Delayed Spontaneous Pneumocephalus After Ventriculoperitoneal Shunt Surgery: A Successful Conservative Treatment

Pneumocephalus is defined as the presence of intracranial air and is a rare but potentially significant complication following ventriculoperitoneal (VP) shunt placement. Delayed presentations are uncommon and remain poorly described in the literature. The report demonstrates the case of a 74-year-old male patient who developed delayed spontaneous intraventricular pneumocephalus 10 months after VP shunt insertion in September 2022 using a high-pressure fixed valve for obstructive hydrocephalus secondary to a tectal plate lesion. The patient presented in July 2023 with posture-dependent frontal headache, tinnitus, and bruit hydroaérique, without fever, infection, or neurological deterioration. Computed tomography revealed intraventricular air and a small air focus adjacent to the mastoid tegmen, suggestive of an occult skull base defect. The presumed mechanism involved sustained negative intracranial pressure related to the siphon effect of the shunt system, facilitating air entry through a pre-existing osteodural defect. Given the patient's clinical stability and absence of infection or shunt malfunction, a conservative management strategy was adopted. Complete clinical and radiological resolution was observed within two weeks, with no recurrence during 12 months of follow-up. This case highlights a rare delayed complication of VP shunting and demonstrates that conservative management may be a safe and effective option in carefully selected, clinically stable patients, after exclusion of infection and shunt dysfunction. It contributes to the limited existing literature on non-invasive treatment strategies for delayed pneumocephalus.