An "airy" image.

A 30-year-old man presented with headache, vomiting, altered sensorium and seizures. There was no history of trauma or surgery. On examination, he was unconscious with signs of meningeal irritation and asymmetrical pupils. Computed tomography (CT) scan of brain revealed pneumocephalus. He died immediately after the CT scan. He was later found to be immunocompetent.

Computed tomography scan (figures 1 and 2) showed moderate dilatation of lateral ventricles with intraventricular air pockets, small bilateral intracranial air pockets in the sulci. The CT features were suggestive of meningitis with ventriculitis.

Figure 1

Computed tomography (CT) scan of the brain. Arrows show moderate dilatation of lateral ventricles with intraventricular air pockets as well as small bilateral intracranial air pockets in the sulci.

Figure 2

Computed tomography (CT) scan of the brain. Arrows show intraventricular air pockets and small intracranial air pockets in the sulci.

Discussion

Pneumocephalus is defined as the presence of air or gas within the cranial cavity. It is classified as extradural, subdural, subarachnoid, intracerebral and intraventricular. Pneumocephalus is usually caused by trauma or surgery.[1] Spontaneous, non-traumatic pneumocephalus is an uncommon condition. In nontraumatic cases, meningitis is a rare cause of pneumocephalus and one should suspect anaerobic infection.[2] It may also be due to anaerobic, aerobic, or mixed infection. It is fatal in most of the cases.[3]