Internal-Medicine

Answers: 1–16 295
in their illness. Only a small proportion develops
progressive disease. (Kasper, pp. 2019–2022)
7. (C) PET scans use glucose analogues to demonstrate
metabolic activity. They are rarely available,
however, and functional MRI scans are
now being used extensively to assess areas of
brain activity. (Kasper, p. 2355)
8. (D) Streptococcus group A can cause a toxic
shock-like syndrome, and has been increasing
in frequency in North America. Streptococcal
toxic shock-like syndrome was so named
because of its similarity to staphylococcal toxic
shock syndrome. The illness includes fever,
hypotension, renal impairment, and the respiratory
distress syndrome. It is usually caused
by strains that produce exotoxin. It may be
associated with localized infection as well; the
most common associated infection is a soft
tissue infection such as necrotizing fasciitis.
The mortality is high (up to 30%), usually secondary
to shock and respiratory failure. The
rapid progression of the disease and its high
mortality demand early recognition and
aggressive treatment. Management includes
fluid resuscitation, pressor agents, mechanical
ventilation, antibodies, and, if necrotizing fasciitis
is present, surgical débridement. (Kasper,
pp. 827–828)
9. (D) Diazoxide acts immediately in malignant
hypertension and is the easiest to administer
for no individual titration of dosage is required.
Nitroprusside is more effective, but requires
an IV infusion. Labetalol is also useful but has
more contraindications. It is particularly useful
in the setting of angina or myocardial infarction.
Regardless of which drug is selected, early
administration of medications for long-term
control is mandatory. (Kasper, p. 1480)
10. (D) This man has primary hyperparathyroidism.
Hypercalcemia induces a tubular concentrating
defect by interfering with ADHmediated
water pore function (aquaporin-2
channel) on distal tubular cells. This results in
the polyuria and polydipsia symptoms of diabetes
insipidus. Chronic hypercalcemia can
also cause renal stones, type 1 (distal) RTA and
chronic renal failure but these effects are not
directly responsible for the polyuria. PTH has
no direct effect on the concentrating ability of
the distal tubule. (Kasper, pp. 1694–1701)
11. (E) Ethosuximide and valproic acid are common
medications used to treat petit mal epilepsy.
Side effects of ethosuximide include GI irritation,
skin rash, and bone marrow suppression.
(Kasper, p. 2367)
12. (B) Hairy cell leukemia is a B-cell malignancy.
Burkitt’s lymphoma is of T-cell origin 5% of
the time. CLL can be of T- or B-cell origin.
Mycosis fungoides and angioimmunoblastic
lymphadenopathy are of T-cell origin. (Kasper,
p. 642)
13. (C) The current case definition of AIDS in a
patient with HIV infection is done by symptoms
and CD4 + T-lymphocyte cell count. Any
category C symptoms (e.g., cervical cancer,
mycobacterium avium infection, CMV, retinitis,
Kaposi sarcoma, etc.) indicates frank AIDS as
does a CD4 + T-cell count