ENT Textbook Flashcards
How much of the external auditory meatus cartilage and how much is bone?
Outer 1/3rd is cartilage
Inner 2/3rd is bone
What nerve supplies the anterior part of the auricle?
Auricotemporal branch of trigeminal
What nerves supply the posterior part of the auricle?
Greater auricular nerve and branches of the lesser optical nerve
What is anotia?
Absence of the ear
What symptoms can wax blocking the EAC cause?
Hearing loss
Attempts at cleaning ear may –> trauma/otitis externa
How can you treat a wax blocked EAC?
Softening drops, e.g. sodium bicarbonate
2nd line: syringing
3rd line: microsuction
What is ear syringing?
Flushing ear with water to wash out wax/debris
What things may predispose to OE?
Trauma
Eczema, psoriasis
What organisms are usually implicated in OE?
Pseudomonas, staphylococcus
Sometimes viral or fungal (e.g. aspergillus/candida)
Mucinous discharge in the ear must originate from where?
Middle ear (EAC doesn’t have any mucous glands)
What are the features of OE?
Auricle is tender, esp. tragus Discharge from ear Reduced hearing Itch, pain Ear may be full of debris, skin cracked etc.
How is OE treated?
Microsuction to remove debris
Antibiotic and steroid ear drops
Who is malignant OE usually seen in?
Elderly patients with diabetes or immunocompromised patients
What is the most common causative organism of malignant OE?
Pseudomonas
What happens in malignant OE?
Infection from OE spreads to bone causing osteitis or OM in the skull base
What are the clinical features of malignant OE?
Pain
Cranial nerve palsies (7, 9, 10, 11)
Granulations in the meatus
How is malignant OE treated?
IV antibiotics and debridement
What are the most common tumours of the auricle?
BCC and SCC
What part of the ossicles is attached to the tympanic membrane?
Handle of malleus
Superiorly there is a small area of the tympanic membrane where the middle fibrous layer is missing - what is this layer called?
Pars flaccida
The rest of the ear drum is the pars tensa
In which quadrant does the cone of light sit?
Anterior inferior
Where does dead skin from the tympanic membrane go?
Moves laterally out the tympanic membrane and then is swept along the EAC
What is the path of the facial nerve in the middle ear?
Crosses medial wall of middle ear, goes posterior to oval window, turns 90 degrees and descends to exit via the stylomastoid foramen
What is the function of the eustachian tube?
Allows air to pass freely between middle ear and nasal cavity
(keep intranasal and middle ear pressure the same and allows O2 to get to middle ear mucosa)
Where is the opening of the eustachian tube into the middle ear?
Anterior wall
How does the eustachian tube open?
Muscles of the pharynx are attached to it and when they contract during swallowing they open it
What are the three ossicles called?
Malleus, incus, stapes
What joint connects the three ossicles?
Synovial joints
What part of the one of the ossicles is attached to the oval window?
Footplate of stapes
What is the role of the ossicles in hearing?
Transmit sound from tympanic membrane to oval window and allow for amplification
How can infection of the middle ear spread?
Superiorly –> temporal lobe of brain, dura (meningitis)
Laterally –> mastoid, cerebellum
Inferiorly –> jugular bulb
Medially –> inner ear, facial nerve
What kind of hearing loss do you get in middle ear pathology?
Conductive (Rinne’s BC > AC, Weber localises to affected side)
Pulsatile tinnitus should rise suspicion of what next to the ear?
Vascular tumour
Why does glue ear cause intense otalgia? What can relieve this pain?
Effusion stretches the ear drum
Relieved when drum perforates
What kind of discharge do you get from middle ear pathology?
Mucopurulent
What things may raise your suspicion that a child has a congenital middle ear problem?
Outer ear deformity, hearing issues
What is inflammation of the middle ear characterised by?
Formation of an effusion
What kinds of effusion can you get in otitis media?
Sterile = glue ear
Suppurative (pus forming in AOM)
What happens in chronic suppurative otitis media?
Repeated suppuration leads to weakening of the ear drum –> non healing perforation
What tends to cause AOM?
URTI that spreads to middle ear via Eustachian tube
What causes the pain in AOM?
Pus accumulates in middle ear and puts pressure on the tympanic membrane
What are the symptoms of AOM?
Hearing loss Pyrexia Otorrhoea Pain Systemic upset
What happens in the healing phase of AOM?
Infection abtes, mucosal oedema subsides, effusion slowly resolves and any TM perforations heal
What organisms tend to cause AOM?
H. influenzae and strep pneumoniae are most common
How is AOM treated?
Analgesia, amoxicillin
Keep ear dry if perforation
Nasal decongestants may help by improving Eustachian tube dysfunction
What are the possible complications of AOM?
Residual perforation Residual effusion Necrosis of ossicles Tympanosclerosis (white scarring of TM) Ossicular adhesions
What causes glue ear?
Poor ventilation to middle ear –> sterile effusion
What things may cause glue ear?
Sequelae of AOM
Infection or allergy of middle ear mucosa
Eustachian tube dysfunction, e.g. due to obstruction by large adenoids
What is the main symptom of glue ear?
Hearing loss –> disrupts school/behaviour
What can glue ear predispose to?
Repeated bouts of AOM
How should suspected glue ear be investigated?
Otoscopy
Hearing assessment
Tympanometry
What is the name of the procedure to fix a perforated ear drum?
Myringoplasty
What is a cholesteatoma?
Sac of keratinising squamous epithelium (skin)
Where do cholesteatomas most commonly occur?
In the attic of the middle ear
How do cholesteatomas tend to present?
Foul smelling discharge
Conductive hearing loss
Attic retraction filled with squamous debris
May present with complication of cholesteatoma (e.g. facial palsy, vertigo, intracranial sepsis)
What substances can the cholesteatoma erode into?
Bone
Can therefore erode into ossicles (–> conductive deafness), facial nerve (–> facial nerve palsy), labrinyth (–> vertigo), roof of middle ear (–> intracranial sepsis)
How is cholesteatoma managed?
Surgical removal (may req. radical mastoidectomy)
How is cholesteatoma diagnosed?
Clinically
What complications can occur with cholesteatoma/middle ear infection?
Mastoiditis Facial nerve palsy Labyrinthitis Petrositis Temporal lobe/cerebellar abscess Sigmoid sinus thrombosis Meningitis Jugular venous thrombosis
What is mastoiditis?
Mastoid air cells fill with pus
Erosion of bone can –> swelling behind ear and thickening of post-auricular tissues –> pinna being pushed out
What is petrositis?
Inflammation of petrous bone
What kind of traumas can occur to the middle ear?
FBs can perforate tympanic membrane –> hearing loss
Air pressure e.g. loud explosion can cause perforation due to a forceful air-pressure wave
How can you confirm the diagnosis of otosclerosis?
Surgical exploration of the stapes footplate
How can you treat otosclerosis?
Removal of the stapes footplate and replacement with prosthesis
What does the membranous labyrinth consist of?
Cochlea (hearing), saccule, utricle and semi-circular canals (balance)
What is the membranous labyrinth surrounded by?
The bony labyrinth which surrounds and protects it
What fluid is in the membranous labyrinth?
Endolymph (similar to plasma)
What fluid surrounds the membranous labyrinth as it sits in the bony labyrinth?
Perilymph (similar to CSF)
What is the vestibular system made up of?
Posterior, lateral, superior semi-circular canals which communicate via the utricle
Each semi-circular canal has a dilatation at the end (=ampulla)
What is found in the ampulla?
Neuroepithelium which can detect movement
What is found in the utricle and saccule?
Also has neuroepithelium capable of sensing movement
What does the neuroepithelium capable of sensing movement found in the ampullae, utricle and saccules have?
Hair cells
What are the hair cells in the utricle and saccule in contact with?
Crystals known as otoliths
What are the utricle and saccule collectively known as?
Macula
What fluid are the sensory organs (i.e. neuroepithelium in the utricle/saccule) of the ear suspended in?
Endolymph
How do the sensory organs of the ear communicate movement with the brain?
When head moves, endolymph (which has its own inertia), takes longer to accelerate than the surrounding labyrinth and neuroepithelium –> shearing movement of hairs/change in otoliths –> stimulation of the vestibular nerve
What kind of movement do the semi-circular canals detect?
Rotatory movement
What kind of movement do the utricle and saccule detect?
Horizontal/vertical acceleration
What is the name of the bony shelf that projects into the centre of the cochlear tube?
Osseous spiral lamina
What are the two membranes into the cochlea?
Reissner’s membrane and basilar membrane
How many spaces are present in the cochlea and what are they called?
3
- Scala media
- Scala vestibuli
- Scala tympani
What fluid does the scala media contain? What structure is it linked to?
Endolymph, linked to saccule
What fluid do the scala vestibuli and tympani contain and what are they linked to?
Joined to each other and they contain perilymph
What is the sensory unit of the cochlea called? Where is it found?
Organ of corti
Sits on basilar membrane
What is the organ of corti composed of?
Hair cells associated with the tectorial membrane which arises from the osseous spiral lamina
VII nerve endings supply the hair cells
Describe how we are able to hear sounds
Sound collected + transmitted to TM by external ear
TM vibrates and converted by ossicles into a rocking motion of the stapes
Stapes footplate overlies oval window and its movement sets up a pressure wave in the perilymph o the scala vestibuli
Scala vestibuli communicates with scala tympani so the perilymph wave travels along these channels and ends at the round window
Movement in perilymph –> vibration of basilar and tectorial membranes, these membranes move in different directions –> shearing of hair cells of organ of corti –> stimulation of hair cells + therefore cochlear nerve
Complete the sentence:
The greater the sound the larger/less the perilymph pressure wave and the more/less hair cells are stimulated
The greater the sound the larger the perilymph pressure wave and the more hair cells are stimulated
How can the cochlea perceive different frequencies?
Different frequencies detected by different parts of areas of cochlea
How does inner ear disease tend to present?
Vertigo, sensorineural deafness, tinnitus
What interuterine infection may cause congenital deafness?
Rubella
What can be used if someone has profound hearing loss that cannot be helped by hearing aids?
Cochlear implant
What is presbycusis?
Old age hearing loss
What causes presbycusis?
Gradual loss of outer hair cells of cochlea
What are the symptoms of presbycusis?
Gradual hearing loss in both ears with or without tinnitus
Difficulty to hear when there is a lot of background noise (confusion in sound)
What frequency is primarily lost in presbycusis?
High frequency
What is labyrinthitis?
Inflammation of the inner ear
What does labyrinthitis usually follow?
URTI
What tends to be the most pronounced symptom of labyrinthitis?
Vertigo
How is labyrinthitis treated?
Vestibular sedatives, e.g. prochloperazine
Rest
Vestibular rehabilitation exercises
What must you suspect if there is bleeding from the ear following a trauma to the head?
Temporal bone fracture
What drugs are ototoxic?
Aminoglycosides e.g. gentamicin
Furosemide
Antimalarials
What is the classic presentation of menieres?
Episodes (usually about 30m-4h):
- spinning vertigo
- sensorineural hearing loss
- tinnitus and aural fullness
Usually unilateral
Hearing loss + tinnitus can become permanent over time
How is menieres managed?
Vestibular sedatives for acute episodes
Long term - betahistine, diuretics, avoidance of caffeine, salt and reassurance
If becomes debilitating - ablate with gentamicin injection or surgically drill out inner ear/cut VII nerve
How does BPPV tend to present?
Episodic vertigo brought on by certain movements, esp. turning head in bed
How is BPPV diagnosed?
Dix Hallpike manoeuvre - observe for rotation nystagmus (towards affected ear)
What causes BPPV?
Dislodged otoliths settling in the posterior semi-circular canals which certain movements causing irritation of the sensory epithelium –> vertigo
How is BPPV managed?
Epley manovure
Can also resolve on its own
Vestibular exercises
What meatus does the vestibulocochlear nerve leave the inner ear?
Internal acoustic meatus
Where does the vestibulocochlear nerve enter the brainstem?
Cerebral pontine angle
What is vestibular neuronitis?
Inflammation of the vestibular portion of the vestibulocochlear nerve –> vertigo
HEARING USUALLY UNAFFECTED
thought to be viral cause
How is vestibular neuronitis managed?
Vestibular sedatives, rest
Any patient that presents with unilateral hearing loss or tinnitus that cannot be explained must be considered for what diagnosis?
Vestibular schwannoma aka acoustic neuroma
What is gold standard Ix for diagnosing acoustic neuroma?
MRI
How are acoustic neuromas managed?
Radiotherapy/surgery
Where is the nucleus for the facial nerve?
Pons
Where does the facial nerve emerge from?
Cerbellar pontine angle
Through what passage does the facial nerve enter the middle ear?
Internal acoustic meatus
Where is the lesion in an UMN lesion?
Above the level of the nucleus, i.e. motor cortex/pons
How can you differentiate a LMN and UMN facial nerve lesion?
UMN –> sparing of forehead (forehead receives innervation from the contralateral motor cortex as well)
What is bells palsy probably due to?
Viral infection of facial nerve (as it is often preceded by an URTI)
Increased pressure on nerve due to swelling in bony canal thought to cause its dysfunction
How is bells palsy managed?
High dose steroids
What causes Ramsay Hunt syndrome?
Herpes zoster virus
How does Ramsay hunt syndrome present?
Facial palsy, vesicles in ear drum/canal/pinna and ear pain
How is Ramsay Hunt syndrome treated?
Aciclovir
What tumours can cause facial nerve palsy?
Parotid tumours
External and middle ear tumours, e.g. SCC
Tumours of the cerebellar pontine angle, e.g. acoustic neuromas
What causes peripheral vertigo?
Problems with labyrinth and ear
What causes central vertigo?
Problems with brain and cranial nerves
What is actual vertigo like?
Room is spinning, pt spinning in room
Anything else is not true vertigo
What are central causes of vertigo?
MS Vestibular neuronitis Acoustic neuroma Head injury Drug induced Vascular occlusion
What are peripheral causes of vertigo?
Labyrinthitis BPPV Menieres Middle ear disease Drugs Post trauma
What things can cause tinnitus?
Drugs Labyrinthitis Trauma Vascular Presbycusis Menieres Noise Otosclerosis
What are conductive causes of hearing loss?
Foreign bodies (e.g. wax, object) Neoplasms Cholesteatoma Otosclerosis Otitis media Neoplasm
What are causes of sensorineural hearing loss?
Presbycusis Labyrinthitis/infection Trauma/ototoxicity Menieres MS Acoustic neuroma Neurological disorders
What kind of secretions are produced by the parotid salivary gland?
Serous
Where does the parotid lie?
Between the mandible and mastoid process
What symptoms to people tend to get in salivary gland disease?
Swelling, pain
May get dryness of the mouth if dysfunction is widespread
Facial nerve palsy and parotid swelling should raise suspicion of what?
A malignant lesion
What is the most common cause of bilateral parotid gland enlargement?
Mumps
What causes pain in parotid swelling?
Stretching of the capsule
What are risk factors for parotitis?
Dehydration
Poor oral hygiene
What are features of parotitis?
Pain
Swelling
Pus coming from parotid duct
What things may cause parotid swellings?
Bacterial/viral infections Systemic infections, e.g. mumps, HIV Granulomatous diseases, e.g. TB, sarcoidosis Sjogrens Drugs Neoplasm
What is sialothiasis?
Stones/calculi forming within the salivary glands
What are the symptoms of sialothiasis?
Pain, swelling, may be able to palpate calculi
What is sjogrens?
Autoimmune disease characterised by dry mouth and dry eyes
How should you investigate a parotid tumour?
FNA, CT, MRI
Excision biopsy
What is the most common parotid tumour?
Pleomorphic adenoma
What are the recurrent laryngeal nerves branches of?
The vagus
What nerve supplies most of the laryngeal muscles?
Recurrent laryngea;
What do the muscles of the larynx do?
Adjust the position of the cords and create tension
Larynx disease presents as one of what two things?
Airway or voice problems (hoarseness, aphonia, pain on speaking/swallowing)
What things may cause the larynx itself to become inflamed?
Vocal abuse, voice strain, exposure to cigarette smoke or alcohol fumes
How is laryngitis treated?
Rest of voice, analgesics
How is epiglottitis treated?
Give IV antibiotics
Take child to theatre, intubate and give ventilatory support until the child recovers
What tends to cause epiglottitis?
Hib
What tends to cause chronic laryngitis?
Smoking
What is the most common tumour of the larynx?
SCC
What tends to cause laryngeal SCC?
Smoking
How does laryngeal cancer tend to present?
Vocal cords - hoarseness (any patient w hoarseness >3w should be referred to ENT urgently)
Tumours elsewhere in larynx may –> sore throat, cough, referred otalgia, swollen LN
What is the cardinal symptom of laryngeal disease?
Hoarseness
Why is the recurrent laryngeal nerve particularly prone to palsy?
It has a very long course, especially on the left side
What investigations are mandatory in hoarseness?
CXR - may be bronchial carcinoma
If normal - CT from skull base to lung hilum to see if any other tumours compressing recurrent laryngeal
What does laryngeal stridor sound like?
high pitched noise on inspiration
What is the first line treatment for acute airway obstruction?
Endotracheal intubation
What is cricothyroidotomy?
Hollow tube is placed into lumen of pharynx via the percutaneous route
What is a tracheostomy?
Hole is made in front wall of trachea and tube maintains airway
Usually for those that req. long term ventilation
