Spontaneous intracranial hypotension is characterized by orthostatic headache in the absence of a history of head trauma or lumbar puncture, and diagnosis is confirmed by a specific cerebrospinal fluid pressure and neuroimaging findings. It rarely presents with coma. A 62-year-old man presented with progressive cognitive decline of 2 to 4 weeks' duration. He was diagnosed with spontaneous intracranial hypotension according to cerebrospinal fluid pressure and neuroimaging findings, and treated conservatively.