Mild intracranial hypotension can lead to classically recognizable symptoms such as
positional headaches, nausea, vomiting, and occasionally blurred vision. Less commonly,
severe cerebrospinal fluid (CSF) hypovolemia can lead to a life-threatening condition
that mimics intracranial hypertension, including transtentorial herniation and subsequent
rapid neurologic decline. In this report we present a unique case of severe intracranial
hypotension from a thoracic tumor resection that led to symptoms initially mistaken
for intracranial hypertension, however ultimately correctly diagnosed as severe CSF
hypovolemia that improved with dural repair. Additionally, we describe a rare angiography
finding associated with CSF hypovolemia, kinking of the basilar artery. Here we report
a 47-year-old female with neurofibromatosis Type 2 found to have a T3 intradural extramedullary
tumor. She initially presented with urinary incontinence and gait/balance difficulty.
She underwent thoracic laminectomies at T3 and T4 for the excision of the lesion.
She was discharged on postoperative day 4. On postoperative day 9, she was noted to
have nausea, vomiting, and decreased consciousness. Head computed tomography (CT)
demonstrated acute downward herniation. She was transferred to our institution from
a community facility obtunded and was intubated for airway protection. She was placed
in the Trendelenburg position with immediate improvement, and declined every time
her head was raised. Angiogram showed significant kinking of her basilar artery. A
CT myelogram revealed a CSF leak from her recent thoracic surgery. She underwent exploration
of her thoracic wound, and a ventral durotomy was repaired. Following this, she began
to tolerate the head of bed elevations and recovered back to her neurologic baseline.
A postoperative head CT angiography obtained before discharge showed improvement of
her basilar kink. Mild intracranial hypotension is a common finding in patients who
undergo procedures that enter the CSF space. Severe intracranial hypotension can easily
be missed diagnosed as the signs on the exam are similar to patients with signs of
intracranial hypertension. It is of paramount importance that the clinician recognizes
brain sag, as the treatment algorithms are vastly different from that of intracranial
hypertension leading to transtentorial herniation.
Key-words:
Angiography - basilar artery kink - brain herniation - brain sag - cerebrospinal fluid
hypovolemia
