Internal-Medicine

Answers and Explanations
1. (D) The symptoms are typical of cryoglobulinemia.
Cryoglobulins are antibodies that precipitate
under cold conditions and are associated
with several diseases. There are three main
types of cryoglobulin syndromes based on the
immunoglobulin composition of the precipitating
antibody. Most cryoglobulinemic vasculitis
is Type II or mixed and seen secondary
to hepatitis C virus infection. Cold agglutinin
disease would present with hemolytic anemia.
The other syndromes would not generally be
temperature sensitive. (Lichtman, pp. 1857–1858)
2. (E) The syndrome is caused by cold-precipitable
proteins (cryoglobulins) that are found in
plasma or serum. These cryoproteins can be of
three classes. Type 1 are single component
(immunoglobulin G, M, or A [IgG, IgM, IgA]),
Type 2 are called “mixed cryoglobulins” (usually
IgG molecules complexed with IgM molecules
having anti-IgG reactivity), and Type 3
are polyclonal immunoglobulins with antiimmunoglobulin
activity. Cryoglobulinemia is
small vessel vasculitis (not medium), and
platelet aggregation is not an important mechanism
for the vessel injury. (Lichtman, pp. 1857–1858)
3. (D) Auer bodies are slender, pink, staining
rods containing lysozyme, and are exclusively
seen in AML. Although similar to normal
azurophilic granules in content and staining
properties, they are distinguished by their
gigantic size. Special stains can enhance the
detection of Auer bodies. They are only seen in
a minority of cases. The Philadelphia chromosome
is a feature of choric myelogenous
leukemia (CML), and a high leukocyte alkaline
phosphatase level is seen in patients with a
high WBC due to a leukemoid reaction. (Lichtman,
pp. 1186, 1192)
4. (B) This is a case of chronic myelogenous
leukemia. The reciprocal translocation involves
the long arms of 22 and 9, and results in translocation
of the ABL proto-oncogene from chromosome
9 adjacent to a portion of the BCR gene
on chromosome 22. The resultant abnormal
chromosome 22 is known as the Philadelphia
(Ph1) chromosome. (Lichtman, pp. 1244–1245)
5. (A) An increased amount of HbF or HbA2
would be expected. As beta-chains are decreased
in beta-thalassemia, the excess alpha-chains
combine with gamma- and delta-chains to make
HbF and HbA2, respectively. (Lichtman, p. 652)
6. (A) Graft-versus-host disease is a frequent complication
of hematopoietic cell transplantation. It
is caused by a reaction of immunologically competent
donor derived T cells that react with recipient
tissue antigens. It can be acute or chronic.
Numerous treatment regimens involving
methotrexate, glucocorticoids, cyclosporine, and
other drugs are used in treatment. (Lichtman,
pp. 309–312)
7. (B) In hemophilia A, there are decreased levels
of functioning factor VIII. This can be due to
reduced amounts of normal VIII, the presence
of a functionally abnormal protein, or a combination
of both. The activated partial thromboplastin
time (APTT) is prolonged, and the
prothrombin consumption test is abnormal.
The prothrombin time, thrombin clotting time,
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