| IHS | Diagnosis | ICD-10 |
|---|---|---|
| 10.1.2 | Diving headache | G44.882 |
| Coded elsewhere | 1. Migraine , 2. Tension-type headache , 4.3 Primary exertional headache , 11.2.1 Cervicogenic headache , 13.6 Supraorbital neuralgia , 13.10 External compression headache and 13.11 Cold-stimulus headache precipitated by diving are coded as those disorders. | |
Diagnostic criteria:
- Headache, no typical characteristics known, fulfilling criteria C and D
- Diving to depth below 10 m
- Headache develops during diving and is accompanied by at least one of the following symptoms of CO2 intoxication in the absence of decompression illness:
- light-headedness
- mental confusion
- dyspnoea
- flushed feeling in the face
- motor incoordination
- Headache resolves within 1 hour after treatment with 100% O2
Comment:
Hypercapnia (arterial PCO2 >50 mm Hg) is known to cause relaxation of cerebrovascular smooth muscle and lead to vasodilatation and increased intracranial pressure. There is some evidence that hypercapnia in the absence of hypoxia is associated with headache. The best clinical example of headache attributed to hypercapnia occurs in divers. Carbon dioxide may accumulate in a diver who intentionally holds his or her breath intermittently (skip breathing) in a mistaken attempt to conserve air, or takes shallow breaths to minimise buoyancy variations in the narrow passages of a wreck or cave. Divers may also hypoventilate unintentionally when a tight wetsuit or buoyancy compensator jacket restricts chest wall expansion, or when ventilation is inadequate in response to physical exertion. Strenuous exercise increases the rate of CO2 production more than 10-fold, resulting in a transient elevation of PCO2 to more than 60 mm Hg. Diving headache usually intensifies during the decompression phase of the dive or upon resurfacing.
Mild non-specific headache is also common in divers with decompression illness, and may be associated with musculoskeletal pain and, in more serious cases, with focal neurological and/or respiratory symptoms, loss of consciousness and/or cognitive deficits.
Headache in divers can also occur as a result of carbon monoxide intoxication which rarely contaminates divers' compressed-air supply if the air intake system is positioned in such a way as to gather improperly directed combustion-engine exhaust. Such headache is coded as 8.1.3 Carbon monoxide-induced headache.
Migraine, tension-type headache, primary exertional headache, cervicogenic headache, supraorbital neuralgia, external compression headache and cold-stimulus headache can occur during a dive, but diving in these instances should be considered a precipitating factor rather than the cause.
