Emergency Medicine Q & A, 2009, Pg

Emergency Medicine Q & A, 2009, Pg


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the most common pathogen is:
a. S. aureus.
b. S. pneumoniae.
c. E. coli.
d. Salmonella species.
e. Enterococcal species.
The answer is d. Up to two-thirds of cases of osteomyelitis in children with sickle cell disease involve Salmonella. It
is unclear why these patients are susceptible to Salmonella speci\ufb01cally. Patients with sickle cell disease are at higher
risk for infection with encapsulated organisms due to the impairment of macrophage function.
2. In alcoholic patients, thrombocytopenia is due to:
a. Toxic effects on megakaryocytes.
b. Liver sequestration.
c. Bone marrow infarcts.
d. Platelet lysis.
e. Unknown.
The answer is e. Apart from acquired immune de\ufb01ciency syndrome (AIDS), alcoholism is probably the leading
cause of thrombocytopenia. However patients generally do not exhibit manifestations of excessive bleeding.
Alcohol-related thrombocytopenia is usually transient, and platelet counts generally return to normal within 1 week
of abstinence. The exact mechanisms underlying alcohol-related thrombocytopenia remain unknown. Some
researchers have suggested that alcohol intoxication itself, rather than alcohol-related nutritional de\ufb01ciencies, causes
the decrease in platelet numbers. This view is supported by \ufb01ndings that thrombocytopenia developed in healthy
subjects who received a diet containing adequate protein and vitamin levels, including large doses of folic acid, and
consumed the equivalent of 1.5 pints (i.e., 745 mL) of 86-proof whiskey for at least 10 days.
115
116 Emergency Medicine Q & A: Pearls of Wisdom ...
3. A 19-year-old man was riding a motorcycle, which collided with a delivery truck. He complains of severe
abdominal pain and is tachycardiac. He tells you that he has a history of von Willebrand disease. The
product you should order to help control improve this patient\u2019s clotting ability is:
a. 4 units of whole blood.
b. A 6 pack of platelets.
c. Recombinant factor VIIa.
d. Packed red cells.
e. Factor VIII.
The answer is e. Patients with von Willebrand disease have normal platelet counts and morphology but have
diminished function due to lack of circulating von Willebrand factor. The ideal choice for this patient to help
improve platelet aggregation would be Factor VIII. The initial dose would be 20\u201330 IU/kg every 12 hours. Fresh
frozen plasma can be used as well in extreme conditions as desmopressin.
4. A 13-year-old girl complains of heavy vaginal bleeding during her menstrual period. She has a history of
menorrhagia. A urine pregnancy test is negative. A platelet count, PT, and PTT are normal. The laboratory
test that might reveal a bleeding diathesis is:
a. Thrombin time.
b. Factor VIII level.
c. Fibrinogen level.
d. Bleeding time.
e. Ristocetin platelet aggregation.
The answer is d. A bleeding disorder should be suspected in any patient with recurrent bleeding, as in this patient
with menorrhagia. Type I von Willebrand disease, the most common inherited bleeding disorder, is an autosomal
dominant trait in which an abnormality in a plasma glycoprotein (von Willebrand factor) results in abnormal
platelet adhesion and a prolonged bleeding time. The PT and PTT are usually normal.
5. A local ambulance company brings you a 25-year-old woman; her husband tells you \u201cshe\u2019s confused.\u201d
Temperature 38.9\u25e6C (102\u25e6F); blood pressure 130/100 mmHg. She has a diffuse petechial rash and
generalized edema. She is oriented only to self and is delirious. Laboratory studies show: BUN, 29 mg/dL;
creatinine, 2.7 mg/dL; platelet count, 27,000/mm3; and hematocrit, 30% with numerous schistocytes seen on
the peripheral smear. WBC count is normal with no left shift. Which of the following statements is TRUE?
a. The patient requires urgent heparinization.
b. A PT and PTT would probably be prolonged in this patient.
c. Antibiotic coverage is indicated.
d. Plasmaphoresis and treatment with fresh frozen plasma is needed.
e. Intravenous steroids are not recommended.
The answer is d. This patient has classic signs of thrombotic thrombocytopenic purpura (TTP) including anemia,
thrombocytopenia, fever, neurologic, and renal dysfunction. Patients may present in coma. The PT and PTT are
not prolonged in TTP. Heparinization is not routinely indicated for the initial treatment of TTP. Large doses of
intravenous steroids are used if the diagnosis is suspected. Plasmaphoresis and transfusion with fresh frozen plasma
may reverse the clinical and laboratory abnormalities.
... CHAPTER 8 Hematologic and Oncologic Emergencies 117
6. ABO matching of donor and recipient is unnecessary in the patient receiving:
a. Whole blood.
b. Platelets.
c. Packed red blood cells (PRBCs).
d. Fresh frozen plasma.
e. Leukocyte-poor red blood cells.
The answer is b. Spontaneous bleeding is unusual when platelet counts are more than 20,000/mm3. Platelet
counts less than 10,000/mm3 may cause spontaneous bleeding. HLA matching may be performed for platelets in
special circumstances. ABO matching is unnecessary.
7. A 20-year-old man with hemophilia A complains of a swollen right knee, which started after he played
basketball. He says that his factor VIII level is generally measured at 7%. His knee is swollen and tense.
Appropriate management for this patient is:
a. Immobilize his knee and insist on several days bed rest with aspirin therapy to reduce joint in\ufb02ammation.
b. Infuse with cryoprecipitate to raise factor VIII level to 30% and repeat infusions twice daily for 3 days.
c. Continuously infuse with fresh frozen plasma to raise factor VIII level to 50\u2013100%.
d. Infuse with standard factor VIII concentrate to raise his factor VIII level to 90%.
e. None of the above.
The answer is e. Factor VIII levels of less than 1% predispose patients with Hemophilia A to frequent, severe
bleeding episodes. Levels between 1% and 5% indicate moderate disease and levels above 5% indicate mild disease.
Heat-treated factor VIII concentrate, monoclonal antibody puri\ufb01ed factor VIII concentrate, and recombinant
factor VIII concentrate cannot transmit HIV or hepatitis viruses. A small hemarthrosis or bleeding episode can be
treated with a single infusion of factor VIII concentrate to achieve a plasma level of factor VIII of 15\u201320%. Each
unit will raise the plasma level of factor VIII by 2% per kg of body weight. Alternatively, DDAVP (desmopressin
acetate) will transiently increase levels of factor VIII. Factor VIII levels should be raised to 25\u201350% of normal for at
least 3 days. Moderate bleeding episodes require twice-daily infusions as the half-life of factor VIII is 12 hours.
Patients with severe trauma or intracranial bleeding should have factor VIII levels raised to 80\u2013100%.
Cryoprecipitate may also be given to raise levels of factor VIII. The risk of transmitting virus with this is low
because cryoprecipitate is not prepared from pooled plasma sources. Fresh frozen plasma has very low factor VIII
activity and requires much greater volume, which limits its use in hemophiliacs.
118 Emergency Medicine Q & A: Pearls of Wisdom ...
8. A 52-year-old man arrives by ambulance complaining of several weeks of progressive lethargy. He is
stuporous but arousable and complains of back pain and constipation. His vital signs are normal. Physical
examination is remarkable for sausage-shaped retinal vessels and decreased consciousness. Neurologic
examination reveals no focal \ufb01ndings. A chest x-ray shows a left pleural-based density with associated bony
destruction. An abdominal series is remarkable for osteopenia of the pelvis. The hematology laboratory
reports the machines keep clogging up. The hematocrit is 21%; RBCs are hypochromic and microcytic with
marked rouleaux formation; WBC is 14,000/mm3 with no left shift. Choose the correct statement:
a. The patient will probably have hypernatremia.
b. The diagnostic test of choice is a CT or MRI scan of the head.
c. Treatment includes \ufb02uid restriction.
d. Hypocalcemia