Chiari Decompression in Patients with Spontaneous Intracranial Hypotension: Presenting Symptoms and Treatment Response.

Spontaneous intracranial hypotension (SIH) is a debilitating and often misdiagnosed condition. One important differential diagnosis is Chiari malformation type I, which differs markedly in its pathophysiology, clinical manifestation, and treatment. We describe 7 patients with SIH, initially misdiagnosed as having Chiari malformation type I, who underwent posterior fossa decompression. Five patients developed temporary symptom relief after posterior fossa decompression, and 6 patients developed rebound intracranial hypertension. Our findings emphasize the importance of considering SIH when evaluating low-lying cerebellar tonsils to prevent unnecessary procedures and delays in appropriate treatment.