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OTOTOXICITYAND TINNITUSA PERSONAL EXPERIENCE
IAN MACKENZIE MD MSc FRCSSENIOR LECTURER
LIVERPOOL SCHOOL OF TROPICAL MEDICINE
UNIVERSITY OF LIVERPOOLDIRECTOR OF WHO PREVENTION OF DEAFNESS PROGRAMME IN THE UKTINNITUS HELP GROUP JUNE 2008
OTOTOXICITY CAN BE BROADLY DEFINED AS TENDENCY OF CERTAIN SUBSTANCES EITHER SYSTEMIC OR
TOPICAL TO CAUSE FUNCTIONAL IMPAIRMENT AND CELLULAR DAMAGE TO THE TISSUES OF THE INNER EAR
ESPECIALLY TO THE END ORGANS OF THE CENTRAL NERVOUS SYSTEM OF
HEARING AND BALANCE.I WILL HOPE TO DESCRIBE MY OWN
EXPERIENCE OF TINNITUS AND HOW THIS MAY GIVE SOME IDEAS ABOUT THE
FUTURE.
OTOTOXICITY:• Is not common in England but more
common in low income countries;
• Generates much interest;
• Controversy for those physicians who treat life threatening conditions on forgetting side effects of drugs in an effort to save lives.
OUTCOMES of drug overdose :
• To lose all or some hearing limits ability to communicate and can be worse with accompanying tinnitus Before travelling to africa I take chloroquine for malaria prophylaxis within 12 hours I have raging tinnitus but it stops 24hours after stopping drug WHY I always ask not an overdose
• To lose ones balance literally – robs ability to perform some physical activity – leads to loss of independence.
ACTION ON COCHLEAABILITY OF OTOTOXIC SUBSTANCES TO AFFECT
SPECIFIC TISSUES OF THE COCHLEA IS DEPENDENT ON ENTRY OF THE SUBSTANCE INTO
THE COCHLEAR COMPARTMENT.THAT TISSUES
ABILITY TO INTERACT WITH THE PHYSIOLOGY OF THE INNER EAR.
OTOTOXICITY SUBSTANCES ENTER COCHLEA USUALLY THROUGH VASCULAR SYSTEM.
THE CSF VIA EITHER THE COCHLEAR AQUEDUCT OF THE INTERNAL AUDITORY MEATUS OR VIA THE
MIDDLE EAR ACROSS THE ROUND WINDOW
MOST COMMON ANATOMICAL CHANGES OF THE COCHLEA IDENTIFIED
WITH OTOTOXIC SUBSTANCES ARE IN THE
OUTER HAIR CELLS WHICH ARE PHYSICALLY DAMAGED
VESTIBULAR LOSS AFFECTS BALANCE NERVE OF HEARING AND BALANCE ARE
ONE CALLED VESTIBULO COCHLEAR NERVE
LIKE TINNITUS THERE ALL THE TIME
UNILATERAL OFTEN LIES PERMANENTLY STILL
BILATERAL COMPLAIN OF OSCILLOPSIA EYES JUMPING UP AND DOWN
JUST CANNOT GET UP
SYSTEMIC TOXICITY
SALICYLATES: USED BY HIPPOCRATES COMMENTED ON AUDITORY PROBLEMS
MULLER 1977 – IDENTIFIED THE EFFECTS OF HIGH DOSE TOXICITY
WITH ASPIRINSERUM SALICYLATE AND PERILYMPH LEVELS HAVE BEEN
MEASURED
SERUM LEVELS IN BLOOD PEAK ½ HOUR AFTER TAKING
PERILYMPH LEVELS IN COCHLEA PEAK 2 HOURS AFTER INGESTION
ASPIRIN
COMMONEST CAUSE OF TINNITUS
VERY EASY TO TAKE OTOTOXIC DOSE
CHEAP AND EFFECTIVE
EVIDENCE OF CELL DAMAGE OF STRIAL VASCULARIS PART OF COCHLEA
MAY BE RELATED TO BLOOD FLOW
ASPIRIN the cheap painkiller
QUININE
COMMONLY USED DRUG IN DEVELOPING COUNTRIES FOR CONTROL OF MALARIA USED IN THIS COUNTRYAND IRELAND FOR PERSISTANT CRAMP OFTEN REVERSIBLETINNITUS AND VERTIGO COMMONTHIS CAN BE TREATEDNIMODIPINECALCIUM CHANNEL BLOCKER
HEAVY METALS
MERCURY
LEAD
IN ASIA – CINNABAR A NATURALLY OCCURRING MERCURIC SULPHIDE USED WITH CHINESE HERBAL MEDICATION FOR 200 YR USED AS A SEDATIVE IN CHILDREN CAN BE CATASTROPHIC
LOOP DIURETICS – EG FRUSEMIDE
ALTER HAIR CELL ENERGY METABOLISM MAY BE TRANSIENT LOSS DEPENDENT ON RATE OF INFUSION
FLUCTUATING HEARING
CHEMOTHERAPY FOR CANCER
MOST OF THESE DRUGS CAUSE DEAFNESS AND TINNITUS
MOST COMMONLY USED
CISPLATINUM
USUALLY GIVEN – INTRAVENOUSLY
YOUNG MEN VULNERABLE 90% SUFFER DEAFNESS OR TINNITUS
CISPLATINUM
- CANCER OF CERVIX
- LUNG CANCER
- OVARIAN CANCER
ACCOMPANYING TINNITUS
DIFFICULT TO CARRY OUT
PURE TONE AUDIOMETRY
CHEMOTHERAPY FOR INFECTIONS
AMINOGLYCOSIDES (PSEUDOMONUS CLOSTRIDIA)
END IN MYCIN
GENTAMYCIN
STREPTOMYCIN
VANCOMYCIN
AVOID ELEVATED TROUGH CONCENTRATION
ALSO AFFECT KIDNEYS
MYCINS RANGE OF DRUGS
COMMONLY PRESCRIBED FOR SEVERE INFECTIONS
OFTEN NOT REVERSIBLE
BLOOD LEVELS IF NOT DONE IN HOSPITAL NEGLIGENT BECAUSE OF SUBSEQUENT DEAFNESS
MYCINS
ROUND WINDOW PRINCIPAL WEAKNESS IN TOPICAL APPLICATIONS
DEGREE OF OTOTOXICITY APPEARS TO BE DIRECTLY RELATED TO THE DURATION AND DOSE OF THE PREPARATION
IS THIS USEFUL KNOWLEDGE?
YES
IF SOMEONE IS TAKING OTOTOXIC MEDICATION, HEARING MAY DETERIORATE QUICKLY
OFTEN DIFFICULT TO TEST BECAUSE OF TINNITUS
THE FUTURE
KNOWN FOR 40 YEARS STREPTOMYCIN AND QUININE CAUSE DEAFNESS AND TINNITUS MAINLY FROM WORK DONE AFTER WW 2 1940-1945
MOST POPULAR DRUGS IN SUB SAHARAN AFRICA FOR TREATMENT OF MALARIA AND T.B.
HOW CAN WHAT WE KNOW HELP THE FUTURE RESEARCH INTO TINNITUS
THE COCHLEAR IS VERY SENSITIVE
WE KNOW SOMETHING TO DO WITH HAIR CELL DAMAGE
WE ARE LOOKING AT THE COCHLEA WITH NEW IMAGING TECHNIQUES USING DYES WHAT CHANGES IN BRAIN WHEN TINNITUS PRESENT
AS FAR AS HAIR CELLS GO CERTAINLY GROWN IN THE EARS OF HAMSTERS NOW TRYING TO GROW IN HUMANS SOLDIERS WITH NOISE DAMAGE
THE FUTURE• THERE IS HOPE SOLDIERS ARE GUINEA PIGS IN AMERICA• NEW TECHNIQUES FOR UNDERSTANDING TINNITUS• NEW TECHNIQUES FOR GROWING PARTS OF THE
COCHLEAR• IF DAMAGED PARTS CAN BE REPAIRED• WHY NOT STOP TINNITUS• NOISE DAMAGED HEARING PILL WITHIN 10 YEARS
• THANKS FOR LISTENING A PREDICTION I HOPE IS LIKELY