Fatal tonsillar herniation in pseudotumor cerebri.

Area of Science:

• Neurology
• Neurosurgery
• Medical Imaging

Background:

• Pseudotumor cerebri (idiopathic intracranial hypertension) is a condition characterized by increased intracranial pressure.
• Lumbar puncture is a diagnostic procedure that can carry risks, particularly in patients with intracranial pressure abnormalities.
• Cerebellar tonsil ectopia, including low-lying cerebellar tonsils, can predispose individuals to complications from procedures that alter cerebrospinal fluid dynamics.

Observation:

• A 27-year-old woman with a history of pseudotumor cerebri underwent a lumbar puncture.
• Five years prior, the same patient had a respiratory arrest following a lumbar puncture.
• Post-mortem examination, including MRI and autopsy, excluded Arnold-Chiari malformation and posterior fossa mass lesions.

Findings:

• The patient died secondary to tonsillar herniation after the lumbar puncture.
• Midsagittal views from imaging suggested the presence of low-lying cerebellar tonsils.
• The previous respiratory arrest may have been an earlier indicator of susceptibility to lumbar puncture complications.

Implications:

• This case underscores the critical need for careful patient selection and risk assessment before lumbar puncture in individuals with suspected or known intracranial pressure issues.
• The findings suggest that even subtle findings like low-lying cerebellar tonsils, without a definitive Arnold-Chiari malformation, can be associated with significant procedural risk.
• Enhanced neuroimaging protocols may be warranted in select patients to better identify risk factors for lumbar puncture-induced herniation.