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Answer: D. CT myelography


Spontaneous intracranial hypotension

  • A treatable cause of new persistent positional headaches that is usually related to spontaneous spinal CSF leaks.
  • Characteristic MRI findings: pachymeningeal enhancement, chronic subdural hygromas, pituitary hyperemia, and downward displacement of posterior fossa structures.
  • CT myelography allows evaluation of CSF opening pressure and localization of spinal CSF leak.
  • Managed with epidural blood patches or fibrin glue, or surgery in refractory cases .

The classical clinical presentation of spontaneous intracranial hypotension (SIH) is that of new onset debilitating headaches that are aggravated by standing and ameliorated by lying. Unfortunately, a general lack of familiarity with this disease entity among clinicians often results in a misdirected workup, inaccurate diagnosis, and ineffective treatment. Cerebrospinal fluid leakage, usually in the spine, is believed to be critical to the development of SIH since most patients will have an abnormally low opening pressure following lumbar puncture. Diminished CSF volume results in reduced intracranial buoyancy force which manifests radiographically as downward migration of posterior fossa structures and a "sagging brain" appearance on MRI. Moreover, a decrease in CSF space results in ex-vacuo engorgement of venous structures and the appearance of subdural hygromas, pituitary hyperemia, and meningeal enhancement as seen on contrast-enhanced MR imaging. After a diagnosis has been made, CT myelography is indicated for identifying the site of CSF leakage. If a leak site is found then fluoroscopically-directed percutaneous treatment with autologous epidural blood patches or transforaminal fibrin glue is performed. However, if no leak is identified then a general epidural blood patch is the choice treatment. Surgical interventions are typically reserved for severe or refractory cases.

References

Mea E, Savoiardo M, Chiapparini L, et al. Headache and spontaneous low CSF pressure syndrome. Neurol Sci. 2007;28:232-234.

Schievink, WI. Spontaneous spinal cerebrospinal fluid leaks and intracranial hypotension. JAMA. 2006;295:2286-2296.


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