15 October 2011

Dear Editor,

Pneumocephalus, defined as the presence of air or gas in the cranial cavity is rare in infants. We report pneumocephalus in an 8-month-old male infant after receiving oxygen through nasal prongs. The boy presented in paediatric emergency with respiratory distress for 1 day preceded by running nose and fever for 3 days. His immunization was up-to-date and there was no history of cough. On examination, he had tachypnoea (respiratory rate 64/min) with subcostal retractions; oxygen saturation in pulse oximetry was 82%. Systemic examination revealed fine crackles in the chest. Chest X-ray showed hyperinflation with mild infiltrations in lungs. He was diagnosed as having bronchiolitis and was given humidified oxygen through nasal prongs at a flow rate of 2 L/min along with other supportive management. The following morning, a soft bulge over anterior fontanel of size 3 × 4 cm was noticed though there was no facial puffiness or subcutaneous emphysema over scalp. Base of the anterior fontanel was apparently closed. Cranial computed tomographic scan revealed the presence of multiple focal areas of air both inside the cranium and bulging out over the anterior fontanel without any evidence of intracranial haemorrhage (Fig. 1). Sepsis screen and blood culture were negative. Guarded lumbar puncture revealed normal cerebrospinal fluid pressure. Biochemical and microbiological examinations were also normal. Oxygen was stopped as retractions became less severe and saturation was maintained at 90–94% at room air. The bulge of anterior fontanel gradually subsided. He was discharged on day 14. Follow-up did not reveal any abnormality over next 1 year.

Figure 1.

Computed tomography scan of brain showing multiple focal areas of air both inside the cranium and bulging out over the anterior fontanel.

Pneumocephalus has been reported in infants in association with meningitis and secondary to meningomyelocele.1–3 Intracranial anaerobic and aerobic infections are known to produce gas by putrefaction of intracellular protein derived from autolysis and by decomposition of glucose.2 In the present child there was no evidence of meningitis or vigorous coughing which might have lead to subcutaneous emphysema. Probably nasal oxygen flow tracked through the cribriform plate into the extra-axia spaces and finally dissected out through cranial sutures and collected over anterior fontanel. Nasal prongs are widely used in infants. Though airway mucosal blood flow is reported to be maintained,4 humidification and temperature may not be maintained and in some cases may cause excessive expiratory pressure loading.5 After extensive literature search we could find only a single case report of pneumocephalus with concomitant use of the high-flow nasal cannula where the authors also found subcutaneous scalp emphysema and pneumo-orbitis.6