ANATOMY OF A DIVER
The brain : Stroke
The likelihood of having a stroke increases as we get older . Dr Megan Evans of DDRC Healthcare sets out the implications
Diving is an increasingly popular sport , and the average age of diver in the UK is going up . This means that we ’ re seeing more divers who have various medical conditions , including stroke . There are around 100,000 people in the UK who suffer a stroke every year , with approximately one quarter of all strokes in people under 65 years old . So , what do we need to consider in a diver who has a stroke ?
What is a stroke ?
A stroke occurs when the blood supply to part of the brain is cut off . Oxygen levels drop ( ischaemia ) and the affected brain cells start to die ( infarct ). Most commonly this is due to a blood clot blocking a blood vessel , but it can be caused by a bleed into the brain , or other rare causes such as fat or air blocking a vessel .
Symptoms depend on what part of the brain is affected . They can include limb weakness and numbness , facial paralysis , and speech or visual disturbances . Some people recover completely ; others are left with long term symptoms . Common risk factors for having a stroke include high blood pressure , high cholesterol , diabetes and smoking .
Can I dive if I have had a stroke ?
Some individuals who have had a stroke may be able to be return to diving with restrictions on the type of diving they do . However , they will definitely need to be assessed by a diving doctor as there are a few issues that need to be considered .
Firstly , an assessment of the risk of you having another stroke is needed from your consultant or GP . If you are considered high risk , then there is a high chance you might have another stroke or other cardiovascular event , such as a heart attack . A stroke or heart attack underwater could be fatal , and for this reason it may not be possible to return to diving .
However , stroke often happens due to underlying problems such as high blood pressure , diabetes and high cholesterol - by addressing and managing these problems effectively , your risk of stroke will be lower and it may be possible for you to return to diving .
It is likely that you will be prescribed an antiplatelet medication such as aspirin or clopidogrel following a stroke , to reduce the risk of further strokes . These could present a risk of bleeding in the event of a decompression illness , so remember to talk to your diving doctor about any medication that you are on . Secondly , if you have residual symptoms after a stroke , this
represents brain tissue that has been permanently damaged . The brain therefore has less capacity to deal with any further damage , so an episode of decompression illness could result in further serious disability . We also need to examine you to know what your baseline function is , so that if you are involved in a diving accident or feel unwell after diving , we can distinguish new symptoms from old ones to make a diagnosis . Finally , some symptoms that people may be left with following a stroke are not compatible with safe diving . Cognitive problems such as poor memory or difficulty processing information will mean an individual should not dive again . However , for other problems like some residual weakness , it may be possible to dive with an adaptive diving programme .
What about a mini stroke ?
A mini stroke is another name for a transient ischaemic attack , or TIA . It is caused by a temporary blockage of a blood vessel that supplies the brain . That part of the brain does not receive enough oxygen ( ischaemia ) due to the blockage , and results in symptoms similar to a stroke . However , with a mini stroke , the symptoms are transient , meaning that they will resolve on their own and last no more than 24 hours .
If you have a TIA , it is important to seek urgent medical advice as you are at a much higher risk of having a stroke in the near future . It is important to receive follow-up medical care , as you will need further tests and may need to start medication to reduce your risk of stroke , or even have surgery to open up the arteries that supply blood to your brain . As the risk factors for TIA are the same as we have discussed for stroke , you should not dive after a TIA until you have taken advice from your consultant or GP and have had a medical with a diving doctor .
Come and speak to us !
When you see a diving doctor for a medical , you ’ ll need to bring along any hospital letters and paperwork you have , as well as details of any medication you take . Remember , as diving doctors , we love diving and don ’ t want to stop people from diving if at all possible - we ’ re here to enable and encourage you to dive safely . �
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