Session 7 Flashcards
commonality of ear conditions and parts of the ear
An organ of hearing and balance (equilibrium)
• Conditions affecting the ear are common – Present in adults and children – Present to primary and secondary care
• Three parts: external, middle and inner ear – Different pathologies can involve these three different areas or specific structures within them
Signs and symptoms of ear disease
Otalgia (ear pain) Discharge Hearing loss (conductive vs sensorineural) Tinnitus Vertigo Facial nerve palsy
Describe the parts of the ear and what each part contains
External - pinna, external auditory meatus, skin lined
Middle - air filled, ossicles, lined with respiratory epithelium, PT connects it to NP
Inner - cochlea, smicircular canals, fluid filled
General sensation of the ear and referred pain
Many Nerves Carry General Sensation from Ear Implications for Referred Pain
• Branches of
• Cervical spinal nerves (C2/C3)
• Vagus
• Trigeminal (auriculotemporal n.)
• Glossopharyngeal (tympanic n.) the medial surface of the tympanic membrane and middle ear cavity is supplied by the glossopharyngeal nerve (CNIX)
• …and a small contribution from CN VII
Special sensory (“hearing and balance”) carried in CN VIII
Otalgia with a normal ear examination should lead you to suspect what?
• Otalgia can be non-otological or otological in origin • There are many non-ontological causes for otalgia • TMJ dysfunction (CN Vc) • Diseases of oropharynx (CN IX) • Disease of larynx and pharynx including cancers
The External Ear:
pinna, external auditory meatus and lateral surface of tympanic membrane
Collects, transmits and focuses sound waves onto the tympanic membrane
Composed of Cartilage, skin and fatty tissue
Pinna (Auricle) and Abnormalities
Congenital Inflammatory Infective Traumatic Facial Palsy…and a painful, red ear with vesicles…? Perichondritis Pinna Haematoma
Pinna Haematoma
Accumulation of blood between cartilage and its overlying perichondrium
• Secondary to blunt injury to the pinna • Common in contact sports
• Subperichondrial haematoma deprives cartilage of blood supply + pressure necrosis of tissue
• Drainage & revent re-accumulation/re-apposition of two layers
• Untreatedfibrosis, new asymmetrical cartilage development ‘cauliflower deformity’
External acoustic meatus
Skin-lined cul-de-sac ~2.5 cm in length
• Lined with keratinising, stratified squamous epithelium continuous onto lateral surface of tympanic membrane
• Cartilaginous (outer 1/3) and bony (inner 2/3)
• Sigmoid shape
• Hair, sebaceous and ceruminous glands line cartilage part: barrier to foreign objects… • Ceruminous glands produce ear wax
• Bony part lacks these glands and hairs
Self-cleaning function…
• Desquamation and skin migration laterally off tympanic membrane out of canal • Epithelial migration
Common Conditions Involving External Acoustic Meatus
Wax/ Foreign bodies
Otits externa
malignant otitis externa - *rare: serious ++, potentially life threatening; immunocompromised inc. diabetics at risk
Tympanic Membrane: common abnormalities
Bulging secondary to bacterial acute otitis media
Retracted and evidence of fluid within middle ear cavity (otitis media with effusion)
Cholesteatoma
Rare..but should not be missed
• Retraction of pars flaccida (TM) forms a sac/pocket • Trapping stratified squamous epithelium and keratin • Proliferates forming cholesteatoma
• Usually secondary to chronic Eustachian Tube (ET) dysfunction • -ve pressures pull the ‘pocket’ into the middle ear
• Painless, often smelly otorrhea (ear discharge) +/- hearing loss
• Not malignant but slowly grows and expands – Potentially more serious consequences due to enzymatic bony destruction e.g. erode ossicles, mastoid/petrous bone, cochlea
The Middle Ear:
Air Filled Cavity Between Tympanic Membrane and Inner Ear Containing Ossicles
• Ossicles connected via synovial joints
• Amplify and relay vibrations from the TM to the oval window of the cochlea (inner ear) • Transmitting vibration to waves in a fluidmedium
• Ossicle movement ‘tampered’ by 2 muscles tensor tympani and stapedius • Contract if excessive vibration due to loud noise (protective; acoustic reflex)
• Malleus • Incus • Stapes
Otosclerosis
One of most common causes of Acquired Hearing Loss in Young Adults
• Both genetic and environmental causes
• Exact cause unknown (?viral ?hereditary triggers?)
• Ossicles fused at articulations due to abnormal bone growth particular between base plate of stapes and oval window • Sound vibrations cannot be transmitted effectively to cochlea
• Present with gradual unilateral or bilateral conductive hearing loss
Pressure control in the middle ear
Pharyngotympanic Tube equilibrates pressure of middle ear with atmospheric pressure
Mucous membrane of middle ear continuously reabsorbs air in middle ear causing negative pressure Pharyngotympanic tube (Eustachian Tube) allows equilibration of pressure within middle ear cavity with that of the atmosphere. It also allows for ventilation of and drainage of mucus from the middle ear
otitis media with effusion
(“glue ear”)
• Not an actual infection.. but can predispose to
• Due to Eustachian tube dysfunction
• Fluid and negative pressure in middle ear • Decreases mobility of TM and ossicles affecting hearing
• Most resolve spontaneously in 2-3 months..
• May persist and/or impede speech & language development/school performance Require grommets (tympanostomy tube) Act to maintain equilibration of pressures
acute otitis media
- Acute middle ear infection – More common in infants/ children than in adults
- Signs and symptoms include – Otalgia (infants may pull or tug at the ear) – Other non-specific symptoms e.g. temperature – Red +/- bulging TM and loss of normal landmarks
- Mostly viral aetiology
- Occasionally bacterial… causes – Streptococcus pneumoniae – Haemophilus influenzae
Why are infants more likely to get middle ear infections?
Pharyngotympanic tube is shorter and more horizontal in infants
In infants therefore: • Easier passage for infection from the nasopharynx to the middle ear • Tube can block more easily, compromising ventilation and drainage of middle ear, increasing risk of middle ear infection and “glue ear”