Case 348.

History A 6-year-old boy with sickle cell disease and a recent episode of acute chest syndrome presented to the emergency department with chest tightness and a 4-day history of progressive right eye swelling, along with pain in the left hand and left leg. Initial laboratory tests showed a hemoglobin level of 6.1 g/dL (61 g/L) (low), hematocrit level of 19.5% (low), white blood cell count of 16 000/µL (16 × 109/L) (high), red blood cell count of 3.03 million/µL (3.03 × 1012/L) (low), platelet count of 338 × 103/µL (338 × 109/L) (normal), reticulocyte count of 4.79% (high), total bilirubin level of 2.3 mg/dL (39 µmol/L) (high), aspartate aminotransferase level of 62 U/L (1.0 µkat/L) (high), alanine aminotransferase level of 16 U/L (0.27 µkat/L) (normal), and alkaline phosphatase level of 660 U/L (11 µkat/L) (high). The differential count was as follows: neutrophils, 69.1% (high); lymphocytes, 22.7% (low); monocytes, 7.2% (normal); basophils, 0.3% (normal); and immature granulocytes, 0.7% (high). Physical examination demonstrated swelling and erythema of the right eye but no significant discomfort or tenderness with eye movement. There was no eye discharge or conjunctival redness. Contrast-enhanced CT of the face was performed (Fig 1), followed by MRI of the brain (Fig 2) and orbits (Fig 3) with and without intravenous contrast agent.