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 44-year-old male immigrant presents to his primary care physician for a new patient visit. The patient reports chronic fatigue but states that he otherwise feels well. His past medical history is not known, and he is not currently taking any medications. The patient admits to drinking 7 alcoholic beverages per day and smoking 1 pack of cigarettes per day. His temperature is 99.4°F (37.4°C), blood pressure is 157/98 mmHg, pulse is 99/min, respirations are 18/min, and oxygen saturation is 100% on room air. Physical exam demonstrates mild pallor but is otherwise not remarkable. Laboratory studies are ordered as seen below. Hemoglobin: 9 g/dL Hematocrit: 33% Leukocyte count: 6,500/mm^3 with normal differential Platelet count: 190,000/mm^3 Mean corpuscular volume (MCV): 60 femtoliters Free iron: 272 mcg/dL Total iron binding capacity (TIBC): 175 mcg/dL Ferritin: 526 ng/mL Reticulocyte count: 2.8% Which of the following is the most likely diagnosis?
AFolate deficiency
BBeta-thalassemia
CIron deficiency
DB12 deficiency
EHemolytic anemia
A 13-month-old girl is brought to the pediatric clinic by her mother due to progressive abdominal distension, poor feeding, and failure to thrive. The perinatal history was uneventful. The family emigrated from Sudan 8 years ago. The vital signs include: temperature 36.8°C (98.2°F), blood pressure 100/55 mm Hg, and pulse 99/min. The physical examination shows conjunctival pallor, hepatosplenomegaly, and parietal and frontal bossing of the skull. The laboratory test results are as follows: Hemoglobin 8.7 g/dL Mean corpuscular volume 62 μm3 Red cell distribution width 12.2% (normal value is 11.5–14.5%) Reticulocyte count 2.1 % Leucocyte count 10,200/mm3 Platelet count 392,000/mm3 The peripheral blood smear shows microcytic red cells, target cells, and many nucleated red cells. Which of the following is the most likely diagnosis?
ASickle cell disease
BBeta-thalassemia major
CCongenital dyserythropoietic anaemia
DAlpha-thalassemia major
EGlucose-6-phosphate dehydrogenase deficiency
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