Internal-Medicine

72 3: Endocrinology
polygenic in its inheritance. The disorder is
common, and heterozygous familial hypercholesterolemia
is felt to affect 1 in 500 individuals.
It can be secondary to other diseases such
as hypothyroidism, nephrotic syndrome, or
even porphyria. Xanthelasmas after the age of
50 are often not related to any dyslipidemia at
all. (Felig, p. 1016)
37. (A) In the rare familial form, raised yellow
plaques appear on palms and fingers, and
reddish-yellow xanthomas occur on the elbows.
This disorder is felt to be secondary to accumulation
of abnormal chylomicron and very
low-density lipoprotein (VLDL) remnants. It is
probably due to inherited homozygous defects
in Apo E-II structure. (Felig, pp. 1024–1025)
38. (E) Triglycerides are over 150 and are raised
by alcohol intake, estrogens, stress, insulin, and
physical activity. Cholesterol levels are average
or mildly elevated. HDL is usually low.
Dietary therapy and the maintenance of ideal
weight is the cornerstone of therapy. (Felig, pp.
1029–1030)
39. (B) Hypertriglyceridemia is usually secondary
to DM or drugs, rather than a genetic disorder.
It can be a normal response to caloric
excess or alcohol ingestion and is common in
the third trimester of pregnancy. (Felig, p. 1027)
40. (C) In DM, there is an obligatory osmotic diuresis,
but in DI there is lack of water resorption in
the tubules. Both result in polyuria, but in DM,
there will be substantial glucosuria as well. The
large amount of urine output (usually >50 mL/
kg/day) is characteristic of polyuric states, such
as DI, not a bladder problem. Psychogenic
polydipsia is commonly seen in patients with
psychiatric problems on medications. (Kasper,
pp. 2098–2099)
41. (D) In Western societies, most dyslipidemias
are secondary. The most common predisposing
cause is diet, and the second common is DM.
Hypothyroidism, renal disease, alcoholism,
and anorexia nervosa are also associated with
secondary dyslipidemias. Many drugs (e.g.,
estrogen, glucocorticoids) can also cause secondary
dyslipidemias. (Felig, pp. 1009–1015)
42. (D) The most important factors in diet-induced
cholesterol elevation are the amount of total
fat and saturated fat consumed. Cholesterol
intake is next in importance. Obesity and
caloric excess usually result in high triglyceride
levels. (Felig, p. 1010)
43. (D) The elevated ALP and hydroxyproline are
diagnostic for Paget’s disease. The bony lesions
are blastic and the sacrum and pelvis are most
frequently involved, followed closely by the
tibia and femur. Hypercalcemia can complicate
immobilization. The etiology is unknown, but
a viral agent has been postulated. Symptoms
may be absent or severe (pain, deformity). In
metastatic cancers of most types the lesion are
lytic, and the other metabolic abnormalities do
not have an elevation in hydroxyproline.
(Kasper, pp. 2279–2281)
44. (A) Many affected persons with vitamin D deficiency
have no demonstrable abnormality
except for hypocalcemia, hypophosphatemia,
and increased PTH levels. Decreased calcium
absorption, which is vitamin D dependent,
results in mild hypocalcemia that leads to the
secondary hyperparathyroidism. This in turn
results in increased renal phosphate excretion
and hypophosphatemia. (Kasper, p. 2248)
45. (B) Atrial fibrillation and cardiomegaly are
common cardiac manifestations, but are more
common in the elderly. Other symptoms include
palpitations, tachycardia, nervousness, sweating,
and dyspnea. Sinus tachycardia is the most
common cardiac manifestation in a young individual
with hyperthyroidism. (Kasper, p. 2113)
46. (B) Needle biopsy can be used in numerous diseases,
but the main rationale is to differentiate
benign from malignant nodules. A thyroid scan
is appropriate if the TSH is suppressed suggesting
a possible “hot” nodule (hyperfunctioning
nodules are very rarely malignant). The specimen
must be read by an experienced cytologist.
It is difficult to diagnose differentiated follicular
carcinoma or to differentiate lymphoma from