Communicating hydrocephalus secondary to superior vena caval obstruction. Occurrence after Mustard's operation for transposition of the great arteries.

Communicating hydrocephalus was observed on computed tomographic (CT) scans in two infants who had previously undergone Mustard's operation for transposition of the great arteries. Obstruction of the superior limb of the intracardiac baffle developed in these children, resulting in venous obstruction to the head and upper extremities that resulted in cranial enlargement. Radiologic clues included a bulging superior vena cava and a prominent azygous system on chest roentgenogram, split cranial sutures on skull films, and enlarged subarachnoid spaces and dilated ventricles on CT scans. Two-dimensional echocardiography showed the obstructed baffle, as well as signs of redirected blood flow. Angiography and measurement of venous pressures confirmed the obstruction, and surgical correction was successful. Follow-up CT scans showed resolution of the hydrocephalus. Increased venous pressure, leading to decreased CSF absorption and increased intraventricular and subarachnoid CSF accumulation in an infant with an expandable cranium, is a possible explanation for the development of cranial enlargement and hydrocephalus under these circumstances.