Here are some Heme questions for your holiday weekend. Enjoy!
1. A 9-year-old female with mild type I von Willebrand’s disease presents with mild gingival bleeding after her first overly vigorous attempt to use dental floss. She stopped as soon as she noticed bleeding, which is limited to the space between her upper central incisors. She is somewhat anxious, but her vital signs are normal. The physical exam is normal except for gingival bleeding between the upper central incisors. Bleeding has continued despite applying pressure to the site for 30 minutes. What is the MOST appropriate action?
A. Subcutaneous DDAVP 0.03 ug/kg.
B. Intravenous DDAVP 0.03 ug/kg over 30 minutes.
C. Intranasal DDAVP 150 ug (one spray in one nostril).
2.A 50-year-old man with known cirrhosis and ascites presents with fever and abdominal pain, and is suspected of having acute spontaneous bacterial peritonitis. The patient is hemodynamically stable and not actively bleeding (negative nasogastric tube aspiration and no occult blood in rectal exam). Initial labs include a prolonged prothrombin time, increased INR, decreased platelets, and a minimally decreased fibrinogen level. Which of the following is indicated prior to performing a paracentesis
B. Fresh frozen plasma (FFP).
C. Platelet transfusion.
D. Desmopressin (DDAVP).
1. C. Patients with type I von Willebrand’s disease, the most common variant, have a quantitative platelet disorder, whereby vWF antigen and vWF activity are 50% below normal. DDAVP is the therapeutic agent used in type I patients, via subcutaneous, intravenous, or intranasal routes. The correct dosage of DDAVP for the subcutaneous or intravenous route is 0.3 ug/kg. If given intravenously, it should be diluted in 30–50 mL saline and infused over 10–20 minutes to decrease hypotension or tachycardia. The intranasal dose of DDAVP in a child older than 5 years would be 150 ug, the amount in a single spray in a single nostril. The adult intranasal dosage is 300 mg, one spray in each nostril. A repeat dose of DDAVP may be required in 8–12 hours, but the amount of released vWF will be less. Cryoprecipitate is also used to manage major bleeding in patients with type I von Willebrand’s disease, but DDAVP would be the first-choice therapy in the patient in this case. Other adjunctive therapies in this case might include dry topical thrombin, oral epsiloaminocaproic acid (an antifibrinolytic agent), and absorbable gelatin sponges.
2. B. FFP is indicated since this coagulopathic, nonbleeding patient requires a diagnostic paracentesis. If the patient were bleeding, cryoprecipate, desmopressin, and platelet and RBC transfusion also would be indicated. FFP provides each coagulation factor, at one factor unit/mL. There is a risk of volume overload since each bag of FFP is 200–250 mL, and repeated doses may be required. Cryoprecipitate provides fibrinogen. DDAVP decreases bleeding time.
Emergency Medicine: Examination & Board Review. 3rd ed.
Promes, Susan B. (2005)