Cerebral venous system and anatomical predisposition to high-altitude headache

The Traumatic Brain Injury Centre, St Mary's Hospital, Imperial College, London, W1 2NY
Annals of Neurology (Impact Factor: 11.91). 03/2013; 73(3). DOI: 10.1002/ana.23796
Source: PubMed

ABSTRACT OBJECTIVE: As inspired oxygen availability falls with ascent to altitude, some individuals develop high-altitude headache (HAH). We postulated that HAH results when hypoxia-associated increases in cerebral blood flow occur in the context of restricted venous drainage, and is worsened when cerebral compliance is reduced. We explored this hypothesis in 3 studies. METHODS: In high-altitude studies, retinal venous distension (RVD) was ophthalmoscopically assessed in 24 subjects (6 female) and sea-level cranial magnetic resonance imaging was performed in 12 subjects ascending to 5,300m. Correlation of headache burden (summed severity scores [0-4] ≤24 hours from arrival at each altitude) with RVD, and with cerebral/cerebrospinal fluid (CSF)/venous compartment volumes, was sought. In a sea-level hypoxic study, 11 subjects underwent gadolinium-enhanced magnetic resonance venography before and during hypoxic challenge (fraction of inspired oxygen = 0.11, 1 hour). RESULTS: In the high-altitude studies, headache burden correlated with both RVD (Spearman rho = 0.55, p = 0.005) and with the degree of narrowing of 1 or both transverse venous sinuses (r = -0.56, p = 0.03). It also related inversely to both the lateral + third ventricle summed volumes (Spearman rho = -0.5, p = 0.05) and pericerebellar CSF volume (r = -0.56, p = 0.03). In the hypoxic study, cerebral and retinal vein engorgement were correlated, and rose as the combined conduit score fell (a measure of venous outflow restriction; r = -0.66, p < 0.05 and r = -0.75, p < 0.05, respectively). INTERPRETATION: Arterial hypoxemia is associated with cerebral and retinal venous distension, whose magnitude correlates with HAH burden. Restriction in cerebral venous outflow is associated with retinal distension and HAH. Limitations in cerebral venous efferent flow may predispose to headache when hypoxia-related increases in cerebral arterial flow occur. ANN NEUROL 2012;

Download full-text


Available from: Michael PW Grocott, Aug 16, 2015
  • Source
    • "Wilson first pointed out the analogy between the Space Adaptation Syndrome and the effects of altitude on the cerebral circulation, since they both lead to venous distension (Wilson et al., 2011). Wilson and colleagues suggest that venous distension plays an important role in high altitude headache (Wilson et al., 2013). Gabriel Willmann followed with a talk on the posterior part of the eye as a window on the brain in conditions of hypoxia (Willmann et al., 2014). "
    High altitude medicine & biology 05/2015; DOI:10.1089/ham.2015.0046 · 1.82 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: 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.
    Neurological Sciences 05/2013; 34 Suppl 1(1):157-9. DOI:10.1007/s10072-013-1374-0 · 1.50 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: High altitude headache (HAH) has been defined by the International Headache Society as a headache that appears within 24 hours after ascent to 2,500 m or higher [1••]. The headache can appear in isolation or as part of acute mountain sickness (AMS), which has more dramatic symptoms than the headache alone. If symptoms are ignored, more serious conditions such as high altitude cerebral edema (HACE), high altitude pulmonary edema (HAPE), or even death may ensue. While there is no definitive understanding of the underlying pathophysiologic mechanism, it is speculated that HAH occurs from the combination of hypoxemia-induced intracranial vasodilation and subsequent cerebral edema. There are a number of preventive measures that can be adopted prior to ascending, including acclimatization and various medications. A variety of pharmacological interventions are also available to clinicians to treat this extremely widespread condition.
    Current Pain and Headache Reports 12/2013; 17(12):383. DOI:10.1007/s11916-013-0383-2 · 2.26 Impact Factor
Show more