Episodic central neurogenic hyperventilation in an awake child with systemic histiocytosis.

A 3 year old boy with systemic histiocytosis, diabetes insipidus and a lytic parietal bone lesion experienced episodes of central neurogenic hyperventilation 3 weeks after radiation to the head but was conscious and alert at presentation. At admission, the PaO2 was 133 mmHg, PaCO2 was 8 mmHg and pH 7.65. Magnetic resonance imaging revealed a pontomedullary lesion that resolved during the ensuring year. Central neurogenic hyperventilation has not been described previously as a complication of systemic histiocytosis.