A 3-year-old boy is brought to the physician because of a 1-week history of yellowish discoloration of his eyes and skin. He has had generalized fatigue and mild shortness of breath for the past month. Three weeks ago, he was treated for a urinary tract infection with antibiotics. His father underwent a splenectomy during childhood. Examination shows pale conjunctivae and jaundice. The abdomen is soft and nontender; there is nontender splenomegaly. Laboratory studies show: Hemoglobin 9.1 g/dL Mean corpuscular volume 89 μm3 Mean corpuscular hemoglobin 32 pg/cell Mean corpuscular hemoglobin concentration 37.8% Hb/cell Leukocyte count 7800/mm3 Platelet count 245,000/mm3 Red cell distribution width 22.8% (N=13%–15%) Serum Bilirubin Total 13.8 mg/dL Direct 1.9 mg/dL Lactate dehydrogenase 450 U/L Which of the following is the most likely pathophysiology of these findings?
ADeficient glucose-6 phosphate dehydrogenase
BDecreased synthesis of alpha chains of hemoglobin
CIncreased hemoglobin S
DDecreased spectrin in the RBC membrane
EDeficiency of pyruvate kinase
A 2-year-old girl with a history of SS-hemoglobin is brought to her pediatrician by her mother, who noted an abdominal mass. On exam, the girl's spleen is palpably enlarged, and her palms and conjunctiva are noted to be extremely pale. Serum haptoglobin levels are decreased. Which of the following is the most likely cause of this patient's symptoms?
AIntravascular hemolysis
BExtravascular hemolysis
CHemolytic uremic syndrome
DComplement-mediated hemolysis
EDecreased red blood cell production
A 27-year-old African American man presents to a primary care physician for a routine checkup as a new patient. The patient states that he has been doing well lately and recently was promoted at his job. He states that 2 weeks ago he went to the ED for severe pain and was treated with morphine and oral fluids and discharged home that night. This had happened once before and he was treated similarly. The patient states that he drinks 7 to 8 alcoholic beverages per night and smokes 1 pack of cigarettes per day. The patient states that he has been gaining weight recently due to a diet consisting mostly of fast food. Basic labs are ordered as seen below. Hemoglobin: 8 g/dL Hematocrit: 28% Mean corpuscular volume: 72 um^3 Leukocyte count: 6,500/mm^3 with normal differential Platelet count: 157,000/mm^3 Serum: Na+: 139 mEq/L Cl-: 100 mEq/L K+: 4.3 mEq/L HCO3-: 25 mEq/L BUN: 20 mg/dL Glucose: 99 mg/dL Creatinine: 1.1 mg/dL LDH: 540 U/L Ca2+: 10.2 mg/dL AST: 12 U/L ALT: 10 U/L Which of the following is the best explanation of this patient's laboratory abnormalities?
AFolate deficiency
BExtravascular hemolysis
CChronic inflammation
DIneffective erythropoiesis
EVitamin B12 deficiency
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