To investigate the clinical features of patients with spontaneous hypotension syndrome.

The clinical data of 75 patients with idiopathic hypocranial pressure syndrome admitted to Department of Neurosurgery, Seventh Medical Center, PLA General Hospital from January 2011 to January 2021 were retrospectively analyzed. The differences in gender and age distribution were analyzed, and the imaging characteristics were summarized.

The mean age of the patients was (43.67±10.30) years, and there were 24 males (32.0%) and 51 females (68.0%). The mean hospital stay was (8.79±6.12) days. The majority (56/75, 75.0%) cases of typical orthostatic headache were improved in the decubitus position. The rate of cervical spondylosis in females was higher than that in males (P=0.02). All patients underwent magnetic resonance imaging [58 (77.3%) cases underwent contrast-enhanced examination], which suggested spontaneous hypotension syndrome in 32 cases (42.7%). There was pituitary enlargement in 15 (20.0%) cases, meningeal enhancement in 28 (37.3%), subdural effusion/hemorrhage in 9 (12.0%), and decent of cerebellar tonsils in 6 (8.0%). Fifty-seven cases underwent lumbar puncture, of which 43 (84.3%) had a cranial pressure < 60 mmH₂O, 8 (15.7%) had a cranial pressure ≥ 60 mmH₂O, and 6 had no cranial pressure recorded. One case was misdiagnosed. Seventy-four cases were treated with infusion (2000-3000 ml/d) and symptomatic treatment, of which 52 (69.3%) were completely improved, 19 (25.3%) were improved, and 4 (5.3%) were not improved at discharge.

The onset peak age of spontaneous intracranial  hypotension is between 30 and 50 years old, and the proportion of females is about twice that of males. The rate of cervical spondylosis in females is higher than that in males. Cranial enhanced MRI is an effective test for definite diagnosis. The vast majority of patients recover better with conservative rehydration.