Nutritional and Metabolic Disorders

Question 1

191. In Tay-Sachs disease, the enzymatic abnormality responsible for the neurologic deficits is deficiency of
     a. Hexosaminidase A
     b. Glucocerebrosidase
     c. Phosphofructokinase
     d. Glucose phosphorylase
     e. Sphingomyelinase

Answer 1

A
(Swaiman, pp 442–444.) Children with Tay-Sachs disease die prematurely and exhibit mental retardation, seizures, and blindness. This is a ganglioside storage disease that occurs more commonly in Ashkenazi Jews than in the general population. The early-onset form will produce macrocephaly and a cherry red spot in the fundus.

Question 2

192. With β-glucosidase deficiency, the affected child is likely to exhibit abnormal accumulations of which of the following?
     a. Glucosylceramide
     b. GM2 ganglioside
     c. Galactosyl sulfatides
     d. Sphingomyelin
     e. Trihexosylceramide

Answer 2

A
(Swaiman, p 452.) The disease responsible for the accumulation of glucosylceramide is Gaucher’s disease. Gaucher’s disease is inherited as an autosomal recessive trait and may be diagnosed by demonstrating deficient glucocerebrosidase in fibroblasts or leukocytes. The severity of disease varies from nonneuronopathic types to acute infantile neuronopathic disease. Gaucher’s disease produces hepatosplenomegaly and may cause lethal CNS disease. It is one of a collection of storage diseases called sphingolipidoses, which include Niemann-Pick disease, Krabbe’s disease, and Fabry’s disease. Fabry’s disease involves the accumulation of another ceramide, trihexosylceramide. All the sphingolipids are nothing more than lipids that contain a sphingosine moiety. Sphingosine is a class of long-chain compounds with hydroxyl groups on carbons 1 and 3 and an amino group on carbon 2. They form ceramides by joining with fatty acids across the subterminal amino group. GM2 ganglioside accumulates in Tay-Sachs disease, and galactosyl sulfatides accumulate in metachromatic leukodystrophy.

Question 3

193. A 53-year-old left-handed man presents with asterixis, esophageal varices, splenomegaly, and abdominal ascites. He is likely to exhibit altered consciousness on the basis of which of the following?
     a. Renal tubular acidosis
     b. Impaired hepatic detoxification of portal blood
     c. Splenomegaly-induced anemia
     d. Copper intoxication
     e. Vitamin B12 deficiency

Answer 3

B
(Rowland, pp 876–877.) The clinical picture presented suggests hepatic failure. Copper poisoning may lead to hepatic failure, but the altered consciousness would be a consequence of the liver disease rather than the heavy metal poison itself. Similarly, vitamin B12 deficiency may lead to dementia, but it would not produce the signs of hepatic insufficiency exhibited by this patient. Encephalopathy that develops with chronic hepatic disease and portal hypertension is often called portalsystemic encephalopathy because of the importance of toxin-laden blood’s bypassing the liver as portal hypertension develops. Precisely what toxins produce the encephalopathy is still debatable, but ammonia is probably the most important one. This type of encephalopathy will develop if flow through the liver is obstructed and the liver is otherwise normal. This is distinct from the terminal coma that may develop with acute hepatic necrosis.

Question 4

194. This patient survives with his disorder for 2 years. At the time of death, he would be expected to exhibit changes in which type of brain cells?
     a. Oligodendrocytes
     b. Striatal neurons
     c. Pigmented cells of the substantia nigra
     d. Astrocytes
     e. Inferior olivary neurons

Answer 4

D
(Rowland, pp 876–877.) Long-standing hepatic disease may produce a profound encephalopathy, but changes in the brain are notably sparse with portal-systemic encephalopathy. The most obvious change is an increase in Alzheimer’s type II astrocytes. These astrocytes are relatively large cells. Rare patients show more dramatic changes, which include neuronal loss and focal necrosis. With chronic alcoholism and hepatic insufficiency, patients exhibit a loss of Purkinje cells in the cerebellum, but this is a consequence of alcohol toxicity or thiamine deficiency rather than of toxic injury from the hepatic dysfunction.

Question 5

195. The cerebrospinal fluid (CSF) protein content with either uremic encephalopathy or hypertensive encephalopathy is likely to be
     a. Abnormally low
     b. Normal
     c. Elevated to less than 100 mg /dL
     d. Elevated to between 500 and 1000 mg /dL
     e. Greater than 2000 mg /dL

Answer 5

C
(Rowland, pp 886–887.) In 60% of patients with uremic encephalopathy, the CSF protein content is greater than 60 mg/dL, but it exceeds 100 mg/dL in only 20%. The elevation with hypertensive encephalopathy is much more variable because intracranial hemorrhage may occur with the hypertensive crisis, but most patients will have protein changes of the magnitude seen with uremic encephalopathy. The increased protein level appears to develop with uremic encephalopathy because of greater permeability to proteins of the brain’s capillaries when the patient is uremic. Dialysis may transiently correct the abnormality.

Question 6

A 65-year-old man has had many years of deteriorating kidney func¬tion due to diabetes. At age 59, dialysis was begun because of electrolyte abnormalities.

196. The most common neurologic complication of chronic renal failure is
     a. Peripheral neuropathy
     b. Delirium
     c. Seizures
     d. Dementia
     e. Labile affect

Answer 6

A
(Rowland, p 887.) The type of peripheral neuropathy most commonly developing with chronic renal failure is a symmetric, distal, mixed sensorimotor neuropathy. The legs are generally affected first and most severely. Men are more commonly affected than women. Most of the peripheral neuropathies in patients with chronic renal failure involve axonal degeneration. The neuropathy usually improves with dialysis.

Question 7

A 65-year-old man has had many years of deteriorating kidney func¬tion due to diabetes. At age 59, dialysis was begun because of electrolyte abnormalities.

197. As the patient becomes uremic, he tends to develop the restless legs syndrome. This may be controlled with
     a. Haloperidol
     b. Clonazepam
     c. Caffeine
     d. Nifedipine
     e. Rifampin

Answer 7

B
(Bradley, pp 1823–1824.) The restless legs syndrome (Ekbom syndrome) is characterized by a feeling of discomfort in the legs that is relieved by movement. The sensation is felt deep within the limb, and is variably described as a pulling, stretching, or cramping. Restless legs syndrome occurs primarily at night, shortly after the patient lies down. It differs from akathisia, which is a restlessness that occurs during the daytime. It may be associated with peripheral neuropathy and anemia and is seen in patients with chronic renal disease, diabetes mellitus, and many other medical conditions. Exercise before going to bed may alleviate much of the discomfort. Agents that may be effective in alleviating symptoms include clonazepam, gabapentin, L-dopa, and opiates. Neuroleptics, calcium channel blockers, and caffeine may worsen symptoms.

Question 8

A 65-year-old man has had many years of deteriorating kidney func¬tion due to diabetes. At age 59, dialysis was begun because of electrolyte abnormalities.

198. The most reliable treatment for the peripheral neuropathy of chronic renal failure is
     a. Thiamine supplements
     b. Clonazepam
     c. Phenytoin
     d. Minoxidil
     e. Renal transplant

Answer 8

E
(Rowland, p 619.) B vitamins are generally replaced when patients receive dialysis. Thiamine is water-soluble and so is easily lost during dialysis, but even replacing thiamine is not nearly as effective in retarding or reversing the neuropathy of chronic renal failure as is renal transplantation. There are presumed to be neurotoxins in the blood of patients with uremia that are not removed by routine dialysis.

Question 9

A 68-year-old man presents with acroparesthesia, sensory ataxia, mem¬ory loss, and impotence. On exam, there are upper motor neuron signs in all four extremities. He also has anemia and a sore tongue. Eventually vitamin B12 deficiency is diagnosed.

199. For vitamin B12 to be absorbed, it must bind to
     a. A cyanide atom and form cyanocobalamin
     b. An intrinsic factor
     c. The parietal cells of the stomach
     d. The ileal mucosa
     e. The jejunal mucosa

Answer 9

B
(Rowland, pp 896–900.) Intrinsic factor is a glycoprotein that is secreted by the gastric parietal cells. In most people with vitamin B12 deficiency, the problem is inadequate production of intrinsic factor rather than inadequate vitamin B12 in the diet. Persons with pernicious anemia usually have an atrophic gastritis with inadequate intrinsic factor production as a consequence. This is presumed to be mediated by an autoimmune disorder.

Question 10

A 68-year-old man presents with acroparesthesia, sensory ataxia, mem¬ory loss, and impotence. On exam, there are upper motor neuron signs in all four extremities. He also has anemia and a sore tongue. Eventually vitamin B12 deficiency is diagnosed.

200. With vitamin B12 deficiency, which of the following accumulates in the blood?
     a. Cysteine
     b. Methylmalonic acid
     c. Methionine
     d. Succinic acid
     e. Propionic acid

Answer 10

B
(Rowland, pp 896–900.) Vitamin B12 (cobalamin) is an essential cofactor in the conversion of L-methylmalonyl-CoA to succinyl CoA and of homocysteine to methionine. Without sufficient vitamin B12, the conversion of propionic acid to succinic acid is blocked, and the intermediate compound, methylmalonic acid, accumulates in the blood. It is readily excreted and may help in the diagnosis of cobalamin deficiency when it is found in excess in the urine. Serum homocysteine levels, but not cysteine levels, may also be elevated because the conversion of homocysteine to methionine is disrupted if vitamin B12 is not available to expedite the methylation of homocysteine. Without this conversion of homocysteine to methionine, folate metabolism is disturbed, which probably interferes with DNA synthesis in red blood cell (RBC) precursor cells.

Question 11

A 68-year-old man presents with acroparesthesia, sensory ataxia, mem¬ory loss, and impotence. On exam, there are upper motor neuron signs in all four extremities. He also has anemia and a sore tongue. Eventually vitamin B12 deficiency is diagnosed.

201. The patient with impaired vitamin B12 absorption is likely to develop a positive Romberg test because of damage to which of the following?
     a. Cerebellar vermis
     b. Cerebellar hemispheres
     c. Spinal cord lateral columns
     d. Basal ganglia
     e. Spinal cord posterior columns

Answer 11

E
(Rowland, pp 896–900.) Both the lateral and posterior columns of the spinal cord are damaged with cobalamin deficiency, but a positive Romberg sign develops with impaired position sense, a sensory modality carried in the posterior columns of the cord. Because both sensory and motor functions are disturbed with cobalamin deficiency, the resulting condition is called combined systems disease. The microscopic changes in the posterior and lateral columns of the spinal cord in the patient with combined systems disease include demyelination, gliosis, and vacuolar degeneration. The regions of the spinal cord most severely damaged are the lower cervical and upper thoracic. The vacuolar changes observed arise in the myelin sheaths of very large nerve fibers. Although this starts as a predominantly demyelinating lesion, it evolves into axonal loss. Patients develop spasticity and weakness, as well as disturbed vibration and position sense. The clinical picture becomes more confused because a peripheral neuropathy may also develop with cobalamin deficiency. The peripheral neuropathy of the sort occurring with vitamin B12 deficiency would ordinarily produce hyporeflexia. The lateral column damage, which involves the corticospinal tracts, would ordinarily cause hyperreflexia. Because both peripheral nerves and corticospinal tracts are damaged with vitamin B12 deficiency, the effect on reflexes is difficult to predict and often changes over time. The patient will usually start with hyperreflexia and then develop either clonus or hyporeflexia.

Question 12

A 68-year-old man presents with acroparesthesia, sensory ataxia, mem¬ory loss, and impotence. On exam, there are upper motor neuron signs in all four extremities. He also has anemia and a sore tongue. Eventually vitamin B12 deficiency is diagnosed.

202. The type of visual field cut most often seen with vitamin B12 defi¬ciency is a
     a. Centrocecal scotoma
     b. Homonymous hemianopsia
     c. Bitemporal hemianopsia
     d. Binasal hemianopsia
     e. Hemianopsia with central sparing

Answer 12

A
(Rowland, pp 896–900.) The blind spot that normally occurs in each eye enlarges and extends temporally to involve central vision in patients with chronic vitamin B12 deficiency. This is similar to the blind spot that is associated with alcohol and tobacco excess, a problem called tobacco-alcohol amblyopia. Tobacco-alcohol amblyopia also seems to develop because of a vitamin B deficiency, but the deficiency is presumed to be of thiamine rather than of cobalamin.

Question 13

203. A 42-year-old woman is being treated with methotrexate for Wegener’s granulomatosis. She is at risk for megaloblastic anemia and peripheral neu¬ropathy because methotrexate disturbs the metabolism of
     a. Cobalamin
     b. Iron
     c. Copper
     d. Pyridoxine
     e. Folate

Answer 13

E
(Braunwald, p 542.) Methotrexate inhibits dihydrofolate reductase, thereby interfering with the metabolism of folate. As is the case with cobalamin deficiency, this results in a megaloblastic anemia. Defective DNA synthesis underlies the marrow disturbance that is seen with both folate and cobalamin deficiencies.

Question 14

A 37-year-old woman develops cholecystitis and requires cholecystec¬tomy. Her family advises the physicians involved that she has a long history of alcoholism and benzodiazepine use, including diazepam (Valium), lorazepam (Ativan), and clonazepam (Klonopin). Approximately 7 days after the surgery, the patient becomes increasingly agitated, delusional, and suspicious. Routine investigations reveal no evidence of focal or systemic infection. Hepatic, renal, and hematologic parameters are largely normal. Within 24 h of these cognitive and affective changes, the patient has a gen¬eralized tonic-clonic seizure. Magnetic resonance imaging (MRI) and com¬puted tomography (CT) studies of the brain are normal, and her CSF is unremarkable.

204. In consideration of the abuse history provided by the family, medica¬tion orders prior to the surgery should have included
     a. Haloperidol
     b. Chlorpromazine
     c. Trihexyphenidyl
     d. Prochlorperazine
     e. Thiamine

Answer 14

E
(Victor, pp 1211–1212.) This woman was at risk for Wernicke’s encephalopathy. She should have received supplemental thiamine for at least 3 days, even though this would not have prevented the cognitive deterioration that she exhibited. There was no indication for using a neuroleptic (e.g., haloperidol, chlorpromazine, or prochlorperazine), even though her alcohol and benzodiazepine use placed her at risk for developing a withdrawal psychosis. The anticholinergic trihexyphenidyl would not be appropriate as either a neuroleptic or an antiepileptic.

Question 15

A 37-year-old woman develops cholecystitis and requires cholecystec¬tomy. Her family advises the physicians involved that she has a long history of alcoholism and benzodiazepine use, including diazepam (Valium), lorazepam (Ativan), and clonazepam (Klonopin). Approximately 7 days after the surgery, the patient becomes increasingly agitated, delusional, and suspicious. Routine investigations reveal no evidence of focal or systemic infection. Hepatic, renal, and hematologic parameters are largely normal. Within 24 h of these cognitive and affective changes, the patient has a gen¬eralized tonic-clonic seizure. Magnetic resonance imaging (MRI) and com¬puted tomography (CT) studies of the brain are normal, and her CSF is unremarkable.

205. The patient’s neurologic deterioration was most probably caused by
     a. A delayed anesthetic reaction
     b. Benzodiazepine withdrawal
     c. Alcohol withdrawal
     d. Unreported cocaine use
     e. Idiopathic epilepsy

Answer 15

B
(Victor, pp 1262–1263.) The delay between surgery and the cognitive deterioration in this benzodiazepine-abusing patient was extraordinarily long to be accounted for by an adverse reaction to the anesthetic agent or by alcohol withdrawal. Paranoid delusions and seizures occurring with alcohol withdrawal are most likely during the first 72 h of abstinence. Benzodiazepine withdrawal may produce problems similar to those experienced with alcohol withdrawal, but a delay of 7 to 10 days between abstinence and the appearance of fulminant withdrawal symptoms is not atypical. Idiopathic epilepsy is not a reasonable diagnosis for a woman this age. Nothing in the history suggested cocaine abuse, but it is worth screening patients admitted with alcohol and benzodiazepine abuse for cocaine and amphetamine levels, especially if illicit drug use could complicate the hospitalization.

Question 16

A 37-year-old woman develops cholecystitis and requires cholecystec¬tomy. Her family advises the physicians involved that she has a long history of alcoholism and benzodiazepine use, including diazepam (Valium), lorazepam (Ativan), and clonazepam (Klonopin). Approximately 7 days after the surgery, the patient becomes increasingly agitated, delusional, and suspicious. Routine investigations reveal no evidence of focal or systemic infection. Hepatic, renal, and hematologic parameters are largely normal. Within 24 h of these cognitive and affective changes, the patient has a gen¬eralized tonic-clonic seizure. Magnetic resonance imaging (MRI) and com¬puted tomography (CT) studies of the brain are normal, and her CSF is unremarkable.

206. In anticipation of the seizures and cognitive deterioration that might occur postoperatively, the physician involved would have been wise to
     a. Consult a psychiatrist and neurologist prior to surgery
     b. Provide intravenous alcohol supplements postoperatively to blunt the alcohol withdrawal
     c. Provide intramuscular or oral chlordiazepoxide several times daily at a dose dictated by the patient’s level of agitation
     d. Start phenytoin as a single dose nightly
     e. Delay surgery until the risk of neurologic problems abated

Answer 16

C
(Victor, pp 1262–1263.) Chlordiazepoxide at relatively high doses of 25 to 100 mg, four to six times daily, will usually block the more malignant features of both alcohol and benzodiazepine withdrawal. This drug is itself a benzodiazepine, but once the patient has passed through the withdrawal period for the drugs he or she has been illicitly taking, the chlordiazepoxide can be systematically and uneventfully reduced. There are no apparent advantages to using an antiepileptic such as phenytoin.

Question 17

207. A 26-year-old man develops hemoptysis and dyspnea over the course of 3 months. His physician suspects tuberculosis and starts him on triple therapy with isoniazid (isonicotinic acid hydrazide), rifampin, and ethambutol. After 1 month of treatment, the patient’s liver enzymes show slight elevations, but the treatment is continued. The hemoptysis stops by 2 months, but the patient complains of pins-and-needles sensations in his feet. Neurologic examination reveals hypoactive deep tendon reflexes in the legs and slightly impaired position sense. Strength is good in all limbs. 
(SELECT 1 DEFICIENCY) 
a. Deficiency amblyopia 
b. Vitamin B12 deficiency 
c. Pyridoxine (vitamin B6) deficiency 
d. α tocopherol (vitamin E) deficiency 
e. Vitamin D deficiency 
f. Thiamine (vitamin B1) deficiency 
g. Nicotinic acid deficiency 
h. Kwashiorkor 
i. Vitamin C deficiency

Answer 17

C
(Victor, p 1395.) Any patient treated with isoniazid must receive supplemental pyridoxine. Isoniazid does not interfere with pyridoxine absorption, but it does interfere with its participation in metabolic pathways. Persistently low pyridoxine activity leads to the development of a peripheral neuropathy. This is most likely to be seen as an isolated deficiency in patients on antituberculous therapy.

Question 18

208. A 50-year-old woman is found wandering in the street and is brought to the emergency room by the police. She is disoriented to time, place, and person, but has no evidence of head trauma. She staggers when she tries to walk, but she has no detectable alcohol in her blood. Eye movements are abnormal with paresis of conjugate gaze, and horizontal nystagmus is apparent. Relatives are contacted, and they report that this woman has a long history of alcohol abuse. (SELECT 1 DEFICIENCY)
     a. Deficiency amblyopia
     b. Vitamin B12 deficiency
     c. Pyridoxine (vitamin B6) deficiency
     d. α tocopherol (vitamin E) deficiency
     e. Vitamin D deficiency
     f. Thiamine (vitamin B1) deficiency
     g. Nicotinic acid deficiency
     h. Kwashiorkor
     i. Vitamin C deficiency

Answer 18

F
(Victor, pp 1206–1212.) An apparently acute deterioration in cognitive function in an alcoholic may stem from any one of sev-eral causes. Bleeding from esophageal varices may have produced a profound anemia. Inapparent head trauma may have produced a subarachnoid hemorrhage or subdural hematomas. If the patient’s problem is due to a nutritional deficiency, it is most likely thiamine deficiency associated with alcoholism. That this patient has no alcohol in her blood at the time of the deterioration is irrelevant. The triad of dementia, gait difficulty, and oculomotor paresis is characteristic of Wernicke’s encephalopathy, the rapidly progressive and potentially lethal form of thiamine deficiency. Peripheral neuropathy commonly develops with thiamine deficiency, but it is not a component of the encephalopathy caused by thiamine deficiency.

Question 19

209. A 46-year-old man complains of progressive visual problems. He notices problems with discriminating objects both up close and far away. His deficits have progressed over the course of 3 months. He has a 12-year history of pipe smoking, a 14-year history of daily aspirin use, and a 20 year history of alcohol intake. He usually drinks 4 oz of gin daily. Examination reveals enlargement of the physiologic blind spot to the point where it extends into central vision. (SELECT 1 DEFICIENCY)
     a. Deficiency amblyopia
     b. Vitamin B12 deficiency
     c. Pyridoxine (vitamin B6) deficiency
     d. α tocopherol (vitamin E) deficiency
     e. Vitamin D deficiency
     f. Thiamine (vitamin B1) deficiency
     g. Nicotinic acid deficiency
     h. Kwashiorkor
     i. Vitamin C deficiency

Answer 19

A
(Victor, pp 1215–1216.) The vitamin deficiency specifically responsible for injury to the optic nerve in persons who chronically smoke tobacco and drink ethanol is still uncertain. It probably arises from combined deficits of vitamins B1, B12, and riboflavin. This condition is also known as nutritional optic neuropathy and as tobacco-alcohol amblyopia. There has been considerable speculation about its arising as a consequence of chronic cyanide poisoning from tobacco smoking combined with vitamin B12 deficiency associated with alcoholism, but this theory has little support.

Question 20

210. A 32-year-old South African woman develops irritability, sleeplessness, and fatigue. Her family believes that she is depressed, but neurologic assessment establishes prominent short- and long-term memory problems. She has anemia and an obvious dermatitis on her face. Her diet is strictly vegetarian and limited almost entirely to grains, such as corn. (SELECT 1 DEFICIENCY)
     a. Deficiency amblyopia
     b. Vitamin B12 deficiency
     c. Pyridoxine (vitamin B6) deficiency
     d. α tocopherol (vitamin E) deficiency
     e. Vitamin D deficiency
     f. Thiamine (vitamin B1) deficiency
     g. Nicotinic acid deficiency
     h. Kwashiorkor
     i. Vitamin C deficiency

Answer 20

G
(Victor, p 1217.) Persons with limited diet devoid of animal fats and rich in corn are at risk for pellagra, a nutritional deficiency of nicotinic acid or its precursor, tryptophan. This disease typically affects the skin, digestive tract, central nervous system, and hematopoietic system. People with diets limited to corn (maize) are especially vulnerable because of the low levels of tryptophan and niacin in this grain.

Question 21

211. A 61-year-old man develops progressive cramping of his legs and a pins-and-needles sensation in his feet over the course of 1 year. He consults a physician when he notices paresthesias in his hands and unsteadiness of his gait. His family reports that he has had some urinary incontinence, but was too embarrassed to report it. On examination, he has a spastic para-paresis with severe disturbance of position and vibration sense in his legs. Despite obvious spasticity in the legs, the deep tendon reflexes are absent at the knees and ankles. Peripheral blood smear reveals hypersegmented polymorphonuclear leukocytes. (SELECT 1 DEFICIENCY)
     a. Deficiency amblyopia
     b. Vitamin B12 deficiency
     c. Pyridoxine (vitamin B6) deficiency
     d. α tocopherol (vitamin E) deficiency
     e. Vitamin D deficiency
     f. Thiamine (vitamin B1) deficiency
     g. Nicotinic acid deficiency
     h. Kwashiorkor
     i. Vitamin C deficiency

Answer 21

B
(Victor, pp 1218–1223.) The slow evolution of gait difficulty, bladder dysfunction, paresthesias, hyporeflexia, impaired position and vibration sense, and anemia suggests combined systems disease, the neurologic equivalent of pernicious anemia. Persons with this disease may have a diet rich in vitamin B12, but they will develop deficiency if they
lack intrinsic factor in the stomach. Patients usually acquire a megaloblastic anemia associated with the spastic paraparesis. Finding hypersegmented polymorphonuclear cells on the peripheral blood smear helps establish the diagnosis.

Question 22

212. A 4-year-old boy develops progressive gait ataxia and limb weakness over the course of 3 months. Neurologic assessment reveals diffusely absent deep tendon reflexes, proximal muscle weakness, ophthalmoparesis, and poor pain perception in the feet. Blood tests reveal elevated creatine phosphokinase (CK) levels and abnormally high serum bilirubin levels. Further investigations of hepatic function reveal that the child has a cholestatic hepatobiliary disorder, but there is no evidence of hepatic dysfunction sufficient to cause an encephalopathy. (SELECT 1 DEFICIENCY)
     a. Deficiency amblyopia
     b. Vitamin B12 deficiency
     c. Pyridoxine (vitamin B6) deficiency
     d. α tocopherol (vitamin E) deficiency
     e. Vitamin D deficiency
     f. Thiamine (vitamin B1) deficiency
     g. Nicotinic acid deficiency
     h. Kwashiorkor
     i. Vitamin C deficiency

Answer 22

D
(Victor, p 1224.) Vitamin E deficiency that causes neurologic disease is rare, but when it does develop it is usually during early childhood. The most common syndrome involves spinocerebellar degeneration, polyneuropathy, and pigmentary retinopathy. Clarke’s columns, the spinocerebellar tracts, the posterior columns, the nuclei of Goll and Burdach, and sensory roots are especially likely to exhibit degeneration in persons with vitamin E deficiency. The most obvious symptom of the deficiency is likely to be ataxia.

Question 23

213. 213. A 9-month-old girl from famine-stricken Ethiopia exhibits profound apathy and indifference to her environment. She is afebrile and appears to have no significant infections at the time of her initial evaluation. Her hair is sparse, and slight edema is evident about her ankles. She is well below the fifth percentile for height in her age group. With handling she becomes irritable, but throughout her examination she exhibits little spontaneous movement. Her mother reports having seen transient tremors in the girl’s hands a few weeks earlier, but these abated after a few days. (SELECT 1 DEFICIENCY)
          a. Deficiency amblyopia
          b. Vitamin B12 deficiency
          c. Pyridoxine (vitamin B6) deficiency
          d. α tocopherol (vitamin E) deficiency
          e. Vitamin D deficiency
          f. Thiamine (vitamin B1) deficiency
          g. Nicotinic acid deficiency
          h. Kwashiorkor
          i. Vitamin C deficiency

Answer 23

H
(Victor, pp 1227–1228.) Protein deficiency states, such as those occurring with kwashiorkor, produce a wide range of neurologic signs and symptoms. Although the CNS is somewhat sheltered from the ravages of malnutrition, severe protein-calorie deficiencies during childhood development may leave the child neurologically impaired for life. Even when dietary supplements have been introduced to correct the chronic deficiency, the children are likely to exhibit little improvement in mobility or alertness for weeks or months.

Question 24

214. A 23-year-old woman with a history of hemophilia notices progressive memory difficulty. She has required little hematologic support, but she did receive transfusion of factor VIII at least five times over the past 7 years. Neurologic examination reveals word-finding difficulty, poor recent and remote memory, gait ataxia, mild dysarthria, and a labile affect. Her right plantar response is extensor and her left brachioradialis reflex is hyperactive with transient clonus. An MRI of the brain is unrevealing. (SELECT 1 DIAGNOSIS)
     a. Postictal state
     b. Hypothyroidism
     c. Uremic encephalopathy
     d. Wernicke’s encephalopathy
     e. Herpes encephalitis
     f. Progressive multifocal leukoencephalopathy(PML)
     g. Meningeal carcinomatosis
     h. Central nervous system (CNS) toxoplasmosis
     i. Multiple sclerosis
     j. Hepatic encephalopathy
     k. Subacute combined systems disease
     l. Meningococcal meningitis
     m. Subacute sclerosing panencephalitis (SSPE)
     n. AIDS encephalopathy
     o. Pickwickian syndrome

Answer 24

N
(Bradley, pp 1415–1416.) This woman is at relatively high risk for AIDS encephalopathy because she has required transfusion of clotting factors that have until recently been available only from pooled samples of blood products. The neurologic deficits that she exhibits are not specific for HIV-1–associated subacute encephalomyelitis (AIDS encephalitis) and are quite compatible with multiple sclerosis (MS). That her MRI does not reveal plaques of demyelination scattered throughout the brain makes the diagnosis of MS improbable. To establish the diagnosis of AIDS encephalopathy, HIV-1 antibodies should be sought and the helper/suppressor (CD4/CD8) T lymphocyte ratio should be checked. Patients with symptomatic AIDS usually have a CD4/CD8 T lymphocyte ratio of less than 0.5.

Question 25

215. A 35-year-old businessman complains of sleep attacks. He runs a chain of dry cleaning stores, but does not usually work with the cleaning fluids. He reports falling asleep several times during the workday, even at business meetings and during interviews. He has developed the sleep attacks only after gaining over 100 lb. His weight at the time of the examination is 324 lb. (SELECT 1 DIAGNOSIS)
     a. Postictal state
     b. Hypothyroidism
     c. Uremic encephalopathy
     d. Wernicke’s encephalopathy
     e. Herpes encephalitis
     f. Progressive multifocal leukoencephalopathy(PML)
     g. Meningeal carcinomatosis
     h. Central nervous system (CNS) toxoplasmosis
     i. Multiple sclerosis
     j. Hepatic encephalopathy
     k. Subacute combined systems disease
     l. Meningococcal meningitis
     m. Subacute sclerosing panencephalitis (SSPE)
     n. AIDS encephalopathy
     o. Pickwickian syndrome

Answer 25

O
(Bradley, p 1798.) Obesity associated with hypersomnia qualifies as Pickwickian syndrome if the patient exhibits other characteristic features, such as sleep apnea. The patient with this syndrome is likely to have hypoxemia and pulmonary hypertension. Smoking increases the risk of developing the syndrome. Sleep attacks usually abate with cessation of smoking and weight loss.

Question 26

216. A 19-year-old man develops obvious personality changes over the course of 2 weeks. He becomes agitated with little provocation and abuses his wife both verbally and physically. His behavior is sufficiently atypical for it to prompt his relatives to seek psychiatric assistance for him. While being interviewed by a psychiatrist, he becomes unresponsive and develops generalized convulsions with opisthotonic posturing, tonic-clonic limb movements, and urinary incontinence. He is hospitalized for investigation of his seizure disorder. On initial examination, he is noted to have a low-grade fever and a mild left hemiparesis. His CSF opening pressure is 210 mmH2O. His CSF cultures yield no growth, and his EEG reveals polyspike and-wave discharges originating in the right temporal lobe. A CT of his brain reveals focal swelling of the right temporal lobe. (SELECT 1 DIAGNOSIS)
     a. Postictal state
     b. Hypothyroidism
     c. Uremic encephalopathy
     d. Wernicke’s encephalopathy
     e. Herpes encephalitis
     f. Progressive multifocal leukoencephalopathy(PML)
     g. Meningeal carcinomatosis
     h. Central nervous system (CNS) toxoplasmosis
     i. Multiple sclerosis
     j. Hepatic encephalopathy
     k. Subacute combined systems disease
     l. Meningococcal meningitis
     m. Subacute sclerosing panencephalitis (SSPE)
     n. AIDS encephalopathy
     o. Pickwickian syndrome

Answer 26

E
(Rowland, pp 146–148.) With herpes encephalitis in the person who is not immunodeficient, the first clinical signs of disease are likely to be psychiatric. Depression, irritability, and labile affect are especially common. The organic basis for the encephalopathy usually becomes self-evident when the affected person has a seizure. Because the temporal lobe is especially involved by herpes encephalitis, the initial seizure is likely to be complex partial, but seizures often become more generalized. EEG will usually reveal the focal character of the cerebral damage. Intracranial pressure is usually increased with a fulminant infection. Temporal lobe swelling may be severe enough to produce lethal herniation.

Question 27

217. A previously healthy 25-year-old woman develops acute loss of vision in her left eye. She awakens with pain in the eye and reduction of her acuity to perception of light and dark. She delays seeing a physician for 1 week, during which time her acuity gradually improves sufficiently to allow her to read. On examination, the physician discovers she has slurred speech and poor rapid alternating movements with the left hand. Ocular dysmetria is evident in both eyes. Her tandem gait is grossly impaired. The physician obtains an EEG, which is normal. (SELECT 1 DIAGNOSIS)
     a. Postictal state
     b. Hypothyroidism
     c. Uremic encephalopathy
     d. Wernicke’s encephalopathy
     e. Herpes encephalitis
     f. Progressive multifocal leukoencephalopathy(PML)
     g. Meningeal carcinomatosis
     h. Central nervous system (CNS) toxoplasmosis
     i. Multiple sclerosis
     j. Hepatic encephalopathy
     k. Subacute combined systems disease
     l. Meningococcal meningitis
     m. Subacute sclerosing panencephalitis (SSPE)
     n. AIDS encephalopathy
     o. Pickwickian syndrome

Answer 27

I
(Rowland, pp 778–781.) Optic neuritis is often the first complaint that motivates the patient with multiple sclerosis to consult a physician. Clumsiness, stumbling, and other symptoms of ataxia are usually dismissed as inconsequential by the patient. Even those with profoundly slow and slurred speech are often unaware of their dysarthria. When the patient finally does consult a physician, multiple neurologic abnormalities are usually evident. This patient would be expected to have a positive swinging flashlight test (Marcus Gunn pupil) and evidence of widespread demyelination on MRI of the head.

Question 28

218. A 17-year-old man complains of headache and photophobia on awakening. His physician discovers a low-grade fever and resistance to neck flexion. The physician advises the patient to take acetaminophen and remain in bed for the next 24 h. Within 12 h, the patient develops nausea and more intense headache. He seems disoriented and inappropriately lethargic. His family brings him to an emergency room. The emergency room physician notes a petechial rash on the legs and marked neck stiffness. CSF examination reveals a glucose content of 5 mg/dL, protein content of 87 mg/dL, and cell count of 112 leukocytes, with 70% polymorphonuclear cells. (SELECT 1 DIAGNOSIS)
     a. Postictal state
     b. Hypothyroidism
     c. Uremic encephalopathy
     d. Wernicke’s encephalopathy
     e. Herpes encephalitis
     f. Progressive multifocal leukoencephalopathy(PML)
     g. Meningeal carcinomatosis
     h. Central nervous system (CNS) toxoplasmosis
     i. Multiple sclerosis
     j. Hepatic encephalopathy
     k. Subacute combined systems disease
     l. Meningococcal meningitis
     m. Subacute sclerosing panencephalitis (SSPE)
     n. AIDS encephalopathy
     o. Pickwickian syndrome

Answer 28

L
(Victor, pp 737, 739.) With acute bacterial meningitis, the time between the first symptoms and death may be only days. A petechial rash developing over the lower parts of the body in the setting of fever, headache, nuchal rigidity, photophobia, and stupor must be considered presumptive evidence of a meningococcal meningitis. Rapid diagnosis and treatment is essential if the patient is to survive. The spinal fluid typically reveals a low glucose content, high protein content, and leukocytosis with a large number of polymorphonuclear cells. Treatment with intravenous penicillin G, 12 million to 15 million U daily (divided into four to six doses) early in the course of illness may decide whether the patient survives more than a few hours or days.

Question 29

219. A 56-year-old man is struck over the parietal area of the head during a robbery. He loses consciousness for 35 min but has no focal weakness or numbness on recovering consciousness. Within 2 days of the incident, his wife finds him unresponsive in bed early in the morning. She calls for an ambulance, but before it arrives her husband becomes more alert and asks for something to eat, saying he wants to have some supper before he goes to bed for the night. The ambulance attendant first on the scene notes that the patient is disoriented to place and time and has weakness of his right arm and leg. (SELECT 1 DIAGNOSIS)
     a. Postictal state
     b. Hypothyroidism
     c. Uremic encephalopathy
     d. Wernicke’s encephalopathy
     e. Herpes encephalitis
     f. Progressive multifocal leukoencephalopathy(PML)
     g. Meningeal carcinomatosis
     h. Central nervous system (CNS) toxoplasmosis
     i. Multiple sclerosis
     j. Hepatic encephalopathy
     k. Subacute combined systems disease
     l. Meningococcal meningitis
     m. Subacute sclerosing panencephalitis (SSPE)
     n. AIDS encephalopathy
     o. Pickwickian syndrome

Answer 29

A
(Bradley, pp 356, 1076.) After significant head trauma, the victim is at considerable risk for a seizure. A patient’s seizure threshold is lowest when he or she is asleep or sleep-deprived. If the post-traumatic seizure occurs during sleep, it may go unnoticed. The patient’s improving cognition suggests a postictal state. His hemiparesis is probably a Todd’s paralysis, but any patient with posttraumatic seizures and focal weakness must be investigated for an acute or chronic subdural hematoma.

Question 30

220. A 35-year-old woman is found unconscious on the floor of her apartment. A bottle of cleaning fluid is found on a table near her. One of the contents indicated in the fluid is carbon tetrachloride. The ambulance crew notes that the patient is breathing independently, but her breath has a distinctly fetid odor unlike that associated with the cleaning fluid. Her limbs are flaccid, and she groans when she is moved. She responds to no inquiries and is poorly responsive to pain. A serum ammonia level obtained at the emergency room is 250 mg/dL, triple the normal level. EEG reveals triphasic waves, most prominently over the front of the head. (SELECT 1 DIAGNOSIS)
     a. Postictal state
     b. Hypothyroidism
     c. Uremic encephalopathy
     d. Wernicke’s encephalopathy
     e. Herpes encephalitis
     f. Progressive multifocal leukoencephalopathy(PML)
     g. Meningeal carcinomatosis
     h. Central nervous system (CNS) toxoplasmosis
     i. Multiple sclerosis
     j. Hepatic encephalopathy
     k. Subacute combined systems disease
     l. Meningococcal meningitis
     m. Subacute sclerosing panencephalitis (SSPE)
     n. AIDS encephalopathy
     o. Pickwickian syndrome

Answer 30

J
(Victor, pp 1184–1188.) Carbon tetrachloride is a potent hepatic toxin. This woman may have attempted to commit suicide by drinking cleaning fluid. As hepatic damage progressed, she developed fetor hepaticus, a distinctive smell to her breath that reflects a profound metabolic disturbance. The serum ammonia level rose as liver function declined. The triphasic waves typically seen in hepatic encephalopathy may occur with uremia and other causes of metabolic encephalopathy.