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Phase 3a > ENT > Flashcards

ENT Flashcards

1
Q

Ear: Divisions of the ear and individual components

A

Outer Ear - Auricle/Pinna + External auditory canal (concha to tympanic membrane)

Middle Ear:
* 1 nerve - facial nerve (CN VII)
* 2 muscles (to restrict movement of ossicular chain, preventing damage from loud noise/and noise from chewing) - stapedius (Innervation - branch to stapedius from CN VII) and tensor tympani (Innervation - CN V3 branch)
*3 bones - malleus, incus, stapes

Inner Ear;
*Vestibular system - 1) Semicircular canals (detect angular acceleration from rotational movements) and 2) Otolithic organs; utricle and saccule within the vestibule (detect linear acceleration from changes of head position relative to gravity)
*Cochlear system - sound detection -> nervous transmission (Ducts - scala media/tymapni/vestibuli and the use of basilar membrane and the Organ of Corti)

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2
Q

Ear: Composition of the external auditory canal and function

A

Outer 1/3 - Cartilage
*Produces wax

Inner 2/3 - Bone

S-shaped, not straight

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3
Q

Ear: Auricle - function, composition, landmarks and clinical relevance

A

Function - capture and direct sound waves towards external auditory canal

Composition - mostly cartilage except for lobule

Landmarks - Helix, Tragus, Concha, Lobule

Clinical Relevance - pinna haematoma (cauliflower ear); shearing forces lead to accumulation of blood between cartilage and overlying perichondrium which can disrupt blood supply to the cartilage -> can lead to avascular necrosis of the cartilage

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4
Q

Ear: Tympanic membrane - landmarks on otoscopy

A

Handle of Malleus

Umbo - Tip of handle of malleus meets membrane at the umbo
* Deepest concavity of the tympanic membrane

Lateral Process of Malleus - Follow the malleus up superiorly to see

Pars flaccida; Flaccid - weakest part of the membrane

Pars tensa; Rest of the membrane

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5
Q

Ear: Tympanic membrane - light reflex explained

A

Position of light from otoscope can help determine which ear is being looked at:
* Right Ear - 5 o’clock position
* Left Ear - 7 o’clock position

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6
Q

Ear: Neurological complication of middle ear surgery?

A

Facial paralysis - CN VII runs in middle ear

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7
Q

Ear: Mastoid process - location, cells + function and clinical relevance

A

Location - area of temporal bone located posterior to ear

Cells + Function - contains air cells that protect the ear and equalise ear pressure

Clinical Relevance - vulnerable to infection from otitis media (swollen area and ear turned forward if mastoiditis)

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8
Q

Ear: Eustachian Tube - location and function

A

Location - connects middle ear to nasopharynx

Function:
1. Middle ear filled with air but no direct contact with atmosphere to tympanic membrane
2. When atmospheric pressure changes, pressure differences can develop between outer and middle ear
3. Eustachian tube opens allowing pressure to equalise:
*Valsalva manoeuvre/swallowing/chewing opens up eustachian tube

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9
Q

Ear: Physiology of semicircular canals

A

Contain endolymph and sensory hair cells which detect direction and flow of endolymph as head moves

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10
Q

Nose: Function - primary and others

A

Primary - ventilation

Others:
* Olfaction
* Humidifies air
* Protects airway from pathogens via mucous production and trapping with hair
* Recieves drainage from:
* Facial sinuses
* Tear ducts
* Eye
* Middle ear ventilation via Eustachian Tube

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11
Q

Nose - anatomy (relevant)

A

External Nose
* Made of cartilage
* Divided in middle by septum
* Superiorly covered by bony skeleton attached to forehead

Nasal Cavity - Starts at the vestibule and extends posteriorly to the nasopharynx

Olfactory Nerve - Sits at superior aspect of nasal cavity with fibres piercing through cribriform plate of ethmoid bone

Turbinates (conchae)
* Location - lateral walls of nasal cavity covered by following turbinates/conchae:
* Superior
* Middle
* Inferior
* Function - Projections that increase the surface area within nasal cavity allowing for:
* Improved humidification
* Temperature change
* Filtration of inspired air

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12
Q

Nose: Arterial supply + Clinical Relevance

A

Anterior Plexus (Little’s Area/Kiesselbach’s Plexus) - Rich blood supply that is the frequent source of epistaxis (Epistaxis - More common, occurs in children/young adults, usually due to mucosal dryness, less severe)

Posterior Plexus (Woodruff’s Plexus) - Epistaxis - Less common, older population, HTN/Atherosclerotic disease, more severe

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13
Q

Head + Neck: Anterior triangle - borders and key structures

A

Borders:
* Superior - mandible
* Medial - midline of the neck
* Lateral - SCM

Key Structures:
* Thyroid + Parathyroid glands
* CN IX, X and XII
* Carotid artery and IJV
* Salivary glands

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14
Q

Head + Neck: Posterior triangle - borders and key structures

A

Borders:
* Anterior - SCM
* Inferior - clavicle
* Posterior - trapezius

Key Structures:
* Subclavian artery and vein
* External jugular vein
* Cranial Nerve XI
* Brachial Plexus

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15
Q

Head + Neck: Clinical relevance - benign neck lumps in neck triangles

A

Anterior triangle - branchial cyst

Posterior triangle - cystic hygroma

(Both are benign malformations that result in neck lump)

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16
Q

Head + Neck: Parotid gland - properties, location and clinical relevance

A
  • Largest salivary gland
  • Located - anterior to ear, superior to angle of mandible
  • Motor branch of facial nerve runs through - so facial paralysis may occur if pathology to parotid gland
  • Stensen’s duct - where the saliva from the parotids are secreted; it is a small bulge just opposite the 2nd upper molar on the inside of the cheek
  • Clinical Relevance - most common site of salivary gland tumours
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17
Q

Head + Neck: Sublingual gland - properties, location and clinical relevance

A
  • Smallest salivary gland
  • Allows for smoother passage of a food bolus down the oesophagus
  • Produces the most mucous secretions
  • Clinical Relevance - mucocoele formation is more likely at this gland and these are called ranula
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18
Q

Head + Neck: Submandibular gland - properties and location

A
  • Found underneath the mandible
  • Responsible for producing most of our saliva when NOT eating
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19
Q

Ear: Meniere’s Disease - definition

A

Disorder of the inner ear of unknown cause, characterised by excessive pressure and progressive dilation of the endolymphatic system
* Recurrent episodes of vertigo, tinnitus and hearing loss
* Episodes typically last 12-24 hours

20
Q

Ear: Meniere’s Disease - epidemiology

A
  • More common in middle-aged adults - but may be seen at any age
  • Similar prevalence in M and F
21
Q

Ear: Meniere’s Disease - clinical features

A

Key Presentation - Vertigo usually prominent symptom

  • 30-60 y/o
  • Attacks of vertigo w/ deafness and tinnitus
    ○ Unilateral affect on ear
    ○ Vertigo NOT triggered by head position
    ○ Tinnitus - initially occurs with episodes of vertigo before eventually becoming more permanent. It is usually unilateral
    ○ Deafness - sensorineural, generally unilateral and affects low frequencies first
    ○ Attacks occur in clusters - episodes can come in clusters over several weeks, followed by prolonged periods (often months) without vertigo symptoms
    ○ Can be very disabling - bed bound, N+V, fluctuating hearing
  • Other features include -
    ○ Sensation of aural fullness or pressure - is now recognised as being common
    ○ Spontaneous unidirectional nystagmus can be seen during an attack
    ○ Unexplained falls (“drop attacks”) without loss of consciousness
    ○ Imbalance, which can persist after episodes of vertigo resolve
    ○ Positive Romberg’s Test

*Bilateral symptoms may occur after a number of years

22
Q

Ear: Meniere’s Disease - management

A

Prophylaxis:
* Betahistine - reduces frequency of attacks
* MOA - H1-Receptor Agonist (and some H3-Receptor Antagonism)
* Contraindication - phaeochromocytoma
*Vestibular rehabilitation exercises - may be of benefit

Acute:
* Prochlorperazine - buccal or IM
* D2 receptor antagonist - predominantly anti-dopaminergic effects acting as an anti-emetic
* Contraindication - phaeochromocytoma
*Admission sometimes required

Surgery - Lacks strong evidence base

DVLA - Inform DVLA; cease driving until satisfactory control of symptoms achieved

23
Q

Ear: Meniere’s Disease - natural history

A
  • Symptom Resolution - majority resolve after 5-10 years
  • Majority left with degree of hearing loss (potentially as result of labyrinth rupture)
  • Psychological distress common
24
Q

Ear: Meniere’s Disease - triad of symptoms

A
  1. Hearing loss
  2. Vertigo
  3. Tinnitus
25
Q

Ear: Meniere’s Disease - pathophysiology

A

Ménière’s disease is associated with the excessive build-up of endolymph in the labyrinth of the inner ear, causing a higher pressure than normal and disrupting the sensory signals.
* This increased pressure of the endolymph is called endolymphatic hydrops

26
Q

Ear: Otosclerosis - definition

A

Remodelling of the small bones in the middle ear, leading to conductive hearing loss
* Oto- refers to the ears
* -sclerosis means hardening
* Most common cause of progressive deafness in adults

27
Q

Ear: Otosclerosis - epidemiology and inheritance

A
  • Can be inherited in an autosomal dominant pattern - often significant family Hx
  • Usually presents before the age of 40 years
  • F > M
28
Q

Ear: Otosclerosis - aetiology

A

Thought to develop from a combination of environmental and genetic factors - exact mechanism not understood
* No specific genetic mutations have been identified

29
Q

Ear: Otosclerosis - pathophysiology

A
  1. Auditory ossicles - tiny bones of middle ear that transmit sound vibrations from tympanic membrane to cochlea (stapes footplate connected to the oval window which transmits vibrations to the cochlea)
  2. In otosclerosis - ossicles affected by abnormal bone remodelling and formation; predominantly the stapes footplate where it attaches to the oval window (eventually fuses to the bone of the cochlea)
  3. This causes stiffening and fixation, preventing it from transmitting sound effectively; progressively gets worse until a maximal conductive hearing loss of 60dB is reached

Results in CONDUCTIVE hearing loss

30
Q

Ear: Otosclerosis - cinical features

A

Key Presentation

  • <40 y/o
  • Unilateral or bilateral hearing loss + tinnitus; tends to affect hearing of lower pitched sounds more than higher-pitched sounds
    ○ Female speech may be easier to hear than male speech (due to generally higher pitch)
    § Reverse of pattern seen in presbycusis
  • Due to conductive hearing loss with intact sensory hearing - patient can experience their voice as being loud compared to the environment (due to bone conduction of their voice)
    ○ This can lead to them talking quietly
31
Q

Ear: Otosclerosis - why can patients start talking quieter than usual

A

Conductive hearing loss with intact sensory hearing - patient can experience their voice as being loud compared to the environment (due to bone conduction of their voice)

32
Q

Ear: Otosclerosis - examination findings

A

Otoscopy:
* The majority of patients will have a normal tympanic membrane
* 10% of patients may have a ‘flamingo tinge’, caused by hyperaemia

Weber’s Test:
* Normal Weber’s - if otosclerosis bilateral (bilateral conductive hearing loss)
* Louder in affected ear if unilateral

Rinne’s Test:
* Sound will be easily heard when the tuning fork is applied to the mastoid process (bone conduction)
* When the patient stops being able to hear the sound during bone conduction, and the tuning fork is removed from the mastoid process and held close to the ear canal, they will still not hear the sound
* Air conduction < bone conduction

33
Q

Ear: Otosclerosis - investigations

A

1st Line: Audiometry - conductive hearing loss pattern
* Bone conduction readings will be normal (between 0 and 20 dB)
* However, air conduction readings will be greater than 20 dB, plotted below the 20 dB line on the chart
* Hearing loss tends to be greater at lower frequencies

Others:
* Tympanometry - show generally reduced admittance (absorption) of sound
* The tympanic membrane is stiff and non-compliant and does not absorb sound, reflecting most of it back
*High Resolution CT Scans - can detect bony changes associated with otosclerosis, although they are not always required

34
Q

Ear: Otosclerosis - management

A

Conservative - Use of hearing aids

Surgical: Generally successful - can potentially restore hearing to normal
* Involves lifting the tympanic membrane and some of the surrounding skin out of the way to access the middle ear through the ear canal

  • Stapedectomy - Removing the entire stapes bone and replacing it with a prosthesis
    • The prosthesis attaches to the oval window and hooks around the incus, transmitting the sound from the incus to the cochlea in the same way the stapes normally would
  • Stapedotomy - Removing part of the stapes bone and leaving the base of the stapes (the footplate) attached to the oval window
    • A small hole is made in the base of the stapes for the prosthesis to enter
    • A prosthesis is added to transmit sound from the incus to the cochlea
35
Q

Ear: Sensorineural hearing loss - definition

A

Caused by malfunction or disease within the cochlea or auditory nerve

36
Q

Ear: Sensorineural hearing loss - aetiology

A

Presbycusis (Age-Related Hearing Loss) - Most common

Noise-Induced Hearing Loss

Congenital Infections -Eg rubella, CMV

Neonatal Complications - Eg kernicterus or meningitis

Drug-Induced Deafness:

Vascular Pathology - Eg stroke, TIA

Meniere’s Disease

37
Q

Ear: Sensorineural hearing loss - drug induced; name 3 ototoxic drug classes and give examples

A
  • Aminoglycosides - eg gentamicin
  • Loop Diuretics - eg furosemide
  • Chemotherapy drugs - eg cisplatin
38
Q

Ear: Sensorineural hearing loss - audiogram results

A
  • Loss of hearing at high frequencies
  • Characterised by - symmetrical progressive hearing loss over many years
39
Q

Ear: Sensorineural hearing loss - definition of sudden onset (SSNHL)

A

Sensorineural hearing loss in last 72 hours - requires urgent ENT referral

40
Q

Ear: Sudden onset (SSNHL) - aetiology

A

Majority are idiopathic

41
Q

Ear: Sudden onset (SSNHL) - investigation and used to exclude what

A

MRI - exclude a vestibular schwannoma

42
Q

Ear: Sudden onset (SSNHL) - management

A

High dose oral corticosteroids for all cases of SSNHL

43
Q

Ear: Conductive hearing loss - definition

A

Caused by the obstruction of sound waves at any point in the outer ear and the foot plate of the stapes in the middle ear

44
Q

Ear: Conductive hearing loss - aetiology

A
  • Wax impaction
  • Otitis media with effusion (glue ear)
  • Eustachian tube dysfunction
  • Ear infections
  • Perforations of the tympanic membrane
  • Chronic suppurative otitis media
45
Q

Ear: Conductive hearing loss - audiogram

A

Present through indifferences in air conduction level and bone conduction level on the audiogram with the bone conduction being greater than air conduction

46
Q

Ear: Otosclerosis - audiogram characteristics

A

An audiometric characteristic of otosclerosis, is Carhart’s notch where there is an apparent loss of bone conduction at 2000 Hz.

Conductive hearing loss

47
Q

Ear: Rinne and Weber’s; explanation

A

Rinne’s Test:
○ In a normal ear, air conduction should be greater than bone conduction. This is a POSITIVE Rinne test
○ Due to obstruction of the ear canal, bone conduction is better in conductive hearing loss. This is a NEGATIVE Rinne test

Weber Test:
* Should be equal in both ears in a normal patient
* Again, because bone conduction is greater than air in conductive hearing loss, the sound lateralises to the affected ear
* In sensorineural hearing loss, the reverse happens; sound is louder in their normal, unaffected ear

No Hearing Loss - Rinne (Air > Bone), Weber (Midline)
Sensorineural - Rinne (Air > Bone), Weber (Normal ear lateralisation)
Conductive - Rinne (Bone > air), Weber (Affected ear lateralisation)

Phase 3a (7 decks)

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