106 Hematology
43. What should you do if you suspect a transfusion reaction?
The first step is to stop the transfusion. If oliguria is present, treat with intravenous fluids
and diuresis (mannitol or furosemide).
44. What are the other risks of transfusion?
There is a small but real risk of infection (usually viral infections such as hepatitis B and C,
human immunodeficiency virus, and cytomegalovirus) and hyperkalemia (from hemolysis). With
large transfusions (> 5 units of packed red blood cells), bleeding diathesis may result from dilu-
tional thrombocytopenia and citrate (a blood preservative and calcium chelator that prevents clot-
ting). Look for oozing from puncture or IV sites.
45. What are the most common causes of disseminated intravascular coagulation (DIC)?
The most common cause is pregnancy and obstetric complications (roughly 50% of cases),
followed by malignancy (33%), sepsis, and trauma (especially head trauma, prostate surgery, and
snake bites).
46. How do I recognize and treat DIC in a classic at-risk patient?
DIC usually manifests with bleeding diathesis but may have thrombotic tendencies. Look for
the classic oozing or bleeding from puncture and IV sites; prolonged prothrombin time (PT), par-
tial thromboplastin time (PTT), and bleeding time (BT). DIC is the only disorder on the Step 2
exam that prolongs all three tests. Other clues include positive D-dimer, increased fibrin degra-
dation products, thrombocytopenia, decreased fibrin, and decreased clotting factors (including
factor 8, which is normal in hepatic necrosis).
Treat the underlying cause (e.g., evacuate the uterus, give antibiotics). You may need to give
transfusions with fresh frozen plasma or, in rare cases, heparin (only if thrombosis occurs).
47. With what conditions is eosinophilia associated?
• Allergy, eczema, and atopy
• Angioedema
• Drug reactions
• Parasitic infections
• Blood dyscrasias (especially lymphoma)
• Loffler's syndrome (pulmonary eosinophilia)
• Autoimmune diseases (e.g., lupus erythematosus, rheumatoid arthritis)
• IgA deficiency
• Adrenal insufficiency
48. With what conditions is basophilia associated?
Allergies or neoplasm/blood dyscrasia.
49. True or false: The lupus anticoagulant causes a clotting tendency.
True. Although the lupus anticoagulant may cause a prolonged partial thromboplastin time,
the patient has a tendency toward thrombosis. Look for associated lupus symptoms, positive
results on the Venereal Disease Research Laboratory or rapid plasma reagin tests for syphilis,
and/or a history of miscarriages to help you recognize this condition.
50. What genetic causes of an increased tendency toward clot-forming may appear on the
Step 2 exam?
The list keeps growing. Watch for factor V Leiden mutation (or activated protein C resist-
ance), prothrombin G20210A mutation, or deficiencies in protein C, protein S, or antithrombin
III (all autosomal dominant except protein C deficiency) as causes of an increased tendency
toward thrombosis. All are treated with anticoagulant therapy to prevent deep venous thrombo-
sis and pulmonary embolus. Suspect these conditions if a person under age 35 develops recurrent
clots or has no risk factors for clot development.
