Spontaneous intracranial hypotension in the absence of magnetic resonance imaging abnormalities.
BACKGROUND
Spontaneous intracranial hypotension (SIH) is a neurologic syndrome of unknown etiology, characterized by features of low cerebral spinal fluid (CSF) pressure, postural headache and magnetic resonance imaging (MRI) abnormalities.


METHODS
Four symptomatic cases of SIH presented to our institution over a six-month period. Magnetic resonance imaging studies were performed in all four cases. Diagnostic lumbar puncture was done in all except one case.


RESULTS
All of the patients on whom lumbar punctures were performed demonstrated low CSF pressure and CSF protein elevation with negative cultures and cytology. Three out of the four patients exhibited MRI findings of diffuse spinal and intracranial pachymeningeal gadolinium enhancement and extradural or subdural fluid collections. One patient had no MRI abnormalities despite prominent postural headache and reduced CSF pressure at lumbar puncture. All patients recovered with intravenous fluids and conservative treatment.


CONCLUSIONS
Magnetic resonance imaging abnormalities are found in most, but not all patients, with SIH. Cerebral spinal fluid abnormalities can be detected even in patients with normal MRI studies. It is important to recognize the variability of imaging results in this usually benign disorder.
Schoffer
Kerrie L
KL
Division of Neurology, Dalhousie University, Halifax, NS Canada.
Benstead
Timothy J
TJ
Grant
Ian
I
D000328:Adult; D015170:Cerebrospinal Fluid Pressure; D005260:Female; D006261:Headache / Q000209:etiology / Q000503:physiopathology*; D006801:Humans; D019585:Intracranial Hypotension / Q000150:complications / Q000473:pathology / Q000503:physiopathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D013129:Spinal Puncture