A 5-year-old boy is brought to the emergency department due to an episode of bright-red urine an hour ago. The boy has no chronic medical conditions, but he had nasal congestion, sore throat, and vomiting last week. Temperature is 37.1 C (98.8 F), blood pressure is 108/66 mm Hg, pulse is 110/min, and respirations are 20/min. The patient is awake and alert. The oropharynx is unremarkable, and the neck is supple with no lymphadenopathy. Cardiopulmonary examination is normal, and the abdomen is soft and nontender. There is no hepatosplenomegaly. Skin examination shows diffuse flat, red pinpoint macules and raised ecchymoses along the lower extremities and trunk. Laboratory results are as follows: Which of the following is most appropriate in management of this patient?

Question

A 5-year-old boy is brought to the emergency department due to an episode of bright-red urine an hour ago.  The boy has no chronic medical conditions, but he had nasal congestion, sore throat, and vomiting last week.  Temperature is 37.1 C (98.8 F), blood pressure is 108/66 mm Hg, pulse is 110/min, and respirations are 20/min.  The patient is awake and alert.  The oropharynx is unremarkable, and the neck is supple with no lymphadenopathy.  Cardiopulmonary examination is normal, and the abdomen is soft and nontender.  There is no hepatosplenomegaly.  Skin examination shows diffuse flat, red pinpoint macules and raised ecchymoses along the lower extremities and trunk.  Laboratory results are as follows:  Which of the following is most appropriate in management of this patient?

Quizplus · Accepted Answer

Explanation: 11ec25c8_d697_4f53_bc81_0bcac95975f7_MD0003_00 This boy's hematuria, ecchymoses, and petechiae (flat pinpoint macules) are likely due to severe thrombocytopenia. Concurrent anemia and leukopenia indicate pancytopenia, which is typically caused by one of the following: Damage to multipotent hematopoietic stem cells in the bone marrow Bone marrow infiltration with atypical cells (eg, malignancy) or fibrosis Destruction of circulating blood cells (eg, thrombotic microangiopathy, hypersplenism) In this patient, the major clue is the minimal reticulocyte response despite significant anemia. Although this can be seen in advanced renal disease due to impaired production of erythropoietin, the normal creatinine makes significant renal impairment unlikely. Therefore, reticulocytopenia most likely reflects bone marrow failure due to hematologic stem cell damage (eg, aplastic anemia) or infiltrative disease (eg, leukemia). A peripheral blood smear and bone marrow evaluation would likely diagnose his condition: In aplastic anemia, peripheral smear shows a paucity of normal-appearing cells, and bone marrow evaluation reveals a profoundly hypocellular marrow with an abundance of fat. In contrast, blast cells on peripheral smear and bone marrow biopsy are indicative of leukemia. Aplastic anemia can be idiopathic or due to drugs or viral infections. In addition to manifestations of thrombocytopenia, patients can have recurrent infections (due to neutropenia) or manifestations of anemia (eg, fatigue). (Choice A) Abdominal ultrasound is used to diagnose hypersplenism, which causes low circulating blood cells due to splenic trapping; however, total body cell counts are normal, so symptoms of pancytopenia (eg, bleeding, ecchymoses) are rare. In addition, the lack of splenomegaly on examination makes this unlikely. (Choice C) Bleeding from idiopathic thrombocytopenic purpura (ITP), a condition in which autoantibodies form against platelet surface antigens, is typically treated with intravenous immunoglobulin. ITP can occur after a viral illness, but patients have isolated thrombocytopenia. (Choice D) Plasma exchange treats thrombotic thrombocytopenic purpura, which is characterized by thrombocytopenia due to the formation of intravascular thrombi and microangiopathic hemolytic anemia. However, because the bone marrow is intact, there would be a strong reticulocyte response to the anemia. (Choices E and F) Evaluation of hematuria with serum complement levels (eg, poststreptococcal glomerulonephritis) or kidney biopsy (eg, IgA nephropathy) may be indicated for suspected glomerular disease, particularly with a recent viral illness. However, other laboratory abnormalities (eg, proteinuria, urinary red cell casts, elevated creatinine) and/or examination findings (eg, hypertension, edema) would be expected. Moreover, glomerulonephritis would not explain this patient's pancytopenia. Educational objective: Pancytopenia with a low reticulocyte response indicates a bone marrow condition, and peripheral blood smear and bone marrow evaluation are diagnostic. In aplastic anemia, peripheral smear lacks normal-appearing cells and bone marrow is profoundly hypocellular with abundant fat cells. References: Acquired aplastic anemia in children. (http://www.ncbi.nlm.nih.gov/pubmed/24237973) Idiopathic aplastic anemia: diagnosis and classification. (http://www.ncbi.nlm.nih.gov/pubmed/24424170)

A 5-Year-Old Boy Is Brought to the Emergency Department Due