Intracranial Hypotension (Low-CSF-Pressure Syndrome)

Clinical Vignette

A vigorous previously healthy 60-year-old physician, who had recently developed severe depression, requiring both a serotonin reuptake inhibitor as well as unilateral electric shock therapy (EST), developed increasingly severe posturally exacerbated headaches. When these were greatly exacerbated while he was a passenger in a small float plane as it landed bouncing over the water, he went to a neurologist. His examination was normal. Postgadolinium MRI demonstrated leptomeningeal enhancement but no mass lesions. CSF pressure was too low to measure. No known relation with the EST was identified. He then recalled having a relatively severe closed head injury 3 weeks earlier when he forcefully struck his forehead on an unexpectedly low-set barn door frame. A 20-mL extradural blood patch was empirically injected at his mid-lumbar spine. The headaches gradually and totally cleared within 2 weeks.

A. Axial FLAIR image with dural thickening.

B. Axial T1-weighted, gadolinium-enhanced image with striking enhancement of the thickened dura.

Figure 52-23 Intracranial Hypotension.

Classic low-CSF-pressure headaches are severe, exacerbated by postural factors, and often mimic the ball valve effect seen in some intraventricular brain tumors. Most commonly, these occur subsequent to a diagnostic lumbar puncture, spinal anesthesia, or a seemingly benign closed head injury. MRI with gadolinium is essential to the diagnosis (Fig. 52-23). When there is no history of a spinal tap or significant head trauma, this clinical setting, as well as the MRI, somewhat mimics various leptomeningeal neoplastic or inflammatory lesions. The MRI imaging with low pressure headache syndrome has a smooth enhancement in contrast to serpiginous irregular enhancement seen with neoplastic infiltration. The CSF analysis primarily helps make this differentiation. Occasionally introduction of a radioisotope into the CSF will identify a source of CSF leak that may require surgical repair. In many of these instances, no site of potential spinal fluid leak is identified. As in the above vignette, a spinal blood patch can provide relief and a therapeutic diagnosis; however, it is not universally successful and in rare instances the patient may have permanent incapacitation not being able to raise his/her head, preventing one from pursuing an occupation or even many routine activities of daily living.

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  • Category: Nervous diseases