Spontaneous intracranial hypotension syndrome: Report of twelve cases

Purpose.-To investigate clinical, MRI, and radioisotope findings and therapeutic outcome of the syndrome of spontaneous intracranial hypotension (SIH). Background.-Spontaneous intracranial hypotension is characterized by orthostatic headache, low CSF pressure, and MRI findings of diffuse pachymeningeal gadolinium enhancement without previous history of head trauma or lumbar puncture. Spontaneous CSF leakage from a spinal dural tear has been suggested as the underlying pathogenic mechanism of SIH. Most patients recover without sequelae, but subdural collections have been described in a few. Methods.-Twelve consecutive patients (10 females, 2 males, mean age 39 years) with headache related to the syndrome of spontaneous intracranial hypotension were investigated. Results.-Eleven patients presented orthostatic headache, one patient had continuous nonpostural headache. Additional clinical symptoms included nausea, vomiting, tinnitus, diplopia, and back pain. All the patients had low CSF opening pressure, seven had increased CSF albumin, and four had pleocytosis. Brain MRI showed diffuse pachymeningeal gadolinium enhancement. Other features included subdural fluid collections (hematoma/hygroma) in four patients, downward displacement of the brain in four patients, and enlargement of the pituitary gland in one patient. Radioisotope cisternography results indicated, in two patients, a CSF leakage site in the cervico-thoracic region, and in one patient showed limited ascent of the tracer to the cerebral convexity and early appearance of radioisotope in the bladder. All the patients had complete resolution of headache with conservative treatment. Conclusions.-Patients with SIH have distinct MRI and sometimes radioisotope cisternographic abnormalities and generally respond favorably to conservative management.