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Sickle cell emergencies in children include vasoocclusive crises, hematologic crises, and infections. All children with sickle cell anemia (SCA) presenting with fever, pain, respiratory distress, or a change in neurologic function require a rapid and thorough ED evaluation.
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Vasoocclusive sickle episodes are due to intravascular sickling, which leads to tissue ischemia and infarction. Bones, soft tissue, viscera, and the central nervous system (CNS) may be affected. Pain may be the only symptom.
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Pain crises are the most common SCA-related presentation to the ED, and typically affect the long bones and back. They can be triggered by stress, extremes of cold, dehydration, hypoxia, or infection, but most often occur without a specific cause. In an individual patient, recurrent pain crises tend to be similar in location and quality to previous episodes. Although, typically, there are no physical findings, pain, local tenderness, swelling, and warmth may occur. Low-grade temperature elevations can occur, but true fever is rare. Infants and toddlers can present initially with dactylitis, a swelling of hands or feet, and low-grade temperature caused by ischemia and infarction of the bone marrow.
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Diagnosis and Differential
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Differentiating between infection and vasoocclusive crisis can be difficult, particularly since infection can precipitate a pain crisis. Fever, limited range of motion of a joint, and pain that differs in location or quality from previous crises should raise concern for an infection. Pain crises can be associated with leukocytosis; however, a left shift is suspicious for infection. Sedimentation rates are unreliable markers for infections in SCA patients due to anemia. All pain crises represent ischemia, but bony infarcts present with severe, difficult to control pain, significant tenderness, and leukocytosis. Patients with bony infarcts are at risk of fat embolism.
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Pain localized to the hip or inguinal area worsening with weight-bearing may be due to avascular necrosis of the femoral head, which may demonstrate flattening and collapse of the femoral head on plain radiograph.
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Abdominal pain resulting from vasoocclusive crises is common and is typically abrupt in onset, and poorly localized. Tenderness and guarding may be present on examination. Rebound and rigidity are usually absent. If not typical of a pain crisis, non-SCA-related causes need to be considered (e.g., appendicitis), as well as SCA-related cholelithiasis/cholecystitis (can occur as early as 2 years of age), intrahepatic cholestasis (sudden right upper quadrant pain and tenderness, jaundice, anorexia, hepatomegaly, and sometimes fever), splenic sequestration, or hepatic sequestration (anemia and hepatomegaly). Constipation, urinary tract infection, and peptic ulcer disease are more common in SCA patients. Laboratories, ultrasound, and CT scan may be necessary to differentiate among these etiologies.
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Emergency Department Care and Disposition
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Pain management must be individualized, using previously effective regimens as ...