Clinical Neurology Test 1 — Questions and Answers
Question 1: A 39-year-old man is admitted to the hospital by his brother for evaluation of increasing forgetfulness and confusion during the past month. His brother reports that the patient has been drinking heavily and eating very little, and has been slightly nauseated and tremulous. He wanders at night because he cannot sleep. On admission to the hospital, intravenous administration of 5% dextrose in water is initiated. Two hours later, the patient has ophthalmoplegia and is completely confused. Which of the following is the most appropriate next step in management?
- Administration of an anticoagulant
- Administration of diazepam
- Administration of large doses of vitamin B1 (thiamine), intravenously (Correct answer)
- Administration of large doses of vitamin C,
- Continued administration of intravenous fluids with magnesium
Correct answer: Administration of large doses of vitamin B1 (thiamine), intravenously
This patient presents with symptoms of chronic alcohol abuse and malnutrition, followed by acute neurological deterioration (ophthalmoplegia, confusion) after receiving intravenous dextrose. This sequence is highly suggestive of Wernicke encephalopathy, which is caused by thiamine (vitamin B1) deficiency. Administering glucose without thiamine can precipitate or worsen Wernicke encephalopathy, making immediate intravenous thiamine crucial to prevent further neurological damage.
Question 2: A 47-year-old man comes to the physician because of a 2-year history of fatigue. He has had progressive difficulty with daytime sleepiness and has intermittently fallen asleep at work. He has no difficulty falling asleep or staying asleep at night but awakens in the morning not feeling well rested. His vital signs are within normal limits. Examination of the throat shows no abnormalities except for hypertrophied tonsils. His hemoglobin concentration is 17.9 g/dL, leukocyte count is 8700/mm3 , and platelet count is 170,000/mm3 . Which of the following is the most likely cause of this patient’s symptoms?
- Chronic Epstein-Barr virus infection
- Chronic fatigue syndrome
- Erythroleukemia
- Polycythemia vera
- Sleep apnea (Correct answer)
Correct answer: Sleep apnea
The patient's chronic fatigue, excessive daytime sleepiness despite adequate sleep duration, and unrefreshing sleep are classic symptoms of sleep apnea. Hypertrophied tonsils are a common anatomical factor contributing to airway obstruction. The elevated hemoglobin concentration (polycythemia) is a significant clue, as chronic nocturnal hypoxemia due to sleep apnea stimulates erythropoietin production, leading to secondary polycythemia.
Question 3: A 45-year-old man has had a 1-week history of increasing neck pain when he turns his head to the right. He also has had a pins-and-needles sensation starting in the neck and radiating down the right arm into the thumb. His symptoms began 3 months ago when he developed severe pain in the neck and right shoulder. Neurologic examination shows limitation of motion on turning the neck to the right. There is 4+/5 weakness of the right biceps and decreased pinprick over the right thumb. Deep tendon reflexes are 1+ in the right biceps and brachioradialis; all others are 2+. Which of the following is the most likely diagnosis?
- Carpal tunnel syndrome
- Cervical root compression (Correct answer)
- Multiple sclerosis
- Thoracic outlet syndrome
- Ulnar nerve compression
Correct answer: Cervical root compression
The patient's symptoms of neck pain radiating into the arm and thumb, associated with weakness in the biceps and decreased sensation in the thumb, along with diminished biceps and brachioradialis reflexes, are highly localized to the C6 nerve root. This pattern of dermatomal and myotomal deficits, exacerbated by neck movement, is characteristic of cervical radiculopathy, most commonly caused by compression of a cervical nerve root due to a herniated disc or osteophyte.
Question 4: A 29-year-old man is brought to the emergency department because he has a severe bilateral headache and irritability. His pulse is 120/min, respirations are 30/min, and blood pressure is 200/120 mm Hg. Ophthalmoscopic examination shows blurring of the optic discs. Deep tendon reflexes are 3+ and symmetric. Which of the following is the most likely diagnosis?
- Alcohol intoxication
- Heavy metal poisoning
- Hypertensive encephalopathy (Correct answer)
- Hyperthyroidism
- Panic disorder
Correct answer: Hypertensive encephalopathy
The acute onset of severe headache, irritability, and neurological symptoms (blurring of optic discs, indicating papilledema, and hyperreflexia) in the setting of extremely elevated blood pressure (200/120 mm Hg) is characteristic of hypertensive encephalopathy. This condition is a medical emergency caused by a rapid and severe increase in blood pressure that overwhelms the brain's autoregulatory capacity, leading to cerebral edema and neurological dysfunction.
Question 5: A 65-year-old man has had increasingly severe headaches and diffuse muscle aches during the past 3 months. He also has a 1-month history of jaw pain when chewing food and decreasing visual acuity in his left eye. His temperature is 38°C (100.4°F). Visual acuity in his left eye is 20/100, and the left optic disc is slightly atrophic. His muscle strength is normal. Which of the following tests should be obtained next?
- Measurement of erythrocyte sedimentation rate (Correct answer)
- Antinuclear antibody assay
- Examination of cerebrospinal fluid
- CT scan of the head
- Electroencephalography
Correct answer: Measurement of erythrocyte sedimentation rate
This patient's age, new-onset headaches, diffuse muscle aches (polymyalgia rheumatica-like symptoms), jaw pain when chewing (jaw claudication), and acute monocular vision loss are classic symptoms of giant cell (temporal) arteritis. This condition is a medical emergency due to the risk of permanent blindness. The most crucial initial diagnostic test is the erythrocyte sedimentation rate (ESR), which is almost always markedly elevated in active giant cell arteritis and guides immediate treatment with corticosteroids.
Question 6: A 19-year-old woman comes to the physician because of a 3-month history of intermittent drooping of her left eyelid each evening and occasional difficulty chewing and swallowing. She also has had two episodes of double vision that occurred in the evening and resolved by the following morning. Examination shows no abnormalities except for slight ptosis on the right. Which of the following is the most likely diagnosis?
- Acute intermittent porphyria
- Brain stem glioma
- Complex partial seizures
- Guillain-Barré syndrome
- Myasthenia gravis (Correct answer)
Correct answer: Myasthenia gravis
The patient's fluctuating symptoms of ptosis, diplopia, and difficulty chewing/swallowing, which worsen with activity or at the end of the day and improve with rest, are highly characteristic of myasthenia gravis. This autoimmune disorder involves antibodies attacking acetylcholine receptors at the neuromuscular junction, leading to fatigable muscle weakness, particularly affecting ocular and bulbar muscles.
Question 7: A 21-year-old college student comes to student health services requesting medication to help her sleep. Four days ago, she returned from a 1-year trip to India where she studied comparative religions. Since her return, she has been unable to fall asleep until 4 or 5 AM and has difficulty awakening before noon. She constantly feels tired, has difficulty concentrating, and does not feel ready to begin classes. Her appetite has not decreased, but she has an aversion to eating meat since following a vegetarian diet in India. She has no history of medical or psychiatric illness. She takes no medications and does not drink alcohol. She appears sleepy. She is 173 cm (5 ft 8 in) tall and weighs 54 kg (120 lb); BMI is 18 kg/m2 . Her pulse is 60/min, and blood pressure is 115/70 mm Hg. She is alert and oriented to person, place, and time. When asked to subtract serial sevens from 100, she begins accurately but then repeatedly loses track of the sequence. Which of the following is the most likely diagnosis?
- Adjustment disorder with depressed mood
- Bipolar disorder
- Circadian rhythm sleep disorder (Correct answer)
- Major depressive disorder
- Malingering
- Primary insomnia
Correct answer: Circadian rhythm sleep disorder
The patient's symptoms of difficulty falling asleep and waking, coupled with fatigue and impaired concentration, immediately following a long-distance international trip (India to presumably a Western country, implying significant time zone change), are classic for a circadian rhythm sleep disorder, specifically jet lag disorder. Her internal biological clock is still aligned with the previous time zone, causing a mismatch with the local day-night cycle.
Question 8: A 67-year-old woman comes to the physician for a follow-up examination. She had a pulmonary embolism and required treatment in the hospital for 3 weeks. She had a retroperitoneal hemorrhage; anticoagulant therapy was temporarily discontinued, and she underwent placement of an inferior vena cava (IVC) filter. She had a hematoma that was resolving on discharge from the hospital 2 weeks ago. Today, she says she has had a persistent sensation of tingling and numbness of her left thigh that she did not report in the hospital because she thought it would go away; the sensation has improved somewhat during the past week. Her only medication is warfarin. Vital signs are within normal limits. Examination of the skin shows no abnormalities. Muscle strength is normal. Sensation to light touch is decreased over a 5 × 5-cm area on the lateral aspect of the left anterior thigh. Which of the following is the most likely cause of this patient’s decreased sensation?
- Cerebral infarction during the hospitalization
- Complication of the IVC filter placement
- Compression of the lateral femoral cutaneous nerve (Correct answer)
- Hematoma of the left thigh
- Spinal cord infarct
- Vitamin B12 (cobalamin) deficiency
Correct answer: Compression of the lateral femoral cutaneous nerve
The patient's symptoms of tingling and numbness specifically over the lateral aspect of the anterior thigh, without motor weakness, are characteristic of meralgia paresthetica. This condition is caused by compression or entrapment of the lateral femoral cutaneous nerve (LFCN) as it passes under the inguinal ligament. A retroperitoneal hematoma, even resolving, or complications from IVC filter placement could have caused direct pressure on this superficial nerve.
Question 9: An 82-year-old man is admitted to the hospital because nursing staff in his skilled nursing care facility report that he has appeared sad and depressed during the past 2 months. It is reported that he has a history of psychiatric illness, but details are not provided. He has been taking olanzapine, paroxetine, and haloperidol for 2 years. He does not appear to be in acute distress. He is 160 cm (5 ft 3 in) tall and weighs 48 kg (105 lb); BMI is 19 kg/m2 . Physical examination shows 2+ cogwheel rigidity of the upper extremities. Neurologic examination shows psychomotor retardation. On mental status examination, he is alert and generally pleasant and cooperative. His affect has little intensity or range. He says he does not feel depressed or anxious. Laboratory findings are within the reference range. Which of the following is the most likely cause of this patient’s current symptoms?
- Adjustment disorder
- Akathisia
- Dementia, Alzheimer type
- Drug-induced parkinsonism (Correct answer)
- Major depressive disorder
Correct answer: Drug-induced parkinsonism
The patient's new onset of cogwheel rigidity, psychomotor retardation, and flat affect, despite denying depression, are classic extrapyramidal symptoms consistent with parkinsonism. Given his medication regimen including haloperidol (a typical antipsychotic) and olanzapine (an atypical antipsychotic, but still with D2 antagonism), drug-induced parkinsonism is the most likely cause. These medications block dopamine D2 receptors, leading to a functional dopamine deficiency that mimics Parkinson's disease.
Question 10: A 25-year-old butcher has had severe episodic pain in his right thumb and right second and third digits for 2 months. The pain frequently awakens him from sleep. He has decreased sensation over the palmar surface of the thumb and index and long fingers of the right hand and atrophy of the thenar muscle mass. Compression of which of the following nerves is the most likely cause?
- Median (Correct answer)
- Musculocutaneous
- Posterior interosseous
- Radial
- Ulnar
Correct answer: Median
The patient's symptoms, including severe episodic pain in the thumb, index, and middle fingers, decreased sensation over the palmar surface of these digits, and thenar muscle atrophy, are classic for carpal tunnel syndrome. This condition results from compression of the median nerve as it passes through the carpal tunnel in the wrist. The median nerve provides sensory innervation to these specific fingers and motor innervation to the thenar muscles.
Question 11: A 27-year-old woman comes to the physician because of a 3-week history of fatigue and blurred vision. She occasionally has had double vision during this period. For the past year, she has had 3- to 4-day episodes of numbness and tingling of her arms and legs. She has no personal or family history of serious illness. Her only medication is an oral contraceptive. She has smoked one pack of cigarettes daily for 5 years. Vital signs are within normal limits. Funduscopic examination shows no abnormalities. Visual acuity is decreased in the left eye. Sensation to light touch is decreased over the hands and feet; sensation to pinprick is increased over the fingers and toes bilaterally. An MRI of the brain shows several hyperintense oval plaques in the periventricular region on T2-weighted images. Which of the following is the most likely diagnosis?
- Glioma
- Guillain-Barré syndrome
- Multiple sclerosis (Correct answer)
- Systemic lupus erythematosus
- Toxoplasmosis
Correct answer: Multiple sclerosis
The patient's recurrent neurological symptoms, such as fatigue, blurred vision, double vision, and episodes of numbness/tingling in different areas (disseminated in time and space), are highly suggestive of multiple sclerosis. The MRI findings of hyperintense oval plaques in the periventricular region on T2-weighted images are characteristic demyelinating lesions seen in MS. This combination of clinical presentation and imaging findings strongly supports the diagnosis.
Question 12: A 57-year-old woman comes to the physician because of a 2-year history of difficulty sleeping. After she gets into bed at night, her legs feel cold and crampy, and she cannot settle into a comfortable position. Walking around temporarily relieves her symptoms. She also has difficulty sitting for a prolonged period of time. She has a mild anxiety disorder but takes no medications. Vital signs are within normal limits. Examination shows no abnormalities. Which of the following is the most likely diagnosis?
- Benign fasciculations
- Major depressive disorder
- Parkinson disease
- REM sleep behavior disorder
- Restless legs syndrome (Correct answer)
- Stiff-person syndrome
Correct answer: Restless legs syndrome
The patient's description of uncomfortable sensations in her legs, particularly at night, that compel her to move them, and which are temporarily relieved by walking, is the hallmark of restless legs syndrome (RLS). RLS is a neurological disorder characterized by an irresistible urge to move the legs, often accompanied by unpleasant sensations, typically worse during periods of rest and in the evening or night.
Question 13: A 77-year-old man comes to the emergency department 1 hour after a 15-minute episode of right arm weakness and an inability to speak in sentences; the symptoms have now resolved. He has a 30-year history of hypertension treated with hydrochlorothiazide. He does not have diabetes mellitus or coronary artery disease. During the past 8 weeks, he has walked 3 miles daily without symptoms. His pulse is 80/min, respirations are 14/min, and blood pressure is 144/88 mm Hg. Examination, including cardiopulmonary and neurologic examinations, shows no other abnormalities. A carotid bruit is heard on the left. An ECG shows a normal sinus rhythm with a ventricular rate of 76/min. Echocardiography shows no abnormalities. Carotid duplex ultrasonography and follow-up MR angiography show an 80% left internal carotid stenosis. Which of the following is the most appropriate next step to prevent cerebral infarction in this patient?
- Prophylactic atorvastatin
- Prophylactic naproxen
- Prophylactic warfarin
- Carotid endarterectomy (Correct answer)
- Extracranial-intracranial bypass surgery
- Percutaneous coronary intervention
Correct answer: Carotid endarterectomy
The patient experienced a transient ischemic attack (TIA) affecting the left cerebral hemisphere (right arm weakness and aphasia), which resolved. The finding of an 80% left internal carotid stenosis is a significant risk factor for future stroke. For symptomatic patients with high-grade carotid stenosis (70-99%), carotid endarterectomy is the most appropriate intervention to prevent cerebral infarction, as it significantly reduces the risk of stroke.
Question 14: A 62-year-old man with alcoholism is admitted to the hospital because of somnolence and hepatic failure. On admission, his serum sodium concentration is 109 mEq/L. Hypertonic saline is administered, and the next day his serum sodium concentration is 138 mEq/L. Three days after admission, he has severe weakness; neurologic examination shows flaccid paresis of both the upper and lower extremities. Which of the following is the most likely cause of this patient’s acute neurologic symptoms?
- Alcohol withdrawal
- Central pontine myelinolysis (Correct answer)
- Hepatic encephalopathy
- Hepatorenal syndrome
- Vitamin B1 (thiamine) deficiency
Correct answer: Central pontine myelinolysis
The rapid correction of severe hyponatremia (from 109 to 138 mEq/L in one day) in a patient with alcoholism and hepatic failure is a classic trigger for central pontine myelinolysis (osmotic demyelination syndrome). This condition results from rapid osmotic shifts, causing demyelination primarily in the pons, leading to severe neurological deficits like flaccid paresis and locked-in syndrome.
Question 15: A 32-year-old woman comes to the emergency department 3 hours after the sudden onset of a severe headache. The pain is associated with nausea and vomiting. Medical history is noncontributory. She is drowsy but easy to arouse. Her temperature is 37.1°C (98.8°F), pulse is 92/min, respirations are 10/min, and blood pressure is 130/70 mm Hg. Examination of the head shows no abnormalities. Flexion of the neck produces pain. The optic fundi are normal. Motor and sensory examinations show no abnormalities. Cranial nerves are intact. Deep tendon reflexes are symmetric. Babinski sign is present bilaterally. Which of the following is most likely to confirm the diagnosis?
- X-rays of the sinuses
- Carotid duplex ultrasonography
- EEG
- CT scan of the head (Correct answer)
- Biopsy of the temporal artery
Correct answer: CT scan of the head
The sudden onset of a 'thunderclap' headache, associated with nausea, vomiting, drowsiness, and signs of meningeal irritation (neck pain with flexion, bilateral Babinski sign), is highly suggestive of a subarachnoid hemorrhage (SAH). A CT scan of the head without contrast is the most appropriate initial diagnostic step to confirm SAH, as it can detect acute blood in the subarachnoid space in the majority of cases.
Question 16: A previously healthy 4-year-old boy is brought to the emergency department 8 hours after the onset of fever and a diffuse, constant headache. He had been well until 2 days ago when he developed malaise. Yesterday, he slept more than usual and had temperatures to 39.2°C (102.5°F). Immunizations are up-to-date. He is lethargic and irritable when aroused. He holds his head extended and cries when his neck is flexed. Muscle strength is normal, and deep tendon reflexes are symmetrically increased. A lumbar puncture yields turbid cerebrospinal fluid. Laboratory studies show: Serum glucose 120 mg/dL Cerebrospinal fluid Opening pressure 250 mm H2O Glucose 10 mg/dL Protein 85 mg/dL Leukocyte count 750/mm3 Segmented neutrophils 95% Lymphocytes 5% Erythrocyte count 0/mm3 A Gram stain of cerebrospinal fluid shows gram-negative diplococci. A CT scan of the head shows no abnormalities. Which of the following is the most likely causal organism?
- Cytomegalovirus
- Haemophilus influenzae
- Neisseria meningitidis (Correct answer)
- Streptococcus agalactiae (group B)
- Varicella-zoster virus
Correct answer: Neisseria meningitidis
The patient's clinical presentation (fever, headache, lethargy, nuchal rigidity) combined with the cerebrospinal fluid (CSF) findings (turbid, high opening pressure, low glucose, high protein, high leukocyte count with neutrophil predominance) is characteristic of bacterial meningitis. The Gram stain showing gram-negative diplococci specifically identifies *Neisseria meningitidis* as the most likely causal organism in this age group.
Clinical Neurology Test 1
A 39-year-old man is admitted to the hospital by his brother for evaluation of increasing forgetfulness and confusion during the past month.
His brother reports that the patient has been drinking heavily and eating very little, and has been slightly nauseated and tremulous.
He wanders at night because he cannot sleep.
On admission to the hospital, intravenous administration of 5% dextrose in water is initiated.
Two hours later, the patient has ophthalmoplegia and is completely confused.
Which of the following is the most appropriate next step in management?