ENT Flashcards
Anatomy and function of
- Outer ear
- Middle ear
- Inner ear
- Pinna, auditory canal, tympanic membrane. Collect sound.
- Ossicles bones = malleus, incus + stapes, opening of Eustachian tube. Convert sound from sound energy to mechanical energy, amplifies and relays it.
- Labyrinth = semicircular canals, vestibule, cochlea, CN8.
What turns the mechanical energy of sound into electrical energy to process
Organ of Corti.
Types of hearing loss
Conductive - sound energy does not reach cochlear. Problem in outer or middle ear. Normal bone conduction. Rinne’s negative.
Sensorineural - cochlea or auditory nerve defect. Problem in inner ear. Rinne’s test positive.
Mixed
Testing hearing loss
512Hz tuning fork 🍴
Rinne’s test = tuning fork on mastoid then in air by ear.
- Air conduction usually better than bone so hear vibrations better when by ear than placed on mastoid or with sensorineural hearing loss.
- If heard louder on mastoid = conductive hearing loss
Weber’s test = tuning fork on forehead
- Normal = equal on both sides.
If sound louder on one side, this suggests:
- Conductive hearing deficit on this side (bone conduction)
OR
- Sensorineural hearing loss on the other side (no air conduction).
Audiogram!!
Audiogram
y axis = hearing level in dB.
x axis = frequency in Hz.
Normal is 0-20dB.
Causes of conductive hearing loss
External canal obstruction = wax, foreign body, oedema from otitis media, otitis externa.
Tympanic membrane perforation
Eustachian tube problems = otitis media with effusion.
Acute mastoiditis
Otosclerosis
Chostesteatoma
Causes of sensorineural hearing loss
Ototoxicity = Gentamicin. Meniere's disease Infections = Mumps, encephalitis, meningitis. Presbycusis Noise induced Acoustic neuroma
Tympanic membrane perforation
Sudden onset, painful hearing loss.
O/E can see perforation.
Rx:
If small heal spontaneously +/- topical Abx.
If larger may need ear drum replacement surgery - Myringoplasty.
Inheritance and pathology of otosclerosis
Autosomal dominant.
More common in women.
Hardening and stiffening of the stapes footplate in oval window of cochlea.
Presentation, Ix and Rx for otosclerosis
Slowly progressive bilateral conductive hearing loss.
Worsen in pregnancy and menses.
May also suffer form tinnitus and transient vertigo.
Ix with audiogram.
Rx = hearing aids, surgical management with stapedotomy (hole to help movement) or replace stapes.
Cholesteatoma pathology and causes
Persistent discharge though a damaged tympanic membrane. Pressure difference causes tympanic membrane retraction. Creates retraction pocket in tympanic membrane which are lined by squamous epithelium (normally resp epithelium) and initiate inflammation.
Can be due to recurrent middle ear infections, perforated tympanic membrane, congenital.
Presentation, Ix and Rx for cholesteatoma
Conductive deafness in affected ear (unilateral)
Discharge (smelly) but not painful (∆ for otitis media).
Local invasion can cause facial paralysis, erosion to brain cavity.
O/E = tympanic membrane retraction.
Ix = CT! if worried about bone erosion. Rx = surgical removal of cholesteatoma via open mastoid cavity technique.
Audiogram in
- Sensorineural loss
- Conductive
- Mixed
- Both air and bone lines are at lower dB
- Only the air conduction line is lower.
- Both lines are low but to different extents.
Main pathogens in acute otitis media
Viral
H.influenza
Streptococcus pneumoniae
Presentation of acute otitis media
Severe acute ear pain (otalgia)
Discharge (discharge release can ease pain).
Kids pull ears, crying, pyrexial.
Conductive hearing loss.
O/E = bulging red tympanic membrane.
Why is otitis media more common in kids
More acute angle of Eustachian tube so harder to clear mucus in area.
Ix and Mx for acute otitis media
Ix = Visualise tympanic membrane with otoscope.
Rx =
- Analgesia (pcm), steam inhalations.
- Can give ABx e.g. amoxicillin if remains symptomatic for over 3 days in kids. Most adults will need ABx as it is unusual for them to get disease.
Complications of acute otitis media
Intracranial = meningitis, encphalitis, brain abscess. Infratemporal = mastoiditis, CN7 palsy, labrynthitis
What is otitis media with effusion and who gets it?
Collection of fluid in middle ear, >3months. Usually following acute otitis media.
- Kids with Eustachian tube acute angle
- Adults with nasopharyngeal carcinoma.
Presentation, Ix and Mx for otitis media with effusion
Painless but feeling of fullness in ear.
Conductive hearing loss - speak quietly.
Tinnitus, cracking/popping.
Hx of AOM.
O/E = opaque, intact tympanic membrane, loss of light reflex.
Ix = Audiogram, tympanogram (flat). If adult must exclude tumour!!!
Mx = Most self limiting in kids within 1yrs sports may not need Rx.
Grommets to act as ventilation tubes and release mucus.
Hearing aids.
Dr tries to treat AOM but it won’t go away.
Cholesteatoma. (‘unsafe chronic otitis media’)
Chronic otitis media
- Chronic inflammation of the middle ear and mastoid cavity. >2weeks.
- CFX = Mild ear pain but lots of mucoid discharge. No systemic illness. Kids may speak quietly and have behavioural problems from poor hearing.
- O/E = granulation tissue in canal, perforation.
- Ix = CT to rule our cholesteatoma bone erosion or abscess.
- Rx = ENT referral to use off licence ABx, ear hygiene (keep dry), maybe steroids too 💊
Mastoiditis
- Causes = cholesteatoma, acute otitis media.
- CFx = swelling and pain in mastoid area. Anterior-inferior displacement of pinna.
- Ix = complete cranial nerve exam, blood cultures, ear discharge mc+s, audiogram, skull XR, LP, CT scan (opacity in mastoid air cells).
- Rx = high dose IV ABx (ceftriaxone) and surgical drainage.
Presentation of otitis externa
Itching.
Ear pain, tenderness at tragus.
Feeling of fullness in ear.
Poor hearing (conductive).
O/E
Furuncles (painful swelling on external ear) if infected hair follicle.
Canal is erythematous, shiny and can be oedematous if severe.
Pathology of otitis externa
RFx = swimming, narrow canal, less wax.
Viral = Ramsey-Hunt V.zoster or Herpes simplex. Bacterial = S.aureus, Pseudomonas aeruginosa. Fungal = Candida albicans, Aspergillus niger.
Name 3 ototoxic drugs
gentamicin
loop diuretics - furosemide
platinim chemo - cisplatin.
Mx of otitis externa
Hygiene = avoid swimming, keep ear dry, can use olive oil to help move wax. Viral = aural toilet, topical antivirals or corticosteroids. Bacterial = aural toilet anf ABx e.g. Ciprofloxacin. Fungal = Clotrimazole.
Complication of otitis externa and who is more likely to get it
Necrotising Otitis Externa 🦻.
More common in immunocompromised and diabetes.
Necrotising otitis externa
- Granulation formation, erosion of bone (temporal bone) and cartilage in ear. Can go on to disrupt CN7, 9, 11, 12.
- More common on P.aeruginosa.
- CFx = severe pain, blood-stained discharge, headache, CN palsy.
- O/E = granulations.
- Rx = IV gentamicin or ciprofloxacin
3 peripheral and 3 central causes of vertigo
Peripheral = Meniere's disease Benign positional vertigo Labyrinthitis Cholesteatoma
Central =
Acoustic neuroma
MS
Head trauma
Episodic tinitus, vertigo and can’t hear low frequency things
Meniere’s disease
Pathology of meniere’s disease
Not completely known.
Endolymphatic hydrops
Probs over-production or impaired absorption of endolymph in inner ear.
Presentation of Meniere’s disease
Episodic sudden onset. Usually episodes last longer than BPPV.
Vertigo
Low frequency, unilateral hearing loss - Sensorineural
Roaring tinnitus
Sense of fullness in ear
‘Drop attacks’ - sudden loss of balance but no LOC.
Ix and Rx for meniere’s disease
Ix = audiogram, normal tympanogram. Exclude other causes with CT, syphilis serology.
Rx = low salt diet. Drugs such as betahistine, trimetazidine (benzo). TELL DVLA 🚘
Age related sensorineural hearing loss
- Presbycusis, loss of outer hair cells in cochlear.
- Struggles to hear in noisy environment.
- Usually loose high frequency hearing first.
- Rx with hearing aid, cochlear implant.
- Cx = loneliness and psych, worsen dementia.
Noise induced hearing loss
Trough on audiogram at 4000Hx/ ‘reversed tick’ sign on audiogram.
Bilateral sensironeural hearing loss.
Tinnitus.
NOT progressive.
Unilateral hearing loss
Tinnitus
Poor facial sensation
Balance problems
Acoustic neuroma
What is an acoustic neuroma
A benign and slow growing tumour arising from the Schwann cells of the vestibularchochlear nerve (CN8) at the cerebellopontine angle.
Presentation of an acoustic neuroma
UNILATERAL HEARING LOSS IS A ACOUSTIC NEUROMA UNTIL PROVEN OTHERWISE.
Unilateral or asymmetrical hearing loss.
Tinnitus
Impaired facial sensation and loss of corneal reflex - involves trigeminal nerve.
Balance problems and ataxia.
Ear ache
If super big = raised ICP.
Ix and Rx for acoustic neuroma
Ix = audiogram (sensorineural loss), MRI.
Rx = Surgical excision, stereotactic radiosurgery
What is the most common cause of vertigo
Benign paroxysmal positional vertigo 🧚♀️🧚🧚♂️
Pathology of benign paroxysmal positional vertigo
Otolith (small calcium carbonate crystals) detach and are free in semicircular canals. When head stops moving they carry on, putting pressure on cilia hair cells causing causing signal of movement to brain.
Presentation of BPPV
Episodic vertigo. Usually comes on when turning over in bed, sitting up, leaning forward.
Short episodes with sudden onset (last 30seconds).
No hearing loss
No tinnitus
Ix and Rx for BPPV
∆ with Dix Hallpike test, get nystagmus. (+ve if BPPV)
Treat with Epley’s manoeuvre which puts otoliths back in urticles..
Presentation of labyrinthitis
Vertigo even at rest but worsens on head movements.
Hearing loss - sensorineural.
Tinnitus
Balance problems.
N+V
Hx of otitis media, mumps, measles or influenza-type illness.
O/E:
- Head Impulse test, Nystagmus Type and Skew: impaired vestibule-ocular reflex (saccades), unidirectional nystagmus, no vertical skew.
3 subtypes of labyrinthitis
Circumscribed = erosion of bony capsule in labyrinth by a cholesteatoma. Serous = non-purulent inflammation of labyrinth. Suppurative = infiltration of inflammatory cells and pus cells. Usually bacterial. Can lead to total, permanent hearing loss.
Mx of labyrinthitis
Depends on type.
Circumscribed = remove cholesteatoma.
Serous = bed rest, labyrinth sedatives (prochlorperazine).
Suppurative = bed rest, prochlorperazine, ABx.
Advise against driving 🚙
Difference between labyrinthitis and vestibular neuritis
VN has no hearing loss, affects vestibular nerve ONLY.
Vestibular neuritis
- Inflammation of vestibular nerve.
- Preceding URT infection. Can be reactivation of H.simplex.
- CFx = NO HEARING LOSS. Sudden vertigo even at rest, worsened on movement, gait instability, N+V.
- O/E = Head Impulse test, Nystagmus Type and Skew: impaired vestibule-ocular reflex (saccades), unidirectional nystagmus, no vertical skew.
- Rx = self-limiting. Prochlorperazine, bed rest, fluids and no driving please 🚙
HINTS
Head Impulse test, Nystagmus Type and Skew
Differentiate labyrinthitis + vestibular neuritis from a stroke.
Labyrthinitis + VN = abnormal head impulse (saccades), unidirectional nystagmus, no vertical skew.Stroke esp PICA = abnormal head impulse, bidirectional nystagmus, vertical skew.
2 types of tinnitus and examples
Objective - noise in head and can be heard by observer. Carotid stenosis, valvular heart disease, tympanic muscle spasm.
Subjective - more common. no noise audible to observer. otosclerosis, Menieres’ disease, MS, acoustic neuroma, syphilis.
Non pharmacological measures to help hearing impaired patients
Electronic hearing aids Environmental aids e.g. flashing light with door bell and telephone calls. Sign language Organisation support e.g. RNID Cochlear implants
Ramsay-Hunt syndrome
- Herpes zoster Oticus.
- Reactivation of Varicella zoster from geniculate ganglia of cranial nerve 7.
- Different from shingles as motor component, Shingles is sensory disease.
- CFx = otalgia, tinnitus, vertigo, vesicles on skin of ear canal, hearing loss.
- Rx = acyclovir if caught in early stage + prednisolone.
Definition of vertigo
Illusion of movement.
Functions of the nose
Olfaction
Airway/ventilation, warms and humidifies air.
Mucus secretion - filtration and infection prevention.