Veda V. Vedanarayanan, MD, FRCPC
CHAPTER CONTENTS
◦Disorders with Specific Sensory Disturbances
•Localization of Motor and Sensory Disturbance
•Clinical Scenarios in Hospital Neurology
•Approach to Diagnosis of Motor and Sensory Disturbance
◦Evaluation in the Emergency Department
◦Evaluation in the Intensive Care Units
◦Anesthetic Complications from Neuromuscular Disorders
◦Patients with Tumors and Organ Transplantation
◦Patients with Rheumatologic disorders
OVERVIEW
This section discusses approach to localization and diagnoses, and this chapter focuses on motor and sensory disturbances.
MOTOR DISTURBANCE
The differential diagnosis for weakness can by quite broad. Narrowing the differential diagnosis starts with a complete history and determining the onset, distribution, and course of the weakness. The examination then determines the type of motor disorder.
Types
Motor disorders can be broadly divided into the following categories:
Weakness has the broadest potential localization. Corticospinal tract involvement is most common. Other localizations include basal ganglia, motor nerve, neuromuscular junction, and muscle.
Incoordination also has a broad potential localization. Corticospinal tract, basal ganglia, and cerebellar lesions are most common, although incoordination can occasionally be manifest by other lesions: for example, neuropathy can produce poorly coordinated movements especially if fairly acute or subacute (e.g., acute inflammatory demyelinating polyneuropathy [AIDP]).
Stiffness can be pyramidal or extrapyramidal. Corticospinal tract dysfunction produces flaccidity acutely but ultimately spasticity. Extrapyramidal conditions such as parkinsonism produces stiffness that is clinically distinct from corticospinal dysfunction.
Abnormal movements run the gamut from tremor to seizure. Determining the type of abnormal movement further localizes the lesion.
Physiologic Localization
Corticospinal lesions produce flaccid weakness initially but ultimately produce spasticity. Reflexes are eventually enhanced, although they will not be acutely. Plantar responses are often extensor immediately on clinical presentation in the ED.
Extrapyramidal lesions can produce increased tone with Parkinsonism and a host of related disorders.
Cerebellar lesions produce incoordination rather than weakness although tone may be reduced.
Motor nerve lesions produce weakness with features dependent on localization:
•Upper motoneuron lesions produce brisk reflexes, clonus, extensor plantar responses, bowel/bladder compromise, and spasticity.
•Lower motoneuron lesions can produce flaccid weakness, depressed or absent reflexes, and prominent muscle atrophy.
Neuromuscular junction lesions produce weakness and fatigue with no sensory symptoms. Reflexes are normal or reduced, depending on the severity of the weakness.
Muscle lesions produce weakness with reduced tone. Reflexes are normal or reduced depending on severity.
Anatomic Localization
Generalized motor disturbance has a broad differential diagnosis. In this case, differentiation between corticospinal, motor nerve, extrapyramidal, muscle, or neuromuscular junction narrows the diagnosis substantially. Few focal lesions produce generalized motor disturbance, although multifocal lesions commonly do.
Focal motor disturbance has a narrower differential diagnosis, although some disorders that produce generalized deficits can initially present with focal findings (e.g., parkinsonism or amyotrophic lateral sclerosis [ALS]).
SENSORY DISTURBANCE
Sensory disturbances can be more vague and subjective than motor disturbance.
Types
Sensory loss is sometimes referred to as numbness, although there are varying lay meanings for this term; some patients use numbness to mean abnormal sensation, pain, or even weakness.
Abnormal sensation is distortion of sensory input. Among these are paresthesias (abnormal spontaneous sensation) and dysesthesias (unpleasant sensation to a nonpainful stimulus). These are most commonly due to damage to the peripheral nerves. However, they can be due to lesions in the spinal cord or brain.
Neuropathic pain is produced by abnormal discharge in nociceptive and non-nociceptive afferents that is interpreted as painful. These manifestations can include hyperesthesia (enhanced sensory experience that can be perceived as discomfort) and hyperpathia (enhanced pain experience). Almost any cause of peripheral nerve damage can produce neuropathic pain.
Sensory ataxia is produced by abnormal sensory input. It can resemble cerebellar ataxia but without other cerebellar signs and with marked exacerbation with eyes closed (i.e., positive Romberg).
Localization
Generalized sensory disturbance is most commonly due to lesions in the peripheral nerves. Polyneuropathy is most common.
Focal sensory disturbance can be due to a lesion at any level. Specifics of the deficits and correlation with motor and reflexes abnormalities narrows the localization (see Table 4.1).1
Table 4.1 Localization of sensory deficits
| Abnormality | Features | Lesion | Potential cause |
| Distal sensory deficit | Sensory loss with or without pain distal on the legs; arms may be affected | Peripheral nerve | Peripheral neuropathy |
| Proximal sensory deficit | Sensory loss on trunk, without limb symptoms | Neuropathy with predominantly proximal involvement | Porphyria, diabetes, plexopathies |
| Dermatomal distribution of pain and/or sensory loss | Pain and/or sensory loss in the distribution of a single nerve root | Nerve root | Radiculopathy due to disc, osteophyte, tumor, herpes zoster |
| Single-limb sensory deficit | Loss of sensation on one limb that spans neural and dermatomal distributions | Plexus or multiple single nerves | Autoimmune plexitis, hematoma, tumor |
| Hemisensory deficit | Loss of sensation on one side of body. May be associated with pain. | Thalamus, cerebral cortex, or projections. Brainstem lesion, spinal cord lesion. Lower lesions do not involve face | Infarction, hemorrhage, demyelinating disease, tumor, infection |
| Crossed sensory deficit: ipsilateral facial and contralateral body | Pain and temperature disturbance of the ipsilateral face and contralateral body. | Lesions of uncrossed trigeminal fibers and crossed spinothalamic fibers | Lateral medullary syndrome |
| Pain/temperature vs vibration/proprioception deficits on opposite sides | Unilateral loss of pain and temperature sensation and contralateral loss of vibration and proprioception sensation. | Spinal cord lesion ipsilateral to vibration and proprioception deficit and contralateral to pain and temperature deficit | Disc protrusion, spinal stenosis, intra-spinal tumor, transverse myelitis; intraparenchymal lesions are more likely to produce dissociated sensory loss. |
| Dissociated suspended sensory deficit | Loss of pain and temperature sensation on one or both sides, with normal sensation above and below | Intramedullary lesion of cervical or thoracic spinal cord | Syrinx, chiari malformation, hydromyelia, central spinal cord tumor, or hemorrhage |
| Sacral sparing | Preservation of perianal sensation, with impaired sensation in legs and trunk | Lesion of the cord, with mainly central involvement sparing peripherally located sacral ascending fibers | Cord trauma, intrinsic tumors of the cord |
Modified From Misulis KE, Murray EL Table 30.4 from Chapter 30 Sensory Abnormalities of the Limbs, Trunk, and Face, from Bradley’s Neurology in Clinical Practice, Daroff RB, Jankovic J, Maziotta JC, Pomeroy SL Eds. Elsevier 2015
Disorders with Specific Sensory Disturbances
Select disorders with sensory manifestations are described here, and the details of these diagnoses are also found in multiple subsequent chapters. Most of these disorders have motor deficits not discussed here, but some of the disorders are discussed in detail in Chapter 21.
•AIDP produces dysesthesias and paresthesias with areflexia early in the course.
•Sensory neuropathy is often sensorimotor neuropathy with burning pain and superimposed dysesthesias and paresthesias. Reflexes are suppressed.
•Carpal tunnel syndrome produces numbness on the thumb, index, and middle fingers without involvement of ulnar and radial distributions.
•Ulnar neuropathy produces loss of sensation on the 4th and 5th digits.
•Syringomyelia produces a cape-like distribution of loss of pain and temperature with suspended sensory loss.
•Thalamic infarction produces an acute onset of unilateral sensory loss and sensory ataxia.
•Thalamic pain syndrome produces unilateral burning dysesthetic pain, especially distally on the limbs.
•Trigeminal neuralgia produces paroxysms of lancinating, electric shock-like pain in the face.
LOCALIZATION OF MOTOR AND SENSORY DISTURBANCE
Lesions at different levels of the neuraxis can be localized through correlation with the disturbances. Details of localization and diagnosis are addressed well in the recent release of Brazis, Masdeu, and Biller; Localization in Clinical Neurology. Comprehensive discussion of stroke syndromes is in the book by Caplan and van Gijn; Stroke Syndromes. Both of these are available as Kindle and iBook ebooks.
Cortical lesions produce motor and sensory loss in the portion of the homunculus encompassing the defect. Most common are hand and face, especially with middle cerebral artery (MCA) infarctions. Anterior cerebral artery (ACA) infarctions produce foot and leg deficits.
Internal capsule lesions can produce contralateral motor and/or sensory deficits. Head-to-toe deficit suggest an internal capsule lesion rather than a cortical lesion.
Basal ganglia lesions can produce a wide variety of symptoms but among these can be contralateral weakness and incoordination.
Thalamic lesions produce contralateral sensory loss. Hemisensory loss without weakness suggests a thalamic lesion.
Brainstem lesions produce bilateral weakness that is often asymmetric. In addition, cranial nerve deficits are common. Crossed findings suggest brainstem lesions, with motor involvement on one side and sensory on the other, sensory involvement of the face on one side and body on the other, or cranial nerve deficits on one side and hemiparesis on the other.
Spinal cord lesions (complete) produce loss of sensation and motor function below the level of the lesion, although the level may be somewhat different on the two sides.
Spinal cord lesions (partial but bilateral) produce loss of motor and sensory function below the lesion, which is often incomplete and asymmetric. The levels of clinical involvement may be quite different between the two sides.
Spinal hemisection (Brown-Sequard) produces loss of vibration and proprioception ipsilateral to the lesion and loss of pain and temperature contralateral to the lesion.
Motoneuron lesions produce weakness without sensory findings. Lesions predominately of the upper motoneuron (e.g., primary lateral sclerosis) produce weakness with spasticity, increased reflexes, and upgoing plantar responses in the post-acute phase. Lesions of the lower motoneuron (e.g., progressive muscular atrophy) produce weakness without sensory loss and without hyperreflexia or upgoing toes. Lesion of both the upper and lower motoneuron (e.g., ALS) produces both profiles of deficits.
Nerve root lesions produce motor and sensory deficits that follow a dermatomal distribution. Generally, motor localization is easier than sensory localization.
Plexus lesions produce motor and sensory deficits in more than one nerve root distribution, but they are generally contiguous, suggesting the plexus localization.
Peripheral nerve lesions produce motor and sensory deficits in individual nerve distributions. Motor and sensory deficits with peripheral nerve lesions are more congruent than with lesions of the plexus or spinal cord.
CLINICAL SCENARIOS IN HOSPITAL NEUROLOGY
Some of the most common and most important clinical scenarios encountered in hospital neurology practice with their motor, sensory, and associated findings are presented here.
Stroke Syndromes
Left MCA infarction: Right hemiparesis affecting face and arm more than leg. Sensory loss in the same distribution. If the left hemisphere is dominant, aphasia develops to a variable extent. Infarction of the MCA anterior division produces expressive aphasia and usually preservation of visual fields. Isolated infarction of the MCA posterior division produces mainly receptive aphasia, and right hemianopia may be present. Combined anterior and posterior ischemia produces combined deficits.
Right MCA infarction: Left hemiparesis affecting face and arm more than leg. Sensory loss in the same distribution. If the right hemisphere is nondominant, there is often neglect of the left side. Left hemianopia may be present with involvement of the MCA posterior division.
Thalamic infarction: Contralateral sensory deficit encompassing the entire side with face, arm, and leg involvement. Motor systems are typically not affected.
Basal ganglia infarction: Contralateral weakness and incoordination. No cortical signs such as aphasia or neglect.
Internal capsule infarction: Contralateral motor and/or sensory deficits involving the entire side. Cortical signs are absent.
PCA infarction: Contralateral hemianopia is typical. Confusion and memory deficit is common.
Brainstem infarction: Broad spectrum of disorders related to ischemia in the distribution of the vertebrobasilar system including branches. Some of the most important are:
•LATERAL MEDULLARY SYNDROME: Usually posterior inferior cerebellar artery or vertebral occlusion. Ipsilateral limb ataxia, sensory loss of the face. Contralateral loss of pain and temperature sensation. Associated with nausea, dysphagia, and hoarse voice.
•LOCKED-IN SYNDROME: Usually basilar artery or branch occlusion. Quadriplegia with corticospinal tract signs, impaired horizontal eye movements – relative preservation of vertical eye movements which may be the only way to communicate with the patient. These patients are often initially considered to be in coma until careful neuro exam is performed.
•BASILAR THROMBOSIS: Basilar artery occlusion. Coma with corticospinal tract signs. Usually preceeded by symptoms and signs of brainstem ischemia including dysarthria, dysphagia, and especially varying combinations of extremity and bulbar motor deficits. Visual changes and ultimately congnitive decline are seen.
Movement Disorders
Parkinsonism: Rigidity, bradykinesia, and resting tremor. Associated with shuffling gait, stopped posture, and propensity to forward falls.
Hemiballismus: Flinging movements on one side are usually due to infarction of the subthalamic nucleus. Nonketotic hyperglycemia and some medications can also cause this.
Essential tremor: Tremor of hands evoked by action or posture.
Enhanced physiologic tremor: Exaggeration of normal fine tremor seen with arms and fingers extended.
Seizures
Seizures: Shaking; most commonly focal or generalized depending on the type of seizure. Motor deficit can follow the seizure and produce temporary paresis or paralysis (Todd’s paralysis).
Ictal paralysis: Rare paralysis without positive motor activity preceding the weakness.
Demyelinating Diseases
Multiple sclerosis (MS): Weakness that can be monoparesis, hemiparesis, or paraparesis, or cranial nerve deficit of subacute onset. Often has findings of more than one lesion.
Neuromyelitis optica (NMO): Myelopathy that can resemble spinal cord involvement of MS but is associated with visual involvement.
Neuromuscular Disorders
AIDP, critical illness neuromyopathy (CIN), and myasthenia gravis (MG) are the most common neuromuscular disorders encountered in hospital neurology practice. Chronic inflammatory demyelinating polyneuropathy (CIDP) is less common but encountered in hospital practice. Rare neuromuscular conditions are not discussed.
•AIDP produces a rapid progression of weakness and sensory change often with neuropathic pain. Areflexia.
•CIDP presents with progressive weakness and sensory deficit over months.
•MG presents with progressive weakness and fatigue that is worse with activity and improves with rest. Ocular muscles are commonly affected, producing diplopia and ptosis.
•ALS presents with progressive weakness with upper and lower motoneuron signs. No sensory findings.
•CIN produces weakness in patients in the ICU especially with sepsis or other prolonged illness. Hypotonia and hyporeflexia are common.
•Inflammatory myopathies such as polymyositis and dermatomyositis, produce progressive weakness that affects predominately proximal muscles.
•Toxic myopathies can present with generalized weakness that is typically symmetrical. Alcoholic myopathy is often accompanied by muscle cramps and muscle tenderness and can lead to rhabdomyolysis and hypokalemia.
•Periodic paralysis is a rare group of muscle diseases that can lead to significant situational weakness without respiratory compromise.
•Botulism produces descending paralysis with cranial nerve involvement.
•Tick paralysis produces progressive paralysis that can resemble AIDP, but there are minimal or no sensory symptoms.
•Organophosphate poisoning usually presents with symptoms of cholinergic excess including miosis, bradycardia, lacrimation, urination, emesis, salivation, bronchorrhea, bronchospasm, and generalized weakness.
•West Nile virus (WNV) can produce a rapid onset of flaccid paralysis in conjunction with encephalopathy.
•Multifocal motor neuropathy (MMN) produces progressive weakness without sensory symptoms.
Psychiatric Disorders
Psychogenic weakness is suspected with motor and often sensory deficit associated with no demonstrable lesion in the motor and sensory systems. Clues to diagnosis can be inconsistency and improbability of localization.
APPROACH TO DIAGNOSIS OF MOTOR AND SENSORY DISORDERS
Evaluation in the Emergency Department
Rapidly progressing muscle weakness suggests consideration of AIDP, MG, and, less often, ALS. Airway, breathing, and circulation are quickly evaluated and addressed. Respiratory and bulbar muscle weakness may require intubation and mechanical ventilation.
Measurement of bedside pulmonary function, forced vital capacity (FVC), and negative inspiratory force (NIF) is helpful in assessing the severity of respiratory compromise.
AIDP is the most common presentation in the ED of severe and generalized weakness with paresthesias of hands, feet, and face, accompanied by areflexia.
Tick paralysis presents similarly to AIDP but tends to occur most commonly in children and has no sensory symptoms.
MG may present in respiratory and bulbar crisis with severe weakness. Ptosis, oculomotor muscle weakness, fatigable weakness, and preserved sensation and tendon reflexes suggest the diagnosis.
Myopathies including inflammatory myopathies and muscular dystrophies usually do not present to the ED for first diagnosis. However, the hospital neurologist will see patients with advanced disease who decompensate, thus precipitating ED visit.
Metabolic disorders causing severe weakness in the ED include hypokalemia or hypophosphatemia. These patients may have absent tendon reflexes.
Infectious diseases may present with muscle weakness including especially WNV. Clinical features of encephalitis may be present.
Evaluation in the Intensive Care Unit
Muscle weakness is an important cause for prolonged stay in ICU, long after the primary cause for ICU admission has resolved. Important causes are iatrogenic or from development of an independent neuromuscular disease. In addition, a previously stable neuromuscular disease can be made worse by illness or concurrent medications.
Undiagnosed neuromuscular diseases that can be uncovered by critical illness include:
•Acid maltase deficiency (adult form)
CIN is generalized muscle weakness that can develop in patients with serious illness. Development of weakness is more likely with sepsis, treatment with multiple medications including corticosteroids, and/or neuromuscular blocking agents, and in those with multiorgan failure. Diagnosis can be hampered by coexistent encephalopathy, which makes examination difficult. This is discussed in Chapter 21.
Polyneuropathy may occur in critically ill patients and usually is mild and seldom a cause for weakness in the muscles of respiration The polyneuropathy is due to axonal injury and probably related to nutritional deficiency, toxicities from medications used, organ failures, and effects of cytokines and inflammatory mediators.
Neuromuscular blockade due to pharmacologic agents may be prolonged, especially with renal and/or hepatic failure. Even metabolites of some of these agents have neuromuscular junction (NMJ)-blocking properties.
Anesthetic Complications from Neuromuscular Disorders
Malignant hyperthermia: This is a pharmacologic adverse effect characterized by hyperpyrexia, rigidity, rhabdomyolysis, and myoglobinuria. Mortality risk is 10–30%. The following patients have increased risk:
•Dystrophin disorder (Becker muscular dystrophy, Duchenne muscular dystrophy, symptomatic female carriers)
Patients with myotonia congenita and other myotonic disorders may experience severe trismus and muscle rigidity on exposure to short-acting neuromuscular blocking agents, such as succinylcholine.
Myotonic dystrophy patients are at higher risk for respiratory failure and difficult extubation after exposure to sedating and anesthetic agents.
MG patients should be treated with neuromuscular blocking agents only with caution. They are more likely to experience prolonged weakness.
Mitochondrial disorder patients need careful monitoring of oxygenation during procedures. Lactated Ringer’s solution should be avoided and blood glucose monitored.
Patients with Tumors and Organ Transplantation
Lambert Eaton myasthenic syndrome, cholinergic neuropathy, and sensory ganglionopathy can be seen with small-cell lung carcinoma.
Necrotizing myopathy causing rapid severe proximal weakness is a rare paraneoplastic presentation seen most often with small-cell lung carcinoma.
Demyelinating polyneuropathy is an uncommon complication seen in patients with lymphoid malignancy and in patients who have had bone marrow transplantation.
Inflammatory myopathy is a rare complication in patients who have undergone bone marrow transplantation.
Progressive polyneuropathy from axonal damage occurs as a side effect of several chemotherapeutic agents, especially vincristine and paclitaxel.
Patients with Rheumatological Disorders
Muscle weakness from myositis occurs in systemic lupus erythematosus, mixed connective tissue disorders, and dermatomyositis.
Mononeuritis multiplex comprises multiple mononeuropathies. This can occur with vasculitis, as in polyarteritis nodosa, Wegener’s granulomatosis, sarcoidosis, or isolated peripheral nerve vasculitis.
Small-fiber polyneuropathy is seen most commonly with diabetes but also with vasculitis and Sjögren syndrome.
Dermatomyositis is an autoimmune myopathy. In 20–30% of patients, it is a paraneoplastic syndrome.
Demyelinating neuropathy can occur from biological agents used for a variety of rheumatologic disorders.2
Patients with Diabetes Mellitus
Multiple causes of motor and sensory deficit can occur from diabetes mellitus (DM):
•Predominantly sensory polyneuropathy is the most frequent neuropathic complication.
•Sensorimotor polyneuropathy is the next most frequent presentation.
•Small-fiber neuropathy with prominent pain occurs in DM and can precede the clinical diagnosis of DM. This is often associated with autonomic symptoms, orthostatic hypotension, and can be associated with arrhythmia.
•Focal neuropathies in upper and lower limbs are common. Susceptibility to compressive neuropathies is increased in patients with DM.
•Cranial neuropathies affecting CN 3, 4, 6, and 7 can occur as complication of DM.
•Diabetic amyotrophy is a proximal plexopathy seen in patients with DM, especially those with poor diabetic control.
Patients with Infectious Diseases
Human immunodeficiency virus (HIV) infection is associated with a variety of neuromuscular disorders:
•Acute demyelinating polyneuropathy is seen in some patients and usually occurs when seroconversion is taking place. Features are similar to AIDP and is treated with intravenous immunoglobulin (IVIg).
•Small-fiber neuropathy is sometimes seen in patients with HIV.
Herpes viruses (cytomegalovirus [CMV], Epstein-Barr virus [EBV], and varicella zoster virus [VZV]) can cause lumbosacral radiculoplexitis; this is a rapidly developing disorder with progressive asymmetric lower limb weakness with pain and sensory loss. Bladder and bowel incontinence are common.
Arboviruses including WNV and Zika virus can be associated with AIDP as well as with acute disseminated encephalomyelitis (ADEM) or MS.
