Diagnostic Criteria for Headache Due to Spontaneous Intracranial Hypotension: A Perspective

Abstract

The clinical and radiographic manifestations of spontaneous intracranial hypotension are highly variable and many patients do not satisfy the 2004 International Classification of Headache Disorders criteria. We developed new diagnostic criteria for spontaneous intracranial hypotension based on cases we have seen reflecting the variable manifestations of the disorder. These criteria provide a basis for change when the classification criteria are next revised.

The diagnostic criteria consist of A, orthostatic headache; B, the presence of at least one of the following: low opening pressure (≤60 mm H₂O), sustained improvement of symptoms after epidural blood patching, demonstration of an active spinal cerebrospinal fluid leak, cranial magnetic resonance imaging changes of intracranial hypotension (eg, brain sagging or pachymeningeal enhancement); C, no recent history of dural puncture; and D, not attributable to another disorder.

The typical patient with spontaneous intracranial hypotension presents with a history of obvious orthostatic headache associated with neck stiffness, tinnitus, hypacusia, and often photophobia or nausea. Brain magnetic resonance imaging (MRI) may show any combination of brain sagging, pachymeningeal enhancement, and subdural fluid collections. Opening pressure is low on lumbar puncture and a cerebrospinal fluid (CSF) leak is demonstrated on spinal MRI, myelography, or cisternography. The headache resolves soon after epidural blood patching. The International Classification of Headache Disorders – second edition (2004; ICHD‐II) criteria exemplify such a typical scenario.1 However, it has become well established that the clinical and radiographic manifestations of spontaneous intracranial hypotension are highly variable2-4 and other diagnostic schemes have been formulated recently to better reflect these variable manifestations.5, 6 In one study it was found that only 3% of patients with spontaneous intracranial hypotension and typical neuroimaging features satisfied the ICHD‐II criteria for spontaneous intracranial hypotension.6

Based on our collective experience with spontaneous intracranial hypotension and recent literature, we propose refined diagnostic criteria for spontaneous intracranial hypotension to encompass the varied clinical and radiographic manifestations of this disorder without compromising objective confirmatory evidence. These criteria provide a basis for change in the ICHD.

Compared to the ICHD‐II,1 no time limit is set for the duration within which the orthostatic headache should worsen and associated symptoms are not taken into consideration. The orthostatic component of the headache often is measured in hours rather than minutes and the associated symptoms are highly variable.2-7 Furthermore, the current criteria indicate epidural blood patching is universally effective – criterion d– this is manifestly not the case. At least one‐fourth of patients are not cured by epidural blood patching and about half require more than 1 blood patch.8, 9

Compared to the set of previously published criteria from which the current criteria were derived,5 demonstration of spinal meningeal diverticula is no longer accepted as a criterion. The diagnosis of spinal meningeal diverticula can be problematic and inter‐observer reliability among neuroradiologists is poor.10 Using the current criteria, the diagnosis can be made in the absence of any radiographic confirmation (eg, orthostatic headache and low opening pressure) – an important consideration when such radiographic means are not readily available. Such a change facilitates treatment.

Compared to criteria proposed by Mea et al,6 the current criteria differ by allowing the diagnosis to be made in the presence of normal imaging results. Up to one‐fourth of patients with spontaneous intracranial hypotension may have a normal brain MRI.5

• Diagnostic criteria for headache due to spontaneous intracranial hypotension

  • A)

    Orthostatic headache

  • B)

    The presence of at least one of the following:

    • 1

      Low opening pressure (≤60 mm H₂O)

    • 2

      Sustained improvement of symptoms after epidural blood patching

    • 3

      Demonstration of an active spinal CSF leak

    • 4

      Cranial MRI changes of intracranial hypotension (eg, brain sagging or pachymeningeal enhancement)

  • C)

    No recent history of dural puncture

  • D)

    Not attributable to another disorder

Orthostatic Headache.— The headache in patients with CSF leaks may resemble a post‐dural puncture headache, where the headache occurs immediately or within seconds of assuming an upright position and resolves quickly (within 1 minute) after assuming a supine position. However, the headache may present with worsening within minutes or hours of being upright and may improve, but not completely resolve, within minutes or hours of being supine. There is a clear postural component in most cases, but it may not be as dramatic or immediate as a post‐dural puncture headache. The orthostatic nature of the headache at the onset of the symptoms should be sought when eliciting a history, as this feature may become much less obvious over time.

While autologous epidural blood patches (EBPs) are frequently effective, the response to a single EBP may not be permanent, and complete relief of symptoms may not occur until 2 or more EBPs are performed. However, some degree of sustained improvement, beyond a few days, is generally expected. In some cases, sustained improvement cannot be achieved with EBPs and surgical intervention may be required. It is not clear that all patients have an active CSF leak, despite a compelling history or brain imaging features compatible with a CSF leak.