Examination

Physicians should note the patient’s age, sex, and handedness, and then review the primary symptom, present illness, medical history, family history, and social history. They should include detailed questions about the primary symptom, associated symptoms, and possible etiologic factors. If a patient cannot relate the history, the physician might interrupt the process to look for language, memory, or other cognitive deficits. Many chapters in Section 2 of this book contain outlines of standard questions related to common symptoms.

After obtaining the history, physicians should anticipate the patient’s neurologic deficits and be prepared to look for disease, primarily of the central nervous system (CNS) or the peripheral nervous system (PNS). At this point, without yielding to rigid preconceptions, the physician should have developed some insight about the problem at hand.

Then physicians should look for the site of involvement (i.e., “localize the lesion”). Localization, one of the initial goals of most neurologic examinations, is valuable in most cases. However, it is often somewhat of an art and often inapplicable in several important neurologic illnesses, such as dementia and migraine headaches.

The examination, which overall remains irreplaceable in diagnosis, consists of a functional neuroanatomy demonstration: mental status, cranial nerves, motor system, reflexes, sensation, and cerebellar system, and gait (Box 1-1). This format should be followed during every examination. Until it is memorized, a copy should be taken to the patient’s bedside to serve both as a reminder and as a place to record neurologic findings.

The examination usually starts with an assessment of the mental status because it is the most important neurologic function, and impairments may preclude an accurate assessment of the other neurologic functions. The examiner should consider specific intellectual deficits, such as language impairment (see Aphasia, Chapter 8), as well as general intellectual decline (see Dementia, Chapter 7). Tests of cranial nerves may reveal malfunction of nerves either individually or in groups, such as the ocular motility nerves (III, IV, and VI) and the cerebellopontine angle nerves (V, VII, and VIII) (see Chapter 4).

The examination of the motor system is usually performed more to detect the pattern than the severity of weakness. Whether weakness is mild to moderate (paresis) or complete (plegia), the pattern, rather than severity, offers more clues to localization. On a practical level, of course, the severity of the paresis determines whether a patient will remain able to walk, require a wheelchair, or stay bedridden.

Three common important patterns of paresis are easy to recognize. If the lower face, arm, and leg on one side of the body are paretic, the pattern is called hemiparesis and it indicates damage to the contralateral cerebral hemisphere or brainstem. Both legs being weak, paraparesis, usually indicates spinal cord damage. Paresis of the distal portion of all the limbs indicates PNS rather than CNS damage.

Eliciting two categories of reflexes assists in determining whether paresis or another neurologic abnormality originates in the CNS or PNS. Deep tendon reflexes (DTRs) are normally present with uniform reactivity (speed and forcefulness) in all limbs, but neurologic injury often alters their activity or symmetry. In general, with CNS injury that includes corticospinal tract damage, DTRs are hyperactive, whereas with PNS injury, DTRs are hypoactive.

In contrast to DTRs, pathologic reflexes are not normally elicitable beyond infancy. If found, they are a sign of CNS damage. The most widely recognized pathologic reflex is the famous Babinski sign. Current medical conversations justify a clarification of the terminology regarding this sign. After plantar stimulation, the great toe normally moves downward (i.e., it has a flexor response). With brain or spinal cord damage, plantar stimulation typically causes the great toe to move upward (i.e., to have an extensor response). This reflex extensor movement, which is a manifestation of CNS damage, is the Babinski sign (see Fig. 19-3). It and other signs may be “present” or “elicited” but they are never “positive” or “negative.” Just as a traffic stop sign may be either present or absent, but never positive or negative, a Babinski sign is present, elicited, or found.

Frontal release signs, which are other pathologic reflexes, reflect frontal lobe injury. They are helpful in indicating an “organic” basis for a change in personality. In addition, to a limited degree, they are associated with intellectual impairment (see Chapter 7).

The sensory system examination is long and tedious. Moreover, unlike abnormal DTRs and Babinski signs, which are reproducible, objective, and virtually impossible to mimic, the sensory examination relies almost entirely on the patient’s report. Its subjective nature has led to the practice of disregarding the sensory examination if it varies from the rest of the evaluation. Under most circumstances, the best approach is to test the major sensory modalities in a clear anatomic order and tentatively accept the patient’s report.

Depending on the nature of the suspected disorder, physicians first may test touch with a fingertip or a wood stick cotton swab, and then three sensations – position, vibration, and stereognosis (appreciation of an object’s form by touching it) – carried by the posterior columns of the spinal cord. Next physicians might test pain (pinprick) sensation, which is carried in the lateral columns, but only in a careful manner with a nonpenetrating, disposable instrument, such as with a broken wood shaft of the cotton swab.

Physicians evaluate cerebellar function by observing several standard maneuvers that include the finger-to-nose test and rapid repetition of alternating movement test (see Chapter 2) for intention tremor and incoordination. If at all possible, physicians should watch the patient walk because a normal gait requires intact CNS and PNS motor pathways, coordination, proprioception, and balance. Moreover, all these systems must be well integrated.

Examining the gait is probably the single most valuable assessment of the motor aspects of the nervous system. Physicians should watch not only for cerebellar-based incoordination (ataxia), but also for hemiparesis and other signs of corticospinal tract dysfunction, involuntary movement disorders, apraxia (see Table 2-1), and even orthopedic conditions. In addition, physicians will find that certain cognitive impairments are associated with particular patterns of gait impairments. Whatever its pattern, gait impairment is not merely a neurologic or orthopedic sign, but a condition that routinely leads to fatal falls and permanent incapacity for numerous elderly people each year.

Formulation

Although somewhat ritualistic, a succinct and cogent formulation remains the basis of neurologic problem solving. The classic formulation consists of an appraisal of the four aspects of the examination: symptoms, signs, localization, and differential diagnosis. The clinician might also have to support a conclusion that neurologic disease is present or, equally important, absent. For this step, psychogenic signs must be separated, if only tentatively, from neurologic (“organic”) ones. Evidence must be demonstrable for a psychogenic or neurologic etiology while acknowledging that neither is a diagnosis of exclusion. Of course, as if to confuse the situation, patients often manifest grossly exaggerated symptoms of a neurologic illness (see Chapter 3).

Localization of neurologic lesions requires the clinician to determine at least whether the illness affects the CNS, PNS, or muscles (see Chapters 2 through 6). Precise localization of lesions within these regions of the nervous system is possible and generally expected. The physician must also establish whether the illness affects the nervous system diffusely or in a discrete area. The site and extent of neurologic damage generally indicate certain diseases. A readily apparent example is that cerebrovascular accidents (strokes) and tumors generally involve a discrete area of the brain, but Alzheimer disease usually causes widespread, symmetric changes.

Finally, physicians should create a differential diagnosis that lists, starting with the most common and most likely possibility, the disease or diseases – up to three – consistent with the patient’s symptoms and signs. Physicians should then consider illnesses that, while unlikely, would be potentially life-threatening. Finally, many neurologists, in a flourish of intellectualism, add unlikely but fascinating explanations. However, even at tertiary care institutions, common conditions arise commonly. Just as “hoof beats are usually from horses, not zebras,” patients are more likely to have hemiparesis from a stroke than mitochondrial disorder. Nevertheless, proposing intellectual challenges is an often gratifying, beneficial characteristic of the practice of neurology.

A typical formulation might be as follows: “Mr. Jones, a 56-year-old man, has had left-sided headaches for 2 months and, on the day before admission, a generalized seizure. He is lethargic. He has papilledema, a right hemiparesis with hyperactive DTRs, and a Babinski sign. The lesion is situated in the left cerebral hemisphere. Most likely, it is a tumor or possibly a stroke. In addition, a bacterial abscess, which would necessitate immediate treatment, might explain his symptoms and signs.” This formulation briefly recapitulates the salient positive and negative elements of the history, and physical findings. In this case, physicians would tacitly assume that neurologic disease is present because of the obvious, objective physical findings. The history of seizures, the right-sided hemiparesis, and abnormal reflexes indicate the localization. Physicians would base their differential diagnosis on the high probability that a discrete cerebral lesion is causing these abnormalities.

To review, the physician should present a formulation that answers the four questions of neurology:

Responding as a Neurologist to Consultations

Psychiatry residents customarily rotate through neurology departments where, under supervision of attending neurologists, they respond to neurology consultations solicited by physicians caring for patients in the emergency department, inpatient medical services, various clinics, and other referring services. When responding, consultants must work with a variation of the traditional summary-and-formulation format.

In contrast to the usual doctor–patient interchange, which usually begins with the patients giving their main symptoms, the consultation begins with the referring physician’s inquiry. While the patient’s interests remain paramount, the consultants’ “client” is the referring physician and their immediate role is to help the patient by answering that particular question.

Both the referring physician and consultant should be clear about the reason for the consultation. The consultant should insist on a specific question and ultimately answer it. Reasons for consultations typically concern a single aspect of a case, such as the importance of a neurologic finding, the significance of a computed tomography report, or a treatment recommendation. Sometimes referring physicians request a broad review, such as when they ask the consultation to provide a second opinion, settle a dispute, or review the case for any omissions. On the other hand, referring physicians, without particularly desiring to know the diagnosis and treatment options, may simply want the neurology service to assume the primary care of the patient. Finally, the consultant should ideally offer at least one teaching point about the case and provide general guidelines for handling similar inquiries.

After evaluating the situation, consultants should frame their summary in the context of the larger picture, but their formulations should primarily or exclusively answer the question posed by the referring physician. Consultants should not expect to follow the patient throughout the illness, much less establish a long-term doctor–patient relationship. Rather, they should direct their attention to the referring physician, who is coordinating the primary care.

Without belaboring the obvious, the consultation note must be neat, organized, and succinct. The primary physician, in an acute care hospital, should be able to digest it in 2 minutes. Long notes are usually boring and tend to lose the attention of the reader. Sloppy handwriting equals mumbling. Notes that are bad, for whatever reason, reflect poorly on the consultant and hamper the patient’s care.

Finally, consultants should show an awareness of the entire situation, which often contains incomplete and conflicting elements. They should also be mindful of the situation of the referring physician and patient. Consultants might be helpful by ordering – not merely suggesting – routine tests, such as blood studies, and important but innocuous treatments, such as thiamine injections. Except in unusual circumstances, consulting residents should not suggest hazardous tests or treatments without first presenting the case to their supervisor. Consultants should not divert the primary physicians’ efforts from the patient’s most important medical problems. In particular, consultants should not suggest embarking on elaborate, time-consuming testing for obscure, unlikely diagnoses when the patient’s illness is obvious and requires the primary medical team’s full attention.