Brain herniation induced by drainage of subdural hematoma in spontaneous intracranial hypotension
A 36-year-old male with intermittent history of headache since 4 weeks presented with acute onset excruciating headache to our emergency department. The headache was generalized, continuous, squeezing with no relief, or aggravation on lying down. Past history was unremarkable, and there was no history of head trauma. On examination he was alert with no neurological deficit. No nuchal rigidity was noted. Blood examination revealed a normal hemoglobin and coagulation profile. Computed tomography (CT) scan findings of bilateral chronic subdural hematoma (SDH) collection with increased attenuation along basal cistern raised the possible diagnosis of acute subarachnoid hemorrhage (SAH) []. Intracranial angiography revealed no evidence of aneurysm or vascular malformations. Conservative treatment including bed rest and careful observation was done. Until then, the diagnosis of SIH was not made, and follow-up intracranial angiography was planned after a week considering the possibility of concealed aneurysm. In subsequent days, the patient's consciousness deteriorated progressively to be lethargic which was interpreted as a sign of increased intracranial pressure due to bilateral chronic SDH. After confirming no aneurysm on follow-up CT angiogram, the patient underwent emergency bilateral burr hole drainage of hematoma. The intraoperative course was unremarkable. Immediate postoperative CT scan demonstrated poor visualization of posterior fossa cisterns [, left] with large pneumocephaly in both cerebral hemispheres [, right]. After the recovery period, the patient did not regain consciousness; instead, there was progressive worsening of consciousness. The 2-h follow-up CT scan revealed a huge epidural hematoma on the left side []. An emergency craniotomy and hematoma evacuation was performed. After the second surgery, the patient was deeply stuporous without any clinical improvement. The 2-day follow-up diffusion weighed magnetic resonance imaging (MRI) evidenced acute cerebral infarction on bilateral territories of posterior cerebral artery and CT scan showed poor visualization of the fourth ventricle [, left] with supratentorial pneumocephalus and subdural fluid collection [, right]. Unusual rapid clinical deterioration despite prompt hematoma evacuation, poor visualization of the fourth ventricle, and pneumocephalus on imaging were now interpreted as the result of downward displacement of the brain, and an underlying spinal CSF leak was suspected. The patient was placed in the Trendelenburg position and an empirical epidural blood patch was applied using a 10 ml autologous blood, one each for a cervico-thoracic and thoraco-lumbar junction. A rapid improvement in consciousness (from Glasgow coma scale score 7-11) was noted over the period of 3 days after the procedure and the CT scan showed well visualization of the fourth ventricle []. The patient demonstrated full clinical recovery, 4 weeks after the epidural blood patch. A complete spine CT myelography performed to evaluate the possibility of remaining CSF leak demonstrated small leaks at cervical C4-5 level []. Because the patient was alert and had no symptoms associated with SIH, no further intervention was performed. The patient was discharged and the 4-month post-operative follow-up brain MRI showed no evidence of subdural fluid collection [] or brain herniation. Bilateral cortical blindness due to bilateral occipital infarction and mild cognitive deficit gradually improved 8 months after the surgery.