A 74-year-woman consults you because of tremor and difficulty completing her daily tasks on time. She has hypertension and takes hydrochlorothiazide 25 mg every morning. She does not smoke and uses alcohol infrequently. On examination, her BP is 126/84; her vital signs are otherwise unremarkable. Eye movements are normal as are her reflexes and motor strength. She moves slowly; her timed get-up-and-go test takes 24 seconds (normal 10 seconds). She has a slow resting tremor with a frequency of about 3 per second; the tremor is more prominent on the right than the left. The tremor decreases with intentional movement. Her handwriting has deteriorated and is small and crabbed.
Which therapy is most likely to improve her functional disabilities?
Parkinson disease (PD) is marked by depletion of dopamine-rich cells in the substantia nigra. The resulting decrease in striatal dopamine is the basis for the classic symptoms of rigidity, bradykinesia, tremor, and postural instability. Many experts consider bradykinesia to be the fundamental feature of PD. Although tremor is often the first manifestation, about 20% of patients do not have a tremor. When present, the tremor occurs at rest, is slower than most other tremors, and decreases with intentional activity (so that a watch repairman with PD is often able to function normally). The most effective treatment for PD is levodopa. Levodopa is converted to dopamine in the substantia nigra and then transported to the striatum, where it stimulates dopamine receptors. This is the basis for the drug’s clinical effect on PD. Levodopa is usually administered with carbidopa (a dopa decarboxylase inhibitor) in one pill. This prevents levodopa’s destruction in the blood and allows it to be given at a lower dose that is less likely to cause nausea and vomiting. The major problems with levodopa have been (1) limb and facial dyskinesias in most patients on chronic therapy, (2) motor fluctuations (“off-on” effects), and (3) the fact that levodopa treats PD only symptomatically and the disease process of neuronal loss in the substantia nigra continues despite drug treatment. Direct dopamine agonists (such as ropinirole or pramipexole), although less potent than dopamine itself, are often used as the first drug in younger patients. Side effects (in particular, motor fluctuations) are often less troublesome. Anti-cholinergic agents, such as benztropine mesylate, work by restoring the balance between striatal dopamine and acetylcholine; they are particularly effective in decreasing the degree of tremor. In the elderly, however, they often cause CNS side effects (especially confusion) and would not be a good choice in this elderly woman. Propranolol will help essential tremor but has no benefit in Parkinson disease. Chronic benzodiazepine use should be avoided because of the risk of habituation as well as confusion and falls in the elderly. Benzodiazepines do not improve the symptoms of PD.
A 72-year-old woman is found unconscious at home by her daughter. The daughter last spoke to her mother 1 day previously, at which time her mother seemed fine. The patient has diabetes, hypertension, atrial fibrillation, and chronic back pain. Her medications include metformin, lisinopril, warfarin, and oxycodone. On examination her blood pressure is 167/70, pulse 48 beats/minute, respiratory rate 12 breaths/minute and irregular, and temperature 37.2°C (98.9°F). There are no signs of trauma. Neck issupple. The patient does not respond to verbal stimuli. Pupils are equally reactive to light. The oculocephalic reflex (doll’s eye maneuver) is normal. On applying firm pressure to the orbital rim, the patient flexes her right arm, but does not move her left arm.
Which of the following is the most likely cause of her condition?
This woman presents with coma that requires rapid and careful evaluation. The most common causes of coma are central nervous system infections (meningitis and encephalitis), structural central nervous system lesions, which produce compression of the brain-stem, metabolic abnormalities, and drug overdose. The neurologic examination is very helpful in the evaluation of comatose patients, and should focus on specific maneuvers: (1) testing for nuchal rigidity, (2) pupillary response to light, (3) patient response to painful stimulus (typically by applying firm pressure to the sternum or orbital rim), and (4) the oculocephalic reflex (doll’s eye maneuver). Neck stiffness and fever in the comatose patient would suggest meningitis or subarachnoid hemorrhage. Pupillary response to light is preserved in metabolic derangements, drug overdose, and early in space occupying lesions. Preserved pupillary light reflex in the absence of an oculocephalic reflex is seen almost exclusively in drug overdose. In space-occupying lesions with early brainstem compression (the so-called diencephalic stage) the pupillary response to light and the oculocephalic reflex are preserved. As brainstem compression progresses to midbrain and then pons compression, pupillary response to light and the oculocephalic reflex are lost. When unilateral arm flexion with painful stimulation occurs in the comatose patient, this suggests a hemispheric mass with mild brainstem compression. As brainstem compression progresses to involve the midbrain, the comatose patient will respond to painful stimulation with arm flexion and leg extension (decorticate posturing). When brainstem compression progresses further to involve the pons, painful stimulation results in extension of both arms and legs (decerebrate posturing). This comatose patient has preserved pupillary and oculocephalic reflexes, and right arm flexion with painful stimulation. This suggests a left hemispheric space-occupying lesion with early brainstem compression. The widened pulse pressure, bradycardia, and irregular breathing (Cushing reflex) also suggest increased intracranial pressure. In this patient on warfarin, these findings are likely due to an acute subdural hematoma, which may occur spontaneously or with trauma (such as falling). Hypoglycemia is uncommon with metformin. Neither hypoglycemia nor drug overdose would cause unilateral arm flexion with painful stimulation. In the absence of fever and neck stiffness, meningitis is unlikely. A lacunar infarct will cause a pure motor or pure sensory stroke but not global brain dysfunction. Anterior cerebral artery occlusion causes motor and sensory deficits of the contralateral leg and foot but does not impair global brain function.
A 37-year-old factory worker develops increasing weakness in the legs; coworkers have noted episodes of transient confusion. The patient has bilateral foot drop and atrophy; mild wrist weakness is also present. His CBC shows an anemia with hemoglobin of 9.6 g/dL; examination of the peripheral blood smear shows basophilic stippling.
Which of the following is the most likely cause of this patient’s symptoms?
Lead poisoning often causes a peripheral neuropathy with primary motor involvement. It can superficially resemble ALS, but upper motor neuron signs (such as hyperreflexia) are not seen in lead poisoning. In addition the cognitive changes of lead encephalopathy are not seen in ALS, in peripheral nerve injuries (eg, carpal or tarsal tunnel syndromes), or in myasthenia. Alcoholism can cause peripheral neuropathy but would not cause this patient’s prominent motor weakness or the basophilic stippling. The presence of any anemia in a patient with peripheral neuropathy should prompt the search for an underlying cause. Lead lines may be seen at the gingiva-tooth border. Laboratory testing focuses on protoporphyrin levels (free erythrocyte or zinc) and blood lead levels. Industries often associated with lead exposure include battery and ceramic manufacturing, the demolition of lead-painted houses and bridges, plumbing, soldering, and, occasionally, exposure to the combustion of leaded fuels.
A 53-year-old woman presents with increasing weakness, most noticeable in the legs. She has noticed some cramping and weakness in the upper extremities as well. She has more difficulty removing the lids from jars than before. She has noticed some stiffness in the neck but denies back pain or injury. There is no bowel or bladder incontinence. She takes naproxen for osteoarthritis and is on alendronate for osteoporosis. She smokes one pack of cigarettes daily. The general physical examination reveals decreased range of motion in the cervical spine. On neurological examination, the patient has 4/5 strength in the hands with mild atrophy of the interosseous muscles. She also has 4/5 strength in the feet; the weakness is more prominent in the distal musculature. She has difficulty with both heel walking and toe walking. Reflexes are hyperactive in the lower extremities. Sustained clonus is demonstrated at the ankles.
What is the best next step in her management?
Cervical spondylosis (arthritis) or midline disc protrusion can cause cervical myelopathy, which can mimic amyotrophic lateral sclerosis. The neck pain and stiffness can be mild, and the patient can have both lower motor neuron signs such as atrophy, reflex loss, and even fasciculations in the arms and upper motor neuron signs such as hyperreflexia and clonus (from cord compression) in the legs. Therefore, the diagnosis of ALS is never made without imaging studies of the cervical cord, as compressive cervical myelopathy is a remediable condition. Starting riluzole to slow the progression of ALS would, therefore, be inappropriate at this point. Disease in the cortex would never cause this combination of bilateral upper and lower neuron disease, so an MRI scan of the brain would be superfluous. Myopathies such as polymyositis or metabolic myopathy cause more proximal than distal weakness and would not be associated with hyperreflexia. You should think of disease of the neuromuscular junction (eg, myasthenia gravis) or muscle when the neurological examination is normal except for weakness. Simply referring the patient for physical or occupational therapy would leave her potentially treatable cervical spine disease undiagnosed. Decompressive surgery can improve symptoms and halt progressive loss of function in cervical myelopathy.
A 73-year-old man has had three episodes of visual loss in the right eye. The episodes last 20 to 30 minutes and resolve completely. He describes the sensation as like a window shade being pulled down in front of the eye. He has a history of hypertension and tobacco use. He denies dyspnea, chest pain, palpitations, or unilateral weakness or numbness. On examination the patient appears healthy; his vital signs are normal and the neurological examination is unremarkable. An ECG shows normal sinus rhythm without evidence of ischemia or hypertrophy. Initial laboratory studies are normal. Both noncontrast CT scan of the head and MR scan of the brain are normal.
What is the best next step in this patient’s management?
This patient has suffered several transient ischemic attacks with the classic description of amaurosis fugax. Although the traditional symptom duration of less than 24 hours is often cited, most TIAs last less than 1 hour, usually 15 or 20 minutes. Many patients whose symptoms last for several hours are found to have ischemic strokes on MRI imaging. TIAs carry a high risk of neurological morbidity and should be promptly evaluated and treated. Five percent of patients will have a full-blown stroke within the next 2 weeks. Assessing the extracranial carotid arteries for evidence of atherosclerosis is crucial in patients with anterior circulation TIAs. If a common or internal carotid stenosis of 70% or greater is found, carotid endarterectomy has been proven to decrease the risk of subsequent stroke. Carotid angioplasty with stenting is used in some centers, but has not been studied as rigorously as carotid endarterectomy. Lesions of the external carotid artery do not cause CNS symptoms. Cardiogenic sources of clots (ie, atrial fibrillation, mitral valve disease, intracardiac tumors) usually cause large vessel ischemic strokes rather than TIAs, so echocardiography would be less important in this patient. The use of anticoagulants in acute stroke has diminished greatly and is primarily used in cases of demonstrated cardiogenic emboli. For the typical atherosclerotic process, antiplatelet therapy is preferred. Testing for thrombophilia is rarely helpful in patients with TIA. These tests may be helpful in patients with large-vessel strokes and no identifiable source of the stroke. Amaurosis fugax would not be a manifestation of seizure disorder.
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