Curious Case of Altered CSF Dynamics

Sir, Intracranial hypertension following cerebral venous sinus thrombosis (CVST) is a well-established entity. As with idiopathic intracranial hypertension (IIH), treatment options include medical management, cerebrospinal fluid diversion procedures, optic nerve sheath fenestration, and dural venous sinus stenting.[1] We describe a unique case of a lady with intracranial hypertension, who developed spontaneous intracranial hypotension following lumboperitoneal shunting. A 35-year-old lady presented to emergency services with a history of severe headache for the past few days. On examination, she had papilledema. There were no focal neurological deficits. MRI of the brain revealed complete thrombosis of the superior sagittal sinus, transverse and sigmoid sinuses, and the right internal jugular vein on the right side. She was diagnosed with CVST and started on low molecular weight heparin. Thrombophilia work-up did not reveal any significant predisposing cause. She was discharged with oral warfarin and tab. Acetazolamide. At follow-up after three months, she continued to have headache. Fundoscopy revealed persistent papilledema. MRI brain revealed dilated optic nerve sheath and empty sella with persistent sinus thrombosis [Figure 1].Figure 1: MRI brain with T2WI axial sequence shows empty sella and small sized lateral ventriclesLumbar puncture with CSF manometry revealed an opening CSF pressure of 41cm of water. A diagnosis of intracranial hypertension secondary to cerebral venous sinus thrombosis was made. MRI brain revealed slit ventricles and dilated CSF space around the optic nerves. In view of intracranial hypertension resistant to medical therapy, she underwent lumboperitoneal shunt using programmable Strata II valve. Six hours following the surgery, she developed sudden severe neck pain and headache. The headache was postural, brought on by sitting up and standing and relieved by lying down. The shunt valve pressure was gradually increased over the next few days to high pressure. However, despite reducing the amount of CSF drainage, she continued to have postural headache suggestive of intracranial hypotension. MRI of the brain done at this time revealed sagging brainstem, bilateral thin frontoparietal subdural hematoma, and diffuse pachymeningeal enhancement suggestive of "intracranial hypotension" [Figure 2]. Intrathecal CT myelography was performed to look for area of CSF leak. It revealed contrast extravasation outside the dura at C2 level posteriorly into the muscular plane [Figure 3]. A diagnosis of "intracranial hypotension" secondary to spontaneous CSF leak at C2 level was made. She underwent epidural blood patch using autologous blood via lumbar puncture. After the blood patch, she was made to lie in head low position for 48 hours. Following the procedure, her headache completely subsided and she made a complete recovery. At one-year follow-up, she was asymptomatic and was doing well.Figure 2: MRI brain with gadolinium enhanced T1WI shows sagging of brainstem, pachymeningeal enhancement, and bilateral frontoparietal thin subdural hematoma suggestive of "intracranial hypotension"Figure 3: CT myelogram axial, coronal, and sagittal images show extravasation of contrast material into the muscular plane at the level of C2 vertebra posteriorly"Intracranial hypotension" following lumboperitoneal shunt for "intracranial hypertension" is extremely rare. Causes include CSF leak around the lumbar catheter and from the holes of the catheter. However, in our case, there was a spontaneous leak at C2 level, far away from the site of the lumbar catheter.[2] One possible reason for development of spontaneous CSF leak at the C2 level is rupture of pre-existing meningocele at the C2 level. Meningoceles are protrusions of meninges through points of weakness along the neuraxis. Spontaneous meningoceles have been described in patients with idiopathic intracranial hypertension.[3] However, we did not have preoperative imaging of the cervical spine to confirm the presence of meningocele at the C2 level. Intrathecal CT/MRI myelography is the confirmatory test to diagnose the site of CSF leak in patients with intracranial hypotension. Epidural blood patch using autologous blood is curative in most patients. In patients who do not respond to epidural blood patch, open repair may be contemplated.[4] Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.