Toxic responses of ear Flashcards
typical drugs that cause tinnitus
salicylates
quinine
whats presbycusis and how does it occur
hearing loss caused by natural aging atrophy of the basal end of organ of corti loss of hair cells stiffening of basilar membranes vascular changes
what might patients experiences if vestibular function compromised
lghtheadedness headahce whirling nystagmus ataxia unsteady gait and function
how does vestibular function improve with time
increased reliance on visual and proprioceptive inputs and central compensatory mechanisms for equilibrium
how do diuretics cause hearing loss
physiologic dysfunction
loss of hair cells
edema at striavascularis
inhibition of potassium pump and g protein associated with adenylcyclase
type of damage with diuretics
reversible
permanent reported
salicyclate hearing loss reversible after
24-72hr after d/c drug
dose of salicylate causing damage
doses above 2.7g inreased ototoxicicyt,
dose >4g/d produces tinnitus and hearing loss
type of hearing loss in salicylates
bilateral and symmetrical
type of hearing loss in erythromycin
bilateral impairment of hearing at all freuencies
slurred speech, double vision, confusion
with all forms
erythromycin dose leading to hearing loss
> 4g/day
<2g in renal or hepatic failure
risk factors for erythromycin hearing loss
high doses with renal or hepatic failure iv admin age use with other ototoxic agents use with inhibitors of erythromycin metabolism
quinine mechanism of hearing loss
prostaglindine and phosphoslipase a2 enzyme inhibition
inhibition of clacium channels
vasoconstriction
inhibition of potassium channel
presentation of phosphodiesterase 5 inhibitor ototoxicity
sudden hearing loss - very rare
unilateral!!
first 24hrs
most toxic aminoglycosides
neomycin
kanamycin
mechanism of aminoglycoside hearing loss
binding to hair cell membrane polyphosphoinositides
membrane disruption
loss of electrolytes
loss in enzyme function and inhibition of protein synthesis
risk factors for aminoglycoside toxicity
severity of illness pre existing hearing loss previous exposure to aminoglycosides duration of therapy peak valley variation other ototoxic drugs pre existng renal failure age noise exposure previous ear infection genetic predisposition
presentation of cisplatinum hearing loss
bilateral cochlear(hearing loss) and vestibular symptoms 2-5days after first or second dose
cisplatinum mechanism of hearing loss
damage to the outer hair cells and stria vascularis
doses for cisplatin ototoxicity
50-100mg/m2
drugs causing irreversible hearing loss
aminoglycosides
cisplatin
drugs causing reversible hearing loss
erythromycin
salicylate
quinine
phosphodiesterase 5 inhibitors
