A 23-year-old woman with known sickle cell disease comes to the emergency department with a 3-day history of malaise, lethargy, and severe exertional dyspnea. She has no cough, chest pain, vomiting, or blood in the stool. Two years ago, she was hospitalized with acute chest syndrome and required mechanical ventilation. Her last hospitalization was 7 months ago for a painful crisis, and she underwent an exchange transfusion at that time. Her current medications are hydroxyurea, folic acid, extended-release morphine, and oxycodone for breakthrough pain.
Her temperature is 100° F (37.8° C), blood pressure is 122/76 mm Hg, and pulse is 112/min and regular. Oxygen saturation is 96% on room air. Examination shows pale palms. Lungs are clear to auscultation. The abdomen is nontender.
Laboratory results are as follows:
Chest x-ray shows no infiltrates. Blood cultures show no growth.
Which of the following is the most likely cause of her symptoms?

Question

A 23-year-old woman with known sickle cell disease comes to the emergency department with a 3-day history of malaise, lethargy, and severe exertional dyspnea.  She has no cough, chest pain, vomiting, or blood in the stool.  Two years ago, she was hospitalized with acute chest syndrome and required mechanical ventilation.  Her last hospitalization was 7 months ago for a painful crisis, and she underwent an exchange transfusion at that time.  Her current medications are hydroxyurea, folic acid, extended-release morphine, and oxycodone for breakthrough pain.
Her temperature is 100° F (37.8° C), blood pressure is 122/76 mm Hg, and pulse is 112/min and regular.  Oxygen saturation is 96% on room air.  Examination shows pale palms.  Lungs are clear to auscultation.  The abdomen is nontender.
Laboratory results are as follows:
 Chest x-ray shows no infiltrates.  Blood cultures show no growth.
Which of the following is the most likely cause of her symptoms?

Quizplus · Accepted Answer

11ec193a_9619_22e7_853d_c5c3a6d837a4_MD0002_00 This patient's presentation of worsening anemia in sickle cell disease (SCD) is likely due to aplastic crisis. SCD can present with acute worsening anemia possibly due to splenic sequestration crisis, aplastic crisis, or hyperhemolytic crisis. Aplastic crisis is a transient bone marrow arrest leading to decreased erythropoiesis, markedly decreased hemoglobin, and little or no reticulocytosis. Patients typically present with profound anemia and pallor, weakness, lethargy, and dyspnea. Parvovirus B-19 is the most likely cause, but other pathogens include Streptococcus pneumoniae, Salmonella, and Epstein-Barr virus. Treatment is mainly supportive (eg, transfusions, rest, analgesics, hydration, and oxygenation). Recurrent aplastic crisis from parvovirus is rare due to immunity. Splenic sequestration is vasoocclusive crisis within the spleen and is seen particularly in young patients who do not yet have a fibrosed spleen. It is characterized by a fall in hemoglobin, persistent elevated reticulocytosis, and rapidly enlarging spleen. Hyperhemolytic crisis is a sudden worsening of anemia with reticulocytosis that can present after acute sickling events (eg, painful crisis, acute chest syndrome), drug exposure, or infections. Both hyperhemolytic crisis and splenic sequestration crisis present with reticulocytosis; aplastic crisis presents with little or no reticulocytosis, as seen in this patient (Choices B and D). (Choice A) Hydroxyurea is an antimetabolite that increases fetal hemoglobin production to decrease the frequency of SCD episodes. Hydroxyurea can cause myelosuppression, commonly resulting in leukopenia/neutropenia first. Severe anemia is rare. (Choice C) Iron deficiency occurs in up to 20% of SCD patients and is due to increased urinary iron loss. However, ferritin is typically <25 ng/mL. This patient's elevated ferritin makes this unlikely and is probably due to previous transfusions and chronic hemolysis. Educational objective: Aplastic crisis may cause acute worsening anemia in sickle cell disease patients and is usually due to a bone marrow infection causing decreased erythropoiesis. Parvovirus B-19 is the most common cause and treatment is supportive (eg, transfusions, rest, analgesics, hydration, and oxygenation). __________ References: Aplastic crisis caused by parvovirus B19 in an adult patient with sickle-cell disease. (http://www.ncbi.nlm.nih.gov/pubmed/11064584) Clinical presentations of parvovirus B19 infection. (http://www.ncbi.nlm.nih.gov/pubmed/17304869)

A 23-Year-Old Woman with Known Sickle Cell Disease Comes to the Emergency