The placement of ventriculoperitoneal (VP) shunt is a common procedure of treatment for hydrocephalus. So, postoperative complications are various and the incidence is not rare. But acute onset pneumocranium is very rare. And this is the first case about barotrauma-related pneumomediastinum ascending to cranial cavity leading to the tension pneumocranium. Herein, the authors reported an extremely rare case of shunt-related complication with early onset tension pneumocranium following pneumomediastinum. The authors also discussed the possible mechanism and management method to deal with it.