You are asked to evaluate a 65-year-old man who was 

admitted with unstable angina 10 days ago. The 

patient has a long history of cardiac disease and under- 

went bypass surgery 5 years before this admission. He 

does not remember having being transfused in the past. 

He was transfused on his second hospital day for a 

hematocrit of 32%. His medications include atenolol, 

aspirin, nitroglycerin, glyburide, heparin, and paroxe- 

tine. The patient's labs are as follows: 

Hospital                                             Day 6                   Day 8 

Hematocrit                                         37%                     35% 

White blood cell count                         8600/mL               15,000/mL 

Platelets                                             289,000/mL          3000/mL 

Prothrombin time                                11 sec                   11 sec 

Activated partial                                  55 sec                   65 sec 

thromboplastin time 

Peripheral blood smear                        Confirms thrombocytopenia 



What would you do next? 

A 17-year-old African-American man presents with 

symptoms of weakness, mild lower abdominal pain, 

and a change in the color of his urine. He noticed these 

symptoms abruptly this morning. Of note, he has been 

having some burning with urination for approximately 

1 week. He went to an urgent care center 2 days ago, 

where he was prescribed trimethoprim/sulfamethoxa- 

zole for suspected prostatitis. He has no known past 

medical history. He states that sickle cell runs in his 

family. He reports that he works at a fast-food restau- 

rant and eats two meals a day there (usually ham- 

burgers). His physical examination reveals a pulse of 

104/min, scleral icterus, some mild low abdominal 

pain without rebound or guarding, and prostatic 

tenderness. Laboratory values are as follows: WBC 

of l0,000/uL; Hgb of 9 g/dL; Hct of 28%; MCV of 

90 fl; platelets of 200,000/L; reticulocyte count of 12%; 

LDH of 500 U/dL; and total bilirubin of 5.0 mg/dL. 

Other labs include a direct bilirubin of 0.4 mg/dL; 

serum haptoglobin of 5 mg/dL (50 to 220 mg/dL); 

BUN of 18 mg/dL; creatinine of 1.0 mg/dL; direct 

antiglobulin negative; Hgb electrophoresis of Hgb 

A 59%, Hgb S 40%, Hgb F 1%; and G6PD screen 

negative. Peripheral smear reveals rare spherocytes, 

occasional fragments, and many "bite" cells. Heinz 

bodies are also seen. What is the condition most likely 

responsible for this patient's hemolytic process? 

A 30-year-old woman is admitted for sudden onset of 

right arm and leg weakness. An MRI reveals evidence of 

an acute cerebral infarct. She has a past medical his- 

tory of several previous miscarriages. Which of the fol- 

lowing is true regarding her disease?