A 67-year-old man noted the acute onset of an exquisitely orthostatic, occipital pressure-type headache associated with nausea and auditory echoing. His symptoms resolved spontaneously over a 2-week period. Two months later, his wife noted the insidious onset of marked behavioral changes that started with poor decision-making and progressed over the next month to include a deterioration in his driving skills and behaviors such as leaving doors open and spilling food and beverages on himself without noticing. He was occasionally mute and hypersomnolent. The initial diagnosis was dementia due to Alzheimer’s disease.

Acute headache that is worse when upright and improved with recumbency is recognized as resulting from low intracranial pressure when it occurs following a lumbar puncture, following spinal surgery, or in a patient with an over-draining CSF shunt. Inadvertent dural punctures following epidural injections and posttraumatic spinal CSF leaks may or may not be recognized promptly. When an orthostatic headache occurs spontaneously, the diagnosis of intracranial hypotension from single or multiple spontaneous spinal CSF leaks is more often delayed or missed.

The headache is usually but not always orthostatic, ranges from mild to severe, typically has an onset over minutes to hours, and is most often occipital or suboccipital but may be diffuse, frontal, or temporal. The headache may occasionally be absent or resolve despite persistence of other signs and symptoms. Common associated symptoms include neck stiffness or pain, nausea with or without vomiting, hearing changes, photophobia, interscapular pain, upper limb radicular symptoms, sense of imbalance, and subtle cognitive dysfunction. Less common symptoms or signs include visual changes, various cranial nerve palsies, Parkinsonism, ataxia, cerebellar hemorrhage, dementia, stupor and coma, stroke, and even death. Clinical stigmata of heritable disorders of connective tissue may be noted.

Because the headache may be relatively acute in onset with associated symptoms that include stiff neck, photophobia, phonophobia, nausea, and vomiting, cranial CT is done in many cases to rule out subarachnoid hemorrhage. While generally less helpful than cranial MRI in the diagnosis of intracranial hypotension, subdural fluid collections or obliteration of subarachnoid cisterns and ventricular collapse may be found.

Following a negative cranial CT, a lumbar puncture may be performed to rule out meningitis or subarachnoid hemorrhage below the detection of cranial CT. Most commonly, the opening pressure will be less than 60 (reference 65–195 mm H₂O) and can be unmeasurable or subatmospheric; however, normal pressures do not rule out a spinal CSF leak. Analysis of the CSF may show xanthochromia, normal or elevated protein, normal glucose, lymphocytic pleocytosis, and normal or high erythrocyte count. A lumbar puncture is not required to make the diagnosis: when clinical suspicion of spinal CSF leak is high, several imaging studies are helpful.

Cranial MRI is abnormal in 80 % and has 5 main findings, remembered by the mnemonic SEEPS:

Subdural hematomas are not uncommon and can often be managed without surgical evacuation but rather by treating the underlying spinal CSF leak. Sagging of the brain may be evident from ventricular collapse, effacement of the perichiasmatic cisterns with bowing of the optic chiasm over the pituitary fossa, effacement of the prepontine cistern with flattening of the pons against the clivus, and descent of the cerebellar tonsils mimicking a Chiari I malformation.

Findings on spinal MRI include meningeal enhancement, meningeal diverticula, extrathecal fluid collections, and dilated epidural or intradural veins. Myelographic sequencing obviates the need for a dural puncture to instill intrathecal contrast; however, intrathecal gadolinium contrast is occasionally used off-label for MR myelography.

CT myelography can define the location and extent of a CSF leak. Meningeal diverticula or nerve root sleeve dilatations may also be visualized. Dynamic CT myelography is usually used to detect rapid leaks.

Digital subtraction myelography is helpful in visualizing rapid and/or extensive leaks seen on other imaging without precise localization, leaks that are anterior to the spinal cord, and more recently recognized csf-venous fistula leaks that drain directly from the intrathecal space into the epidural veins.

Radioisotope cisternography may confirm the presence of CSF leaking by virtue of early accumulation of tracer in the kidneys and bladder and a paucity of tracer activity over the cerebral convexities but is insensitive in localizing leaks.

Patients are often misdiagnosed with various primary headache disorders such as migraine or tension headaches, nonspecific new daily persistent headache, or headache secondary to viral meningitis. There is limited published data to suggest that patients with headache attributed to chronic whiplash may have a traumatic spinal CSF leak. Delayed diagnoses are primarily due to the lack of familiarity by treating physicians; however, over the last decade, awareness of spontaneous spinal CSF leaks appears to be improving.

Not all orthostatic headaches are caused by spinal CSF leaks. Postural orthostatic tachycardia syndrome (POTS) may present with prominent positional headache. In practice, this may be difficult to sort out since patients with spinal CSF leaks may have positional tachycardia to compensate physiologically for intracranial hypotension, may have preexisting POTS, or can develop secondary POTS. Headaches may also be positional in diabetes insipidus and cervicogenic headaches and in patients that are post decompression surgery for Chiari malformation without CSF leak.

Cranial MRI done as part of the diagnostic workup for dementia showed severe sagging of the brain and meningeal enhancement, diagnostic of spontaneous intracranial hypotension. CT myelography showed a low opening pressure of 20 mm H₂O and a large ventral extrathecal fluid collection.