About This Page
This is a clinician-written, evidence-based guide aligned to the MCC Examination Objectives. It is structured by clinical presentation — the way the MCCQE tests and the way patients actually present. Management reflects current Canadian guidelines (CMA, CFPC, CPS). Always cross-reference with institutional protocols and clinical judgment.
The Bottom Line
- Classify hearing loss as conductive, sensorineural, or mixed using history, otoscopy, tuning forks, and audiometry
- Sudden unilateral sensorineural hearing loss is an emergency: urgent audiogram and ENT referral; treatment benefit is time-sensitive
- Conductive causes include cerumen, otitis media with effusion, tympanic membrane perforation, cholesteatoma, and otosclerosis
- Sensorineural causes include presbycusis, noise exposure, ototoxicity, Ménière disease, vestibular schwannoma, infection, and autoimmune disease
- All infants require hearing screening; delayed recognition affects speech, language, learning, and psychosocial development
Approach to the Presentation
Hearing loss can be gradual or sudden, unilateral or bilateral, fluctuating or progressive. The MCCQE1 approach begins with time course and laterality, then separates conductive from sensorineural loss. Conductive loss localizes to the external or middle ear and is often visible on otoscopy. Sensorineural loss localizes to the cochlea, auditory nerve, or central pathways and is particularly urgent when sudden and unilateral. Ask about otalgia, otorrhea, tinnitus, vertigo, neurologic symptoms, noise exposure, ototoxic medications, trauma, infections, autoimmune symptoms, and family history. Perform otoscopy, cranial nerve exam, bedside hearing assessment, and tuning fork tests. Formal audiometry is the diagnostic anchor.
Differential Diagnosis
| diagnosis | likelihood | key features | distinguishing test |
|---|---|---|---|
| Sudden Sensorineural Hearing Loss | must-not-miss | Rapid unilateral hearing loss over ≤72 hours, often with tinnitus and aural fullness; otoscopy may be normal. May be idiopathic, viral, vascular, autoimmune, or retrocochlear | Urgent audiogram showing sensorineural loss; MRI internal auditory canals if asymmetric/retrocochlear concern |
| Vestibular Schwannoma / Retrocochlear Lesion | must-not-miss | Unilateral asymmetric sensorineural hearing loss, unilateral tinnitus, imbalance, facial numbness or weakness if larger | MRI internal auditory canals with gadolinium |
| Cholesteatoma | must-not-miss | Conductive hearing loss with chronic foul otorrhea, retraction pocket or pearly mass; can erode ossicles and cause intracranial complications | Otoscopy/microscopy + audiogram; CT temporal bone for surgical planning |
| Acoustic / Barotrauma or Temporal Bone Trauma | must-not-miss | Hearing loss after blast, loud noise, diving/flying, slap injury, head trauma; may have vertigo, TM perforation, haemotympanum, facial palsy | Otoscopy + audiogram; CT temporal bone if fracture suspected |
| Cerumen Impaction | common | Gradual conductive hearing loss, blocked sensation, visible wax, often after cotton bud use or hearing aid use | Otoscopy; symptoms improve after safe removal |
| Otitis Media with Effusion | common | Conductive hearing loss, fullness, popping, recent URTI/allergy, retracted or dull TM with fluid level; common in children | Pneumatic otoscopy/tympanometry showing effusion |
| Presbycusis | common | Gradual bilateral high-frequency sensorineural hearing loss, difficulty hearing speech in background noise, older adult | Audiogram: bilateral high-frequency SNHL |
| Noise-Induced Hearing Loss | common | History of occupational/recreational noise exposure; difficulty with high-frequency sounds; tinnitus common | Audiogram: high-frequency notch, often around 4 kHz |
| Ménière Disease | less common | Episodic vertigo, fluctuating low-frequency hearing loss, tinnitus, aural fullness | Audiogram; clinical criteria after excluding other causes |
| Otosclerosis | less common | Progressive conductive hearing loss in young/middle-aged adult, often family history; normal TM; may worsen in pregnancy | Audiogram with conductive loss; absent stapedial reflex; CT if needed |
| Ototoxicity | less common | Bilateral sensorineural hearing loss after aminoglycosides, cisplatin, loop diuretics, high-dose salicylates, or chemotherapy; tinnitus may precede loss | Medication history + audiometry; serial monitoring in high-risk therapy |
Red Flags & Key History
Symptoms
Sudden unilateral hearing loss within 72 hours — sudden sensorineural hearing loss until proven otherwise
Hearing loss with vertigo, severe headache, facial weakness, diplopia, ataxia, or focal neurology — central or skull base pathology
Unilateral tinnitus with asymmetric hearing loss — retrocochlear lesion concern
Chronic foul otorrhea with conductive hearing loss — cholesteatoma
Hearing loss after head trauma, blast, diving, or flying — traumatic/barotrauma complication
Gradual bilateral high-frequency loss in older adult — presbycusis
Aural fullness after URTI/allergy — otitis media with effusion or eustachian tube dysfunction
Speech delay, inattentiveness, school difficulty, or failed newborn screen — paediatric hearing loss concern
Signs
Normal otoscopy with sudden unilateral loss — suggests sensorineural pathology
Facial nerve palsy or other cranial neuropathy — skull base, temporal bone, or retrocochlear disease
Pearly attic mass/retraction pocket — cholesteatoma
Weber lateralizes to affected ear with Rinne negative — conductive hearing loss
Weber lateralizes to unaffected ear with Rinne positive bilaterally — sensorineural hearing loss
Middle-ear effusion, retracted TM, or air-fluid level — conductive loss from effusion
Approach to Investigation
First-line
OtoscopyLook for cerumen, foreign body, otitis externa, TM perforation, effusion, haemotympanum, retraction pocket, cholesteatoma, or chronic otorrhea
Bedside hearing assessment and tuning forksRinne and Weber help distinguish conductive from sensorineural loss but do not replace audiometry
Formal audiometryPure tone audiogram defines type, severity, laterality, and frequency pattern. Urgent for sudden sensorineural hearing loss
TympanometryUseful for otitis media with effusion, eustachian tube dysfunction, and conductive loss assessment
Second-line
MRI internal auditory canals/brainFor asymmetric sensorineural hearing loss, unilateral tinnitus, cranial neuropathy, or concern for vestibular schwannoma/central lesion
CT temporal boneFor cholesteatoma, ossicular disease, temporal bone fracture, congenital malformation, or surgical planning
Medication and exposure reviewIdentify ototoxic medications, occupational noise, recreational noise, chemotherapy, aminoglycosides, and loop diuretics
Specialist
Urgent ENT referralSudden sensorineural hearing loss, cholesteatoma, temporal bone trauma, cranial neuropathy, or persistent unilateral/asymmetric loss
Audiology / hearing rehabilitationHearing aids, assistive devices, communication strategies, workplace accommodations, and cochlear implant assessment where indicated
Management Principles
MCC Objective 40 + Canadian Family Physician hearing loss approach + Canadian otolaryngology Choosing Wisely recommendations1
Sudden sensorineural hearing loss
- Treat as an otologic emergency; arrange urgent audiogram and ENT referral
- Consider prompt corticosteroid therapy when clinically appropriate and after weighing risks; intratympanic steroid may be used by ENT
- Do not delay referral for extensive blood work or CT when the presentation is classic
- MRI internal auditory canals is used to exclude retrocochlear pathology in asymmetric SNHL
2
Conductive causes
- Cerumen: cerumenolytics, manual removal, or irrigation only when tympanic membrane is intact and no contraindications exist
- Otitis media with effusion: watchful waiting initially; assess hearing and speech impact; ENT referral if persistent or high-risk
- Cholesteatoma: ENT referral; definitive management is surgical
- Otosclerosis: audiology/ENT for hearing aids or stapes surgery evaluation
3
Sensorineural chronic causes
- Presbycusis/noise-induced loss: hearing protection, hearing aids, communication strategies, audiology follow-up
- Ototoxicity: review medication necessity, stop/substitute if possible, monitor audiometry, and coordinate with prescribing team
- Ménière disease: salt moderation, trigger management, vestibular suppressants only short-term for acute vertigo, ENT follow-up
4
Infants and children
- Ensure newborn hearing screening follow-up and early referral after failed screen
- Assess speech/language development, school performance, recurrent otitis media, and family history
- Early audiology and ENT involvement prevents developmental and educational consequences
Complications & Pitfalls
- Missing sudden SNHL: A normal ear exam with sudden unilateral hearing loss is not wax or eustachian tube dysfunction until proven otherwise.
- Delaying steroid consideration: Treatment benefit for sudden SNHL is time-sensitive.
- Over-ordering CT: CT does not rule out sudden SNHL or vestibular schwannoma; audiogram and MRI are more relevant.
- Ignoring paediatric hearing loss: Speech delay and school difficulty may be the presenting features.
- Unsafe wax removal: Avoid irrigation when TM perforation, prior surgery, active infection, or only-hearing-ear status is present.
MCCQE1 Exam Tips
- 1The first classification step is conductive vs sensorineural. Otoscopy + Weber/Rinne + audiogram is the core sequence
- 2Sudden sensorineural hearing loss: urgent audiogram and ENT referral. Do not reassure or wait for spontaneous recovery
- 3Weber lateralizes to the affected ear in conductive loss and away from the affected ear in sensorineural loss
- 4Cholesteatoma stem: chronic foul discharge + conductive hearing loss + retraction pocket/pearly mass
- 5Vestibular schwannoma stem: unilateral tinnitus + asymmetric SNHL ± imbalance/facial numbness; MRI internal auditory canals
- 6Presbycusis is bilateral, gradual, high-frequency, and worse in background noise
- 7In children, hearing loss may present as speech delay, inattentiveness, or school difficulty rather than a direct complaint
practicetest your knowledge on hearing lossApply what you've learnt with MCCQE1-style questions from the iatroX Q-Bank — ent & ophthalmologic and beyond.
open q-bank