Flashcards in ENT - Otology Deck (86):
What is the difference between conductive and sensorineural hearing loss?
Conductive deafness is caused by failure of transmission of sound waves across the outer or middle ear. This prevents sound energy from reaching the cochlear fluid.
Sensorineural hearing loss is caused by defective function of the cochlear or the auditory nerve. This prevents nerve impulses being transmitted to the auditory cortex of the brain.
Is it possible to distinguish between conductive and sensorineural hearing loss on examination?
Yes. Rinne and Weber's tests (or tuning fork tests) can help distinguish between the two.
Rinne's test should be performed first but will tell you nothing about cochlear function, it only tests the middle ear. A 512Hz tuning fork is held close to the patients ear and then on the mastoid process. The patient is asked which from the air (AC) or bone (BC) is louder.
If AC>BC this is POSITIVE and shows a normal middle ear.
If BC > AC this is NEGATIVE and means there is defective function of the outer or middle ear (conductive deafness).
Weber's test is helpful in distinguishing the type of deafness and deciding which ear has better cochlear function. The base of the tuning fork is held on the middle of the skull and the patient is asked whether the sound is heard centrally or is referred to one or other other ear.
In conductive deafness the sound is heard in the deafer ear (abnormal one).
In sensorineural deafness the sound is heard in the better- hearing ear (normal).
A patient has a positive Rinne's test in both ears and the Weber test is referred to the left ear. What type of hearing loss is present?
Positive Rinne's test in both ears shows there is no conductive hearing loss - i.e. AC>BC for both, indicating normal middle ear function. In sensorineural hearing loss the sound refers to the good ear so the patient has a right sided sensorineural hearing loss.
The key hear is that Rinne's test is positive in both ears, showing that there can be no conductive loss.
A patient has a negative Rinne test on the right and a positive one on the left. They also have a Weber test that refers to the right ear. What type of hearing loss is present?
Firstly, a negative Rinne test indicates that there is a conductive hearing problem. BC>AC on the right ear shows that there is an abnormal middle ear on the right side. Weber test refers to the affected ear in conductive hearing loss so this patient has conductive deafness on the right side.
Name some common causes of conductive hearing loss?
- acute otitis media
- injury of the tympanic membrane
NB - rarer causes are mostly congenital
Name some common causes of sensorineural deafness?
- presbycusis (deafness in old age)
- noise induced (prolonged exposure)
- congenital (meternal rubella, CMV, anoxia, jaundice)
- drug induced (aminoglycosides, diuretics)
- Meniere's disease
- infection (chronic otitis media, mumps etc)
What is the commonest cause of deafness in children?
The commonest cause of deafness in children is fluid in the middle ear due to otitis media. This causes a temporary conductive deafness.
Sensorineural loss is rare but when it does occur it is usually permanent.
NB - early identification can greatly improve outcome
What babies are "at risk" of deafness and should be tested as soon after birth as possible?
1) prematurity and low birth weight
2) perinatal hypoxia
3) Rhesus disease
4) family history of hereditary deafness
How should sudden sensorineural deafness be managed?
Sudden deafness may be unilateral or bilateral and most cases are regarded as being viral or vascular. Sudden onset sensorineural hearing loss is an emergency and warrants hospital admission.
What is an acoustic neuroma? When are they bilateral?
Despite being called a neuroma, acoustic neuromas are actually a Vestibular Schwannoma. They are benign tumours in the internal auditory meatus or cerebello-pontine angle at the base of the skull.
They are usually unilateral except in rare familial neurofibromatosis type 2.
In the early stages it causes progressive hearing loss and imbalance. As it gets bigger, it may compress the trigeminal nerve in the CP angle and cause loss of corneal sensation. Advanced stages are associated with raised ICP and brainstem displacement. MRI is the best modality to view them.
In what type of deafness are cochlear implants suitable?
Bilateral profound deafness.
What are "protruding ears"?
These are protrusions in the ear caused by the absence of the ante helical fold in the auricular cartilage. Surgical correction can be carried out after the age of four. This consists of exposing the lateral aspect of the cartilage from behind the pinna and scoring it to produce a rounded fold.
What is an accessory auricle? Where are they usually found?
These are small tags often containing cartilage on a line between the angle of the mouth and the tragus.
What is a pre-auricular sinus?
Pre-auricular sinus is a small blind pit that occurs most commonly anterior to the root of the helix. It is sometimes bilateral and may be familial.
If they become recurrently infected they are best removed surgically.
What is microtia? What is it associated with? What is Treacher Collins syndrome?
Microtia is failure of the development of the pinna.
It may be associated with atresia of the ear cannal.
Treacher Collins syndrome is associated with absence or severe malformation of the external ear. Patients can be treated with a bone anchored hearing aid (BAHA) and then a prosthetic ear.
Why does a subperichondrial haematoma cause cauliflower ear if left untreated?
Haematoma of the pinna is usually caused by shearing forces. The pinna gets ballooned and the outline of the cartilage is lost.
The blood supply of the cartilage comes from the perichondrium so an untreated haematoma will cause severe deformity - a cauliflower ear.
Treatment consists of evacuating the clot and reapposition of cartilage and perichondrium by pressure drainage.
What is the usual cause of acute dermatitis affecting the pinna?
This is usually caused by extension of meatal infection in otitis externa or sensitivity reaction to topically applied antibiotics, especially chloramphenicol and neomycin.
The golden rule of treatment here is that if otitis externa gets worse following treatment then it is usually due to a sensitivity reaction and antibiotics should be stopped.
What causes perichondritis of the pinna?
Perichondritis ("inflammation of the perichondrium") may follow injury to the cartilage, mastoid surgery or ear piercing.
Treatment must be vigorous with parenteral antibiotics. Piercings should be removed.
What malignancies occur on the pinna?
Both squamous cell carcinoma and basal cell carcinoma can occur on the pinna, usually the upper edge. They are related to exposure to sunlight.
Chondrodermatitis chronicis helicis occurs in the elderly as a painful ulcerated lesion on the rim of the helix. It resembles a neoplasm and should be removed for histology.
What glands produce wax in the ear and how should impacted wax be treated?
Wax is produced by ceruminous glands in the outer ear. When it is produced it migrates along the meatus laterally. Because of this, ears are "self cleaning".
Impacted wax can cause irritation or conductive hearing loss, and is best treated by syringing.
What solution is used for waxing and what is the technique involved?
Sodium bicarbonate 4-5g to 500ml or normal saline is ideal. The temperature of the solution is important and should be 38 degrees so it does not cause dizziness.
The stream of the solution should be directed along the roof of the external auditory canal.
What is otitis externa?
This is diffuse inflammation of the skin lining the outer ear canal. It may be bacterial or fungal.
3) pain (usually moderate, sometimes severe, increased by jaw movement)
4) deafness (mild)
Signs include meatal tenderness, especially on movement of the pinna or compression of the tragus; and moist debris which when removed shows red, desquamated skin and oedema of the meatal walls and tympanic membrane.
What causes otitis externa?
Some patients are prone to otitis externa - e.g. narrow external canal, bathing in hot climates, exposure to swimming pools, underlying skin diseases (eczema or psoriasis).
A mixed infection of varying organisms is typical, the most common are:
- strep faecalis
- aspergillus niger (black spores are often visible)
What is the management of otitis externa?
The key to managing otitis externa is good aural toilet - clean the debris and keep the ear clean and dry. No medication will be effective if the ear is full of debris and pus. Aural toileting is best performed using dry mopping with cotton wool - don't miss the antero-inferior recess which may be difficult to clean.
When should dressings be used in otitis externa? What should you suspect if the patients condition has not improved after 7-10 days?
Dressings can be used if otitis externa is severe and has not responded to good aural toileting. Gauze impregnated with medication is gently inserted into the meatus and is changed daily until the meatus has returned to normal.
If after 7-10 days of regular dressing changes the meatus has not improved then re check the tympanic membrane. This could be a case of otitis media with discharging perforation of the membrane which will not heal with dressings alone.
What medications can be useful for treating otitis externa? What antibiotics can be used if otitis externa is less severe?
The following medications are useful on dressings:
- 80% aluminium acetate
- 10% ichthammol in glycerine
- ointment of gramicidin, neomycin, nystatin and triamcinolone
In fungal otitis externa use dressings of 3% amphoteracin, miconazole or nystatin.
If otitis externa is less severe and there is little meatal swelling it may respond to a combination of antibiotic and steroid drops. Antibiotics most commonly used are neomycin and gramicidin but there is a worry with putting aminoglycosides into the inner ear as they can cause deafness. Use ciprofloxacin drops if you suspect a perforated tympanic membrane.
What is furunculosis?
This is a "boil" of the external canal resulting from infection of a hair follicle in the lateral part of the meatus. Staph is the usual organism.
Symptoms - pain is as severe as that of renal colic; pain is made much worse by movement of the pinna or pressure on the tragus. Deafness is usually mild and caused by meatal occlusion by the furuncle.
Signs - there is often no visible lesion but use of a speculum causes intense pain. If the faruncle is large it will be seen as a red swelling in the outer meatus and there may be more than one faruncle present.
How is furunculosis treated?
In advanced stages the furuncle may cause an abscess so antibiotic treatment is required. Firstly, a wick soaked in 10% ichthammol in glycerine is inserted. This painful but provides rapid relief.
Flucloxacillin is given parenterally for 24h followed by oral medication. Analgesics are essential.
Recurrent cases are not common so exclude diabetics and take a nasal swab in case the patient is a recurrent staph carrier.
What are exostoses?
These are bony outgrowths or small osteomata of the external auditory meatus. They are fairly common and usually bilateral and are much more common in those who swim a lot in cold water but the reason for this is not clear.
There may be two or three small tumours arising in each bony meatus. They are hard, smooth and very sensitive to touch. They tend to grow slowly and may give rise to no symptoms.
How can the tympanic membrane become damaged?
The tympanic membrane is well protected but can be injured by direct or indirect trauma:
- direct trauma is caused by poking the ear with a sharp implement such as hair grips in an attempt to clean the ear, or foreign bodies
- indirect trauma is usually caused by pressure from a slap with an open hand or from a blast injury; it may occur from temporal bone fracture in a severe head injury
What are the symptoms of tympanic membrane injury?
- pain, acute at the time of rupture, usually transient
- deafness, not usually severe, conductive in type. The cochlear may be injured if the stapes is driven into the inner ear in which case there is sensorineural deafness
- tinnitus may be persistent - cochlear damage
- vertigo (rare)
What are the signs of tympanic membrane injury?
- bleeding from the hear - haemotympanum
- blood clot in the ear canal
- tear in the tympanic membrane of otoscopy
How should injured tympanic membranes be managed?
Do NOT clean out the ear
Do NOT put drops in
Do NOT syringe
Give antibiotics if there is evidence of infection
Arrange careful surveillance until the hearing has returned to normal
Most traumatic perforations of the eardrum heal with no long term adverse effects.
What is otitis media?
Otitis media is inflammation of the middle ear but the term includes several different disease entities:
1) Acute otitis media (AOM) = short lived infection of the middle ear (usually 1-5 days)
- recurrent otitis media (ROM) refers to repeated episodes, typically more than 3 in a 6 month period
2) Otitis media with effusion = also common in children, fluid - often thick, sticky "glue" - accumulates in the middle ear behind an intact drum. Because some fluid in the middle ear is normal after an episode of AOM, OME requires fluid to be present for at least 3 months
3) Chronic otitis media = implies that the eardrum is perforated, the perforation has failed to heal and the infection is ongoing
4) Cholesteatoma = accumulation of squamous epithelium in the middle ear, usually in an ear with longstanding perforation. This is the most serious form of chronic supperative otitis media (CSOM) - often used to emphasize the tendancy for ears with long standing perforations to become infected and discharge
What is acute otitis media and what patients are more likely to develop it?
Acute otitis media (AOM) is a common infection of children and is mostly bilateral. It can follow an upper respiratory tract infection and may be bacterial or viral. A viral infection is short lived (1 or 2 days) and often accompanies some general features of an upper respiratory tract infection - e.g. pharyngitis and coryzal symptoms
What are the signs and symptoms of AOM?
- earache (otalgia) - may be slight in a mild case but is usually throbbing and severe. The child may cry constantly until the ear perforates and the pain is relieved
- deafness - is always present in acute otitis media. It is conductive and may be accompanued by tinnitus. In an adult, deafness or tinnitus may be the first complaint
- pyrexia - child is flushed an ill, with a high temperature
- tenderness - there is usually some tenderness to pressure on the mastoid bone
- tympanic membrane - varies in appearance according to the stage of infection. In an early infection the drum is red, it becomes tense and bulging and may perforate with discharge of pus. Mucoid discharge from the ear must mean perforation of the tympanic membrane (no mucous glands in the external canal)
What is the pathology of AOM?
AOM is infection of the mucous membrane of the whole of the middle ear cleft, including the Eustachian tube, tympanic cavity and mastoid air cells.
Bacteria responsible for AOM are - strep. pneumoniae (35%), haemophilus (25%), moraxella (15%) group A strep and staph aureus may also be responsible.
Describe the sequence of events in the pathology of AOM?
1) organisms invade the mucous membrane causing inflammation, oedema, exudate and pus
2) oedema closes the Eustachian tube, preventing aeration and drainage
3) pressure from the pus rises, causing the drum to bulge and perforate
4) most cases resolve spontaneously. A small number cause complications or persistant peforation
What is the treatment of AOM?
- adequate analgesia is essential, AOM is painful!
- simple analgesics such as aspirin (not in under 16s) and paracetamol should suffice but use adequate doses
- antibiotics can be withheld as most cases are self limiting and often viral, but make sure you can review the child after 24h
- if antibiotics are needed then penicillin or cephalosporins such as cefaclor are the drugs of choice
Eardrops are of not value in AOM with an intact drum
When is myringotomy used in AOM?
Myringotomy is the creation of a small perforation in the eardrum. It is very rarely necessary when bulging of the tympanic membrane persists, despite adequate antibiotics therapy or if there are complications.
The ear may already be discharing - natures myringotomy!
When is AOM "cured"?
AOM is not cured until the hearing and the appearance of the membrane have returned to normal. If there is no resolution suspect:
1) nose, sinuses or nasopharynx. Infection may be present
2) low grade infection in the mastoid cells
What increases the risk of recurrent AOM?
Children who are not breast fed and exposed to passive smoking predisposes them to recurrent AOM.
Rarely there will be an underlying immunologic defect that needs investigation.
Recurrent AOM is treated with grommet insertion or long term treatment with low dose antibiotics.
What is chronic otitis media?
Chronic otitis media implies that the eardrum has perforated, the perforation has failed to heal and there is still infection. This happens following an attack of acute otitis media where there is perforation and persistent discharge.
This leads to worsening conductive deafness.
What factors predispose to chronic otitis media?
1) Late or inadequate treatment of AOM
2) Upper airway sepsis
3) Lowered resistance - e.g. malnutrition, anaemia, immunological impairment
4) Particularly virulent infections - e.g. measles
What are the consequences of ear perforation?
A perforated ear drum may be asymptomatic. If it is unilateral, the relatively minor conductive hearing loss causes little or no problem. The ear may discharge during upper respiratory tract infections though.
Patients with longstanding perforation tend to have ears that discharge - chronic suppurative otitis media (CSOM).
What are the 2 types of CSOM?
There is persistent mucosal infection (active CSOM) with tympanic membrane perforation. In these cases there may be underlying nasal or pharyngeal sepsis that will require treatment if the ear is going to heal. There is mucoid discharge and the perforation can either be large or small.
The second type is bony CSOM.
What treatment is preferred in mucosal CSOM?
A short course of antibiotic eardrops can help dry up the discharging ear but many preparations contain aminoglycosides which can cause deafness. Ciprofloxacin is better. Good aural toilet is important as well. A small perforation may heal.
What is bony CSOM?
Persistent infection can cause erosion of bone (bony CSOM) and infection can eventually spread beyond the ear - e.g. intracranial. Serious complications are very rare, but if left untreated the condition may result in permanent deafness or intracranial sepsis.
Squamous epithelium can collect in the middle ear and this is called cholesteatoma. This IS serious as it can erode adjacent structures and cause serious complications.
Is the repair of a tympanic membrane perforation using a tissue graft. The most common being autologous temporalis fascia which is taken from above the patients ear.
Bony CSOM or cholesteatoma
This is where chronic infection of the middle ear leads to bone erosion. This can include the ossicles, the mastoid air cells and bony walls of the middle ear.
The erosion normally occurs in 2 directions - either postero-superior or in the pars flaccida.
Why is cholesteatoma serious?
Cholesteatoma is formed by squamous epithelium within the middle ear. It results in accumulation of keratotic debris which is visible through the perforation as keratin flakes that are white and smelly. It expands and damages vital structures such as dura, the facial nerve and the semicircular canal. Mastoidectomy is nearly always required together with regular aural toilet in early cases of osteitis.
Extracranial complications of middle ear infection
1) Acute mastoiditis - extension of acute otitis media into the mastoid air cells with suppuration and bone necrosis
- pain - persistant and throbbing
- ear discharge
- increasing deafness
- swelling and redness in the postauricular region (pinna is pushed down and forwards)
- tympanic membrane is either perforated and discharging or it is red and bulging
2) Facial paralysis - can occur from both acute and chronic otitis media
- acute otitis media - especially in children, but is uncommon. Prognosis for complete recovery is excellent
- chronic OM - cholesteatoma may erode the bone around the facial nerve, and infection and granulations can cause facial paralysis
3) Labyrinthitis - infection can spread from the middle ear to the cochlea but the inner ear is protected in a bony covering so this is a rare event. Fistula formation occurs in cholesteatoma. Can cause severe dizziness and sensorineural deafness
What is the treatment of acute mastoiditis as a complication of inner ear infection?
When the diagnosis of mastoiditis has been made, it is important not to delay. The patient should be admitted to hospital for:
- IV antibiotics - start amoxycillin and metronidazole if the organism is not known
- Surgery - pus needs to be drained under anaesthesia if there is no response to antibiotics
How should facial paralysis be treated?
Treatment for facial nerve paralysis as a complication of otitis media depends on the type of infection.
In acute OM a full recovery is to be expected with antibiotics.
If due to chronic suppurative otitis media (CSOM) mastoidectomy is required with clearance of disease from around the facial nerve.
NB - facial palsy in the presence of chronic ear disease is NOT Bell's palsy and active treatment is needed if the palsy is not to become permanent. Do NOT give steroids.
Intracranial complications of otitis media?
These arise when the infection spreads from the ear into and beyond the meninges. A number of complications can occur - e.g. meningitis, extradural abscess, brain abcess, subdural abscess, venous sinus thrombosis
1) Meningitis - patient is unwell, pyrexia, neck rigidity, Kernig's sign, photophobia
- LP is essential unless there is raised ICP
2) Brain abscess - otogenic (coming from the ear) brain abscesses may occur in the cerebellum or in the temporal lobe of the cerebrum. Infection spreads by (i) direct spread via bone and meninges or (ii) via blood vessels
How should a brain abscess be diagnosed?
Any patient with chronic ear disease who develops a headache, neurological signs or any features of meningitis - e.g. neck stiffness - should be suspected of having intracranial extension.
Any patient who has otogenic meningitis, labyrinthitis or lateral sinus thrombosis may have a brain abscess as well.
LP is the best way to confirm, but may be dangerous due to pressure coning. Seek advice and get an urgent neurosurgical review. Imaging by CT or MRI will allow confirmation and localisation.
How should a brain abscess as a complication of inner ear infection be treated?
It is the brain abscess that will kill the patient so this needs to be removed first. The abscess should be drained through a burr hole or excised via a craniotomy. Then if the patient is stable enough, mastoidectomy should be performed under the same anaesthetic. Pus should be sent for culture and aggressive antibiotic therapy should follow.
What is otitis media with effusion? Does it always require treatment?
Children will be slightly deaf for several weeks following an episode of acute otitis media due to accumulation of fluid in the middle ear. Sometimes this fluid accumulates even without a prior episode of OM - called a middle ear effusion. As long as this is short lived and resolves completely it is a normal part of childhood and needs no treatment.
If fluid persists in the middle ear with an intact drum - i.e. no perforation - for a continuous period of 3 months or more this is pathological and is termed otitis media with effusion (OME) or "glue ear".
Aetiology of OME
Most cases of OME follow an acute episode of OM and are due to persistence of fluid after the infection has subsided.
Adenoids may play a role in other cases.
What is otosclerosis?
This is usually a hereditary disorder that causes abnormal bone to be formed around the stapes footplate preventing its normal movement. This causes a conductive hearing loss.
More rarely, the bone of the cochlea may be affected which results in a sensorineural hearing loss.
What are the clinical features of otosclerosis?
1) Usual onset in the 2nd and 3rd decades
2) 2/3 give a family history
3) 2/3 are female - the gene is not sex linked but pregnancy makes the deafness worse
4) Deafness may be unilateral or bilateral
5) Tinnitus is often present - it may not be relieved by an operation
What is the main treatment option for otosclerosis? What is the major risk with this?
Stapedectomy - the middle ear is exposed by folding the tympanic membrane over, the stapes superstructure is removed and the stapes footplate perforated. A prosthesis of stainless steel in place of the stapes is attached to the long process of the incus with its distal end in the oval window. The patient is usually discharged the following day and should be advised to avoid strenuous exercise for at least 1 month.
There is a risk the patient will lose hearing in the operated ear, and should be warned of this BEFORE the procedure.
What are the causes of earache (otalgia)?
Earache may be due to ear disease or may be referred from disease elsewhere. Referred earache often causes a challenging diagnosis.
Causes can be summarized as follows:
i) Aural causes
ii) Referred earache
ii) Specific circumstances
Give some aural causes of earache?
Earache can be caused by any disease of the external or middle ear cleft and diagnosis is usually obvious on clinical examination. The most common causes are:
- Acute mastoiditis (rare)
Malignant disease of the ear will cause intractable earache.
If the ear is not convincingly abnormal then look for causes of referred pain.
What nerves can cause referred earache?
1) auriculo-temporal branch of the trigeminal - carious teeth, TMJ, tongue etc
2) tympanic branch of the glossopharyngeal nerve - tonsillectomy, Quinsy, carcinoma of base of tongue
3) sensory branch of the facial nerve - herpes zostar
4) auricular branch of the vagus nerve - laryngeal carcinoma
5) greater auricular nerve and lesser occipital nerve - cervical spondylosis
What associated features of earache would be concerned for cancer?
Earache, cervical lymphadenopathy, and dysphagia is cancer until proven otherwise!
What is tinnitus?
Tinnitus is the complaint of noise in the ear. It may be constant or intermittent and usually varies in its intensity and character.
Tinnitus is NOT a disease but a symptom!
The causes can be divided into local and general.
What are the local causes of tinnitus?
Tinnitus may be a symptom of any abnormal condition of the ear and may be associated with any form of deafness. Certain conditions deserve a special mention:
- presbycusis - often causes tinnitus
- Meniere's disease - tinnitus is usually worse with acute attacks
- noise induced deafness - tinnitus may be worse immediately after exposure to noise
- otosclerosis - tinnitus may be relieved by stapedectomy but should NOT be the major indication for surgery
- glomus jugulare tumour - tinnitus is pulsatile and may be audible through a stethoscope
- aneurysm, vascular malformation and some vascular intracranial tumours can also cause tinnitus
Name some general causes of tinnitus?
Tinnitus is often a feature of general ill health, as for example:
- fever of any cause
- cardiovascular disease - HTN, atheroma, HF
- blood disease - anaemia, raised viscosity
- neurological disease - MS, neuropathy
- drug treatment - aspirin, quinine, ototoxic drugs (e.g. gentamicin)
- alcohol abuse
How should tinnitus be managed?
The management of tinnitus can be difficult as very little can be done to improve a patients symptoms. The following may be helpful:
1) Thoroughly examine the patient
2) If an abnormality of the ear is found (e.g. impacted wax) treatment will usually cure the tinnitus
3) Tinnitus due to chronic degeneration (e.g. presbycusis, ototoxicity or noise induced deafness) will be permanent to some degree
4) Drug treatment such as antidepressants or sedatives may help the patient but will not alleviate the tinnitus. Anticonvulsant drugs and vasodilators may be of some benefit but their effectiveness cannot be predicted
5) Patients with depression are particularly susceptible to the effects of tinnitus and should be treated expertly
6) If a patient with tinnitus is also deaf, a hearing aid is very helpful in masking tinnitus as well as relieving deafness
The mainstay of treatment for tinnitus is tinnitus retraining therapy.
What is the true definition of vertigo?
Vertigo is a subjective sensation of movement and is usually rotatory but sometimes linear. It is often accompanied by pallor sweating and vomiting.
The objective sign of vertigo is nystagmus.
What are the key features of a vertigo history?
1) Timing - episodic, persistant
2) Aural symptoms - deafness, fluctuating or progressive; tinnitus; otalgia; discharge
3) Neurological symptoms - loss of conscioussness; weakness; numbness; dysarthria; diplopia; fitting
These features can help confirm the diagnosis - e.g. episodic vertigo with aural symptoms is either Meniere's disease or migraine
What is Meniere's disease?
Meniere's disease is a condition of unknown aetiology in which there is distension of the membranous labyrinth by accumulation of endolymph. It can occur at any age, but its onset is most common between 40 and 60 years.
It usually starts in one ear only but in 25% of cases, both ears become affected.
What are the clinical features of Meniere's disease?
1) Vertigo is intermittent but when present may be profound, and usually causes vomiting. The vertigo rarely lasts for more than a few hours and is normally rotational
2) A feeling of fullness in the ear may precede an attack by hours or even days
3) Deafness is sensorineural and is more severe before and during an attack. It is associated with distortion and loudness intolerance. Despite fluctuations the deafness usually is progressive
4) Tinnitus is constant but more severe before an attack
What general medical measures can be used in the treatment of Meniere's disease?
In acute attacks when vomiting is likely to occur, oral medication is of limited value but cinnarazine or prochlorperazine hourly are useful preparations.
Prochlorperazine can be given as a suppository, and chlorpromazine (25mg) can be given IM.
Between attacks, various methods of treatment are useful:
1) Fluid and salt restriction
2) Avoidance of smoking and excessive alcohol or coffee
3) Regular therapy with betahistine hydrochloride 8-16mg t.d.s
4) If attacks are frequent, regular medication with labyrinthine sedatives such as cinnarazine 15-30mg t.d.s or prochlorperazine are of value. Low dose diuretic therapy may also be helpful
What are the surgical treatment options of Meniere's disease? When should they be explored?
1) Labyrinthectomy is effective in relieving vertigo, but should only be performed in the unilateral case when the hearing is already severely impaired
2) Drainage of the endolymphatic sac by the transmastoid route
3) Division of the vestibular nerve either by the middle fossa or by the retrolabyrinthine route; this operation preserves the hearing but is a more dangerous approach
4) Intra-tympanic gentamicin is helpful in reducing vestibular activity but with a 10% risk of worsening the hearing loss
What is vestibular neuronitis?
Vestibular neuronitis is damage to the vestibulo-cochlear nerve and is usually viral in origin. It causes vestibular failure.
The resulting vertigo is usually explosive in onset but there is neither tinnitus nor deafness. Steady resolution takes place over a period of 6-12 weeks but the acute phase usually clears in 2 weeks.
What is BPPV?
Benign paroxysmal positional vertigo is a degenerative condition of the utricular neuroepithelium and may occur spontaneously or following a head injury. It is also seen in CSOM.
Attacks of vertigo are precipitated by head movements; it occurs following a latent period and lasts for a period of several seconds unlike Meniere's disease.
Nystagmus is classically observed using the Dicks-Hallpike manouvre - the patients head is turned towards the examiner whilst sat upright and then abruptly moved to a supine position.
It can be treated using the Eply manouvre, but most cases are self limiting.
How does vertebrobasilar insufficiency cause vertigo?
Vertebrobasilar insufficiency may cause momentary attacks of vertigo precipitated by neck extension, e.g. hanging washing on a line.
The diagnosis is more certain if other evidence of brainstem ischaemia such as dysarthria or diplopia is also present. Severe ischaemia may cause drop attacks without loss of consciouss.
What ototoxic drugs can cause vertigo?
The most important ototoxic drugs to be aware of are gentamicin and the other aminoglycoside antibiotics. These cause disabling ataxia by destruction of labyrinthine function. Such ataxia may be permanent and the risk is reduced by careful monitoring of serum levels, especially in patients with renal impairment. There is not usually any rotational vertigo.
When does syphilitic labyrinthitis occur?
Syphilitic labyrinthitis usually occurs in congenital syphilis (remember syphilis is one of the TORCH organisms). It is very rare but may cause vertigo and/or progressive deafness.
What are the features of an acoustic neuroma?
Acoustic neuroma (vestibular schwannoma) is a slow growing, benign tumour of the vestibular nerve that causes hearing loss and slow loss of vestibular function. Imbalance rather than vertigo occurs.
What is Ramsay Hunt syndrome?
This is geniculate herpes zoster and usually causes vertigo along with facial palsy and severe pain in the ear.
Severe pain precedes the facial palsy and the herpetic eruption in the ear. The patient usually has vertigo and the hearing is impaired.
What approach should be made when diagnosing facial nerve paralysis?
Causes of facial nerve paralysis are either supranucleuar or infranuclear. It is important to remember that in supranuclear lesions the movements of the upper part of the face are likely to be unaffected as the forehead muscles have bilateral cortical innervation.
Infranuclear lesions can further be distinguished based on their location along the course of the nerve:
- impaired taste? = lesion is above the origin of chorda tympani
- hyperacusis with loss of stapedius reflex? = lesion is above nerve to stapedius
- reduced lacrimation? = lesion is above geniculate ganglion
- weakness in the distribution of a specific nerve and lacrimation and salivation retained? = peripheral nerve course
What is Bell's palsy?
Bell's palsy is idiopathic facial paralysis and is caused by lower motor neurone facial palsy of unknown cause. It is possibly viral.
Bell's palsy may be complete or incomplete, the more severe the palsy the worse the prognosis. In practice full recovery is expected in approx. 85% of cases.
Bell's palsy is NOT forehead sparing so causes hemifacial paralysis.