Primary stabbing headache (PSH) is a primary syndrome of unknown aetiology, characterised by brief, jabbing stabs predominantly felt in the orbital, temporal and parietal areas, whose frequency may vary from one to many per day, usually responding to
indomethacin. PSH frequency in the general population is not well defined, but recent evidence suggests it could be more frequent than previously thought. In clinical series, PSH incidence was 33/100,000 per year, while in a population study 35.2 % prevalence was found. PSH was previously described as isolated or associated to other
headache syndromes, most frequently with
migraine. There is evidence that an
idiopathic intracranial hypertension without
papilledema, a condition usually associated to significant
stenosis of dural sinuses (93 % sensitivity and specificity), is much more prevalent than believed and may run asymptomatically in up to 11 % of otherwise healthy individuals. In migrainous prone people, a sinus
stenosis-associated
intracranial hypertension without
papilledema (ss-IHWOP) comorbidity may represent a powerful risk factor for progression of
pain. Besides
migraine, significant sinus
stenosis has been found overrepresented also in chronic
tension type headache as well as in exertional,
cough, sexual activity-associated
headaches (all
indomethacin responsive primary
headaches) and in altitude
headache (an
acetazolamide responsive condition). To explore the possible association between venous outflow disturbances and PSH, we retrospectively investigated the co-occurrence of sinus venous
stenosis in patients referring to our
headache centre since 2004 diagnosed with PSH who completed the diagnostic protocol. Out of 50 consecutive patients reporting PSH as the main or as accessory complaint, 8 (6 females, 2 males) performed MR venography (MRV). All MRV revealed significant unilateral or bilateral sinus
stenosis. Mean age at PSH onset was 35.3 ± 18.9 years (range 11-67 years). Duration of attacks ranged 1-3 s. Median daily frequency of attacks was 4 (range 2-20); median number of days per month with PSH presentation was 14 (range 4-30). Six patients described attacks in temporal or parietal areas, one at the top of the head, and one in the occipital area. Only one patient had isolated PSH; all the others were diagnosed also with
migraine without aura. Seven out of eight patients responded to
indomethacin 75 mg/die, and one to
topiramate 100 mg/die. Interestingly, both drugs share with
acetazolamide a CSF pressure lowering effect. Our findings indicate that PSH is associated with central sinus
stenosis and suggest that an undiagnosed ss-IHWOP might be involved in PSH pathogenesis.