Sudden hearing loss is not restricted to divers, but pressure changes can sometimes cause long-term ear problems, says CAREN LIEBSCHER, who has a sample case-history
GABRIEL, AN EXPERIENCED Spanish diving instructor in his 40s, had travelled to Italy with friends by car. He was enjoying his first dive of the day using a closed-circuit rebreather. He was on trimix (oxygen, helium and nitrogen) and wearing a Petrel dive-computer.
By the end of his dive, he had clocked up a total bottom time of 95 minutes at a depth of 40m (with 45m as the maximum depth). His dive was uneventful, but during his ascent he felt a muffled sensation in his right ear, an effect that didn’t disappear right away.
This was not the first time he had experienced something similar, so he didn’t worry too much about it.
He assumed that the sensation would clear up in the ensuing hours, as it always had done. However, 30 hours went by, without any improvement. Unfortunately, Gabriel felt worse.
Two days later, Gabriel realised that he couldn’t hear anything from his right ear after trying to use his mobile phone.
He was getting worried now, and also experienced some postural vertigo.
Gabriel felt miserable and wanted to go home. He decided to return to Spain the following day, and seek medical treatment there.
Back in Spain, Gabriel went along to the ER of a hospital, where the doctors diagnosed an ear barotrauma and recommend ibuprofen. Being an experienced diver and instructor, Gabriel tried to explain that he didn’t believe it was any “common” ear barotrauma that was causing the problems.
Unfortunately, the doctors simply recommended that he come back the next day for a more detailed ear, nose & throat (ENT) check. It was already late in the evening, so what else could he do? He returned home.
Next morning, Gabriel decided to get a second opinion from doctors specialising in diving-related illnesses and hyperbaric treatment at another hospital. He was not at all surprised to receive a new diagnosis – sudden deafness.
The doctor explained that sudden deafness in a diver was not a sequel of decompression illness but the result of a problem with the stato-acoustic sensorineural nerve.
It’s not necessarily a dive-related condition. Anybody, even non-divers, can get it, but because of the pressure changes it can happen to divers, too.
The hyperbaric doctor prescribed 20 sessions of hyperbaric oxygen therapy (HBOT). He also explained that sudden deafness could not be treated with classic ENT treatments but that sometimes HBOT produced improvements or even complete recovery.
Improvement never happens after a single HBOT session, he said, but good results had been recorded with three-week treatments. Sometimes there was sudden restitution of hearing towards the middle or end of the treatment period. Gabriel was started on the HBOT.
In “sudden sensorineural hearing loss” (sudden deafness) the stato-acoustic sensorineural nerve is affected for some unexplained reason and causes rapid loss of hearing—usually in one ear—either at once or over several days.
If it occurs, it is vital for patients to see a doctor immediately. Delaying diagnosis and treatment can decrease the effectiveness of any treatment.
People often notice the hearing loss when they try to use the deafened ear – by using a phone, for example. Dizziness and/or ringing in the ears (tinnitus) can be symptoms.
Typically adults in their 40s and 50s are affected. About half of them recover their hearing spontaneously, usually within one to two weeks. Eight-five per cent of patients receiving treatment recover at least some of their hearing.
In about 15% of the cases the cause can be identified as an infectious disease, head injury or brain trauma, an auto-immune disease, drugs that harm the sensory cells in the inner ear, blood circulation problems, a tumor on the nerve that connects the ear to the brain, neurologic disorders like multiple sclerosis, or disorders of the inner ear.
The condition means complete and permanent hearing loss and therefore impairment for most activities. It’s a rare problem but it has been known in the diving field for many years as being triggered by pressure changes.
Hyperbaric oxygen therapy is one approach, but another common treatment among non-divers is with corticosteroids. These reduce inflammation and swelling and help the body to fight illness.
Steroids can be taken orally or injected directly behind the eardrum into the middle ear (intratympanic corticosteroid therapy). Additional treatment may be needed if an actual underlying cause is discovered.
Infections, drug allergies or auto-immune disorders can cause the immune system to attack the inner ear. Antibiotics, immune-system suppression or other drug treatments may help.
A hearing test called pure tone audiometry is the method of choice.
This helps to determine whether the hearing loss is caused by sound not reaching the inner ear because something obstructs the way, or by a sensorineural deficit, meaning that the ear cannot process the sound.
The diagnosis is positive if the test shows a loss of at least 30 decibels in three connected frequencies.
Unfortunately, we heard from Gabriel that, despite the HBOT treatment, his hearing had yet to return. We wish him the best and hope his hearing will eventually recover.
ASK DAN’s EXPERTS
I understand that feeling tired after a dive may be a symptom of decompression illness, but I almost always feel tired post-dive. Should I be concerned?
The expectation of normal (non-pathological) tiredness following diving varies from person to person. Factors such as individual fitness, thermal stress, gear constriction, diving skill, work done on the dive, psychological stress (positive or negative) and distraction can all affect how tired one feels.
These variables make it difficult to quantify tiredness as a symptom of DCI, but unusual fatigue has long been documented in association with other DCI symptoms.
The mechanism behind fatigue as a symptom of DCI remains elusive, but it is possibly a response to a cascade of physiological events taking place in various tissues. It could be through direct stimulation of nervous tissues or indirectly through the stimulation of other tissues.
It’s possible that the attention currently directed towards identifying biochemical DCI markers will help resolve the questions. Meanwhile, it’s fair to say that DCI represents a complex, multifocal response to a decompression injury.
Unusual or “undue“ fatigue (more than normal fatigue for a given individual/diving exposure) is a recognised symptom.
DAN Europe is a not-for-profit worldwide organisation that provides emergency medical advice and assistance for underwater diving injuries. It also promotes diving safety through research, education, products and services
Appeared in DIVER June 2017