H&N: Ear Flashcards
Which bone are parts of the ear found?
-Temporal bone
What is Ramsay hunt syndrome?
- Chicken pox of the facial nerve
- Geniculate ganglion affected by reactivation of the chicken pox virus
What is cauliflower ear?
- Secondary to blunt injury to the pinna
- Accumulation of blood between cartilage and perichondrium
- Ischaemia of the cartilage leading to necrosis due to lack of blood supply
- If untreated or poorly treated it can lead to fibrosis and new asymmetrical cartilage development leading to cauliflower ear
How can cauliflower ear be treated?
- Prompt drainage of the haematoma and measures to prevent re-accumulation and re-apposition of two layers are necessary
- Provides the cartilage back its blood supply
What is the purpose of the arrangement of hairs and production of wax in the ear canal?
- Prevent objects entering deeper into ear canal
- Aids in desquamation and skin migration out of canal
How long is the external acoustic meatus?
-2.5 cm
What is the effect of facial nerve lesion on the middle ear?
- Tensor tympani and stapedius are no longer innervated
- Excessive vibrations are no longer impeded
- Patient presents with hyperacousis
What is otosclerosis?
- Ossicles fused at articulations in particular between base plates of stapes and oval window
- Sound vibrations cannot be transmitted
- Causes deafness
What is glue ear?
- Build of fluid and negative pressure in middle ear
- Due to Eustachian tube dysfunction and can predisposes to infection as the fluid is the ideal growth medium for bacteria
- Decreases mobility of TM and ossicles affecting hearing
How is glue ear treated?
- Most resolve spontaneously in 2-3 months but some may persist
- May require grommets to ventilate middle ear. Equilibriation of pressure is the purpose of the grommet
What is acute otitis media?
- Acute middle ear infection
- More common in infants, children than in adults
What is the symptoms of acute otitis media?
- Otalgia
- Temperature
- Red +/- bulging TM and loss of normal landmarks
Why is acute otitis media more common in children?
- Pharygotympanic tube is shorter and more horizontal in infants
- Easier passage for infection from nasopharynx to the middle ear
- Tube can block more easily, compromising ventilation and drainage of middle ear, increasing risk of middle ear infection
What are some complication of acute otitis media?
- Tympanic membrane perforation
- Facial nerve involvement
- Mastoiditis
Intracranial complications
- Meningitis
- Sigmoid sinus thrombosis
- Brain abscess
What is mastoiditis?
- Middle ear cavity communicates with mastoid air cells via mastoid antrum and auditus.
- Provides a potential route for middle ear infections to spread to mastoid bone
Which nerve can be affected by middle ear pathology?
- Facial nerve
- Chorda tympani branch may be involved as it runs through the middle ear cavity
What is cholesteatoma?
- Abnormal skin growth growing into the middle ear eroding strructures such as ossicle, mastoid bone, cochlea
- Not malignant
- Usually secondary to chronic ear infections or secondary to Eustachian tube dysfunction
What are the symptoms of choleastoma?
- Painless
- Often Smelly otorrhea
- Sometimes Hearing loss
Which regions normally lead to sensorineural hearing loss?
Inner ear
Which regions normally lead to conductive hearing loss?
- Middle ear
- External Ear
How can we hear?
- Auricle and external auditory canal focuses and funnels sound waves towards tympanic membrane which vibrates
- Vibration of ossicles sets up vibrations in cochlear fluid through the oval window
- Sensed by sterocilia in cochlear duct
- Movement of the stereo cilia in organ of Corti trigger action potentials in cochlear part of cranial nerve VIII
- Primary auditory cortex
What are examples of diseases of middle ear?
- Merniere’s disease
- BPPV
- Labrynthitis: inner ear infection
What are the symptoms and signs of inner ear?
- Vertigo
- Hearing loss and tinnitus
- Nystagmus
What are some causes of sensorineural hearing loss?
- Presbyacusis
- Meniere’s disease
- Acoustic neuroma
- Ototoxic medications
How does the sensation of the ear popping occur?
- Eustachain tube is normally closed
- Salpingopharyngeus
- Pull of attached palate muscle when swallowing or yawning cause it to open
- This is noticed as ears popping
What are the ossicles called found in the middle ear?
- Malleus
- Incus
- Stapes
What forms the wax in the external auditory meatus?
-Cerumen from skin lining and discarded cells of the skin
What equipment is used to examine the external auditory canal inspected?
- Otoscope
- Speculum
How is the external auditory canal straightened for examination?
-Up, back and out for better visualisation
In children down and back
What are the results of a normal person in a Rinner’s and Weber’s test?
- Air Conduction>Bone Conduction
- Centre
What is the purpose of the Weber’s test?
Lets you know which side is affected but not whether it is sensorineural or conductive
What are the results of a conductive hearing loss in a Rinner’s and Weber’s test?
- Bone Conduction>Air Conduction
- Louder at the affected ear in Weber’s test
What are the results of a sensorineural hearing loss in a Rinner’s and Weber’s test?
- Air Conduction>Bone Conduction
- Louder at the unaffected ear in Weber’s test
Describe the theory behind the Weber’s Test
- Normal ambient sounds are conducted
- The ringing is conducted to the inner ear
- If the conductive affect the normal ambient sounds aren’t transmitted so the sound from the tuning fork is heard louder
- If sensorinerual, the ambient sounds are heard more than the tuning fork so the sound in heard louder at the unaffected side
