Intracranial hypotension results from decreased CSF pressure. While often spontaneous, secondary causes may result from trauma including lumbar puncture (either diagnostic or from anesthesia). In this case, acute intracranial hypotension resulting in a subdural hematoma is a rare complication following spinal anesthesia. In a review of 35 patients, risk factors included pregnancy, multiple punctures, use of anticoagulants, intracranial vascular abnormality, and cerebral atrophy.
Clinically, these patients present with a characteristic orthostatic headache. Other common symptoms included nuchal pain (as in our patient), nausea, and vertigo.
MR imaging is diagnostic, and characteristic features include subdural hygromas and hematomas (as in our patient), distension of dural sinuses, and downward displacement of the midbrain. Post contrast images of the brain may demonstrate characteristic diffuse pachymeningeal enhancement.
Therapeutically, radiologists may offer an epidural blood patch, which provides an immediate tamponade effect. For patients with large dural tears or clinical deterioration, surgical management is suggested.