Special senses Flashcards
what is the function of the aqueous humour of the eye
transports nutrients to the eye and waste products from the eye.
what is IOP
intraocular pressure
- It is the balance between aqueous humour production and aqueous humour removal.
What is normal IOP
12-21 mmHg
- IOP usually lowest at night and highest during the day
What is Glaucoma
Optic nerve damage due to an increased IOP.
- Loss of retinal ganglion cells
- atrophy of optic nerve
^ these are usually asymptomatic - then peripheral vision is lost, if left untreated could cause blindness.
What is POAG
Primary open angle glaucoma
- a type of glaucoma: where the drainage channels of the eye become blocked, causing an increase in IOP.
- where the anterior chamber angle appears to be normal, but IOP is high with no sign of disease.
POAG treatment:
Decrease IOP by 20-40%
Drug therapy
then
laser therapy
then
surgery
What are 5 common reasons for treatment failure generally ?
1) lack of adherence
2) Intolerance to treatment
3) Hypersensitive to excipient
4) OTC drugs
5) Other contraindicated prescription drugs, not disclosed during prescribing.
What types of drugs reduced aqueous humour production
B antagonists
- carbonic anhydrase inhibitors
Examples and side effects of Beta antagonists that reduce aqueous humour production
Examples:
Timolol
Betaxolol
Brinzolamide
Dorzolamide
Acetazolamide
Side effects
Timolol: Blurred vision, burning/ stinging in the eye, discharge.
Betaxolol: Nausea, diarrhoea, joint pain, heart burn
Brinzolamide:
Eye irritation, blurred vision, allergic reaction
Dorzolamide: blurred vision, skin rash, redness or sweeling of the eye.
Acetazolamide:
Skin rash, swelling, headache, nausea, vomit.
Timolol mechanism of action ?
Decreases aqueous humour production, causing decrease in blood supply to ciliary body, decreasing IOP.
What type of drugs reduce aqueous humour production and increase aqueous humour removal
(dual effect)
Alpha 2 receptor agonists
Examples and side effects of A2 agonists (dual effect)
Examples:
Apraclonidine
Brimonidine
Side effects:
Apraclonidine:
Red swollen. itchy eyes
blurred vision
irregular heartbeat
dry eyes
Brimonidine:
Itchy eyes
eye irritation
red stinging/burning eyes
dry eyes
blurred vision
headache
drowsiness.
What type of drugs increase Aqueous humour removal
Prostaglandin analogues
Examples and side effects of prostaglandin analogues
Bimatoprost: itchy eye, red eye, eye swelling, blurred vision, headache.
Latanoprost: change in eye colour, dry eyes, headache, dizziness
Travoprost: Eye discolouration, dry eye, eye discomfort, headache, blurred vision
What is another drug type that treats POAG ?
And what is the MOA ?
Cholinergic agents
- by stimulating cholinergic receptors in the eye,
causing spasm of ciliary muscle and contraction of the pupil
causes trabecular meshwork to open and increases aqueous humour removal out of the eye. Lowering IOP.
Examples and side effects of cholinergic agents?
Pilocarpine: headache, nausea, diarrhoea, fainting
Carbachol: blurred vision, headache, stomach pain
Other treatment options for POAG
Laser trabeculoplasty: 120 burns made in the trabecular meshwork, to increase drainage of aqueous humour, causing lower IOP
Laser ciliary body ablation: applying burns to ciliary body, reduces aq humour production, lower IOP.
PCAG
Primary closed angle glaucoma
- Increase in IOP, due to decreased aqueous humour removal, due to the closure of the chamber angle by the peripheral iris.
symptoms of pcag
headache
blurred vision
vomit
What may cause PCAG
1) Small or large lens size
2) small corneal diameter
3) secondary to late stage POAG
4) Dilator and
5) sphincter muscle theory
Dilator muscle theory (PCAG)
1) Dilator muscle contracts, causing posterior movement , increases apposition between iris and anteriorly located lens.
2) pupil dilates simultaneously
3) Peripheral iris becomes more flaccid, causing posterior chamber pressure to increase
4) Iris bows anteriorly, peripheral iris obstructs angle, IOP increases.
Sphincter muscle theory
1) Sphincter of the pupil precipitates angle closure
2) pupilary blocking force of the sphincter is highest when diameter of pupil is around 4mm.
Pre surgery preparation for PCAG
1) Timolol 0.5% (one drop every 30 mins) 2 doses
2) Pilocarpine 2-4% one drop every 15 mins for the first 1-2 hours
3) Apraclonidine 0.5-1% one drop every 30 mins (2 doses)
4) Acetazolamide 500mg oral initially, then 250 mg every 6 hrs.
5) Osmotic agent (e.g. oral glycerol) 1ml/kg diluted with a equal amount cold water
Viral conjuctivitis treatment
warm compress and eye drops
Adults chronic onjuctivitis treatment
chloramphenicol or fusidic acid
Neonatal conjunctivitis treatment
Oral erythromycin (50mg/kg 4 times a day for 14 days)
Scleritis
NSAIDs
symptoms of excess build up of earwax
Earache
hearing loss
tinnitus
itchiness in/around ear
Vertigo (spinning sensation)
ear infection
Rinne test (ear test)
1) Strike a 512 Hz tuning fork gently
2) Place the vibrating tuning fork onto the mastoid bone, located behind the ear.
3) Ask patient, when they can no longer hear the sound.
4) move the tuning fork to the auditory meatus, which is in the front of the ear canal
5) Ask the patient when they can no longer hear the sound.
Weber’s test (ear test)
same as rinnes but hold the fork by the stem and place it on the middle of the patient’s head,
- then ask if they hear the sound louder in one ear, or equally.
Non pharmalogical treatment for earwax build up
Olive oil drops
warm water in a bulb syringe
Different types of Pharmalogical ear drops ?
1) sodium bicarbonate
2) urea-hydrogen peroxide
3) docusate sodium
Sodium bicarbonate MOA (ear drops)
Reacts with ear wax neutralising it to produce water and salt, dissolves ear wax.
causes ear wax to break down
Urea-hydrogen peroxide MOA (ear drops) 2 ways
Releases oxygen, breaking up ear wax
- Reduces keratin load in ear wax debris, by inducing keratolysis.
Docusate sodium MOA (ear drops)
Emulsifying action, softens ear wax plug.
Should ear drops be used if the ear drum is perforated
no
What to do if ear drops don’t work
Syringing
use warm water to wash out softened ear wax
- dont use cold water- could cause diziness
- can cause increased risk of ruptured ear drum, infection, tinnitus
- if syringing doesn’t work- then transferred to ENT specialist
what are the 3 different ways ear wax removed by ENT
1) ear irrigation: electric pump pushes water in ear and washes wax out
2)Micro suction: Small device sucks ear wax out of ear
3) Aural toilet: small instrument used to clean and scrape ear wax out
Otitis Externa
inflammation of the external ear canal
- also known as “swimmers ear”
- usually only one ear is affected
Symptoms of otitis externa
1) ear pain
2) itchy ear canal
3) Discharge
4) Hearing loss
What are the 4 main causes for otitis externa ?
1) Seborrheic dermatitis: Skin condition, where greasy areas of the skin become irritated and inflamed, which can affect the ears.
2) Fungal infections: more common if ear drop use is long term.
3) Middle ear infection (otitis media): an infection deeper in the ear, causes discharge, may lead to otitis externa.
4) Allergies
6 drugs to treat otitis externa:
1) Otomize
2) Sofradex
3) Gentamicin
4) FML drops
5) Clotrimazole drops
6) Betnesol
Otomize mechanism of action (otitis externa)
The glacial acetic acid present, creates an acidic environment making it harder for the bacteria to grow.
Sofradex mechanism of action (otitis externa)
1) contains antibiotics framycetin sulfate and gramicidin, to kill bacteria
2) contains dexamethasone: to stop inflammation and itching.
Gentamicin
Bind to the 30S subunit of the bacterial ribosome, causing an affect on protein synthesis.
FML drops mechanism of action
Fluorometholone
A type of corticosteroid
induce phospholipase A2 inhibitory proteins (lipocortin). This causes inhibition of arachidonic acid, which affects synthesis of prostaglandins and leukotrienes.
Clotrimazole drops mechanism of action
1) reduces permeability of the cell membrane of fungi
2) Causes inhibition of ergosterol
3) cell no longer able to construct a functional cell membrane.
Betnesol moa
Betamethasone
1) Blocks production of prostaglandins
- also reduces activity of leukocytes and macrophages in the inflamed area.
2) Reduces inflammation (redness, itching and soreness).
Neomycin
1) Binds to 30S sub unit of bacterial ribosome, prevents synthesis of proteins.
two types of otitis media
1) Otitis media with effusion (OME)- non infection: just thick fluid build up behind tympanic membrane in the middle ear. Also known as glue ear
2) Acute Otitis media (AOM)- infection
symptoms: earache/fever, hearing loss, perforated ear drum, feeling unwell.
- treated with paracetamol/ibuprofen
or if antibiotics necessary: then amoxicillin, or clarithromycin/erythromycin if allergic to penicillin.
how to reduce middle ear infection (children)
1) keep up to date with routine vaccine
2) avoid smoky environments
3) breastmilk over formula milk
4) not giving dummy after 6-12 moths of age
5) avoid contact with other children that are infected.
complications of otitis media and their signs
1) Mastoiditis: fever, swelling behind ear, redness/ pain behind ear, headache, hearing loss.
2) cholesteatoma: hear loss, dizziness, tinnitus
3) labyrinthitis: vertigo, dizziness, loss of balance
facial paralysis
4) meningitis: severe headache, high temp, stiff neck, blotchy red rash, rapid breathing.
5) brain abscess: pus filled swelling. signs: headache, confusion, weakness/paralysis, high temp, seizure.
Pharmalogical treatment motion sickness
anticholinergics: hyoscine hydrobromide
antihistamines: cinnarizine
phenothiazines: prochlorperazine
promethazine
cyclizine
non-pharmalogical treatment
- distract themselves- listen to music
- remain still
- look at a stable object
- fresh air
- eating ginger
Tinnitus symptoms
hearing sound, when there is no external sound
ringing sound
cause: damage of tiny sensory hair cells in cochlea of inner ear.
Pharmalogical treatment tinnitus
benzodiazepines or antidepressants
non pharmalogical treatment tinnitus
- hearing aid
- ## sound therapy: dont keep environment to quiet
what is vertigo
sensation that the environment around you is spinning
Pharmalogical treatment vertigo
betahistine
cinnarzine
non Pharmalogical treatment vertigo
vestibular rehabilitation
simple head movements to treat BPPV
sleep with head slightly raised
Meniere disease
Affects inner ear, and can cause vertigo and tinnitus and pressure deep in ear feeling,
symptoms of Meniere disease
vertigo, dizziness, imbalance and spatial disorientation, vision disturbance, hearing changes, cognitive changes
treatment of meniere disease
antihistamines
betahistine
vestibular rehabilitation
balance training
benzodiazepenes
Antihistamines
moa: prevents histamine from binding to H1 receptor
example: cinnarizine
indications vertigo, nausea, motion sickness
counsel: may cause drowsiness, avoid alcohol, cautious whilst driving
Phenothiazines
moa: blocks D2 dopamine receptors, blocks CTZ
indications: nausea, vomiting, motion sickness
counsel: may cause dystonic functions (involuntary muscle contraction), monitor movement disorders.
Anti- vertigo
moa: improves blood flow to inner ear
example: betahistine
indication: vertigo, tinnitus
counsel: take with food
Anti-emetics
moa: blocks serotonin, acetylcholine, dopamine receptors from reacting with 5-HT3 receptor.
examples: metoclopramide, domperidone, ondansetron.
indication: nausea, vomiting
counsel: may cause drowsiness, or affect bowel movements.
Topical steroids
example: vistamethasone
indication: ear inflammation (otitis externa).
counsel: avoid long term use, monitor for skin thinning.
Topical anitbiotics
example: gentisone
indication: otitis externa
counsel: avoid if perforated eardrum
Anti-muscarinics
moa: blocks muscarinic acetylcholine receptors (M1,M2, M3).
example: hyoscine
indication: motion sickness, nausea
counsel: can cause dry mouth, blurred vision, drowsiness.
Benzodiazepines
moa: enhances effects of GABA, by binding to GABA-A, causing chloride channel to open, leading to influx of cl- ions into neurons, causing hyperpolarisation, less likely to fire action potential.
examples: diazepam, lorazepam, alprazolam
indications: anxiety, insomnia, seizures.
counsel : may cause drowsiness, avoid alcohol.
What are the 4 classes of antidepressants ?
1) SSRI: Fluoxetine, sertraline, citalopram
2) SNRI: Venlafaxine, duloxetine, desvenlafaxine
3) TCAs: Amitriptyline, nortriptyline, Imipramine
4) MAOI: Phenelzine, tranylcypromine, isocarboxazid
Lubricating ear drops
moa: moisturises and prevents dryness
example: olive oil
indication: earwax removal
counsel: not for perforated ear drum.
ear wax preparations
moa: softens and removes earwax
examples: Otex, sodium bicarbonate
indication: earwax removal.
counsel: follow instruction to avoid ear canal damage.
questions to ask if eye symptoms ?
1) Has vision been affected: loss of vision ?
2) discomfort: itchy eyes (could be conjunctivitis)
3) Discharge: common for conjunctivitis
4) Duration: e.g. red eye for more than a week should be referred, unless its due to conjunctivitis.
5) nausea/vomiting: could suggest glaucoma
6) cold symptoms: could suggest conjunctivitis
treatment of blepharitis
- Pharmalogical treatment rare but topical antibiotic like erythromycin ointment can be given.
- don’t wear contact lenses
- clean eye lids daily
- warm compress 3/4 times a day (5-10 mins)
what is cause of motion sickness
conflict between sensory input from vestibular organs in the inner ears and eyes.
symptoms of motion sickness
skin paleness
cold sweating
dizziness
nausea, vomiting
increased saliva production
general treatment for mild dermatitis
- OTC emollients: Exocream, Dermacool
- topical corticosteroids: hydrocortisone, Hc45 hydrocortisone cream
example of mild, moderate, potent, very potent topical corticosteroids ?
mild: hydrocortisone
moderate: alclometasone dipropionate
clobetasone butyrate
hydrocortisone butyrate
potent: betamethosone, fluticasone, mometasone furoate
very potent: clobetasol propionate
cellulitis treatment
for streptococci: cefuroxime
for penicillin allergies: clindamycin or vancomycin
prevention and treatment of staphylococcal infections
flucloxacillin
what causes acne
blockage of hair follicles by keratin build up
Pharmalogical treatment acne
1) Benzoyl peroxide
2) or combo with clindamycin
to treat systemically use doxycycline
or isotretinoin (its a retinoid) for severe acne
isotretinoin dose
0.5 mg/kg/day for 4 weeks
increase until dose of 120-150 mg/kg reached
Pharmalogical treatment genital warts
podofilox (topical)
Pharmalogical treatment for anogenital warts
Trichloroacetic acid
cryotherapy
Pharmalogical treatment for warts and veruca
verruca gel
Bazuka
(salicylic acid and lactic acid)
shingles treatment
povidone iodine
aciclovir
aciclovir moa
activated by thymidine kinase and is converted into aciclovir triphosphate
competes with deoxyguanosine triphosphate for viral dna chain
aciclovir triphosphate then prevents further elongation of viral DNA chain.
ring worm treatment
antifungal: terbinafine
- inhibits squalene epoxidase, leading to accumulation of squalene, which is toxic to fungal cell
antifungal: griseofulvin
- binds to fungal microtubules inhibiting and disrupting fungal cell division
amphotericin B
treatment for systemic fungal infection
same moa as nystatin
same as ketoconazole and itraconazole, fluconazole
nyastatin
indication; oral candidiasis
- binds to ergosterol in fungal cell membrane, disrupting structure, forming pores, weakening structure, cell contents leak.
how do most antifungals work
by inhibiting fungal cytochrome p450 enzyme, disrupting ergosterol synthesis, causing fungal membrane damage
ring worm and athletes foot OTC treatment
miconazole 2% cream
terbinafine
headlice OTC treatment
dimeticone gel 4%
headlice comb
