Exposure to reduced ambient pressure may result in decompression sickness (DCS). Headache is among the DCS symptoms encountered and is usually regarded as neurological DCS, which is traditionally classified as serious DCS. Since cranial sutures may be considered joints, it is possible that some headaches are actually joint pain and when associated with decompression sickness need not be neurological DCS. Records were individually recovered from the Davis Hyperbaric Laboratory at Brooks City-Base, TX. Information was extracted using a detailed survey instrument. Possible joint pain headache cases were identified using three criteria: headache localized at a suture, normal neurologic exam, and resolution within 30 min of hyperbaric oxygen treatment. A total of 729 records documenting treatment for DCS were scrutinized. Of these, 70 cases of altitude DCS with headache were examined. Analysis, using the three criteria, showed 23% (16 cases) of altitude headache DCS symptoms could potentially be re-classified as joint pain. Generally, headache DCS is considered neurological DCS. However, since cranial sutures are joints, both histologically and functionally, and since DCS most commonly affects joints, headache DCS may, at times, be joint pain DCS. Indeed, retrospective data analysis suggests that this possibility exists. Such a reclassification from neurological to joint pain DCS would lessen the aeromedical impact of a DCS headache.

Bryce, Butler, Pilmanis, King, , , , , (2005). Headache and altitude decompression sickness: joint pain or neurological pain? Aviation, space, and environmental medicine, 2005 Nov;76(11):1074-8. https://www.ncbi.nlm.nih.gov/pubmed/16313145