Background:Pneumocephalus is the presence of air in the cranial cavity. When this intracranial air causes increased intracranial pressure and leads to neurological deterioration, it is known as tension pneumocephalus (TP). TP can be a major life-threatening postoperative complication, especially after evacuation of chronic subdural hematoma. We report a case of TP after evacuation of chronic subdural hematoma and review the literature.Case Description:A 70-year-old man developed right-sided weakness after being admitted with minor head trauma a few weeks earlier. He was found to have a chronic subdural hematoma and underwent burr-hole evacuation. On day 3, he suddenly deteriorated and needed intubation and ventilation. Computerized tomography (CT) of the brain showed typical Mount Fuji’s sign due to TP. Immediately, 20-30 mL of air was aspirated from the intracranial fossa, and a catheter drain was inserted. The patient became fully awake after few hours and was extubated successfully. The drain was removed on day 5, and he was transferred to the ward before being discharged home.Conclusion:TP after evacuation of a chronic subdural hematoma is a neurosurgical emergency and needs immediate resuscitation and therapy; hence it is of vital importance that all acute-care physicians, intensivists and neurosurgeons be aware of this clinical emergency.