Nutritional and Metabolic Disorders

Question 1

1. 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. Hexosaminidase A
a. Hexosaminidase A
a. Hexosaminidase A

Question 2

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

Answer 2

a. Glucosylceramide

Question 3

3. 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 B
   12
   deficiency

Answer 3

b. Impaired hepatic detoxification of portal blood

Question 4

4. 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. Astrocytes

Question 5

5. 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. Elevated to less than 100 mg /dL

Question 6

Items 6–8
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.

6. 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. Peripheral neuropathy

Question 7

7. 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

e. Rifampin

Question 8

8. 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

b. Clonazepam

Question 9

9–12
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.

9. 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. An intrinsic factor

Question 10

10. With vitamin B 12
deficiency, which of the following accumulates in
the blood?
a. Cysteine
b. Methylmalonic acid
c. Methionine
d. Succinic acid
e. Propionic acid
12

Answer 10

e. Propionic acid

Question 11

11. The patient with impaired vitamin B
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. Spinal cord posterior columns

Question 12

202. The type of visual field cut most often seen with vitamin B 12 
deficiency
is a
a. Centrocecal scotoma
b. Homonymous hemianopsia
c. Bitemporal hemianopsia
d. Binasal hemianopsia
e. Hemianopsia with central sparing

Answer 12

a. Centrocecal scotoma

Question 13

202. The type of visual field cut most often seen with vitamin B 12 
deficiency
is a
a. Centrocecal scotoma
b. Homonymous hemianopsia
c. Bitemporal hemianopsia
d. Binasal hemianopsia
e. Hemianopsia with central sparing

Answer 13

a. Centrocecal scotoma

Question 14

1. 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 14

a. Hexosaminidase A
a. Hexosaminidase A
a. Hexosaminidase A

Question 15

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

Answer 15

e. Folate

Question 16

14–16
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 generalized
tonic-clonic seizure. Magnetic resonance
imaging (MRI) and computed tomography
(CT) studies of the brain are normal, and her CSF is unremarkable.

14. 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 16

e. Thiamine

Question 17

15. 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 17

b. Benzodiazepine withdrawal

Question 18

16. 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 18

c. Provide intramuscular or oral chlordiazepoxide several times daily at a dose
dictated by the patient’s level of agitation

Question 19

Items 17–23
For each clinical scenario, select the nutritional deficiency that is most
likely responsible.
a. Deficiency amblyopia
b. Vitamin B6 deficiency
c. Pyridoxine (vitamin B12) 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

17. 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.

Answer 19

c. Pyridoxine (vitamin B12) deficiency

Question 20

18. 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.

Answer 20

f. Thiamine (vitamin B1) deficiency

Question 21

19. 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 20year
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.

Answer 21

g. Nicotinic acid deficiency

Question 22

20. 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.

Answer 22

a. Deficiency amblyopia

Question 23

21. 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 paraparesis
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.

Answer 23

b. Vitamin B6 deficiency

Question 24

22. 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.

Answer 24

d. α tocopherol (vitamin E) deficiency

Question 25

23. 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.

Answer 25

h. Kwashiorkor

Question 26

Items 24–30
For each clinical scenario, select the most likely 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

24. 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.

Answer 26

n. AIDS encephalopathy

Question 27

25. 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.

Answer 27

o. Pickwickian syndrome

Question 28

6. 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
lowgrade
fever
and
a
mild
left
hemiparesis.
His
CSF
opening
pressure
is
210
mmH
O. His CSF cultures yield no growth, and his EEG reveals polyspikeand-wave
discharges

originating in the right temporal lobe. A CT of his
brain reveals focal swelling of the right temporal lobe.

Answer 28

e. Herpes encephalitis

Question 29

27. 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.

Answer 29

i. Multiple sclerosis

Question 30

8. 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.

Answer 30

l. Meningococcal meningitis

Question 31

9. 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.

Answer 31

a. Postictal state

Question 32

0. 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.

Answer 32

j. Hepatic encephalopathy