Internal-Medicine

198 9: Muscles and Joints
76. (D) Deficient or defective 1,25(OH)2 vitamin D
receptors will result in vitamin D resistance.
Parathyroid hormone levels increase secondary
to decreased vitamin D effect. The 1(OH) vitamin
D is an intermediate metabolite. (Kasper, p. 2247)
77. (C) Aging decreases the responsiveness of the
renal 25(OH) D-1-hydroxylase to parathyroid
hormone (PTH), thus decreasing circulatory
levels of the active metabolite 1,25(OH)2 vitamin
D. This results in decreased calcium
absorption from the gut. There is not a close
relationship of 1(OH) vitamin D levels and
osteopenia. (Kasper, pp. 2246–2247)
78. (B) Muscle weakness is common in both rickets
and osteomalacia, and proximal leg muscles are
particularly involved. The combination of leg
deformity and muscle weakness in rickets can
result in an inability to walk. The presentation
of osteomalacia is more insidious in the elderly,
but proximal myopathy may be severe enough
to cause a waddling gait and mimic a primary
muscle disorder. The other clinical findings
listed are found only in rickets. (Kasper, p. 2247)
79. (D) The term pseudogout refers to crystal deposition
disease not due to uric acid (gout). By far
the most common cause of pseudogout is calcium
pyrophosphate deposition (CPPD). The
major predisposing factors are advanced age
and preexisting joint disease. The knee is the
most common joint involved, and presentation
can mimic acute gout. However, in the majority
of cases, the deposition of calcium pyrophosphate
seems to be asymptomatic. (Kasper, p. 2047)
80. (E) Unfortunately, there is no medical means to
remove the deposits of CPPD. Colchicine does
seem to decrease the rate of recurrence.
NSAIDs, steroids (systemic or intra-articular),
and colchicine are all helpful in acute attacks.
(Kasper, pp. 2048–2049)
81. (C) Although gout and CPPD disease are found
in chronic renal failure, hydroxyapatite deposition
is characteristic of end-stage renal failure.
The crystals are very small, nonbirefringent, and
only seen on election microscopy. Treatment is
symptomatic, and similar to the treatment of
gout or CPPD disease. (Kasper, p. 2049)
82. (E) “Milwaukee shoulder” represents an
unusual manifestation of calcium hydroxyapatite
deposition disease. Once destruction
changes start occurring, medical management
is relatively unsuccessful. The exact reason why
destructive arthritis occurs is not understood.
The knee is the other joint affected in this
manner. (Kasper, p. 2048)
83. (C) The high white cell count suggests infection.
In RA and crystal-induced arthritis, the
white cell count is usually less than 50,000/µL.
Staphylococcus aureus infection is the most
common type in RA. (Kasper, p. 2050)
84. (B) Churg-Strauss is a granulomatous vasculitis.
Pulmonary involvement often dominates
the clinical presentation with severe asthma
attacks and pulmonary infiltrates. Peripheral
eosinophilia is present in virtually all cases.
(Kasper, p. 2007)
85. (A) PAN is a multisystem, necrotizing vasculitis
of small- and medium-sized muscular arteries.
Aneurysmal dilations of the arteries are
characteristic. Nonspecific signs and symptoms
are the usual method of presentation. Renal
involvement is clinically present in 60% of cases
and is the most common cause of death in
untreated cases. (Kasper, pp. 2007–2008)
86. (F) A high percentage of patients with
Wegener’s develop ANCAs. In particular, cytoplasmic
or c-ANCAs are both sensitive and
specific for Wegener’s. However, tissue diagnosis
is still required. (Kasper, pp. 2004–2006)
87. (C) Henoch-Schönlein purpura, characterized
by palpable purpura, arthralgias, GI symptoms,
and glomerulonephritis, can be seen in
any age-group but is most common in children.
It can resolve and recur several times over a
period of weeks or months and can resolve
spontaneously. (Kasper, p. 2010)
88. (I) Behçet’s syndrome is a leukocytoclastic
venulitis characterized by episodes of oral
ulcers, genital ulcers, iritis, and cutaneous
lesions. Eye involvement can rapidly progress
to blindness. (Kasper, pp. 2012, 2014)