ORL601 — Otology: Lecture Note

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la-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS

la-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Course code: ORL 601 Course title: Otology Course credit load: 2 Units Series 1: Otological Diagnosis and Differentials • Part 1.1: Clinical Assessment of the Ear o Sub Part 1.1.1: History taking in otological disease o Sub Part 1.1.2: Otoscopic examination technique o Sub Part 1.1.3: Tuning fork tests and basic audiological assessment • Part 1.2: Diseases of the External Ear o Sub Part 1.2.1: Otitis externa o Sub Part 1.2.2: Impacted cerumen and foreign bodies o Sub Part 1.2.3: Exostoses and other pinna and external canal conditions • Part 1.3: Diseases of the Middle Ear o Sub Part 1.3.1: Acute otitis media o Sub Part 1.3.2: Chronic suppurative otitis media o Sub Part 1.3.3: Otitis media with effusion and other middle ear conditions • Part 1.4: Diseases of the Inner Ear and Differential Diagnosis of Hearing Loss o Sub Part 1.4.1: Sensorineural hearing loss: causes and differential diagnosis o Sub Part 1.4.2: Meniere's disease and other vestibular disorders o Sub Part 1.4.3: Differentiating conductive from sensorineural hearing loss Introduction Welcome to ORL 601: Otology. Confident, competent otological practice begins with a systematic approach to history taking, examination, and differential diagnosis of ear disease, both the common conditions encountered daily in general practice and the less common presentations that demand a higher index of clinical suspicion. This opening Series establishes the clinical assessment skills and diagnostic framework required across the external, middle, and inner ear, forming the essential foundation for the emergency and surgical topics examined in the next Series of this course.

la-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS The aim of this Series is to equip you with a thorough understanding of the clinical assessment of the ear and the diagnosis and differential diagnosis of common and uncommon diseases affecting the external, middle, and inner ear. This Series begins with the clinical assessment of the ear, before examining diseases of the external ear. We then turn to diseases of the middle ear, concluding with diseases of the inner ear and differential diagnosis of hearing loss. Series Learning Outcomes At the end of this Series, you should be able to: • SLO 1.1: take a systematic history relevant to otological disease • SLO 1.2: demonstrate correct otoscopic examination technique and basic audiological assessment using tuning fork tests • SLO 1.3: recognise and describe the diagnosis of otitis externa • SLO 1.4: recognise and describe the diagnosis of impacted cerumen, foreign bodies, and other external ear conditions • SLO 1.5: recognise and describe the diagnosis of acute otitis media • SLO 1.6: recognise and describe the diagnosis of chronic suppurative otitis media and otitis media with effusion • SLO 1.7: describe the causes and differential diagnosis of sensorineural hearing loss and vestibular disorders, and • SLO 1.8: differentiate conductive from sensorineural hearing loss using clinical and tuning fork assessment. 1.1 Clinical Assessment of the Ear 1.1.1 history taking in otological disease Systematic enquiry directing subsequent examination A systematic otological history should establish the specific nature, laterality, and time course of the presenting complaint, generally centred on one or more of a limited set of core symptoms, otalgia (ear pain), otorrhoea (ear discharge), hearing loss, tinnitus, and vertigo, each carrying distinct diagnostic implications.

la-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Further essential history includes enquiry regarding preceding upper respiratory tract infection, discussed further later in this Series in relation to otitis media, prior ear surgery or trauma, occupational or recreational noise exposure, discussed in relation to sensorineural hearing loss later in this Series, and relevant family history, particularly for hearing loss presenting in childhood. Fill in the blank: A systematic otological history should establish the presenting complaint among a limited set of core symptoms, including otalgia, otorrhoea, hearing loss, tinnitus, and ________. 1.1.2 otoscopic examination technique Correct otoscopic examination requires gentle traction on the pinna, generally upward and backward in adults, to straighten the external auditory canal, discussed in relation to external ear anatomy later in this Series, before careful insertion of an appropriately sized speculum under direct visualisation. Systematic assessment of the tympanic membrane should note its colour, translucency, position (normal, retracted, or bulging), and the presence or absence of the light reflex and visible landmarks, including the handle of malleus and umbo, with any perforation described according to its size and specific quadrant location. Fill in the blank: Correct otoscopic examination requires gentle traction on the pinna, generally upward and backward in adults, to straighten the external auditory ________. 1.1.3 tuning fork tests and basic audiological assessment The Rinne test, performed by comparing the loudness of a vibrating tuning fork, generally 512 Hz, held against the mastoid process, testing bone conduction, against the same fork held beside the ear canal, testing air conduction, is recorded as Rinne positive when air conduction is heard louder, the normal finding, or Rinne negative when bone conduction is heard louder, suggesting conductive hearing loss in that ear. The Weber test, performed by placing a vibrating tuning fork in the midline of the forehead or vertex, assesses lateralisation, with the sound lateralising to the affected ear in conductive hearing loss, and to the unaffected ear in sensorineural hearing loss, providing an essential bedside complement to formal pure tone audiometry, discussed further later in this Series. Fill in the blank: The Weber test assesses lateralisation, with sound lateralising to the affected ear in conductive hearing loss, and to the unaffected ear in ________ hearing loss.

la-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Figure 1.1: Diagram illustrating correct otoscope and pinna positioning for examining the external auditory canal. Pilot questions 1.1 1. List the five core symptoms that should be specifically enquired about in an otological history. (Linked to SLO 1.1) 2. Describe the correct technique for pinna traction during otoscopic examination in an adult. (Linked to SLO 1.2) 3. List the features that should be assessed on otoscopic examination of the tympanic membrane. (Linked to SLO 1.2) 4. Describe how the Rinne test is performed and interpreted. (Linked to SLO 1.2) 5. Describe how the Weber test is performed and interpreted. (Linked to SLO 1.2)

la-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS 1.2 Diseases of the External Ear 1.2.1 otitis externa Inflammation of the external auditory canal skin and soft tissue Acute otitis externa is an infective or inflammatory condition of the external auditory canal skin, most commonly bacterial, particularly Pseudomonas aeruginosa and Staphylococcus aureus, presenting with otalgia characteristically worsened by pinna traction or jaw movement, canal oedema, and otorrhoea. Malignant, or necrotising, otitis externa represents a rare but serious progression of infection into the surrounding bone, discussed further as an emergency in the next Series of this course, occurring almost exclusively in diabetic or otherwise immunocompromised patients, and requiring urgent recognition given its considerable potential morbidity if inadequately treated. Fill in the blank: Malignant, or necrotising, otitis externa occurs almost exclusively in diabetic or otherwise ________ patients. 1.2.2 impacted cerumen and foreign bodies Impacted cerumen, or ear wax, presents with conductive hearing loss, discussed earlier in this Series, a sensation of ear fullness, and, at times, tinnitus, generally managed with cerumenolytic drops or careful syringing, microsuction, or instrumental removal under direct vision where simple measures prove insufficient. Foreign bodies within the external auditory canal, discussed particularly in relation to children, range from inert objects to, occasionally, live insects, requiring careful, atraumatic removal, generally by microsuction or fine instrumentation, with a low threshold for specialist referral where the foreign body is adherent to the canal wall or the tympanic membrane itself. Fill in the blank: Impacted cerumen is generally managed with cerumenolytic drops or careful syringing, microsuction, or instrumental removal under direct ________. 1.2.3 exostoses and other pinna and external canal conditions Exostoses are benign, bony outgrowths of the external auditory canal, strongly associated with repeated cold water exposure, discussed in relation to occupational and recreational history earlier in this Series, and generally producing progressive canal narrowing, occasionally requiring surgical removal if significantly obstructing or symptomatic.

la-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Further recognised pinna and external canal conditions include perichondritis, infection of the cartilaginous framework of the pinna, often following minor trauma or piercing, and relapsing polychondritis, a rare autoimmune condition producing recurrent inflammation of cartilaginous structures including the pinna, each requiring prompt recognition to prevent permanent cartilage destruction. Fill in the blank: Exostoses are benign, bony outgrowths of the external auditory canal strongly associated with repeated ________ water exposure. Table 1.2: Comparing common conditions of the external ear. Condition Typical cause Key clinical feature Otitis externa Bacterial infection (Pseudomonas, Staphylococcus) Otalgia worsened by pinna traction Impacted cerumen Accumulated ear wax Conductive hearing loss, ear fullness Exostoses Repeated cold water exposure Progressive canal narrowing Pilot questions 1.2 1. Describe the typical clinical presentation of

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