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A 22-year-old woman presents with fever, headache, and confusion. She has not been herself for the past 2 days, including not going to work and forgetting events. On examination, she is moving all her limbs, but not oriented to place or time. The remaining examination is normal. A CT scan shows bilateral, small, lowdensity temporal lobe lesions. Cerebrospinal fluid (CSF) shows mononuclear cell pleocytosis, increased protein, and normal glucose. The electroencephalogram (EEG) shows bilateral periodic discharges from the temporal leads and slow-wave complexes at regular intervalsof 2–3/sec. Which of the following is the most appropriate treatment for her condition?
This patient has herpes simplex virus encephalitis. Acyclovir selectively inhibits viral deoxyribonucleic acid (DNA) polymerase. Acyclovir is currently the treatment of choice because of better efficacy and less toxicity than previous drugs. Because it is so nontoxic, therapy can be started even if the diagnosis is only presumptive.
A 67-year-old woman with hypertension presents with sudden onset of headache, vomiting, and left-sided weakness. On examination, she has weakness of the left face, hand, and leg (graded three out of five), blood pressure of 180/100 mm Hg, and respiration of 20/min. Which of the following is the most appropriate initial diagnostic test?
CT scan is still superior to MRI in certain circumstances, particularly in the emergency setting, for diagnosing acute subarachnoid hemorrhage, intracerebral bleeding, fractures of the face, temporal bone, and base of the skull. A CT is useful in evaluating patients with osseous spinal stenosis and spondylosis, but an MRI is preferred if there are neurologic defects.
A 77-year-old woman develops acute hoarseness, difficulty swallowing, dizziness, and falling to the right side. On examination, there is decreased sensation to pain on the right side of her face and left side of her body. The palate and pharynx move very little on the right side, and there is loss of coordination of the right arm and leg. Motor power in the arms and legs is normal. While attempting to walk, she falls to the right side, and complains of vertigo. An MRI scan confirms the diagnosis of the ischemic stroke. Which of the following is the most likely location of the stroke?
The lateral medullary syndrome (also known as Wallenberg syndrome) causes ipsilateral numbness but also contralateral involvement of pain and thermal sense by affecting the spinothalamic tract. It can be caused by occlusion of the vertebral arteries; posterior-inferior cerebellar arteries; and superior, middle, or inferior medullary arteries. Ipsilateral ataxia and falling to the side of the lesion are common. Ipsilateral paralysis of the tongue is characteristic of medial medullary syndrome, which also causes contralateral paralysis of arm and leg. Paralysis of the body is not characteristic of lateral medullary syndrome, but ipsilateral paralysis of palate and vocal cord does occur. Ipsilateral Horner syndrome, nystagmus, diplopia, vertigo, nausea, and vomiting are characteristic.
A 27-year-old woman, a recent immigrant from the Caribbean basin, has had progressive leg weakness. Physical examination revealsincreased tone of both legs with weakness, clonus, extensor plantar responses, and brisk reflexes. There is also loss of vibration and position senses in the feet. The upper extremities are normal. A clinical diagnosis of tropical spastic paraparesis (TSP) is made. Which of the following is the most likely cause of this condition?
TSP is frequently associated with a retroviral (HTLV-1) infection that can be spread through blood transfusion, sexual contact, intravenous drug use, and vertical transmission from mother to child. It is slowly progressive, and bladder involvement is characteristic. Sensory symptoms are usually mild, and a true sensory level is almost never found. On occasion, cranial nerve findings, frontal release signs, and cerebellar signs (tremor, dysmetria) are present.
A 40-year-old woman complains of episodes of severe unilateral, stabbing facial pain that is intermittent for several hours, and then disappears for several days. Physical examination is entirely normal. Which of the following is the most likely diagnosis?
The cause of trigeminal neuralgia (tic douloureux) is unknown, although some cases may be caused by compression of the trigeminal nerve by arteries or veins of the posterior fossa. The pain occurs in paroxysms and is strictly limited to one or more branches of the fifth cranial nerve. Paroxysms may be brief or last up to 15 minutes. There is no objective sensory loss, but the patient may complain of hyperesthesia of the face. Watering of the eye on the involved side may occur during an attack.
A 63-year-old man suddenly becomes acutely ill with headache and fever of 38.9°C. There is pain in the eye, and the orbits are painful to pressure. There is edema and chemosis of the conjunctivae and eyelids, and the eye bulbs are proptosed. Diplopia and ptosis are present, and the pupils are slow in reacting. Which of the following is the most likely diagnosis?
Cavernous sinus thrombosis is usually secondary to traumatic, neoplastic, or suppurative processes in the orbit, the nasal sinuses, or the upper half of the face. The optic discs are swollen, and there may be numerous surrounding small or large hemorrhages if the orbital veins are occluded. Visual acuity is normal or moderately impaired. Involvement of the cranial nerves in the cavernous sinus (third, fourth, sixth, and V1 and V2 divisions of the fifth) causes diplopia, ptosis, and sensory loss on the face.
A 20-year-old woman presents with a history of rapid loss of vision in one eye. Examination reveals pain on movement of the eyeball. The appearance of the fundi is normal, but the afferent pupillary response is diminished. Perimetry shows a large central scotoma. Which of the following is the most likely diagnosis?
In the vast majority of cases, retrobulbar neuritis occurs as an episode in a demyelinating disease such as multiple sclerosis. It is the first manifestation of multiple sclerosis in 15% of cases and occurs at some point in 50% of all patients with the disease. The course of the retrobulbar neuritis is that of gradual spontaneous improvement.
A 67-year-old man has two episodes of numbness on the left side of his body, which last 5 minutes. He now experiences transient loss of vision in his right eye lasting 2 minutes. On examination, his blood pressure is 155/90 mm Hg, pulse 80/min regular, and visual fields, extraocular movements, and pupils are all normal. The remaining motor and sensory examination is also normal. Which of the following is the most likely diagnosis?
Internal carotid artery insufficiency is the most likely diagnosis. Abnormalities are found in the extracranial arteries in more than one-half of the patients with symptomatic cerebral infarction. Current treatment is carotid endarterectomy for severe stenosis and aspirin therapy for lesser degrees of stenosis.
An 18-year-old man develops fever, headache, confusion, and generalized seizures. On examination, he is moving all his limbs, but incoherent. A CT scan shows bilateral, small, low-density temporal lobe lesions. CSF shows mononuclear cell pleocytosis, increased protein, and normal glucose. The EEG shows bilateral periodic discharges from the temporal leads and slowwave complexes at regular intervals of 2–3/sec. Which of the following is the most appropriate next step in management?
The patient’s findings strongly suggest herpes simplex encephalitis. This is generally caused by herpes simplex virus type 1 (HSVI). When the disease is suspected, appropriate antiviral therapy (acyclovir) should be started immediately. CT scan is not helpful in diagnosis because it becomes positive only late in the disease, but MRI scans may be helpful. Brain biopsy, once the diagnostic test of choice, is the most definitive test but is rarely performed.
A 24-year-old woman presents with foot and leg weakness that is progressively getting worse over the past 1 week. Initially, she developed tingling in her feet and noticed that they would drag, but now she has difficulty standing and walking due to the leg weakness. Three weeks ago she had a “chest cold,” which resolved on its own. On examination, muscle bulk is normal, motor strength is two out of five in the quadriceps, and one out of five in the feet. Reflexes at the ankle and knee are absent, and sensation testing is normal. The upper limb examination is normal. The CSF protein is very high, glucose is normal, and cell count is slightly elevated. Which of the following is the most likely diagnosis?
Guillain-Barré syndrome often appears days to weeks after a viral upper respiratory or gastrointestinal (GI) infection. The initial symptoms are due to symmetric limb weakness. Paresthesias may be present. Unlike most other neuropathies, proximal muscles may be affected more than distal muscles early in the disease. Tendon reflexes are usually lost within a few days. Protein content of the CSF is usually high within a few days of onset.
A 37-year-old woman complains of drooping eyelids, double vision, and fatigue at the end of the day. Further history reveals difficulty in chewing food, and some weakness in climbing stairs. The symptoms improve with resting. On examination, there is weakness of the eyelids, masticatory muscles, and thigh flexors. Her handgrip decreases with repetitive action. There is no sensory abnormality, and reflexes are normal. Her chest x-ray (CXR) is shown in Fig. 7–2 a and b. Which of the following is the most likely diagnosis?
This patient has myasthenia gravis and the thymus tissue is often abnormal, with encapsulated tumors occurring in about 15% of cases. Almost all thymomas occur in patients over age 30. Even without thymoma, thymectomy can result in remission in patients with generalized myasthenia. Its benefit is delayed for months or more, so it is not an emergency treatment for myasthenia.
A 79-year-old woman is seen in the office for “dizziness.” Which of the following findings would suggest true vertigo?
Vertigo is defined as an illusory or hallucinatory feeling of movement of the body or environment, usually spinning. Dizziness can be caused by multiple factors in the elderly, including orthostatic hypotension, hypoglycemia, and depression.
A 65-year-old woman complains of recurrent episodes of sudden-onset dizziness and nausea. She notices an abrupt onset of a spinning sensation when rolling over or sitting up in bed. The symptoms last for 30 seconds and then completely resolve. She has no hearing change or other neurologic symptoms, and her physical examination is completely normal. A DixHallpike maneuver reproduces her symptoms. Which of the following findings on vestibular testing favors the diagnosis of benign paroxysmal positional vertigo (BPPV) over central positional vertigo?
Patients with BPPV, in contrast to those with central positional vertigo, have a latent period from the time of onset of the offending position to development of symptoms. With maintenance of the position, patients with BPPV become less symptomatic (fatigability), and repeated positioning also lessens the symptoms (habituation). As well, in BPPV, although the symptoms are usually severe, they can be quite variable from one testing period to the next.
A 23-year-old man complains of intermittent double vision and fatigue at the end of the day. Further history reveals difficulty in chewing food, and some weakness in climbing stairs. He has stopped working as a courier because of easy leg fatigue and weakness. The symptoms improve with resting. On examination, there is weakness of the eyelids, masticatory muscles, and thigh flexors. Having him look up at the ceiling for a long period brings on his double vision. His handgrip decreases with repetitive action. There is no sensory abnormality, and reflexes are normal. Which of the following treatments is contraindicated in this patient?
Anticholinergic drugs exacerbate the underlying defects. Cholinergic drugs are largely inhibitors of cholinesterase. Prednisone may improve as many as 80% of patients. Thymectomy helps patients with no thymoma, but thymoma patients do not do as well. Plasmapheresis benefits most patients but needs to be repeated at intervals.
A 55-year-old man presents with increasing shortness of breath, decreased urine output, malaise, nausea, and vomiting. He has a history of hypertension, chronic renal failure, and coronary artery disease. His laboratory data reveal very high urea and creatinine, consistent with acute on chronic renal failure. He also notes having intermittent “twitching” in his arms and legs that started recently.
Myoclonic seizures are sudden, brief, single, or repetitive muscle contractions involving one body part or the entire body. Loss of consciousness does not occur unless other types of seizures coexist. These seizures can be idiopathic or associated with Creutzfeldt-Jakob disease, uremia, hepatic failure, subacute leukoencephalopathies, and some hereditary disorders. Recent evidence has linked a variant form of Creutzfeldt-Jakob disease with bovine spongiform encephalopathy (BSE), a prion disease of cattle. This variant form usually presents with ataxia and behavior changes prior to myoclonus and dementia.
A 24-year-old woman complains of having intermittent bouts of smelling burning rubber followed by lip smacking and chewing movements as observed by others. During these spells, she does not respond to questions. There has never been any complete loss of consciousness during these episodes either. An MRI of the brain reveals temporal lobe sclerosis.
Complex partial seizures were once classified as temporal lobe epilepsy. Although the temporal lobe (especially the hippocampus or amygdala) is the most common site of origin, some seizures have been shown to originate from mesial parasagittal or orbital frontal regions.
A teenager has a long history of “daydreaming” in school. EEG reveals evidence of a generalized seizure disorder, but there has never been a history of convulsive muscular activity.
Pure absence seizures consist of the sudden cessation of ongoing conscious activity without convulsive muscular activity or loss of postural control. They can be so brief as to be inapparent but can last several minutes. There is usually no period of postictal confusion.
A 23-year-old woman has a history of repetitive involuntary movements of her right hand associated with abnormal facial movements. At times, the movements spread to involve the entire arm.
Simple partial seizures can occur with motor, sensory, autonomic, or psychic symptoms. When a partial motor seizure spreads to adjacent neurons, a “Jacksonian march” can occur (e.g., right thumb to right hand and right arm to right side of face). Face and hand movements are frequently linked because their cortical controlling regions are adjacent.
This form of epilepsy almost always starts in childhood.
Absence seizures almost always begin in young children (age 6–14). They may first present as learning difficulties in school. The EEG is diagnostic, revealing brief 3-Hz spike and wave discharges occurring synchronously throughout all the leads.
A 63-year-old man is noticed to have asymmetric pupils. He is completely well and has no symptoms. On examination, the left pupil is small, round, and has a brisk response to light and near stimuli (accommodation). There is also ptosis of the left eyelid, but no other ocular movement abnormality or symptoms of double vision.
Valproic acid can be used for typical and atypical seizures, myoclonic seizures, and tonic-clonic seizures. It causes little sedation and does not impair cognition. However, the blood count and liver tests must be monitored for a time after initiation of therapy to ensure the safety of the patient.
A 23-year-old woman is noticed to have irregular pupils on routine examination. She has one large pupil, which has minimal response to light stimulation, but it does respond to accommodation. The eye movements are normal and she experiences no double vision.
The tonic pupil (Holmes-Adie syndrome) is caused by a parasympathetic lesion at or distal to the ciliary ganglion. The pupil is large and usually unilateral, with absent response to light. A bright room, by causing constriction of the normal pupil, accentuates the anisocoria. The tonic pupil can be associated with ShyDrager syndrome, amyloidosis, or diabetes. However, it is most commonly seen in otherwise healthy young women.
A 57-year-old woman presents for evaluation of memory loss. She is noticed to have small, irregular pupils that respond poorly to light but pupillary response to accommodation is normal.
Argyll Robertson pupils are small, irregular, and often bilateral. The response to light is impaired, but the response to near vision is preserved. Argyll Robertson pupils can be a manifestation of syphilis, a treponemal infection. It can also be associated with lesions of the dorsal midbrain (obstructive hydrocephalus, pineal region tumors) and after aberrant regeneration.
A 24-year-old man notices different size pupils. The left pupil is 1 mm larger than the right. Both pupils respond normally to light and accommodation. The discrepancy in the pupils is still there in low, medium, and bright light conditions. He reports no other visual symptoms
This patient has physiologic or essential anisocoria, which can be seen in up to 20% of the population at some time. Its hallmarks are a normal response to light and accommodation and the asymmetry is maintained in different lighting conditions. It can also be variable from day to day.
A 64-year-old woman is having double vision and severe headaches. On examination, the left pupil is dilated compared to the right, and the light response is diminished.
Compression of the oculomotor nerve (third cranial nerve) results in paresis of the oculomotor muscles supplied by the nerve and symptoms of double vision. The parasympathetic fibers running along the outside of the nerve are also affected resulting in dilation of the pupil. Increased intracranial pressure from any mass lesion (blood, abscess, or tumor) leading to uncal herniation and compression of the nerve is the usual cause.
A 48-year-old man complains of muscle weakness in his right hand (dominant hand). On examination, the hand muscles are smaller than on the left, and the reflexes are decreased out of proportion to weakness.
Peripheral nerve lesions result in reflex loss greater than the degree of weakness. Reflex loss is variable in anterior horn cell disease and decreased proportionately in muscle disease. In neuromuscular junction disorders, reflexes are characteristically normal.
A 26-year-old woman complains of early fatigue and weakness in doing strenuous activity. Her symptoms are worse near the end of the day. She appears well, muscle bulk, tone, and reflexes are normal. Handgrip strength decreases with repetitive testing.
Diurnal fluctuations and pathologic fatigue are common in disorders of neuromuscular transmission (e.g., myasthenia gravis).
A 63-year-old woman has noticed weakness in her right hand such that she is having difficulty writing and doing up buttons. On examination, there is marked atrophy of the forearm and hand muscles with fasciculations. Tone is increased and reflexes are brisk. Sensory testing in the hand is normal. There are also fasciculations on her thighs, which she has never noticed before.
In diseases of the anterior horn cell (such as ALS), atrophy is marked and early. Muscle disease can result in marked atrophy, but much later in the course of the disease. Atrophy is generally moderate in peripheral nerve disease and absent in disorders of the neuromuscular junction.
A 49-year-old man notices weakness and numbness in his left hand. He had recently slipped on a wet floor and injured his elbow. Examination of the hand reveals predominantly weakness to abduction and adduction and sensory loss over the fourth and fifth fingers.
Peripheral nerve disease is the most likely to cause distal weakness and is the only one of the four to also cause sensory symptoms.
A 67-year-old man with lung cancer notices symptoms of weakness in his arms and legs. He describes difficulty in rising out of chair or going upstairs, but no pain or discomfort. On examination, proximal muscle strength is four out of five in the upper and lower limbs, but the reflexes, tone, and sensation are normal. He has a colored rash on his eyelids, and raised papules on his knuckles.
Dermatomyositis is one of the inflammatory myopathies that has a characteristic rash on the eyelids (heliotrope) and knuckles (Gottron’s papules). It is associated with certain cancers as a paraneoplastic syndrome. The muscle enzyme creatine kinase (CK) is elevated is most cases, but the condition is painless. Symptoms are those of proximal muscle weakness, with normal reflexes and tone on examination.