Table 1 Diagnostic criteria of RCVS

ICHD-2 (code 6.7.3) [6]

Headache attributed to benign (or reversible) angiopathy of the CNS

A. Diffuse, severe headache of abrupt or progressive onset, with or without focal neurological deficits and/or seizures and fulfilling criteria C and D

B. ‘Strings and beads’ appearance on angiography and SAH ruled out by appropriate investigations

C. One or both of the following:

 1. headache develops simultaneously with neurological deficits and/or seizures

 2. headache leads to angiography and discovery of ‘strings and beads’ appearance

D. Headache (and neurological deficits, if present) resolves spontaneously within 2 months

ICHD-3, beta version (code 6.7.3) [14]

Headache attributed to RCVS

A. Any new headache fulfilling criterion C

B. RCVS has been diagnosed

C. Evidence of causation demonstrated by at least one of the following:

 1. headache, with or without focal deficits and/or seizures, has led to angiography (with ‘strings and beads’ appearance) and diagnosis of RCVS 2. headache has either or both of the following characteristics:

   a) recurrent during ≤1 month, and with thunderclap onset

   b) triggered by sexual activity, exertion, Valsalva maneuvers, emotion, bathing and/or showering

 3. no new significant headache occurs >1 month after onset

D. Not better accounted for by another ICHD-3 diagnosis, and aneurysmal SAH has been excluded by appropriate investigations.

ICHD-3, beta version (code 6.7.3.1) [14]

Headache probably attributed to RCVS

A. Any new headache fulfilling criterion C

B. RCVS is suspected, but cerebral angiography is normal

C. Probability of causation demonstrated by all of the following:

 1. at least two headaches within 1 month, with all three of the following characteristics:

   a) thunderclap onset, and peaking in <1 minute

   b) severe intensity

   c) lasting ≥5 minutes

 2. at least one thunderclap headache has been triggered by one of the following:

   a) sexual activity (just before or at orgasm)

   b) exertion

   c) Valsalva-like maneuver

   d) emotion

   e) bathing and/or showering

   f) bending

 3. no new thunderclap or other significant headache occurs >1 month after onset

D. Not fulfilling ICHD-3 criteria for any other headache disorder

E. Not better accounted for by another ICHD-3 diagnosis, and aneurysmal SAH has been excluded by appropriate investigations.