CSF leakage and headache, aka Spontaneous Intracranial Hypotension (SIH).
A healthy woman in her forties was admitted at the Martin Cleveland Clinic in Stuart, Florida, for severe positional headache associated with nausea, occasional vomiting and failure of response to increased use of caffeine and intake of corticosteroids. It all started three days prior after an episode of exercise. Then she experienced a mild headache and low back pain. The following day, the pattern of severe postural headache began in earnest. Whenever in the upright position, she would have a searing pain in the a fronto-occipital distribution associated with an acute neck stiffness. Patient drank plenty of fluid and also took some caffeine and rested by necessity in the supine position. The next day, she began a corticosteroids pack and when she went to a restaurant, while sitting upright, the pain was such she had to go home to rest.
Her physical exam was unremarkable. The tentative diagnosis of postural headache was made, and patient was evaluated by neurologist. MRI with and without contrast of brain, cervical, thoracic and lumbar spine was done, and result was respectively negative, nonspecific with degenerative changes and some bulging discs and the lumbar spine only showed congenital scoliosis. However, the thoracic spine revealed a complex collection of fluid in posterior paraspinal musculature on the right. No CSF leak was identified in any of the imaging studies. Patient was treated with IV saline, caffeine, bed rest to no avail. A spine surgeon evaluated patient and indicated there was no indication for any intervention. An ultrasound of the abdomen revealed a resolving hematoma or seroma complex. Patient was evaluated by an anesthesiologist and underwent a blind epidural blood patch (EBP)1. Patient remained in supine position for many hours after the procedure, but the following day was still symptomatic. A CT scan myelogram was then done and it revealed diffuse leak at the level of the thoracic spine. The consulting neurologist made several phone calls and the local expert in the condition within a ninety-mile radius, Dr. Michal Obrzut, is located at the Cleveland Clinic campus in Weston, Florida, and he would not be available until three days later. Patient decided to go home and to go to see the neuroradiologist as outpatient as soon as he would return from his vacation. The neurologist did make the arrangement and then 3 days after discharge, the patient was evaluated. She did bring along all the imagings done at our institution. She underwent two more blind EBPs, one at the level of lumbar and another at the thoracic level. Patient stayed home in supine position for next 24+ hours and started feeling better right away. However, when reached 4 days later, patient claims the headache is resuming, albeit not as intense as before. She will have another CT myelogram with the goal of doing a targeted EBP this time around.
According to the accepted dogma, the most common presenting symptom for the diagnosis of SIH is orthostatic headache (89%)2, however 8% of cases are associated with no orthostatic headache and 2% without any headache at all. The diagnostic criteria are evolving. Whereas a low CSF opening pressure was once considered necessary, now it is known that the opening pressure may be normal. MRI of brain is the most sensitive way to make the diagnosis, showing diffuse pachymeningeal enhancement in 72% of cases. Demonstration of CSF leak by imaging can be problematic. The sensitivity ranges from a low of 48% to a high of 67%, depending on the imaging study used with digital subtraction myelography offering superior capability. At this point, spinal MRI remains the first screening method and subtraction myelography used to detect the site of the leak2. In another review article published by Kranz et al from Duke, our state of knowledge on this condition is in a state of flux5. He states that the available evidence leads us to question the notion of hypotension because the majority of patients have a normal CSF opening pressure but instead have a low volume of CSF due to the leakage.
3 etiologies have been discovered so far: (1) nerve root sleeves dural weakness, (2) ventral dural tears associated with disk herniations, and (3) CSF-venous fistulas. The third one is more difficult to diagnose and tends to occur more commonly in the thoracic nerve roots. SIH occurs predominantly in females, usually forty or less and tends to present acutely.
- Clinical grounds. A history of sudden postural headache is the classic presentation. One needs to remember that other types of headache can have a postural pattern of intensity but the history is different.
- Imaging. No one single study suffices to rule out the diagnosis and each type offers a different sensitivity. It’s recommended to do a brain MRI with contrast first because “diffuse, symmetric, smooth dural (i.e., pachymeningeal) enhancement is one of the most common and suggestive signs of SIH2.” Then the spine needs to be looked at to find the source of the leakage. CT myelogram offers more sensitivity but MRI with contrast is noninvasive and may be done first because it may find the source. There is now a technique called digital subtraction myelography that is picking up CSF-venous fistula that may not show up in traditional CT myelogram.
Treatment. EBP done blindly-without detection of source of leakage- or targeted toward the source are the mainstay of treatment and offers a success rate of 64%. Conservative approach such as bed rest and IV fluid works in only 28% of cases. It’s observed that a patient may need more than one treatment for efficacy. Targeted treatment seems to offer greater success2,3,4,5. Surgery is occasionally done.
Complication of treatment. The spinal puncture rarely can cause further dura tear. Another complication of the treatment is Spontaneous Intracranial Hypertension. In this condition, the headache occurs in the supine position and treatment is the opposite: withdrawal of CSF.
- Tubben RE, Jain S, Murphy PB. Epidural Blood Patch. [Updated 2019 Apr 20]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2019 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK482336/
- D’Antona L, Jaime Merchan MA, Vassiliou A, et al. Clinical Presentation, Investigation Findings, and Treatment Outcomes of Spontaneous Intracranial Hypotension Syndrome: A Systematic Review and Meta-analysis. JAMA Neurol. 2021;78(3):329-337. doi:10.1001/jamaneurol. 2020.4799
- Urbach H, Fung C, Dovi-Akue P, Lützen N, Beck J. Spontaneous Intracranial Hypotension. Dtsch Arztebl Int. 2020;117(27-28):480-487. doi:10.3238/arztebl.2020.0480
- Zheng, Y., Lian, Y., Wu, C. et al. Diagnosis and treatment of spontaneous intracranial hypotension due to cerebrospinal fluid leakage. SpringerPlus 5, 2108 (2016) doi:10.1186/s40064-016-3775-z
- Kranz, P.G., Malinzak, M.D., Amrhein, T.J. et al. Curr Pain Headache Rep (2017) 21: 37. https://doi.org/10.1007/s11916-017-0639-3
Reynald Altéma, MD