The Journal of Neurology, Neurosurgery and Psychiatry has published a first-ever multidisciplinary, consensus-based guideline on the diagnosis and management of spontaneous intracranial hypotension (SIH).
SIH due to leakage of cerebrospinal fluid (CSF) is readily treated, with nontargeted epidural blood patches figuring prominently in the early treatment pathway. However, as the guideline authors noted, misconceptions and lack of awareness of SIH in the wider clinical community often result in misdiagnosis or late diagnosis. Heterogenous treatment protocols may also have worse outcomes.
Therefore, 29-member special-interest group developed the SIH guideline; this group represented neurology, neuroradiology, neurosurgery, and anesthesiology specialties, as well as the local patient community. The consensus guideline focuses on best practices to increase awareness of SIH, and promote efficient and accurate diagnosis and consistent treatment protocols. The guideline is aimed particularly toward nonexpert clinicians.
The evidence underpinning the subsequent guideline statements was graded as to strength of recommendations and quality of evidence, using the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) system.
We hope that this multidisciplinary consensus clinical guideline will lead to improved and more uniform pathways in the investigation and management of SIH in the UK, and potentially internationally …
Clinical features of SIH
Orthostatic headache is a key symptom that should prompt suspicion of SIH. Under the current working definition, orthostatic headache is minimal on waking, increases within 2 hours of upright activity, and substantially improves within 2 hours of returning to recumbent posture.
Differential Diagnosis of SIH
Differential diagnosis should include postural tachycardia and orthostatic hypotension, cervicogenic headache, and migraine.
The guideline authors noted that a patient’s history may not suggest predisposition to CSF leak.
Investigational and referral pathways
Nonurgent cases may be referred to a locally available neurologist. Urgent or ambiguous cases should be directed to a specialized clinic, ideally 1 with access to advanced myelography and expertise in both nonsurgical (eg, epidural blood patch) and surgical procedures.
Brain and spine magnetic resonance imaging (MRI) studies are preferred over computed tomography (CT) for initial investigation. Rarely, MRI studies may be normal in SIH, and are suggestive of CSF-venous fistula. Such diagnostic ambiguity should promptly referral to a multidisciplinary specialist clinic. It is uncertain whether empirical (nontargeted) blood patches are efficacious in diagnosing such cases.
Lumbar puncture is not recommended as a routine diagnostic procedure.
The guideline authors acknowledge that myelography is used to localize a CSF leak and plan targeted treatment. Contrast and nuclear myelography likely have only limited applications.
Conservative and Interventional Treatments for SIH
Conservative strategies may include bed rest, hydration, abdominal binders, avoidance of Valsalva maneuvers, and possibly caffeine administration. Bed rest carries risks for deconditioning and deep vein thrombosis.
Nontargeted vs Targeted Epidural Blood Patching
Nontargeted epidural blood patching may be indicated following failure of conservative management after 2 weeks. Not more than 2 nontargeted blood patches are recommended, when there is no sustained response to the first patch.
Targeted, image-guided epidural blood patches may be indicated if conservative management and/or nontargeted patching have failed. Targeting requires localization of the CSF leak via CT myelography and/or digital subtraction myelography.
Informed consent should be obtained for nontargeted and targeted blood patches, and fibrin sealant patching; and patients should receive appropriate aftercare and follow-up.
Other Treatment Considerations
Endovascular procedures may be considered as first-line treatment for myelogram-confirmed CSF-venous fistula.
Neurosurgical treatment should be considered in the event of failure of conservative and/or nontargeted and targeted patching. Decision making should include the patient and a multidisciplinary specialist team.
Patients with musculoskeletal deconditioning, and those with orthostatic intolerance, may benefit from orthostatic rehabilitation.
Management of SIH Complications
Important sequelae of SIH include headache, superficial siderosis, subdural hematoma, and cerebral venous thrombosis. Suspicion of such complications should inform diagnostic and treatment pathway.
Asymptomatic patients with radiographic evidence of pathology may remain at risk of superficial siderosis and/or other long-term sequelae. Those patients should be managed by a multidisciplinary team, and followed for repeat imaging on an annual or biannual basis.
Pharmacological management of SIH-related headaches may include acetaminophen (paracetamol) and certain nonsteroidal anti-inflammatory drugs (NSAIDs). Long-term opioid administration is not advised. Certain pain medications lower CSF and require caution in the context of SIH; these include indomethacin, topiramate, candesartan, and beta blockers.
Post-treatment rebound headache may indicate secondary intracranial hypertension, and should prompt re-evaluation. Current evidence does not support use of acetazolamide, topiramate, or diuretics in this context.
Other neurological concomitants of SIH, such as nausea and vomiting, may benefit from additional nonpharmacologic and pharmacologic management; but little evidence exists to support specific measures.
Follow-Up Care After SIH Treatment
All patients should have access to follow-up after any SIH treatment. Early review should occur within 48 hours; late-stage follow-up may extend as far as 6 months. Reassessment should include survey of headache and other relevant symptoms, and measures of function and disability. Post-recovery follow-up imaging can be conducted at specialist clinicians’ discretion; but invasive imaging techniques are not indicated in this context.
Implementation of SIH Guideline Recommendations
“We hope that this multidisciplinary consensus clinical guideline will lead to improved and more uniform pathways in the investigation and management of SIH in the UK, and potentially internationally, stimulating interest in the topic and highlighting future research questions,” the guideline authors wrote.
They acknowledged that lack of local resources for certain advanced myelographic procedures, and/or for non-targeted and targeted blood patching, could limit implementation of the guideline recommendations. Furthermore, the evidence base for some recommendations currently is limited. However, as the relevant literature continues to expand, an update to this guideline document is planned for 3 years post-publication.
Disclosure: Several study authors have declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of the author’s disclosures.