He reports that these started 3 days ago. His headache is worse when he stands, and resolves when he lies down. Valsalva maneuver makes the headache much worse. The headaches are present in the occipital region. He also has noticed the onset of tinnitus. A physical exam reveals that his blood pressure is 110/70 mm Hg, his pulse is 60 beats per minute, and his temperature is 36.4° C. His standing BP is 105/60 mm Hg and standing pulse is 66 bpm. Both his neurologic exam and noncontrast head CT scan are normal.
Which of the following is the most likely diagnosis?
A) Subarachnoid hemorrhage
B) POTS (Postural orthostatic tachycardia syndrome)
C) Hypnic headache
D) Spontaneous intracranial hypotension (SIH)
E) Acoustic neuroma
The most likely cause for this patient’s headaches given his set of symptoms is spontaneous intracranial hypotension. Orthostatic headaches are common with POTS, but the absence of tachycardia with standing makes this diagnosis unlikely.
Dr. Paauw
Spontaneous intracranial hypotension has symptoms that we are all familiar with in the post–lumbar puncture patient. In patients with post-LP headache, the positional nature makes it easy to diagnose. Patients who have had a lumbar puncture have a clear reason they have a cerebrospinal fluid (CSF) leak, leading to intracranial hypotension. Those with SIH do not.
Related research
Schievink summarized a lot of useful information in a review of patients with spontaneous intracranial hypotension.1 The incidence is about 5/100,000, with the most common age around 40 years old. The most common symptom is orthostatic headache. The headache usually occurs within 15 minutes upon standing, and many patients have the onset of headache rapidly upon standing.
Usually the headache improves with lying down, and it is often brought on with Valsalva maneuver. Many patients report headaches that are worse in the second half of the day.
Orthostatic headache occurs in almost all patients with spontaneous intracranial hypotension, but in one series it occurred only in 77% of patients with SIH.2 The patients who did not have typical headaches are more likely to have auditory symptoms such as tinnitus and muffled hearing.3
When you suspect SIH, appropriate workup is to start with brain MR imaging with contrast. Krantz and colleagues found dural enhancement was present in 83% of cases of SIH, venous distention sign in 75%, and brain sagging in 61%.4
About 10% of patients with SIH have normal brain imaging, so if the clinical features strongly suggest the diagnosis, moving on to spinal imaging with CT myelography or spinal MR are appropriate next steps.5
The causes of SIH are meningeal diverticula (usually in the thoracic or upper lumbar regions), ventral dural tears (usually from osteophytes), and cerebrospinal fluid–venous fistulas. Treatment of SIH has traditionally included a conservative approach of bed rest, oral hydration, and caffeine. The effectiveness of this is unknown, and, in one small series, 61% had headache symptoms at 6 months.6
Epidural blood patches are likely more rapidly effective than conservative therapy. In one study comparing the two treatments, Chung and colleagues found that 77% of the patients who received an epidural blood patch had complete headache relief at 4 weeks, compared with 40% of those who received conservative measures (P < .05).7
Clinical pearls
- Strongly consider SIH in patients with positional headache.
- Brain MR should be the first diagnostic test.
Dr. Paauw is professor of medicine in the division of general internal medicine at the University of Washington, Seattle, and serves as 3rd-year medical student clerkship director at the University of Washington. He is a member of the editorial advisory board of Internal Medicine News. Dr. Paauw has no conflicts to disclose. Contact him at imnews@mdedge.com.
References
1. Schievink WI. Spontaneous spinal cerebrospinal fluid leaks and intracranial hypotension. JAMA. 2006;295:2286-96.
2. Mea E et al. Headache attributed to spontaneous intracranial hypotension. Neurol Sci. 2008;29:164-65.
3. Krantz PG et al. Spontaneous Intracranial Hypotension: 10 Myths and Misperceptions. Headache. 2018;58:948-59.
4. Krantz PG et. al. Imaging signs in spontaneous intracranial hypotension: prevalence and relationship to CSF pressure. AJNR Am J Neuroradiol. 2016;37:1374-8.
5. Krantz PG et al. Spontaneous intracranial hypotension: Pathogenesis, diagnosis, and treatment. Neuroimaging Clin N Am. 2019;29:581-94.
6. Kong D-S et. al. Clinical features and long-term results of spontaneous intracranial hypotension. Neurosurgery. 2005;57:91-6.
7. Chung SJ et al. Short- and long-term outcomes of spontaneous CSF hypovolemia. Eur Neurol. 2005;54:63-7.