, have a weak correlation with stroke, but pose a synergistic risk when paired with others. For example, cigarette smoking correlates with stroke; however, with concomitant use of oral contraceptives or in sufferers of migraine with aura, it becomes a moderately powerful risk factor. More strikingly, smokers who are hypertensive have a 20-fold greater risk. Curiously, total serum cholesterol carries a strong risk for myocardial infarctions but a weak risk for stroke.

Age older than 65 years constitutes a powerful risk factor. Yet, about 25% of stroke victims are younger than 65 years and 12% younger than 45 years. Stroke even occurs in adolescents and young children. Hypertension, another major risk factor, similarly leads to strokes in younger individuals as well as in adults. It is also probably the most common cause of stroke-induced dementia.

Various cardiac conditions – valvular disease, prosthetic valves, acute myocardial infarction, and atrial fibrillation – comprise another risk factor because they tend to produce thromboses on valves and endocardial surfaces that embolize to the brain and elsewhere. Treatment with an anticoagulant greatly reduces the incidence of embolic stroke in patients with these cardiac diseases.

Diabetes mellitus and elevated total cholesterol represent powerful risk factors for myocardial infarction but less so for stroke. In fact, for individuals younger than 45 years, elevated total cholesterol carries little risk of stroke.

Cigarette smoking and inhaling second-hand smoke convey a significant risk factor for stroke. Even former cigarette smokers retain an almost twofold greater risk of stroke. Although judicious alcohol drinking (one drink daily to weekly) provides a slight protective effect, heavy alcohol intake poses a risk.

Migraine – in general – represents a risk factor, but one with minor significance. Any increased risk is probably restricted to migraineurs who smoke, use oral contraceptives, or have migraine with aura. Drug abuse frequently causes strokes through intravenous injection of particulate material, episodes of anoxia and hypotension, cerebral vasculitis, hypertension, and vasospasm. For example, amphetamines and cocaine are sympathomimetic stimulants that induce bursts of hypertension and prolonged arterial vasospasm that routinely lead to stroke or myocardial infarction. In particular, cocaine alkaloid (“crack cocaine”) notoriously leads to cerebral hemorrhage. By way of contrast, marijuana intoxication or even its chronic use is not associated with strokes. Studies have also implicated over-the-counter medicines, particularly phenylpropanolamine and ephedra, which are sympathomimetic ingredients of weight loss and cough suppressant medicines. Because of their association with strokes, the Food and Drug Administration has banned many of these medications.

Estrogen, when used alone as for postmenopausal hormone replacement, slightly increases the stroke risk. The danger from oral contraceptives is probably restricted to the original, high-dose estrogen preparations. Currently available low-dose estrogen preparations confer only a negligible risk for stroke.

Elevated serum concentration of homocysteine serves as a marker for an increased risk. In the autosomal recessive genetic condition, homocystinuria, children have a Marfan-like habitus, ocular lens displacement, and other anatomic abnormalities. More importantly, they routinely suffer strokes in childhood. Elevated homocysteine levels in adults are associated with the use of antiepileptic drugs and coronary artery and peripheral vascular disease, as well as stroke. Folic acid reduces elevated serum homocysteine concentrations (see Fig. 5-8), as well as reducing the incidence of fetal neural tube defects (see Chapter 13), but surprisingly, it does not reduce the incidence of strokes.

Although most risk factors relate to atherosclerosis, credible data suggest that systemic infection or vascular inflammation can also give rise to strokes. For example, elevated serum concentrations of a marker for inflammation, C-reactive protein, has a strong association with strokes. Other compelling data link periodontal disease to subsequent stroke.

The presence of anticardiolipin antibodies constitutes another example of systemic inflammation constituting a risk factor for stroke. These antibodies are a hallmark of the antiphospholipid syndrome. This syndrome is a hypercoagulable state in which mostly young women develop repeated deep vein thromboses (DVT), suffer miscarriages, and have a susceptibility to migraine and stroke. Treatment, mostly aimed at preventing thromboses, consists of anticoagulants and sometimes immunosuppressives. Although the antiphospholipid syndrome carries no specific direct psychiatric comorbidity, its associated migraines and repeated miscarriages have psychiatric repercussions. Thus, a young woman who seeks psychiatric consultation for depression following two or more miscarriages and has a history of migraine and DVT may actually have the antiphospholipid syndrome.

Examples abound of hematologic disorders causing strokes. For example, sickle cell disease and, under certain circumstances, sickle cell trait lead to strokes. Because pregnancy also induces a hypercoagulable state, it causes a small but significantly increased incidence of strokes during pregnancy, delivery, and the postpartum period. In addition, several obstetric problems, such as eclampsia, venous sinus thrombosis, cortical vein thrombosis, and ruptured aneurysms, lead to stroke-like brain damage.

Surgery is a risk factor. Not surprisingly, cardiac surgery is riskier than noncardiac surgery, urgent surgery is riskier than elective surgery, and older surgery patients are more vulnerable than younger ones.

Thrombosis and Embolus

Thromboses may simply occlude cerebral arteries and deprive the “downstream” brain of its blood flow. Similarly, emboli from the heart, aortic arch, cervical extracranial arteries, or intracranial arteries may lodge in a cerebral artery and disrupt cerebral blood flow. Because cerebral thromboses and emboli deprive a region of the brain of its oxygen supply, they cause ischemic infarction. Comprising up to 85% of all strokes, cerebral ischemic infarctions are by far the most common form.

Other important conditions that lead to stroke include vasculitis, drug abuse, sickle cell disease, and other blood dyscrasias. In short, the most frequent cause of stroke consists of an abnormality of the heart, blood vessels, or blood.

As if Napoleon’s dictum “Geography is destiny” lives, present-day neurologists readily explain that the interrupted vascular supply lines of a stroke determine neurologic deficits. The time course of a stroke suggests whether it originated in an embolus or a thrombosis. Cerebral emboli-induced infarctions develop suddenly as the embolus lodges in a cerebral vessel. Usually deficits are maximal at the onset of an embolic stroke and resolve to a certain extent over the next several days. Cerebral thromboses, in contrast, generally develop slowly or intermittently and often begin during sleep. With both embolic and thrombotic strokes, the region surrounding the infarction becomes edematous. In large strokes, edema is most severe and neurologic deficits are most pronounced during the third to fifth days. Some clinical improvement occurs as the edema resolves and ischemic areas recover; however, the infarction remains a functionless scar.

In addition to creating permanent clinical deficits, stroke scars are potentially epileptogenic. Approximately 50% of seizures that develop in adults older than 65 years originate from these lesions (see Chapter 10). Thus, patients with a history of having sustained a stroke who develop confusion, unresponsiveness, or abnormal behavior may have suffered a complex partial seizure as well as another stroke or TIA.

Necrosis

Ischemic strokes, like brain tumors, gunshot wounds, and other destructive processes, lead to cell death by necrosis. Cellular necrosis requires no cellular energy to begin or progress, but the necrotic debris (dead cells) elicits a cellular inflammatory response. In contrast, cell death by apoptosis takes place in amyotrophic lateral sclerosis (ALS), Huntington disease, and many other neurodegenerative diseases. Apoptosis also serves as the mechanism for the normal involution of several organs, including the thymus gland and ductus arteriosus. Unlike necrosis, apoptosis requires cellular energy to begin and progress, and the dead cells do not evoke an inflammatory response.

Infarctions in the Carotid Artery Distribution

Cerebral artery thrombosis and embolism produce an infarction in the distribution of the occluded artery. These strokes result in well-known clinical deficits (see Fig. 11-1 and Box 11-4):

Infarctions in the Basilar Artery Distribution

Infarctions in the basilar artery distribution cause brainstem, cerebellar, or posterior cerebral injuries. Small brainstem infarctions usually cause constellations of cranial nerve injuries and hemiparesis, and large ones usually cause coma, if not immediate death. In contrast to cerebral-hemisphere infarctions, brainstem infarctions generally spare language or intellectual function and do not cause seizures (see Box 11-4).

The posterior cerebral arteries, as previously noted, are actually terminal branches of the basilar artery. Infarction of a posterior cerebral artery causes a contralateral homonymous hemianopsia and occasionally alexia without agraphia (see Chapter 8). Bilateral posterior cerebral artery strokes can cause (cortical) blindness, which sometimes leads to Anton syndrome (see Chapter 12).

Neurologists love to localize small brainstem infarctions for both clinical and academic reasons. Lesions of the midbrain cause ipsilateral oculomotor nerve and contralateral paresis (see Fig. 4-9). Those in the pons cause ipsilateral abducens nerve and contralateral paresis (see Fig. 4-11). Infarctions involving the midline of the midbrain or pons cause the medial longitudinal fasciculus syndrome (see Chapters 12 and 15). Finally, lateral medullary infarctions, which are the most common brainstem infarction, cause a complex, apparently disparate, combination of ipsilateral limb ataxia, palatal paresis, Horner syndrome, and alternating hypalgesia (see Wallenberg syndrome, Fig. 2-10).

The clinical implication of such precise localization indicates that, if the lesion is situated in the brainstem, the patient’s cognitive functions will remain intact. For example, a patient with right hemiparesis and a left sixth cranial nerve palsy is unlikely to have aphasia or dementia. Even extensive, devastating brainstem lesions will spare intellectual function and preserve cognition – as in the locked-in syndrome (see later).

Hemorrhages

Cerebral or cerebellar hemorrhages typically occur abruptly and, because of increased intracranial pressure, produce the triad of headache, nausea, and vomiting. Patients usually lose consciousness and have profound neurologic deficits determined by the hemorrhage’s location. One special example is the cerebellar hemorrhage because it potentially leads to rapidly fatal compression of the fourth ventricle and the underlying medulla. Compression of the fourth ventricle blocks the flow of cerebrospinal fluid (CSF), which causes obstructive hydrocephalus. Pressure on the medulla depresses respiratory drive and causes coma. Physicians can diagnose cerebellar hemorrhage by its clinical manifestations – occipital headache, gait ataxia, dysarthria, and lethargy. Once imaging studies confirm a diagnosis of cerebellar hemorrhage with hydrocephalus, neurosurgeons often immediately evacuate the hemorrhage, insert a ventricular shunt, or both to relieve the pressure on the fourth ventricle and brainstem.

Hemorrhages, which are most often the result of hypertension, usually erupt in the basal ganglia, thalamus, pons, or cerebellum (see Figs 20-13 and 20-14). Trauma and use of cocaine also cause hemorrhages, but their location is not as predictable as with hypertension-induced ones. In a classic problem, patients who take a monamine oxidase inhibitor (MAOI) antidepressant and then, inadvertently or in a suicide attempt, consume certain foodstuffs, notoriously aged cheese or red wine, or receive meperidine (Demerol), develop cerebral hemorrhages. These combinations, which are sympathomimetic, lead to a burst of hypertension sufficient to cause the hemorrhage. (Notably, MAOI-A antidepressants may cause this problem, but MAOI-B medications, such as those used to treat Parkinson disease, generally do not [see Chapter 9].)

Subarachnoid hemorrhage (SAH), although usually traumatic in origin, sometimes results from a ruptured berry aneurysm. SAH most often produces a prostrating headache that patients classically describe as the “worst headache” of their life. SAH also produces nuchal rigidity and lethargy, but usually no lateralized signs. Exercising, straining at stool, and other usually benign activities can rupture an aneurysm and precipitate an SAH. A diagnostic dilemma occurs when a sudden, profound headache interrupts sex. In this case, the exertion may have led to an SAH, but more often coital cephalalgia is responsible (see Chapter 9). Thus, TGA, SAH, and a migraine variant are hazards of sexual activity.

When an aneurysm ruptures, CT and MRI usually reveal blood in the subarachnoid space at the base of the brain or within the ventricles. A lumbar puncture (LP) yields bloody or xanthochromic (yellow) CSF. Depending on the particular case, neurologists may order CT angiography, MRA, or conventional angiography to detect an aneurysm.

The traditional treatment of a ruptured aneurysm consisted of a craniotomy to clamp the neck of the aneurysm. Even for aneurysms located in accessible positions, surgical complications included vascular spasm, rupture of the aneurysm that had only been leaking, and inadvertent occlusion of the parent vessel. Current treatment options, which represent a major medical advance, include minimally invasive procedures, such as intravascular insertion of coils, epoxies, and other substances that fill the aneurysm. However, surgery remains the only option for aneurysms inaccessible by an intravascular approach.

Neuropsychologic Sequalae

Several large or many small (lacunar) strokes cause vascular cognitive impairment, previously labeled vascular dementia, and before that multi-infarct dementia. The preliminary version of the DSM-5 labels it Vascular Neurocognitive Disorder. Ironically, despite the implication of these terms, the dementia stems from the neuropathologic changes of Alzheimer disease that accompany those of cerebral vascular disease (see Chapter 7).

Occlusion of a cerebral artery typically destroys a discrete critical area of the cerebral cortex. Commonly occurring strokes produce well-known neuropsychologic syndromes, such as aphasia, Gerstmann syndrome, and hemi-inattention (see Chapter 8). Strokes of both frontal lobes, which may occur either simultaneously or in succession, cause pseudobulbar palsy and frontal lobe dysfunction (see Chapters 4 and 8).

In another mechanism, hypoxia, hypotension, carbon monoxide poisoning, or similar catastrophes cause generalized cerebral anoxia. This insult leads to dementia, cortical blindness, a persistent vegetative state (PVS: see later), and postanoxic myoclonus (see Chapter 18). A variation of generalized anoxia occurs when cerebral anoxia affects only the fine, terminal branches of cerebral arteries that perfuse the extensive circumferential regions of the cerebral cortex, which neurologists call the watershed or borderzone area. An episode of cerebral anoxia that reduces the oxygen supply below a critical point in the watershed area produces a watershed infarction. These infarctions often leave patients with cognitive motor impairment and, if the relatively well-perfused perisylvian language arc survives, isolation aphasia (see Fig. 8-3D).

Post-Stroke Depression

Depending on many variables – criteria, severity, time after the stroke, and whether the patient remains in a rehabilitation facility or has returned home – the prevalence of depression in stroke victims ranges from 20% to 50% within the first year and it peaks within the first 6 months of the stroke. Mood disturbances of all varieties follow stroke more frequently than they follow either a medical illness or orthopedic injury that produces similar disabilities. The majority of patients with post-stroke depression enjoy a remission within the first year after the stroke, but 20% remain depressed at 3 years.

Risk factors for post-stroke depression begin with the generally recognized risk factors for depression, such as a history of depression, close family member with depression, and ill health. Disease-specific risk factors reflect the severity of the stroke, such as dependence, functional impairments, degree and extent of paresis, curtailed activities of daily living (ADL), and cognitive impairment, including aphasia. By way of comparison, depression complicates vascular dementia more often than Alzheimer disease dementia.

If it occurs, post-stroke depression impairs patients’ recovery and lengthens their hospitalization. Depressed patients do not fully participate in their rehabilitation program or optimize their remaining cognitive function. They ultimately recover fewer ADLs. As a corollary of this, physicians might investigate stroke patients for depression if, for unclear reasons, they fail to meet expectations for recovery.

In addition to inducing morbidity, post-stroke depression portends increased mortality. Mortality rates are significantly higher at 1 and 10 years for post-stroke depression patients. Moreover, even though the physical incapacity of many stroke victims prevents their acting on suicide ideation, their suicide rate is twice that of age-matched controls. To place that figure in context, suicide occurs, compared to the general population, up to 10 times more frequently in Huntington disease patients, 7 times in multiple sclerosis patients, and 4 times in epilepsy patients. Risk factors for suicide in stroke patients include prior stroke, impaired ADLs, and depressive symptoms.

In some, but not all, studies, remission of post-stroke depression has correlated with improved rates of recovery of ADLs and other physical measures. Remission also has correlated with improved cognitive function.

Before leaping to the diagnosis of post-stroke depression, physicians should keep in mind that some stroke symptoms mimic depression. Failing to appreciate them may lead to misdiagnosis and unwarranted prescriptions. For example, patients with a nondominant-hemisphere stroke may deny having a hemiparesis, not because of depression, but because of anosognosia. Also, their conversations may lose their emotional tone because of aprosody (see Chapter 8). In another situation, strokes – individually or in succession – that damage both frontal lobes frequently result in apathy, pseudobulbar palsy with unprovoked crying and emotional incontinence (see Chapter 4), or a paucity of verbal output because of abulia (see Chapter 7). Finally, following several strokes, patients often develop sleep disturbances and vegetative symptoms.

To compound the diagnostic difficulty, medical care itself may produce complications that mimic depression. For example, some medications – beta-blockers and antiepileptic drugs – routinely administered to stroke patients may induce or exacerbate depressive symptoms and cognitive impairment. Also, sleep deprivation, uncomfortable or painful procedures, and psychologic factors, such as disorientation, fear, and isolation, may express themselves as withdrawal and expressions of hopelessness.

Finally, physicians should further pause before concluding that depressive symptoms result from either a neurologic or psychiatric process. Such “either/or” diagnostic reasoning is fraught with potential for error. Whatever a stroke’s sequelae, patients may have subtle post-stroke depression comorbid with neuropsychologic deficits. In fact, the two factors may act synergistically.

In another consideration, several studies have challenged the classic notion that strokes in the left frontal lobe most often cause post-stroke depression. These studies have reported equally strong correlations between depression and lesions in the right as well as the left cerebral hemisphere, and occasionally depression secondary to ones in the basal ganglia, thalamus, and other subcortical structures. In addition, some studies correlated the stroke’s location with depression only during the immediate post-stroke period.

Several trials of treatment of post-stroke depression have reported success with tricyclic antidepressants, selective serotonin reuptake inhibitors, and, in the elderly, psychostimulants. However, most trials found that antidepressants did not prevent depression or improve functional outcome. Moreover, no consensus emerged as to the best antidepressant, much less showed that any had a major impact. Psychological treatments in several studies improved patients’ mood, but they did not help other parameters. Although electroconvulsive therapy may cause more confusion than usual in stroke patients, it is overall safe and effective compared to other treatments.

Altered Levels of Consciousness

Depending on their etiology, multiplicity, and location, strokes may induce cognitive impairment, altered level of consciousness, or specific neuropsychologic deficits. These disturbances often affect patients’ decisional capacity. Families, medical colleges, and lawyers often ask psychiatrists and neurologists to determine if a patient’s stroke has deprived them of their decisional capacity.

Neurologists usually describe the levels of consciousness, in descending order, as alert, lethargic, stuporous, or comatose. Not to belabor the obvious, but alert patients are characteristically awake and have their eyes open. Being alert is a prerequisite – but certainly not a guarantee – for the essential human qualities of awareness, cognitive functioning, and emotional capability. Being alert usually reflects an underlying, functioning cerebral cortex, brainstem, and reticular activating system. However, patients who appear alert have not necessarily retained consciousness or decisional capacity. For example, patients with advanced Alzheimer disease and those who have survived profound cerebral anoxia may seem alert because they have open eyes and look at physicians and family members, but they typically have incapacitating cognitive impairment. In the opposite situation, some patients with no motor function, such as those with the locked-in syndrome (see later), retain their cognition, human qualities, and decisional capacity.

In contrast, lethargic patients remain with their eyes closed and appear asleep, but with stimulation, they open their eyes and temporarily assume an alert state. Nevertheless, when temporarily alert, they are typically inattentive, disoriented, and cognitively impaired.

Although lethargy is often a variation of a normal situation, such as sleep deprivation, it may represent dysfunction of the entire cerebral cortex or the brainstem, particularly its reticular activating system. Greater depression in the level of consciousness – stupor and coma – reflects even more profound impairment of these structures. Common disorders that cause lethargy and more depressed levels of consciousness include toxic-metabolic aberrations, multiple or large structural lesions, traumatic brain injury (TBI), and increased intracranial pressure. Lethargy is also the most common symptom of delirium, which neurologists call “toxic-metabolic encephalopathy”; however, patients in delirium often have hallucinations, physical agitation, and hypervigilance rather than lethargy.

Compared to lethargy, stupor is a more depressed level of consciousness. Stuporous patients remain unarousable with their eyes closed. For example, verbal or tactile stimuli elicit only rudimentary motor or verbal responses. Structural lesions, metabolic aberrations, and increased intracranial pressure may all cause stupor. In addition, structural lesions usually produce lateralized signs, such as hemiparesis, and indications of increased intracranial pressure, such as papilledema.

Coma, which neurologists often grade using the Glasgow Coma Scale (see Chapter 22), is the most profound depression of consciousness. Comatose patients have closed eyes, make little or no verbal response, and move their limbs only as a reflex.

In practice, these states of depressed levels of consciousness last several hours, several days, or, at most, several weeks. In other words, stupor and coma are transient conditions. Even patients with widespread neurologic injuries, if they survive, eventually resume the appearance of an alert repose with open eyes. Survivors with extensive brain damage frequently enter the locked-in syndrome, PVS, or minimally conscious state.

Locked-In Syndrome

Among their innumerable patients who have sustained strokes, TBI, or other structural lesions and appear completely incapacitated, neurologists search for the patient with the locked-in syndrome. This rare but important condition describes patients who remain mute, quadriplegic, bedridden, and totally dependent on caregivers; however, they actually are alert, have intact decisional capacity, and can communicate by moving their eyes. In other words, their completely disabled body encases (“locks in”) an intact mind.

The locked-in syndrome usually results from a stroke that damages the base (ventral portion) of the pons (basis pontis, see Fig. 2-9) and medulla (bulb). The exact cause is usually a thrombosis or embolus that occludes a branch of the basilar artery (see Fig. 11-2). The stroke causes bulbar palsy and bilateral interruption of the corticospinal tracts. It renders patients mute, quadriplegic, apneic, and dysphagic. Patients almost always require tracheostomy, ventilator support, and feeding tubes. Although locked-in patients have lost almost all their motor ability, their higher functions, like language comprehension and cognitive ability, remain intact.

The locked-in syndrome may not only result from brainstem strokes. Several peripheral nervous system (PNS) diseases, such as myasthenia gravis, ALS, and Guillain–Barré syndrome (see Chapters 5 and 6), may cause extensive enough paresis of cranial and limb muscles to cause it and require mechanical supports.

Despite the devastating damage in the locked-in syndrome, the upper brainstem, reticular activating system, and cerebral cortex remain intact. Moreover, the physiologic circuits between the cerebral cortex and upper brainstem, including the thalamus, continue to reverberate (Fig. 11-3). Thus, locked-in patients retain cognition, affective capacity, and, given sufficient clues, a sleep–wake cycle. Patients who are otherwise completely paralyzed can still purposefully move their eyes and eyelids. By closing their eyelids in a “yes” or “no” pattern, they can communicate by answering questions. The preserved circuits between the thalamus and cerebral cortex generate a relatively normal EEG.

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FIGURE 11-3 The locked-in syndrome usually results from an infarction of the ventral or basilar portion of the lower brainstem, typically at the basis pontis (see Fig. 2-9). A lesion in this area (indicated by the bar) would sever the corticospinal tracts and directly injure cranial nerves IX through XII. However, it would not damage several vital systems: (1) the reticular activating system of the brainstem; (2) the cerebral hemispheres, particularly the cerebral cortex; and (3) the cerebral and brainstem system that governs ocular movement (see Fig. 12-12). This lesion, which is nowhere near the cortex, would not affect the brain’s cognitive, language, or visual centers. The EEG is relatively normal because the lesion also spares the circuits reverberating between the thalamus and the cerebral cortex (indicated by the loop), which generate the organized, relatively regular background EEG activity.

Physicians should base management of locked-in syndrome patients on its inherent preserved cognizance and decisional capacity. These patients comprehend people talking and reading to them. They can convey their wishes, including decisions regarding their medical care. In fact, locked-in syndrome patients may direct the removal of their own artificial life-sustaining equipment. Patients in a locked-in syndrome from a brainstem stroke may partially recover, but their overall prognosis is poor. In contrast, patients debilitated from a PNS illness often fully recover.

Physicians might examine stroke victims (and those with severe, extensive PNS disease) for the locked-in syndrome if they are unable to speak or move their limbs, but have their eyelids open and voluntarily look from side to side. The physician should ask these patients to blink a certain number of times. If they correctly respond, the patient, physician, and family can establish a system of communication. If patients can blink meaningfully, the physician should test their ability to see and calculate. Afterward, physicians can undertake detailed mental status testing.

One Navy veteran, who was in a stroke-induced locked-in syndrome, communicated using eyelid blinks in Morse code. In another example, a motor vehicle accident left an editor of a Paris fashion magazine, Jean-Dominique Bauby, in the locked-in syndrome. By blinking to an assistant, he dictated a short autobiography that was made into the film with the same title, The Diving Bell and the Butterfly. Currently, an EEG–computer interface shows promise.

Persistent Vegetative State

Extensive cerebral cortex damage – without brainstem damage – may cause PVS. Like locked-in patients, PVS patients remain bedridden with quadriparesis and incontinence, but with their eyelids open and eyes moving about. However, in stark contrast, because of the cortex damage, PVS patients lack awareness of themselves and their surroundings, have no cognitive function, and cannot communicate in any manner. With their lack of consciousness, patients in PVS can neither perceive pain nor suffer. Neurologists sometimes describe this state as “wakefulness without awareness” (Figs 11-4 and 11-5). Nevertheless, the undamaged brainstem continues to regulate the body’s vegetative functions, e.g., metabolism, breathing, temperature regulation, and digestion. Also, unlike comatose patients, PVS patients continue their sleep–wake cycle.

Damage of the cortex and cortical–brainstem connections in PVS renders the EEG abnormal. The damage also causes positron emission tomography (PET) and functional MRI (fMRI) to show generalized, markedly reduced cerebral glucose metabolism and blood flow.

In what might constitute a misleading appearance of consciousness, PVS patients lie in bed with open eyelids, retain sleep–wake periods, and move their limbs as a reflex or in response to noxious stimulation. In addition, their eyes, moving spontaneously and randomly, may momentarily fix on a face or reflexively turn toward voices or other sounds. However, PVS patients perform none of these actions consciously or deliberately. Unfortunately, relatives may misinterpret patients’ appearance, eye movements, and other activities as appreciating their presence or understanding their words. Relatives often not only overestimate the patient’s cognition, they may treat the patients as if they were suffering, in a state of suspended animation, or only temporary unconsciousness.

Extensive cerebral insults, including TBI, anoxia, profound hypoglycemia, and multiple or massive strokes, or progression of neurodegenerative illnesses, particularly Alzheimer disease and childhood-onset metabolic disorders, often lead to PVS. After existing for 1 month in a vegetative state, patients fall into the category of persistent vegetative state. After an acute insult, some patients remain comatose for weeks before entering a vegetative state and, from there, the persistent state. Patients with neurodegenerative illnesses usually slip into the PVS without first entering coma. Once patients have been in TBI-induced PVS for 1 year or from neurodegenerative illness for 3 months, they have no realistic chance of recovery.

Beyond its heart-wrenching aspects, PVS raises important ethical and legal considerations. Acting on patients’ living wills or other directions that they “not live like a vegetable,” some relatives have sought to discontinue nutrition and artificial supports. On the other hand, other relatives have sought to maintain artificial supports despite its futility. Several well-known legal cases have explored the limits of maintaining PVS patients in accordance with their own or their proxy’s wishes or in the absence of any known wish. With no known wish, courts generally have allowed the health care proxy to make decisions, including removing food and nutrition.

Managing Stroke

Laboratory Tests

In most cases, CT or MRI confirms a diagnosis of stroke or reveals common alternatives, such as brain tumor, abscess, or subdural hematoma (see Chapter 20). CT indicates the presence and location of most strokes, except those that are very acute, small, or located in the brainstem or other regions of the brain located in the posterior fossa (where bone artifacts may obscure them). Compared to CT, MRI provides better resolution of small strokes, visualizes ones in areas of the brain surrounded by bone, and, by using special software subprograms, shows acute infarctions. MRA can visualize extra- and intracranial cerebral arteries and most regions of stenosis and occlusion (see Chapter 20). As diagnostic tests in this situation, skull X-rays and EEGs are superfluous.

Examination of the CSF through an LP may reveal signs of an SAH or infection, such as meningitis and encephalitis, that mimic a stroke. However, LP is unnecessary for a routine stroke and physicians should avoid performing the procedure in the presence of an intracranial mass lesion (see transtentorial herniation, Chapter 19).

Therapy

For acute ischemic strokes, neurologists may administer thrombolytic agents, such as tissue plasminogen activator (tPA), that ideally will dissolve cerebral arterial occlusions and restore cerebral blood flow. As could be anticipated, tPA carries the potential for cerebral hemorrhage and other complications. Because of its dangers, neurologists must administer tPA according to a demanding set of guidelines, including giving it within 3 hours in most patients and 4.5 hours in selected patients after the onset of a stroke, and withholding it if the patient has undergone major surgery within the previous 14 days, the blood pressure exceeds 185/110 mmHg, bleeding parameters fall outside a narrow range, or a CT shows signs of intracranial hemorrhage. Administering thrombolytic agents by angiography directly to an occlusion and neuroprotective agents (medications that preserve ischemic brain tissue) remains in development. Steroids, oxygen, and vasoactive medicines have no proven benefit.

Medical and nursing care aims to prevent stroke complications, such as aspiration pneumonia, decubitus ulcers, DVTs, and urinary tract infections. It also aims to prepare stroke patients for rehabilitation. If the patient is not alert or has a depressed gag reflex, neurologists administer medications and nutrition intravenously or through a nasogastric tube. To prevent decubiti, which are unsightly, malodorous, and liable to lead to sepsis, neurologists usually order air mattresses, sweat-absorbent bed surfaces (e.g., artificial sheepskins), and elbow and heel cushions for paretic limbs. Because urinary incontinence adds to the likelihood of developing decubitus ulcers, leaves patients cold and wet, and creates repugnant odors, neurologists generally order catheters or diapers.

The medical staff should place the patient’s bed against the wall so that visitors and staff approach the patient from the side without perceptual impairment. For example, the staff should place the bed of a patient with a left hemiparesis and a left homonymous hemianopsia with the wall to the patient’s left. In that situation, with visitors approaching only from the right side, patients will see them in their right visual field, and patients’ right hand can grasp important objects from the bedside table (e.g., call buttons, television controls, and telephone).

In the initial phase, relatives of stroke patients can be helpful by orienting the patient and bringing a luminous dial clock, a calendar, and pictures; repositioning the patient; moving paretic limbs to avoid contractures; and locating appropriate rehabilitation facilities. Eventually many relatives have difficulty in coping with the patients’ disabilities and develop caregiver stress. They have depression at about three times the usual rate.

Physical therapy will often maintain the patient’s muscle tone, forestall decubitus ulcers, and prevent contractures. It will usually help patients with simple hemiparesis to regain the ability to walk, circumvent some impediments, and avoid maladaptive but expeditious physical compensations. Moreover, physical therapy necessarily entails the “laying-on of hands,” which conveys emotional as well as physical support.

Speech therapy may help with dysarthria and offer patients encouragement; however, it probably does not restore language function in aphasia. “Cognitive and perceptual skill training” for impaired mentation, sensory impairment, and visual loss remains without proven value.

Hemi-inattention and anosognosia usually resolve spontaneously within the first month. However, aphasia usually improves to almost its fullest extent by 4–6 weeks. Deficits persisting after that time usually do not resolve. Poor prognostic factors for recovery – as any physician might sense – are advanced age, dementia, incontinence, bilateral brain damage, and prior strokes. If asked for a consultation, psychiatrists might particularly search for depressive symptoms with or without anxiety, maladaptation, denial, and other defense mechanisms.

References

Barnes DE, Haight TJ, Mehta KM, et al. Second hand smoke, vascular disease, and dementia incidence: Findings from the cardiovascular health cognition study. Am J Epidemiol. 2010;171:292–302.

Brott TG, Hobson RW, Howard G, et al. Stenting versus endarterectomy for treatment of carotid-artery stenosis. N Engl J Med. 2010;363:11–23.

Chimowitz MI, Lynn MJ, Derdeyn CO, et al. Stenting versus aggressive medical therapy for intracranial arterial stenosis. N Engl J Med. 2011;365:993–1003.

Cruse D, Chennu S, Chatelle C, et al. Bedside detection of awareness in the vegetative state. Lancet. 2011;378:2088–2094.

Dafer RM, Rao M, Shareef A, et al. Poststroke depression. Top Stroke Rehabil. 2008;15:13–21.

Dong JY, Zang YH, Tong J, et al. Depression and risk of stroke: A meta-analysis of prospective studies. Stroke. 2012;42:32–37.

Giacino JT, Ashwal A, Childs N, et al. The minimally conscious state: Definition and diagnostic criteria. Neurology. 2002;58:349–353.

Goldstein LB, Adams R, Alberts MJ, et al. Primary prevention of ischemic stroke: A guideline from the American Heart Association/American Stroke Association Stroke Council. Stroke. 2006;37:1583–1633.

O’Donnell MJ, Xavier D, Liu L, et al. Risk factors for ischaemic and intracerebral haemorrhagic stroke in 22 countries. Lancet. 2010;376:112–123.

Pan A, Sun Q, Okereke OI, et al. Depression and risk of stroke morbidity and mortality: A meta-analysis and systemic review. JAMA. 2011;306:1241–1249.

Quinette P, Guillery-Girard B, Dayan J, et al. What does transient global amnesia really mean? Review of the literature and thorough study of 142 cases. Brain. 2006;129:1640–1658.

Schmid AA, Kroenke K, Hendrie HC, et al. Poststroke depression and treatment effects on functional outcomes. Neurology. 2011;76:1000–1005.

Solfrizzi V, Scafato E, Capurso C, et al. Metabolic syndrome and the risk of vascular dementia: The Italian Longitudinal Study on Ageing. J Neurol Neurosurg Psychiatry. 2010;81:433–440.

Surtees PG, Wainwright NWJ, Luben RN, et al. Psychological distress, major depressive disorder, and risk of stroke. Neurology. 2008;70:788–794.

Wechsler LR. Intravenous thrombolytic therapy for acute ischemic stroke. N Engl J Med. 2011;364:2138–2146.

Willey JZ, Disla N, Moon YP, et al. Early depressed mood after stroke predicts long-term disability. Stroke. 2010;41:1896–1900.

21–30. After having a steadily worsening left-sided headache for 1 week, a 74-year-old man seeks a neurologic evaluation. The examination reveals a nonfluent aphasia and right-sided hemiparesis, hyperreflexia, a Babinski sign, and homonymous hemianopsia. Which of the following should be considered as likely possibilities (Yes/No)?

Answers:

21. No. Cerebral hemorrhages are usually catastrophic processes, heralded by a severe headache, that develop between several minutes and a few hours.

22. No. The headaches of a subarachnoid hemorrhage are usually cataclysmic and incapacitating. The examination would show nuchal rigidity and a depressed level of consciousness. Also, because subarachnoid hemorrhage occurs outside the brain substance, patients usually do not have lateralized signs, such as aphasia and homonymous hemianopsia. An exception would be a posterior communicating artery aneurysm rupture, which compresses the adjacent third cranial nerve.

23. Yes. A brain tumor is a valid diagnostic choice in this case. Tumors, such as the glioblastoma, produce symptoms over a period of weeks. Also, they may cause multiple signs because they infiltrate or, as in the case of metastases, are multicentric.

24. Unlikely. Although the headache and hemiparesis are consistent, subdural hematomas and other masses outside the brain substance (i.e., extra-axial lesions) rarely cause aphasia or hemianopsia.

25. No. A basilar artery occlusion would interrupt the reticular activating system. It would cause coma, apnea, and quadriplegia.

26. Yes. During a week, carotid artery stenosis can lead to complete occlusion and infarction of an entire cerebral hemisphere. Carotid artery stenosis may also cause ipsilateral headache.

27. Yes. As with a brain tumor, an abscess and its surrounding edema can expand rapidly enough to impair an entire cerebral hemisphere. Surprisingly, traditional signs of infection, such as fever and leukocytosis, are often minimal or entirely absent in cases of brain abscess.

28. No. Cerebral toxoplasmosis develops almost only as a complication of immunosuppression. Moreover, because toxoplasmosis typically produces multiple sites of infection, it produces multiple symptoms and signs.

29. No. Although the findings are compatible, the time course is inconsistent. Emboli occur acutely.

30. No. The single focus and older age are inconsistent with MS. Moreover, it usually does not cause a headache.

37–41. A 74-year-old man sustained a right cerebral infarction the previous year. He has residual left-sided hemiparesis. His family has just brought him to the emergency room after he developed the sudden, painless onset of mutism and right hemiparesis. On examination, he has bilateral paresis and no verbal output. Although his eyes are frequently open, he fails to establish eye contact or respond to either voice or gesture. He has no papilledema. He seems to have normal sleep–wake cycles.

Answers:

53–56. The family of a 20-year-old woman brings her to the emergency room because she suddenly lost her ability to speak or move her right arm or leg. The patient looks directly forward and does not follow verbal or gestured requests. On inspection of her fundi, her eyes constantly evert. She seems to respond to visual images in all fields. The right arm and leg are flaccid and immobile, but her face is symmetric. The neurologist finds symmetric deep tendon reflexes (DTRs) and no Babinski signs. She does not react to noxious stimuli on the right side of her face or body.

Answers:

67. An internist asked a psychiatry consultant to evaluate a 60-year-old stroke patient who, for no apparent reason, began to scream at the nurses, complained loudly about the food, and demanded that the physical therapists leave his room. The internist had admitted the patient the previous day after he awoke with left hemiplegia. Although the patient had obviously sustained a stroke, he was not eligible for tissue plasminogen activator (tPA) because more than 3 hours probably elapsed since its onset. A CT and MRI showed a right middle cerebral artery distribution infarction. After a cardiac evaluation disclosed atrial fibrillation and mitral stenosis, the cardiologist planned to institute anticoagulation. The psychiatrist found that the patient, who was fully alert, attentive, and lucid, had been functioning very well both at work and at home. He had no preceding psychiatric history and had been using no psychotropics, illicit drugs, or excessive alcohol. The patient insisted that he did not know why he was in the hospital or that he had any cardiac disease. He also said that he was “fine” until the internist, apparently confusing him with the other patient in the room, gave him a “preposterous” diagnosis of a stroke. He added that he wanted to leave the hospital that evening, but the nurses and the “idiot doctor” refused to discharge him. Which is the most likely explanation for the patient’s irrational and potentially self-injurious behavior?

Answer:

d. The internist most likely precipitated a catastrophic reaction in a patient with anosognosia for his left hemiplegia. The first three explanations – depression, psychosis, and drug-seeking – are tenable, but patients with those diagnoses usually are aware, perhaps overly so, of their physical deficits, and their denial is not limited to stroke-related deficits. This patient does not have toxic-metabolic encephalopathy (delirium) because he maintains a normal level of consciousness and attention.

Patients with anosognosia tend to employ classic defense mechanisms. Informing them about their deficits requires a great deal of skill. If possible, the discussion should be carried out over the course of several days. The physician, who may have to introduce the issue over several days, might have to show patients that they have impediments rather than frankly stating the severity and extent of their paresis or other deficit. By continuing to deny their deficits, patients with anosognosia may not make realistic plans or participate in rehabilitation programs.

Answer:

c. The most common cause of multiple ring-enhancing cerebral lesions in young adults is toxoplasmosis, which is a typical manifestation of acquired immunodeficiency syndrome (AIDS). Cerebral lymphoma is another AIDS complication, but it usually causes only a single lesion. Cerebral cysticercosis (not offered as a choice), which remains endemic in South and Central America, develops insidiously and usually presents with a seizure. Cerebral infarctions in a 28-year-old man are rare; however, cocaine use, sickle cell disease, arterial dissections, antiphospholipid syndrome, and cardiac diseases that lead to emboli can cause them. With cerebral embolic infarctions, the scans usually show a wedge or pie-shaped pattern. Cerebral hemorrhage is typically a sudden event, associated with blood density on scans. A glioblastoma would also be rare in a 28-year-old individual, and the scans would have indicated an infiltrating tumor. A meningioma is likewise rare in young adults. When it does occur, a meningioma is extra-axial and slowly growing.

Answer:

c. The patient sustained an infarction of the anterior spinal artery where it perfuses the thoracic spinal cord, i.e., a stroke of the spinal cord. The anterior spinal artery is thin, delicate, and vulnerable to atheromatous debris dislodged during any surgery involving the aorta. The anterior spinal artery supplies the anterior two-thirds of the spinal cord (see Chapter 2). Infarctions of this artery cause paraplegia and anesthesia because of damage to the corticospinal and lateral spinothalamic tracts. Immediately after acute spinal cord injuries, patients lose DTRs and muscle tone because of “spinal shock,” but several days to weeks later they develop hyperactive DTRs, Babinski signs, and spasticity. Because multiple small intercostal arteries supply the posterior portion of the spinal cord, infarction of the anterior spinal artery spares the posterior columns. In this infarction, position and vibration sensations are spared (see figure).

Bilateral anterior cerebral artery infarctions can cause paraplegia, but cognitive and personality changes are more prominent. Also, DTRs become hyperactive and Babinski signs are often present.

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Top: A cross-section of a myelin stain of the normal thoracic spinal cord shows that the anterior spinal artery perfuses the anterior two-thirds of the cord. This region contains the corticospinal and lateral spinothalamic tracts (see Fig. 2-15). Bottom: If atheromatous material were to occlude the anterior spinal artery, this region of the spinal cord would undergo infarction. The patient would lose strength in the legs and sensation below the site of the infarction. However, because this infarction spares the posterior columns, the patient would still perceive position and vibration sensation.