Complications of polycythemia in patients who have cyanotic congenital heart disease.

A 13-mo-old child is brought to his pediatrician following sudden onset of left-sided hemiplegia. The pediatrician accompanies the child and family to the emergency room. The pediatrician has been following the child, who has a diagnosis of possible cyanotic congenital heart disease. The child has never been known to have had a hypercyanotic episode. Oxygen saturation determinations by pulsed oximeter had been in the range of 84% to 88%. On one occasion, when the child was very upset, a reading of 78% was observed. At his 1-year visit, his hemoglobin level was 13 g/dL. On admission to the emergency department, a computed tomographic scan of the head was ordered. It demonstrated a right-sided nonhemorrhagic cerebrovascular lesion.