Risk factors for pneumoencephalus:
(1) facial or head trauma, including barotrauma
(2) cervico-thoracic trauma
(3) intracranial surgery
(4) intracranial tumor
(5) meningitis or other intracranial infection
(6) head and neck surgery (including cervical, maxillofacial, other ENT)
(7) lumbar puncture
(8) lumbar epidural injection
(9) chronic otitis media
(10) diverticulitis
(11) recurrent colorectal carcinoma
(12) nasogastric or nasotracheal tube insertion
(13) epidural or spinal anesthesia
(14) nitrous oxide anesthesia
(15) tumor of the skull (sinus osteoma, tumor of skull base)
If no inciting cause is found then it is termed spontaneous.
