Ear Flashcards
What is the sensory supply to the pinna?
Upper lateral surface - CN V3 auriculotemporal
Lower lateral/medial - C3 - greater auricular
Superior medial - C2/C3 lesser occipital nerve
External auditory meatus - auricular branch of vagus
So can perform regional nerve blocks
What is the anatomy of the external ear?
Auricle/pinna and external acoustic meatus
Lateral third of external acoustic meatus is cartilage, medial two thirds are bony from temporal bone
Contains keratinised squamous epithelium
What is the vascular supply to the auricle?
External carotid artery, superficial temporal, occipital
What is the innervation of the external acoustic meatus?
Auriculotemporal nerve branch of trigeminal
Auricular nerve - branch of vagus CN X
What is the tympanic membrane?
Middle layer of connective tissue
Oblique angle to maximise sound localisation
At centre - umbo attaches to handle of malleus
Transmits sound waves from external ear to ossicles of the middle ear
What is the innervation of the middle ear?
Vagus nerve and glossopharyngeal nerve
What is the anatomy of the middle ear?
Auditory ossicles - malleus, incus, stapes form oval window and transmit and amplify sound vibrations
Tensor tympani, stapedius muscles
What is the function of the Eustachian tube?
Aerates the middle ear to equalise pressure
For optimum movement of the tympanic membrane
What is the anatomy of the inner ear?
Vestibulocochlear organs, receives sound waves to convert into electrical signals
Bony labyrinth - vestibule, three semi circular canals and the cochlea. Vestibule contains saccule and utricle to detect linear motion.
Semicircular canals - rotatory movements
Cochlear contains organ of corti containing epithelial cells converting sound waves to electrical impulses
What is ear trauma commonly related to?
Sports injuries
Violence
How severe is ear trauma normally?
Normally uncomplicated and treatable under local anaesthetic
How should a laceration with exposed cartilage be managed?
Cover any exposed cartilage with skin
What may be done if there is skin loss or a skin laceration can’t be closed by primary closure?
Plastic reconstructive surgery
What is the main risks with bites to the ear?
Infection from skin commensal or oral commensal of offending creature/person
Staph epidermis and S hominid are most prevalent coagulase negative commensals
How would you manage a patient with an ear bite?
Take a good history - work out likely organism
Leave wound open
Irrigate wound thoroughly
Antibiotics
Why are pinna haematoma’s dangerous?
Disrupt blood supply to cartilage as it normally obtains nutrients via diffusion from vessels in the perichondrium.
Can lead to avascular necrosis
What is cauliflower ear?
Cartilage undergoes avascular necrosis which stimulates the formation of new cartilage but it grows asymmetrically
What can cause a tympanic membrane perforation?
Blunt force - trauma to side of head
Penetrating trauma - e.g. cotton bud
Otitis media
Barotrauma - explosion/scuba diving
How does a tympanic membrane perforation present?
Pain
Conductive hearing loss (possibly)
Can get tinnitus and serosanguineous discharge
How can tympanic membrane perforation be managed?
Most heal within 8 weeks- monitoring
Antibiotics if contamination
Keep clean and cry
Not healing after 6 months or hearing loss/recurrent infection - myringoplasty
What can cause haemotympanum?
Basal skull fracture - most common
Nasal packing
Bleeding disorders/anticoagulants
Recurrent ear infections
How does haemotympanum present?
Seen through tympanic membrane
Associated with conductive hearing loss
Sense of fullness in ear
Pain
How is haemotympanum managed?
Treat conservatively but follow up to ensure no residual hearing loss
However commonly associated with other issues - head trauma
What is otitis externa and causes?
Inflammation of the skin of the external ear canal
Acute - less than three weeks, chronic >3
Swimmer’s ear - water causes inflammation in ear
Bacterial infection, fungal, eczema, seborrhoeic dermatitis, contact dermatitis
When is it important to think about fungal infection as a cause for otitis externa?
Patients who have had multiple courses of topical antibiotics - kills friendly bacteria that have protective function against fungal infections
What are the two most common bacterial causes of otitis externa?
Pseudomonas aeruginosa - gram neg aerobic rod shaped bacteria, grows in moist oxygenated environments e.g. CF
Staphylococcus aureus
What is the presentation of otitis externa?
Ear pain, discharge, itchiness, conductive hearing loss if becomes blocked
On examination - erythema, swelling, tenderness of canal
Pus or discharge, lymphadenopathy
What is the management of otitis externa?
Mild - acetic acid 2% antifungal and antibacterial
(Otomize ear spray)
Moderate - topical antibiotic and steroid e.g.
Neomycin, dexamethasone, acetic acid
Neomycin and bethamethasone
Fungal infections with - clotrimazole ear drops
What is it important to exclude before prescribing aminoglycosides?
e.g. gentamicin or neomycin
Potentially ototoxic, if get past tympanic membrane
So exclude perforated tympanic membrane
What is malignant otitis externa?
Severe and life threatening form of otitis externa
Infection spreads to bones of ear canal
Progresses to osteomyelitis of temporal bone
Risk factors e.g. diabetes, immunosuppressants, HIV
Causes persistent headache, severe pain and fever
Granulation tissue at junction between bone and cartilage
What is the treatment for malignant otitis externa?
Admission to hospital, ENT treatment
IV antibiotics
Imaging - CT or MRI head
What complications can malignant otitis externa lead to?
Facial nerve damage and palsy Other cranial nerve involvement Meningitis Intracranial thrombosis Death
What is otitis media?
Infection of middle ear, often preceded by viral upper respiratory tract infection
What is the cause of otitis media?
Strep pneumoniae most common cause
Haemophilus influenzae
Moraxella catarrhalis
Staph aureus
What is the presentation of otitis media?
Ear pain
Reduced hearing in affected ear
Generally feeling unwell, symptoms of upper airway infection
Can cause issues in balance and vertigo if affecting vestibular system
Discharge if tympanic membrane perforated
What is seen on examination of the ear in otitis media?
Bulging red inflamed looking membrane (as opposed to pearly grey translucent and shiny)
If perforation, may see discharge and hole in membrane
What is the management of otitis media?
Most cases resolve without antibiotics after 3 days-wk
Simple analgesia for pain and fever
Immediate abx if significant co-morbidities, systematically unwell or immunocompromised.
Delayed prescription - collected after 3 days if still bad
Amoxicillin for 5-7 days, clarithromycin if allergic, erythromycin in penicillin allergic women
What are the complications of otitis media?
Otitis media with effusion Temporary hearing loss Perforated tympanic membrane Labyrinthitis, mastoiditis, abscess Facial nerve palsy Meningitis
What is chronic suppurative otitis media?
Chronic inflammation of the middle ear and mastoid
Presents with recurrent ear discharges through a tympanic perforation
What are the causes of chronic suppurative otitis media?
Pseudomonas aerugonisa Staph aureus Proteus species Aspergillus Candida albicans
What are the risk factors for chronic suppurative otitis media?
Younger age - under five Allergy/atopy URTI Acute or recurrent otitis media Exposure to second hand smoke Social deprivation Snoring
What is the management of chronic suppurative otitis media?
Appropriate antibiotic given topically - careful use of aminoglycosides
Intensive microsuction to remove debris
Control of granulation tissue
What are the types of chronic otitis media?
Active or inactive depending on whether the ear is discharging or not
Can be subdivided into mucosal disease or squamous
Active - chronic discharge from the middle ear through a tympanic perforation
Inactive mucosal disease - tympanic perforation
Inactive mucosal - dry perforation
Inactive squamous - retraction pocket which has potential to become active with retained debris (keratin)
Active mucosal - wet perforation with inflamed middle ear mucosa and discharge
Active squamous - cholesteatoma
What is active squamous disease in chronic otitis media?
Cholesteatoma
If this is present, surgery is required
What is otitis media with effusion?
Middle ear effusion without the signs of infection
Glue ear
What are the causes of OME?
Eustachian tube dysfunction - in children smaller and more horizontal, impairing middle ear ventilation
Cleft palate
Beware of nasopharyngeal tumours in adults which can block drainage
What is the presentation of OME?
Conductive hearing loss, behavioural changes
May be asymptomatic in an infant
Poor speech development
Otoscopy - tympanic membrane is dull, visible fluid level
What are the investigations for OME?
Pure tone audiogram - conductive hearing loss
Tympanometry will show flat trace due to reduced compliance of the tympanic membrane - type b curve
In an adult with unilateral effusion, flexible nasoendoscopy FNE to rule out nasopharyngeal tumour
What is the treatment for OME?
Antibiotics have no benefit
Watch and wait - 50% of OME will resolve spontaneously within 3 months
Hearing aids may be useful while waiting to resolve
Myringotomy and ventilation tube insertion - grommets that will self extrude after 9 months
What common bacterial pathogens can cause an infection/ottorhoea?
Pseudomonas aeruginosa Staph aureus Proteus spp. Strep pneumonia Haemophilus influenza Moraxella catarrhalis
What are the differentials for otorrhoea?
Fungal otitis externa - itchy ear canal, fluffy white discharge/coating of the canal
Acute otitis media +- perforation - recent URTI, deep severe ear pain, mucoid ear discahrge
Otitis externa - thin watery discharge
Necrotising otitis externa/malignant - foul smelling discharge, cranial nerve palsies, unilateral severe pain
Cholesteatoma - ear drum retraction, perforation, keratin accumulation, unilateral chronic offensive smelling ear
CSF otorrhoea - clear watery discharge, history of trauma or skull base injury
What is otosclerosis?
Remodelling of the small bones of the middle ear
Leads to conductive hearing loss
Usually presents before age 40
Base of stapes attaches to oval window, causing stiffening and fixation and preventing it from transmitting sound correctly
Autosomal dominant