Migraines, PFO and AS2299
Hi all,
Would love a consensus opinion on an interesting situation I've had up here in Townsville.
Saw a 25yo Marine Biology PhD from the university who has had issues with obtaining her AS 2299 medical. Amateur diver for nearly 10 yrs, and has completed >200 dives without complication.
She has a history of migraines with aura, which includes both a hemiopia and paraesthesia of her left face and right arm. Migraines not triggered by diving, and never has one whilst diving. MRI is normal. Had an echo by her GP, which revealed a PFO (?small) on bubble contrast on valsalva.
Saw Hyperbaric Physician at a different hospital who recommended she cease all diving activities, including recreational, but referred her for PFO closure.
Came to me wanting advice regarding migraines, as concerned that even with successful PFO closure, the migraines would still preclude her from gaining her AS 2299.
My understanding is that she is correct; migraines with focal neuro events are contraindicatory to diving according to AS 2299.
My question for the forum is, if she has her PFO closed, and her migraines cease (albeit unlikely), would anyone grant her a AS 2299 medical? If so, how long would you want her to be migraine free?
She is able to continue with her PhD without diving.
Thanks.
Clinton
Agree broadly with Glen. She would need to be free of migraine with aura for 12 months - then I would probably be happy to pass her with an exiry date to get her back for review. Sticky one...
Mike
Hi Clinton,
1) I think that if she get severe migraines with neurological manifestations then she shouldn't dive. The fact that she hasn't gotten them in the 200+ dives is not really relevant as dive number 256 is the one I am always worried about (tongue in cheek).
2) If she has a PFO closure and is migraine free then the issue becomes more complicated. Does she have a precipitating factor for her migraines (tiredness, stress, food type etc?). I would wait at least 1 year minimum and she would have to have zero migraines in that period and a confirmed ECHO that her PFO was completely closed with the occlusion device with valsalva.
3) I think that she is probably well advised to get the PFO closed with the severity of the migraines (as that has other life effects) but the diving shouldn;t be the reason for having it done. However if the closure solves the problem then I would consider letting her dive again based on the work of Wilmshurst and PFO closure to resume diving (migraine resolution has to be added to this recommendation however).
Regards Glen
Dear Clinton
I am an adult congenital cardiologist with an interest in diving medicine in the UK (on UK SPorts diving Medical Committee). I close about 100 PFOs a year, about 25% in divers - for several years now. Firstly with such a clear history of migraine with neurology (aura) I would question whether the PFO is small. The bubble testing protocol that should be used is that of Peter Wilmshurst as this is the one validated the best for divers. Unfortunately this is a difficult test to do well and in the UK many hospitals do not do it properly. It requires good bubble contrast - blood 1ml, air, 1 ml and saline 8mls to be forced too and fro through a 3 way tap and then injected such that it fills the right atrium (Gelofusin contrast goes through the lungs and gives false positives so don't use that). THe Valsalva has to be long enough to keep blood out of the thorax so that the pressure in the left atrium drops and the left ventricle gets smaller. On release the right atrium fills and the left atrium remains at a lower pressure. If there is a PFO, bubbles will be "sucked" across the septum. Straining or bearing down without a significant rise in intrathoracic pressure to reduce LV volume is not enough. Only if the study meets the quality control criteria can you quantify the PFO size. I have many examples of "small PFO" or "no PFO" that have PFO diameters of 8mm or more - one last week sent to me in a woman with stroke who had a 9mm PFO - she had a local bubble test - 10 bubbles (small) - when I tested her there were > 200 bubbles.
There are 2 reasons to have the migraine regulation - firstly to weed out those with big PFO and stop them diving - but PFO closure would mitigate this risk. Secondly to avoid difficult diagnostic situations after diving - ? DCI ? migraine. You as a community should decide if the latter is sufficient to preclude diving, but in the UK we make people fit after PFO closure if it is successful (and properly checked that no siginificant residual shunt - back to testing properly), even if the migraine does not go away. Clinically the migraine aura tends to be the same for a given patient, so documenting what that is or asking the patient if it is the "usual" migraine aura is usually sufficient.
If you leave the PFO open we recommend to dive to 15 metres (or air equivalent on Nitrox) one dieve per day only or to use DCIEM tables. We do not have a randomised trial on this either, but it is the practise of the UK Sports diving medical committee (an organisation led by Peter Wilmshurst and now Phil Bryson in the UK so well versed in PFO related issues - look at these names in the literature and you will see they know as much as anyone about PFO).
Lastly the migraine often improves after PFO closure if there is a big shunt, but total cure is less likely. Randomised trials have been criticised, so proof of tis is still lacking, but is the clinical experience of most operators closing PFO for divers or stroke patients.
Sorry to write such a long post, but I have only just joined your organisation as I was looking at coming to SPUMS scientific meeting next year, as the UHMS and EUBS are so hyperbaric and I am interested in diving. I also hear the diving is not so bad and the company congenial! Feel free to e-mail me direct if you need further evidence to back up my statements above.
Mark Turner
markturner45@hotmail.com