A 20-year-old man from northern Europe comes to the emergency department with a 2-month history of intermittent right upper quadrant pain. The patient's medical history is unremarkable, and he considers himself healthy. His mother had her gallbladder removed at a young age. Abdominal ultrasound reveals cholelithiasis. Laboratory results show a hemoglobin level of 10.2 g/dL. Peripheral blood smear is shown in the image below. This patient most likely has which of the following additional laboratory findings?

Question

A 20-year-old man from northern Europe comes to the emergency department with a 2-month history of intermittent right upper quadrant pain.  The patient's medical history is unremarkable, and he considers himself healthy.  His mother had her gallbladder removed at a young age.  Abdominal ultrasound reveals cholelithiasis.  Laboratory results show a hemoglobin level of 10.2 g/dL.  Peripheral blood smear is shown in the image below.  This patient most likely has which of the following additional laboratory findings?

Quizplus · Accepted Answer

11ec25c8_d41c_15f5_bc81_e53b879b71b4_MD0003_00 This patient is anemic and has spherocytes (small, round, hyperchromic red blood cells [RBCs] without central pallor) on peripheral smear, which are indicative of hereditary spherocytosis (HS). HS is usually an autosomal dominant disorder and is most common in northern Europeans. A defect in RBC membrane proteins (eg, spectrin, ankyrin) results in spherocytes that are less deformable than normal biconcave RBCs and are more prone to splenic sequestration. peripheral smear Depending on the extent of hemolysis, patients can have the classic triad of hemolytic anemia, jaundice, and splenomegaly (generally seen with severe hemolysis). Pigment gallstones can develop from excess bilirubin and cause right upper quadrant pain, as seen in this patient. Laboratory studies usually show elevated mean corpuscular hemoglobin concentration due to membrane loss and RBC dehydration. Other findings include reticulocytosis, normal to elevated red cell distribution width due to various RBC forms (eg, reticulocytes, spherocytes, normal RBCs), and low to normal mean corpuscular volume (Choice D). Diagnosis is clinical but can be confirmed with specific tests (eg, acidified glycerol lysis test, eosin-5-maleimide binding test). Treatment is generally supportive (eg, folic acid, transfusions for severe anemia); in severe cases, splenectomy may be considered to improve anemia and reduce gallstone risk. (Choice A) The CD55 molecule helps protect cells from complement-mediated destruction, and its absence leads to the hemolytic anemia seen in paroxysmal nocturnal hemoglobinuria. This condition typically presents with red urine and normal RBC morphology on blood smear. (Choice B) Hemoglobin A2 levels are increased in patients with beta thalassemia trait. Hemoglobin F levels are increased in patients with sickle cell anemia, beta thalassemia, congenital aplastic anemia, and hereditary persistence of fetal hemoglobin. These conditions do not cause spherocytes on peripheral smear. (Choice E) Iron deficiency anemia presents with low serum iron, low serum ferritin, and peripheral smear showing microcytic and hypochromic RBCs. microcytic and hypochromic RBCs Educational objective: Hereditary spherocytosis is usually an autosomal dominant disorder characterized by hemolytic anemia, jaundice, splenomegaly, and spherocytes on peripheral blood smear. Mean corpuscular hemoglobin concentration is elevated due to red blood cell dehydration and membrane loss. Pigment gallstones are a common complication. References: Guidelines for the diagnosis and management of hereditary spherocytosis-2011 update. (http://www.ncbi.nlm.nih.gov/pubmed/22055020)

A 20-Year-Old Man from Northern Europe Comes to the Emergency