W Most patients who receive treatment for intracranial hypotension do well , with improved quality of life or complete cure . W
Diagnosis
The diagnosis of intracranial hypotension relies primarily on the symptoms and history of the patient . The positional aspect of the headache is a key feature in most , but not all , cases . A patient may report a recent history of a lumbar puncture , epidural anesthesia or injection ( s ), surgery , or trauma . A previous diagnosis of postural orthostatic tachycardia syndrome ( POTS ) is not uncommon . POTS refers to a condition in which moving from a lying to standing position causes an abnormal increase in heart rate and a range of other signs and symptoms . A patient ’ s positional symptoms may be due to POTS or due to a spinal CSF leak or both . Underlying inherited disorders of connective tissue ( Marfan syndrome ,
DIAGNOSTIC CHALLENGES
• low awareness contributes to delayed diagnosis and misdiagnosis
• not every headache due to intracranial hypotension is positional
• not every positional headache is due to intracranial hypotension
• not every patient with intracranial hypotension has a headache
• common and uncommon presentations and findings may not be recognized as secondary to intracranial hypotension ( subdural hematomas , tremor , unsteady gait , dementia , low lying cerebellar tonsils , coma , stroke , spinal cord manifestations )
• normal CSF pressures are not uncommon
• imaging interpretation requires experience and training
• brain MRI is normal in ~ 20 %
• spinal imaging is negative in ~ 50 %
• more than one type of spinal imaging is often needed
Ehlers-Danlos syndromes , others ) may or may not be recognized prior to the onset of symptoms related to a spinal CSF leak . A few patients may have received a diagnosis of Chiari I due to the brain imaging finding of low-lying cerebellar tonsils ( part of brain at back of head ). Chiari I is a congenital condition in which the back part of the skull is abnormally small or misshapen , and part of the brain , the lower part of the cerebellum , extends into the spinal canal . In intracranial hypotension , the finding of low lying cerebellar tonsils and brain sag is due to the loss of CSF volume and is reversible with treatment of the leak , so it is often called pseudo- Chiari . It can be challenging for clinicians to sort out if this finding on brain imaging is from congenital Chiari or from low CSF volume of intracranial hypotension or from a combination of both . Minimal response to medications used for migraines can be an additional clue to the diagnosis .
A diagnostic lumbar puncture to determine pressure measurement or CSF analysis is not usually performed unless another disorder such as meningitis is being ruled out . Minor CSF abnormalities may be noted and cerebrospinal fluid pressure may be low , normal , or even high .
An MRI of the brain with contrast should be done in all suspected cases to determine several classic findings although imaging findings are absent in about 20 % of patients . Spinal imaging is used to locate leaks or other abnormalities for targeted treatment – but may be negative in up to one-half of suspected cases due to the limits of sensitivity . A full spine MRI without contrast is often the initial choice because the testing is non-invasive . Myelography , which involves lumbar puncture for the injection of contrast , uses CT , MR , or digital subtraction techniques . More than one type of spinal imaging is often needed .
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