Dr Peter Wilmshurst has been a qualified doctor for over 25 years. He has served on the BSAC Medical Committee since 1977 and also advises the HSE on diving.
Control of the blood Are there any contra-indications for divers on chronic anticoagulation drugs? Julio. Anticoagulant drugs (such as Warfarin or Coumadin) are given to people with increased risk of blood clotting. When considering whether a person on anticoagulants should be allowed to dive, one has to look at a number of factors. First, why is the anticoagulant being given? Some individuals take anticoagulants because they have diseases (often heart diseases or strokes) which would preclude diving. Second, consider the level of control of anticoagulation. If there is under-control, then the problem that the anticoagulants are meant to prevent could occur during or after a dive. A small stroke, chest pain or breathlessness during a dive might produce incapacity in the water, endangering the diver and his/her buddy. After a dive, these symptoms might be mistaken for decompression illness and lead to inappropriate treatment. Conversely, excessive levels of anticoagulation might cause spontaneous bleeding which could also produce problems during a dive. Even if anticoagulant control has been successful over a period of time, there is a third consideration. If bleeding occurs, normal therapeutic levels of anticoagulation will increase the bleeding, and clotting is affected by diving, particularly if the diver gets decompression illness. So, even if the diver is permitted to dive while taking anticoagulants, restrictions should be imposed to reduce the risk of decompression illness.
My 48-year-old husband had a defective aortic valve from birth. He recently had his third open heart surgery, to replace an aortic aneurysm of the ascending aorta with dacron. This also involved his prosthetic valve, which was replaced with a Medtronic-Hall single leaflet. He developed bradycardia and had to have a pacemaker put in. He takes Coumadin. Should he continue diving? Linda. There are a number of reasons why diving might present a high risk in this case. The patient is taking an anticoagulant drug and the same comments made above about anticoagulants apply. In addition the patient has underlying disease of a heart valve and the aorta, which could cause incapacitating symptoms underwater or confusion with DCI on surfacing. He has also had three operations in the chest which might have produced lung injury, placing him at risk of pulmonary barotrauma. Finally he has a pacemaker, which is compressed by the hydrostatic pressure underwater. If one goes deep enough, all pacemakers will start to malfunction, but some tolerate the increased pressures better than others. In tests under hyperbaric conditions, the Thera pacemaker's function started to deteriorate at pressures equivalent to only 20m depth. Some other pacemakers tolerate pressures much better. On balance I believe that this man has too many problems to dive.
Venous thrombosis Is it possible to dive after having a venous sinus thrombosis? I have had one in the last month at the age of 35, and at the moment none of my doctors appear able to say one way or another. I am now taking Warfarin while awaiting the test results. David. It is not possible to say at this stage whether diving in the future will be permitted. We need to wait until the cause of the venous sinus thrombosis has been determined, until we know whether long-term anticoagulation is planned and until we know the level of anticoagulation control in the future. Certainly it will be months before any decision about diving in the future can be made.
Playing with fire coral On a recent dive, I brushed against some fire coral and got a terrible itch. What should I do to help get rid of it? Peter. Coral stings can cause itching that may last for many weeks. This is best treated by applying a steroid cream, but first it is important to make sure there is no infection present. If steroids are applied to an infected area, the infection may get worse.
Tooth truth I have recently had a number of filled teeth cracking and breaking up, sometimes after contact while eating something hard. I told my dentist that I dived and he said that could be the cause. Gerald. There is only one way in which diving commonly causes damage to teeth. If one has a filling that is already partly loose, or a cavity in a tooth, a small gas pocket can be created. During ascent and descent of a dive, the volume of the trapped gas will change. This can further loosen the filling or cause cracking of the tooth. This type of dental barotrauma is associated with toothache during or immediately after the dive. Unless you get dive-related toothache, you should think of other causes for the problem.
Which lens? Which contact lenses are the best for diving? Allan. There are two main problems with contact lenses when diving. First is the danger of them being washed out if the mask floods. This could mean that for the rest of the dive, and after surfacing, the diver may not be able to see properly. Second, bubbles of gas come out of solution in the tears on ascent and become trapped between the contact lens and the cornea. These press on the cornea and cause indentations that distort vision for an hour or two after surfacing. Corneal decompression illness is more common on longer and deeper dives. The problem is greater for hard, non-permeable contact lenses but can occur with any type. However, there is no evidence of any long-term damage. The answer to this question amounts to personal preference.
Diving with epilepsy My wife has suffered from epilepsy for many years. She takes medication, which has stabilised the condition, and has not had an attack for at least 12 years. Can she learn to dive? Peter. Anticonvulsant drugs used to prevent epileptic attacks are believed to interact with the narcotic effects of nitrogen underwater, so people using them are not permitted to dive. In the UK some people with a history of epilepsy, but who have been off anticonvulsants for a number of years without recurrence of fits, are permitted to dive as amateurs. In some other countries an individual is banned from diving as an amateur for life if they have a history of convulsions.
Eye trouble I have had glaucoma in both eyes and recently had a cataract extraction operation. Are there contra-indications for diving with either eye condition? Ezra. After any form of surgery we have to ensure that tissues have healed fully before resuming diving. When the eye has been operated on, we must ensure that healing has produced strong joins, because we are concerned about the risks of trauma to the eye if mask squeeze occurs. We are also keen to ensure that the diver has appropriate lens corrections so that he/she can see adequately. However, if healing is good and vision is adequate, a past cataract extraction and the presence of glaucoma is permissible.
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