Acute Prostatitis Altitude Sickness Anaphylaxis Angina Appendicitis Asthma Athlete's Foot Cataracts Causes of Allergies Chlamydial Infections Common Cold Cryptococcosis Depression and Mood Disorders Depression at Christmas Dermatitis Diabetes Diarrhea Diver's Disease Eating Disorders Epilepsy Food Allergies Food Poisoning Foreign Bodies Gastritis Genital Herpes Gonorrhea Hair Loss Head Injury Hepatitis Overview HIV and AIDS HIV Myths HIV Prevention Insect Allergies Malaria Panic Attacks Pneumonia Psoriasis Salmonella Sinusitis Syphilis Tuberculosis Typhoid Fever Typhus	Illnesses/Diseases
	Diver's Disease (Decompression sickness)
	Over the past 10 to 20 years, diving has become extremely popular, both at home and abroad. But diving is not without its dangers. It is vital to attend a recognised diving school for training, and subsequently make sure that you keep your skills up to date. Diving must be planned and carried out in a responsible manner, making sure that first aid equipment and relevant telephone numbers are at hand should an accident take place. Finally, it is important to know the signs of decompression sickness and be able to give the right first aid to an affected diver.  What is decompression sickness? Decompression sickness, also called the bends, is caused by nitrogen bubbles forming in the blood stream and tissues of the body. The bubbles occur if you move from deep water towards the surface, where the surrounding pressure is lower, in too short a space of time.  The symptoms of decompression sickness occur soon after the dive has finished. The symptoms are varied, ranging from headache, vertigo and tiredness to joint pain, disturbed sensation, paralysis, and in the most serious cases, unconsciousness or death. If you suspect decompression sickness, stop the dive, initiate first aid, and summon assistance from a specialist in divers' medicine. Treatment is 100% oxygen on site and during transportation, followed by treatment in a decompression chamber.  How does decompression sickness occur? Nitrogen makes up 70% of the air we breathe (in the air around us and in our diving bottles). During a dive, large amounts of nitrogen are taken into the body's tissues. This is because the diver is breathing air at a higher pressure than if they were at the surface. The quantities of dissolved nitrogen depend on the depth and duration of the dive. The deeper and longer the dive, the more nitrogen is taken up by the body. This does not present a problem as long as the diver remains under pressure. As the diver begins to ascend to the surface, the surrounding pressure falls, and nitrogen is released from the body via the lungs when the diver breathes out. If the rate of ascent exceeds that at which nitrogen can be released, it forms bubbles in the blood and tissues (similar to opening a bottle of fizzy drink too quickly).  To minimise the risk of bubbles forming and consequently of divers developing decompression sickness, various tables have been drawn up that show the relationship between a given depth of water and the time a diver can stay down. In addition, divers are advised to make a safety stop every 5 metres, and not to ascend at a pace of more than 10 metres a minute. If the dive has been deep or of long duration, it may be necessary to stop one or more times on the way up, making so-called decompression stops.  However, following the advice of the tables is no guarantee of avoiding decompression sickness. This is because the risk of developing decompression sickness is not only determined by the depth and length of the dive but also by any safety/decompression stops. Factors such as cold, current, exertion and lack of fluid also play a part. Personal characteristics such as age, sex, percentage of body fat and physical condition must also be considered. Women are more at risk of decompression sickness than men. Similarly, the risk becomes greater the older a diver is and also depends on the level of physical fitness.  What are the symptoms of decompression sickness? The symptoms of decompression sickness vary because the nitrogen bubbles can form in different parts of the body. The diver may complain of headache or vertigo, unusual tiredness or fatigue. He or she may have a rash, pain in one or more joints, tingling in the arms or legs, muscular weakness or paralysis. Less often, breathing difficulties, shock, unconsciousness or death may be seen.  The symptoms generally appear a relatively short period after the diver has completed a dive. Almost 50% develop symptoms within the first hour after the dive, 90% within 6 hours and 98% within the first 24 hours. In practice this means symptoms that appear more than 24 hours after the dive are probably not decompression sickness. An exception to this is if the diver has travelled in an aircraft has been travelling in the mountains. Under these circumstances, low pressure can still trigger decompression sickness more than 24 hours after the last dive, and as a result it is wise not to fly within 24 hours of a deep dive.  What measures can be taken to avoid decompression sickness? Dive within the limits set out in the diving tables. Keep your rate of ascent to a maximum 10 metres per minute. Don't plan any dives that need a decompression stop in the water. Make a 3-minute safety stop at a depth of 5 metres. Don't dive more than three times in one day. If you plan more than one dive in one day, start by making the deepest dive first. Have a dive-free day after 2 to 3 days, if you are diving for several days in a row. Don't do any hard work before or after diving. Drink lots of liquid before diving. Lack of fluid due to heat or excess alcohol is dangerous. Make sure you are in good physical condition and well rested. Have regular medical check-ups. Make sure there is an interval of at least 24 hours between diving and travel by air or climbing up mountains. If you have had decompression treatment the recommended interval before the next dive is at least 48 hours.  What should you do if you or a friend have symptoms of decompression sickness? Stop the dive and keep calm. If the diver is unconscious give step-by-step first aid. Summon the emergency services immediately. Breathe pure oxygen if possible. Avoid over-exertion. Make sure there is an interval of at least 24 hours between diving and travel by air or climbing up mountains. If you have had decompression treatment the recommended interval before the next dive is at least 48 hours.  Drink plenty of liquid. It must be emphasised that any unusual condition after a dive could be decompression sickness. So, if in doubt, get medical help. How is the disease diagnosed? In most cases, the diving history, i.e. information on the number of dives, diving depth, dive time, rate of ascent and decompressions, as well as information on contributory factors such as cold, current, work and the diver's physical condition will give some indication as to whether it could be a matter of decompression sickness. After a thorough examination, which includes investigating balance, coordination, sense of feel, reflexes and muscular strength, the doctor can build up a complete picture on which to evaluate whether decompression sickness is likely and decide if the diver requires treatment in a decompression chamber.  Future prospects Mild forms of decompression sickness can resolve themselves without treatment or by breathing 100% oxygen at the site of the accident. However, if there is any suspicion of decompression sickness, the diver must be examined by a doctor, as the condition may deteriorate, although it might not seem serious at the time.  If the diver receives treatment at an early stage, the chances of avoiding permanent injury are good. The longer that treatment is delayed, the greater the risk of serious consequences. After treatment for decompression sickness, a diver should take a rest from diving. The length of this rest depends on the severity of the decompression sickness and the effects of treatment, and should be discussed with a specialist in divers' medicine.  How is decompression sickness treated? At the diving station and during transport: Step-by-step first aid, if the diver is unconscious. 100% oxygen by mask, at a rate of 10-15 litres per min. Plenty of fluid to drink. Do not let the diver exert himself or get cold. In hospital and specialised centres: A decompression chamber is a steel tank that can be pressurised. There are decompression chambers in various places in the UK - some of these are situated at naval centres. The pressure in a decompression chamber can be increased by closing the doors and pumping air in.  During treatment for decompression sickness, pressure is increased to correspond to the pressure found 18 metres under water. In some cases, the pressure in the chamber is set at 50 metres. During treatment, the diver breathes pure oxygen through a mask, which improves exhalation of nitrogen. At depths in excess of 18 metres, and also after adequate intervals, the mask can be removed, and the diver allowed to breathe normal air. Pressure in the chamber is reduced gradually until the diver reaches surface pressure again.  Treatment typically lasts between 5 and 6 hours. Throughout the entire course of treatment, a specially trained helper stays with the diver in the chamber. During treatment, the diver's condition is closely monitored by further examination of coordination and balance, sense of feel, etc. If necessary, the diver's medical specialist can join the diver in the chamber, but otherwise takes charge of the treatment outside the chamber in co-operation with the specially trained helper.  After treatment, the diver will be kept for 24 hours for observation, in case his or her condition deteriorates. In most instances, one course of treatment is adequate, but occasionally several treatments may be needed. After treatment for decompression sickness, a diver should take a rest from diving. The length of this rest should be discussed with a specialist in divers' medicine. There is no medicine that is used as a matter of routine in treating decompression sickness.