The tissues of the inner ear can be targeted by toxic substances.
The toxic substances may include solvents, foods and also medical drugs.
Some medical drugs can affect cochlear or vestibular tissue depending on their sensitivity. When administered systemically (oral, intravenous or intramuscular) these drugs spread throughout the body, reaching the inner ear and entering the labyrinth liquids, vestibular and cochlear tissues. For the hair cells in particular, they cause damage to the membranes and intracellular organelles, resulting in cell death. These effects produce symptoms of vertigo, tinnitus and hearing loss, which may progress to complete deafness. A wide range of drugs can cause this damage, the best known of which are the antibiotics belonging to the aminoglycoside class, aspirin and some non-steroidal anti-inflammatory drugs, the quinine antimalarials and particularly platinum salts, including cisplatin, which is used in chemotherapy.
The damage is bilateral and is a limiting factor for the chemotherapy, requiring dose-adjustment and occasionally a change in chemotherapy protocol.
This ototoxicity is a serious problem in adults in oncology and is more so in children due to higher sensitivity to the toxicity and higher survival rates (>75%). Hearing loss occurs in children during the critical learning period and may therefore interfere with the child’s overall development and specifically with the development of language and social integration.
At present there is no curative treatment for lesions which have developed and prevention of risks is limited to monitoring auditory function (with an audiogram) before and during treatment in order to assess its impact on hearing and possibly adjust the treatment. Prevention of this damage is therefore a major area of real unmet medical need.