Presentation
Confusion, neck rigidity and decreased level of consciousness. History of otalgia of 1 week duration.
Patient Data
Multiple small gas locules are noted intracranially, adjacent to the right mastoid bone.
Bone window shows partial opacification of the right mastoid air cells. Irregularity of the posterior wall of the right mastoid bone is noted with a suspected bony defect.
No focal brain abnormality. Normal ventricular system. No shift of midline structures.
Abnormal hyperintense signal is seen on FLAIR sequences in the sulci of both frontoparietal regions. Hyperintense signal is also noted on diffusion-weighted images. Findings suggest meningitis.
Right mastoid air cell effusion, which in the setting of bony erosion on the prior CT is in keeping with otomastoiditis.
Partial opacification of the right mastoid air cells with erosion of the posterior wall of the right mastoid air cells with resolution of the previously seen air locules.
Case Discussion
This patient presented with a decreased level of consciousness, neck rigidity and fever. Initial brain CT revealed mastoiditis and pneumocephalus. The patient was admitted for further investigation. Brain MRI and lumbar puncture were performed which confirmed the diagnosis of meningitis.
The combination of meningitis and pneumocephalus as complications of otomastoiditis is rare.
Pneumocephalus is classically associated with surgery, trauma or tumors. The mechanism, in this case, was most likely due to a cortical defect in the right mastoid as a result of the patient’s mastoiditis allowing direct communication with the posterior cranial fossa.