Spontaneous intracranial hypotension is a medical condition caused by loss of cerebrospinal fluid from the spinal canal, resulting in headaches and neurological symptoms. It most commonly presents with orthostatic headaches that are less apparent over time. Brain MRI and spine MRI are used to diagnose and locate CSF leaks. Treatment involves conservative measures, percutaneous patching of leaks, or surgical closure. Spontaneous intracranial hypotension can lead to complications like subdural hematomas if not properly diagnosed and treated.

1. A D E W I J A Y A , M D – M A Y 2 0 2 3
Spontaneous Intracranial Hypotension

2. Introduction
 A debilitating medical condition caused by loss of
CSF from the spinal canal
 Not life threatening but cause considerable
morbidity, result in significant long-term disability,
and in rare cases leads to decreased level of
consciousness and coma
Takai K, Niimura M, Hongo H, et al. Disturbed Consciousness and Coma: Diagnosis and Management of Intracranial Hypotension Caused by a Spinal Cerebrospinal Fluid Leak. World
Neurosurg 2019; 121: e700–11.
Kranz PG, Gray L, Malinzak MD, Amrhein TJ. Spontaneous Intracranial Hypotension: Pathogenesis, Diagnosis, and Treatment. Neuroimaging Clin N Am 2019; 29: 581–94.
Paris D, Rousset D, Bonneville F, et al. Cerebral Venous Thrombosis and Subdural Collection in a Comatose Patient: Do Not Forget Intracranial Hypotension. A Case Report. Headache 2020;
60: 2583–8.

3. Epidemiology
 Incidence: 5 cases per 100 000 person-years
 Female : Male = 2 : 1
 The peak incidence is around 40 years of age, and
SIH is rare but not absent in children
 Risk factors: connective tissue disorder such as
Marfan syndrome and Ehlers-Danlos syndromes
Luetzen N, Dovi-Akue P, Fung C, Beck J, Urbach H. Spontaneous intracranial hypotension: diagnostic and therapeutic workup. Neuroradiology. 2021 Nov;63(11):1765-72.
Dobrocky T, Nicholson P, Häni L, Mordasini P, Krings T, Brinjikji W, Cutsforth-Gregory JK, Schär R, Schankin C, Gralla J, Pereira VM. Spontaneous intracranial hypotension: searching for the
CSF leak. The Lancet Neurology. 2022 Feb 25.
Samanta D. Headaches in Loyes-Dietz Syndrome. J Child Neurol 2019; 34: 144–7.
Pichott A, Bernstein T, Guzmán G, Fariña G, Aguirre D, Espinoza A. Dural ectasia and intracranial hypotension in marfan syndrome. Rev Chil Pediatr 2020; 91: 591–6.

4. Clinical Presentation
 Orthostatic headache; less apparent over time,
making correct diagnosis more challenging
 Non-orthostatic forms of headache include
thunderclap, non-positional, exertional, cough-
related, and “second-half-of-the-day
 Any patient with unexplained chronic headache
should be evaluated for potential SIH
Häni L, Fung C, Jesse CM, et al. Insights into the natural history of spontaneous intracranial hypotension from infusion testing. Neurology 2020; 95: e247–55.
Mokri B, Aksamit A, Atkinson J. Paradoxical Postural Headaches in Cerebrospinal Fluid Leaks. Cephalalgia 2004; 24: 883–7.

5. Pathophysiology
 Increased efflux of CSF in the upright position,
leading to traction on pain-sensitive fibers within the
dura mater
 Vestibulo-cochlear disturbances may result from
negative intracranial pressure transmitted through
the patent cochlear aqueduct and perilymph leading
to endolymphatic hydrops and Meniere’s disease

6. Pathophysiology
 Additional symptoms such as diplopia, dysgeusia,
and vestibulo-cochlear disturbances may also occur
and are related to brain sagging and traction on the
cranial nerves. This phenomenon is due to the
decrease in buoyant force normally provided by the
CSF, which under physiological conditions reduces
downforce of the brain and uplifts the structures
despite gravity
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Advances. InTech, 2017: 62–87.
Yamamoto M, Suehiro T, Nakata H, et al. Primary low cerebrospinal fluid pressure syndrome associated with galactorrhea. Intern Med 1993; 32: 228–31.

7. Classification of CSF Leaks

8. Diagnosis
 Imaging modality (MRI, CT, fluoroscopy,
ultrasound) – CT/MRI cysternography
 Additional diagnostic tools include lumbar infusion
testing, optic nerve sheath ultrasound and
intrathecal gadolinium enhanced spine MRI.
Dobrocky T, Nicholson P, Häni L, Mordasini P, Krings T, Brinjikji W, Cutsforth-Gregory JK, Schär R, Schankin C, Gralla J, Pereira VM. Spontaneous intracranial hypotension: searching for the
CSF leak. The Lancet Neurology. 2022 Feb 25.

9. Brain MRI (Bern Score)
Dobrocky T, Grunder L, Breiding PS, Branca M, Limacher A, Mosimann PJ, Mordasini P, Zibold F, Haeni L, Jesse CM, Fung C, Raabe A, Ulrich CT, Gralla J, Beck J, Piechowiak EI (2019)
Assessing spinal cerebrospinal fluid leaks in spontaneous intracranial hypotension with a scoring system based on brain magnetic resonance imaging findings. JAMA Neurol 76:580–587

10. Spine MRI
 T2-weighted sequences show so-called spinal
longitudinal extradural fluid (contrast) (SLEC) in
60% of patients.
Luetzen N, Dovi-Akue P, Fung C, Beck J, Urbach H. Spontaneous intracranial hypotension: diagnostic and therapeutic workup. Neuroradiology. 2021 Nov;63(11):1765-72.

11. Diagnostic Algorhytm
Luetzen N, Dovi-Akue P, Fung C, Beck J, Urbach H. Spontaneous intracranial hypotension: diagnostic and therapeutic workup. Neuroradiology. 2021 Nov;63(11):1765-72.

12. Luetzen N, Dovi-Akue P, Fung C, Beck J, Urbach H. Spontaneous
intracranial hypotension: diagnostic and therapeutic workup.
Neuroradiology. 2021 Nov;63(11):1765-72.

13. Farb RI, Forghani R, Lee SK, Mikulis DJ, Agid R. The
venous distension sign: a diagnostic sign of intracranial
hypotension at MR imaging of the brain. American
Journal of Neuroradiology. 2007 Sep 1;28(8):1489-93.

14. Farb RI, Forghani R, Lee SK, Mikulis DJ, Agid R. The venous distension sign: a diagnostic sign of intracranial hypotension
at MR imaging of the brain. American Journal of Neuroradiology. 2007 Sep 1;28(8):1489-93.

15. Complications
 Formation of subdural hematomas
 Transtentorial herniation with compression of the
diencephalon and traction on cerebral sinuses
resulting in deep venous thrombosis  decreased
level of consciousness and coma
 Brain superficial siderosis
 Nonconvulsive status epilepticus
 Cognitive decline (frontotemporal brain sagging
syndrome)
Dobrocky T, Nicholson P, Häni L, Mordasini P, Krings T, Brinjikji W, Cutsforth-Gregory JK, Schär R, Schankin C, Gralla J, Pereira VM. Spontaneous intracranial hypotension: searching for the
CSF leak. The Lancet Neurology. 2022 Feb 25.

16. Differential Diagnosis
Dobrocky T, Nicholson P, Häni L, Mordasini P, Krings T, Brinjikji W, Cutsforth-Gregory JK, Schär R, Schankin C, Gralla J, Pereira VM. Spontaneous intracranial hypotension: searching for the
CSF leak. The Lancet Neurology. 2022 Feb 25.

17. Treatment
 Multidisciplinary setting by neurologists,
neuroradiologists and neurosurgeons
 Conservative: bed rest and caffeine
 Percutaneous treatment with epidural patching
(targeted or non-targeted)
 Surgical or endovascular closure of the CSF leak or
fistula
Dobrocky T, Nicholson P, Häni L, Mordasini P, Krings T, Brinjikji W, Cutsforth-Gregory JK, Schär R, Schankin C, Gralla J, Pereira VM. Spontaneous intracranial hypotension: searching for the
CSF leak. The Lancet Neurology. 2022 Feb 25.

18. Treatment
 Epidural blood patching in patients with SIH often
fails to provide permanent relief
 Surgical repair of spinal CSF leaks can be curative
but requires precise preoperative leak localization
 Spinal CSF-venous fistulas typically do not resolve
with blood patching and instead require surgical
obliteration or endovascular embolization
Dobrocky T, Nicholson P, Häni L, Mordasini P, Krings T, Brinjikji W, Cutsforth-Gregory JK, Schär R, Schankin C, Gralla J, Pereira VM. Spontaneous intracranial hypotension: searching for the
CSF leak. The Lancet Neurology. 2022 Feb 25.

19. Summary
 Orthostatic headache
 Brain and spine MRI
 Low lumbar puncture opening pressure is not a
reliable marker of SIH
 Consider a spinal CSF-leak in non-geriatric patients
with non-traumatic (bilateral) subdural hematoma

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