We have all experienced sometimes the feeling of dizziness, giddiness, unsteadiness, lightheadedness, we understand that all these symptoms means some kind of body balance disturbance. The causes are diverse ranging from simple and well known causes to most of us like low blood pressure, low blood glucose level, fever, sea sickness, electrolyte imbalance, gastro- intestinal problems, or (simply tired and did not sleep enough) to a diverse and serious number of central and peripheral nervous system illnesses.
So What is Vertigo? Vertigo is simply hallucination of movement leading to the feeling that either the objects are moving in a certain direction around the patient ( objective vertigo ) or the patient himself ( herself ) is moving in a certain direction. It is always associated with Nystagmus ( continuous involuntary oscillatory side to side movement of the patient's eye pupils). I think most of us have never experienced that feeling except sometimes if you visited your ENT ( ear, nose and throat) specialist for an ear wash. or unfortunate ear drum perforation due to inability to equalize the pressure on your ear drums while diving.
Disturbance in the vestibular pathway (semicircular canals in the inner ear and their connections to the brain) lead to this feeling.
Causes of Vertigo in diving 1. Unequal stimulation of both inner ears (vestibular system) a.This happens if external ear canal is obstructed (partially or totally) by cerumen (wax), inflammation in the external ear canal ( swimming pool fungal or bacterial infections ) tight fitting hood, preventing the flow of water freely in both ears.
b. Tympanic membrane (ear drum) perforation, due to unequal pressure on both sides of ear drum in case of middle ear barotrauma of descent. middle ear barotraumas of ascent. External ear barotrauma. Shock wave.
2. Inner ear barotraumas This happens as serious complication of middle ear barotraumas when the membranes separating middle and inner ear also rupture (round and oval windows) with damage and hemorrhage in the inner ear. *** serious inner ear barotraumas can happen by forceful valsalva maneuver ( pressure equalization on the ear drums during diving)
3. Decompression Sickness Inner ear decompression sickness explanations are diverse, but the definite outcome is pathology in the inner ear ( hemorrhage, edema( tissue swelling and tissue fluid accumulation) caused by nitrogen or helium bubbles ( in technical divers) formation in the inner ear space. This space is limited by the surrounding bones, so the manifestations of the pathology are rapid and dramatic.
Case Report A 42 years experienced diver ( Air) in a vacation to the red sea , in the month of April , has been diving for 3 days every day 2 dives, the depths ranging from 25 meters 12 meters, dive times were relatively long ( 60-70 minutes) due to his excellent air consumption, on the fourth day and about 10 minutes after his first dive ( 28 meters, 72 minutes), he experienced a sense of dizziness, he started vomiting, the best position for him is laying down, closing his eyes and with the slightest movement, he again feels dizzy and vomits.
This diver was very experienced, but he thought that he might have eaten something bad especially; he had some diarrhea from the day before. His wife as a nurse was not convinced especially when the boat docked and her husband can not stand up or walk steadily, but still he insisted he is OK.OK.
Any how, I saw this patient 4 hours later, when he started to think may be there is something and under pressure from his wife.
He was dizzy? No he had vertigo. So a simple question? Do you feel the surrounding moving around with your eyes opened or you are moving yourself around? If the answer is YES, give him oxygen and transfer to the nearest recompression chamber. So this was a case of straight forward Inner ear decompression sickness
During the chamber treatment and afterwards this diver kept repeating the same question? Why me? I did not make any thing wrong check my computer !
The answer is you are dehydrated by : 1. You are coming from home ( Europe ) in April already dehydrated . How much do you drink ( Water ) at home in April ? 2. Repetitive long dives. 3. Travelers' diarrhea.
And also physiological variation as you are now 42 years old (of course he did not like this one).
This is a scenario that can happen to any of us especially on diving safaris.
To end the discussion about vertigo, there are other causes less important to divers,
But for us the expression dizzy, giddy, lightheaded, not feeling ok after any dive is not ok and should be well interpreted by the dive guide and not mislead by the experienced diver.
Dr. Hanaa Nessim
Dehydration: A major risk factor in diving practice
Dehydration (the decrease of the fluid content of the body) is one of the major predisposing factors in the occurrence of Decompression Sickness (DCS) as it renders the blood more viscous. This condition reduces perfusion of tissues interfering with the effective elimination of inert gas from the body.
During diving there is a continuous loss in body fluids due to three factors:
1. Perspiration, especially on a hot day (a common hazard of diving in the tropics) 2. Dry gas breathing that needs to be humidified mainly by extracting water vapor from the lungs. 3. Immersion (even in warmer waters) that, in itself, increases urination by shifting blood from extremities to the core of the body. This gives body receptors a false feeling that the blood volume has increased, thereby enhancing urine formation. * Immersion in clod water would excessively increase urine formation by the same blood shifting mechanism due to closure of the peripheral blood vessels.
Dehydration can happen as a result of:
1. Inadequate fluid intake 2. Drinking dehydrating agents like all kinds of alcohol and strong coffee 3. Conditions causing body fluid loss such as diarrhea and vomiting.
So, divers coming to dive in the tropics from relatively temperate climates cannot simply import their drinking habits with them. Drinking enough fluids is supposed to be top of the list when briefing newcomers to a diving resort especially in the summer.
However, drinking excessive amounts of water without adequate salt intake will eventually lead to the wash out of salts from the body leading to a status of imbalance in the body electrolytes. This can lead to symptoms of tiredness, malaise, nausea, dizziness and sometimes vomiting. Therefore divers on a dive vacation in the tropics and subtropics are advised to take sufficient rehydration salts in addition to drinking enough fluids, especially when hot.
Divers should also be advised to avoid drinking dehydrating agents, and to avoid diving, when suffering from severe diarrhea or vomiting. Instructors and dive masters should also avoid allowing students or divers to sweat in their wet suits while waiting for the other divers to get ready by effectively coordinating their diving activities.
In the few days preceding menstruation, the hormonal changes in the body tend to shift the body fluids from the blood and lymphatic systems to the body tissues (the so called third body compartment) leading to their engorgement (edema) Which forms an odd form of dehydration that would also render the blood more viscous with the increased incidence of DCS. Drinking sufficient fluids does not actually help much in the adjustment of this situation, so female divers should take in consideration employing much safer dive profiles in this period.
Amongst the other conditions that increase the viscosity of blood are high blood cholesterol level and using drugs that can increase the coagulability of blood such as oral contraceptives (birth control pills).
May everybody enjoy a safe and pleasant diving vacation!
