Hematologic and Neoplastic Diseases
A 2-year-old child is seen in the emergency center with the complaint of bruising. His parents report that for the previous 2 days he has developed bruising on his legs, back, and arms. He has been in good health his entire life with occasional upper respiratory infections, the last about 2 weeks ago, and one episode of otitis media at age 8 months. He lives with his parents and 4-year-old sibling. On physical examination the temperature is 37°C (98.6°F), heart rate is 100 beats per minute, respiratory rate is 20 breaths per minute, and blood pressure is 100/70 mm Hg. He is awake, alert, and in no distress. Neck is supple. The mucous membranes are pink, moist, and without lesions; a tiny bit of blood oozing from the gums is noted. Pupils are equally round and reactive. The chest is clear. Heart has a normal S1 and S2 without murmur. The abdomen is soft and nontender without hepatosplenomegaly. No adenopathy is noted. Neurologic examination is nonfocal. Numerous fresh-appearing bruises are noted over the shins and scattered over the arms and back; generalized petechiae is found. Laboratory data show:
Which of the following therapies is most appropriate?
a. Desmopressin 0.3 µg/kg IV
b. Vincristine weekly for 4 weeks
The answer is c. (Hay et al, pp 859-861. Kliegman et al, pp 2390-2392, 2402-2404, 2437-2445. Rudolph et al, pp 1582-1583.) In children, ITP is the most common form of thrombocytopenic purpura. In most cases, a preceding viral infection can be noted. Autoantibodies to platelet membrane antigens cause increased platelet destruction by macrophages, particularly those in the spleen. No diagnostic test identifies this disease; exclusion of the other diseases listed in the question is necessary. In this condition, the platelet count is frequently less than 20,000/µL, but other laboratory tests yield essentially normal results, including the bone marrow aspiration (if done). Complications are uncommon; significant bleeding occurs in only 5% of cases and intracranial hemorrhage is even rarer. The treatment of childhood ITP is controversial. Patients with mild symptoms such as bruising and self-limited epistaxis may be observed, while patients with significant bleeding should be treated. IVIG and corticosteroids are effective in causing a rapid increase in platelet count, but controversy exists surrounding the use of prednisone before ruling out leukemia with a bone marrow aspirate. For Rh-positive patients with a working spleen, the use of anti-D immunoglobulin also results in an increase in platelet count. Platelet transfusion usually is not indicated, as antiplatelet autoantibodies will target the transfused platelets as ...