The infant or child with increasing pressure within the cranial cavity must be identified early and treated promptly in order to prevent serious complications or death. When the pressure elevation is gradual it is frequently well tolerated, and the patient may seem deceptively well. There is a critical point, however, beyond which any further increase in pressure leads to a catastrophic deterioration in the patient's condition.1 When this occurs, the outlook for quality survival is poor despite the best therapy. Unfortunately, this can occur when the underlying process is benign and would have been reversible if recognized and treated promptly. For prompt recognition and treatment, the physician must be familiar with the pathophysiology of raised intracranial pressure.