MRCP revision battle 32.1: Deafness: Rinnes and Webers

Final day in the hat trick of eyes and neurology battles...


MRCP revision battle 32.1: Deafness: Rinnes and Webers
MRCP revision battle 32.2: Tinnitus
MRCP revision battle 32.3: TIA
MRCP revision battle 32.4: Epilepsy
MRCP revision battle 32.5: Macular degeneration
MRCP revision battle 32.6: Glaucoma
MRCP revision battle 32.7: Autonomic neuropathy



MRCP revision battle 32.1: Deafness: Rinnes and Webers

Hearing loss and Rinne and Weber's tests are MRCP favourites.


Remember there are 2 types of deafness:

• conductive deafness
• ear wax
• otosclerosis
• otitis media
• glue ear
• sensorineural deafness
• acoustic neuroma
• Pagets
• MS
• CVA
• Menieres
• head trauma
• noise exposure
• drugs
• aminoglycosides (gentamycin)
• furosemide
• lead

Tests are done with a 256- 512 Hz tuning fork





Rinne's test:

• hold vibrating tuning fork next to ear meatus, then place on mastoid
• ask which is louder
• air conduction (AC) > bone conduction (BC) = normal, or, if hearing is decreased, suggests sensorineural loss
• BC>AC = conductive deafness = Rinne negative
• Remember as: ALS (like the course) - air loudest: sensorineural.  

Weber's test:

• hold vibrating tuning fork on forehead
• ask which side it is heard loudest in
• in sensorineural loss it laterals to the unaffected side
• in conductive loss it laterals to the affected side
• midline if normal, or bilateral sensorineural loss
• Remember as: SUCA - sensorineural unaffected, conductive affected.

Next up - a spot of tinnitus...

MRCP revision battle 32.2: Tinnitus

Tinnitus is ringing/buzzing in ears.


Causes include:

• eax
• viral infections
• presbyacusis
• head injury
• Menieres
• drugs
• aspirin
• furosemide
• gentamycin

Pulsatile tinnitus may indicate carotid artery stenosis or dissection



Now on to the meatier topic of TIAs...

MRCP revision battle 32.4: Epilepsy

Epilepsy is defined as a recurrent tendency to spontaneous, intermittent, abnormal electrical activity in part of the brain, manifest as seizures (OHCM definition)



Epileptic seizures are subdivided into:

• partial seizures = features come from one part of the brain
• simple partial = consciousness not impaired
• complex partial = consciousness impaired - usually temporal lobe, aura may preceed and automatisms may feature
• generalised seizures = features not localisable to one part of the brain
• absence = petit mal = brief <10 second pauses - 3Hz spikes
• atonic = becomes flaccid
• tonic-clonic - classic stiffening and jerking
• myoclonic

Treatment is usually started after the second seizure.   It would be started after the first if any of the following conditions apply:

• neurological deficit
• structural abnormality
• EEG unequivocal
• pt/family/carers keen for treatment

First line treatment depends on the seizure type:

• generalised
• 1st line: sodium valproate
• 2nd line: lamotrigine
• partial
• 1st line: carbamezepine
• 2nd line: sodium valproate
• absence
• sodium valproate or ethosuximide
• note that carbamazepine may worsen absence seizures

Remember that both sodium valproate and lamotrigine are associated with Steven Johnson syndrome.




Cannot drive until seizure-free for 1 yr, or 3 yrs of night time only seizures.
HGV drivers need to be off meds and seizure-free for 10 yrs.



If a pt has no seizures for 2 yrs, you may consider stopping meds over 2-3 months.


On to battle 32.5...

MRCP revision battle 32.3: TIA

TIA (=transient ischaemic attack) = sudden onset of focal CNS phenomena which last <24 hours.  Caused by temporary occlusion of part of the cerebral circulation.



Causes of TIAs:

• thromboembolism
• chiefly from carotids
• may be from heart - AF, mural thrombus etc)
• hyperviscosity
• myeloma
• polycythaemia
• sickle cells
• very high white cells

Management depends on the ABCD2 score, which is calculated as shown below:

• age >60 : 1 point
• BP greater or equal to 140/90 : 1 point
• clinically:
• unilateral weakness : 2 points
• speech disturbance without weakness : 1 point
• duration
• >60 mins : 2 points
• 10 - 59 mins : 1 point
• diabetes : 1 point

ABCD2 score of 4 or more, or crescendo TIAs (=2 or more in one week):

• specialist review within 24 hrs
• start 300mg aspirin OD

ABCD2 score of 3 or below, or symptoms >1 week ago:

• specialist review within a week
• start 300mg aspirin od

After specialist review, usually 75mg aspirin OD and dipyridamol OD for 2 yrs.
If pt is aspirin intolerant, prescribe monotherapy of clopidogrel.




If assessed to be a candidate for carotid endarterectomy, imaging should be performed within 1 week of symptom onset and if carotid stenosis of:

• 50–99% according to NASCET criteria, or 
• 70–99% according to ECST criteria 

carotid endarterectomy should be performed within 2 weeks of symptom onset.



Remember pt must inform DVLA and no driving for 1 month (car) or 1 yr (lorry).  This increases to 3 months for car if multiple TIAs.



Of course other risk factors (hypertension, alcohol, smoking, etc etc etc) should also be addressed.




Differentials for TIA may include:

• migraine
• epilepsy
• hypoglycaemia
• malignant hypertension 
• MS

Lets move on to tackle epilepsy...

MRCP revision battle 32.5: Macular degeneration

Macular degeneration is the commonest cause of blindness in the UK.


There are 2 types:

• dry 
• drusen - yellow spots in Bruchs membrane
• wet
• choroidal neovascularisation
• worse prognosis

Below is an image of dry macular degeneration showing drusen.  To link to an image of wet macular degeneration click here

Risk factors for macular degeneration are:

• age >60
• female
• smoking
• caucasian
• family history

Treatment - there is no cure:

• high dose beta caratene - but may increase risk of lung cancer in smokers
• vitamin C and E - but vit E may increase risk of heart failure
• zinc
• for wet:
• photocoagulation
• anti VEGF
• Ranibizumab
• photodynamic therapy

Keeping on eyes, next up is glaucoma...

MRCP revision battle 32.6: Glaucoma

Glaucoma is damage to the optic nerve, generally due to increase in intra-ocular pressure.


There are 2 types of glaucoma:

1. acute = closed angle glaucoma
2. chronic = open angle glaucoma

Acute closed angle glaucoma

Acute closed angle glaucoma presents as:

• pain
• decreased visual acuity
• worsening of pain with mydriasis
• hard, red eye
• halos around lights
• semi-dilated, non-reactive pupil
• pt systemically unwell

Risk factors for closed angle glaucoma include hypermetropia and pupillary dilation.


Management is:

• urgent opthalmic review
• IV acetazolamide (a carbonic anhydrase inhibitor; decreases aqueous secretions)
• topical pilocarpine (constricts pupil)

Open angle glaucoma


This affects 2% of over 40s.


Risk factors include:

• family history
• black
• myopia
• hypertension
• diabetes

Features include:

• peripheral field loss
• decreased visual acuity
• optic disc cupping

Treatments include:

• eye drops (beta blockers or prostaglandins)
• possibly surgery.

Now to our final battle of the day, autonomic neuropathy

MRCP revision battle 32.7: Autonomic neuropathy

Autonomic neuropathy is characterised by:

• postural hypotension
• erectile dysfunction
• constipation or diarrhoea
• urinary retention
• inability to sweat
• loss of decreased heart rate on deep breathing
• Horners
• Holmes-Adie pupil

Causes:

• endocrine
• diabetes
• infective
• HIV
• syphilis
• leprosy
• autoimmune
• SLE
• other
• GBS
• MSA
• parkinson's disease
• liver/renal failure.

Treatment is symptomatic; remember fludrocortisone as an option for severe postural hypotension.


On that list-intensive battle lets retire for the day.

MRCP revision battle 31.1: Wernicke's Encephalopathy

Day 2 of 3 for lots of neuro...


MRCP revision battle 31.1: Wernicke's Encephalopathy
MRCP revision battle 31.2: Korsakoff's Syndrome
MRCP revision battle 31.3: Multiple Sclerosis
MRCP revision battle 31.4: Menieres Disease
MRCP revision battle 31.5: CJD
MRCP revision battle 31.6: Herpes Zoster Opthalmicus
MRCP revision battle 31.7: Ramsey Hunt Syndrome




MRCP revision battle 31.1: Wernicke's Encephalopathy


Wernicke's encephalopathy is caused by thiamine (=vitamin B1) deficiency.


The classic triad associated with Wernicke's encephalopathy is:

• opthalmoplegia
• ataxia
• confusion

There may also be hypothermia and hypotension.


Thiamine deficiency may result from:

• alcoholism
• carcinoma of stomach
• anorexia
• vomiting

CT brain may show petichial haemorrhages and a low red cell transketolase blood test could prove thiamine deficiency (rarely performed)


Treatment is parenteral thiamine (pabrinex)

If untreated, 20% of patients will die and 85% will develop Korsakoffs.


Which leads us nicely into revision battle 31.2: Korsakoffs syndrome....

MRCP revision battle 31.2: Korsakoff's Syndrome

Korsakoff's Syndrome is a condition in which there is an inability to build new memories but preservation of other cognitive functions.


It is a chronic disorder, usually following Wernicke's encephalopathy.


The patient has an inability to consolidate new info, retrograde amnesia, patchy preservation of long term memory, a lack of insight and confabulates (=fabricates information to make up for memory loss)


Treatment is with thiamine but under 20% of patients respond.


On to 31.3... MS...

MRCP revision battle 31.3: Multiple Sclerosis

Multiple sclerosis is a cell-mediated autoimmune disorder characterised by plaques of demyelination at sites throughout the CNS but not in the peripheral nerves.


4 main types:

1. relapsing-remitting
• accounts for 80% of cases
2. secondary progressive
• up to 50% of relapsing-remitting patients eventually develop this
3. primary progressive
• 10-15% of cases
• older age of onset
4. progressive-relapsing

Initial presentation tends to be a single symptom, such as:

• optic neuritis 
• pain on eye movement and rapid deterioration in central vision, loss of colour vision
• treatment is methylpred
• single episode gives 40-60% chance of subsquent MS
• numbness or tingling in limbs
• leg weakness
• ataxia

Diagnosis is by (NB none is specific):

• lesions disseminated in time and location
• T2 weighted MRI showing demyelinating plaques
• delayed visual evoked response potentials
• oligoclonal bands in CSF but not serum

Good prognostic factors are:

• relapsing-remitting course
• female
• young onset
• sensory symptoms

Risk of MS is increased 20-40% in siblings and there is 25% concordance in monozygotic twins.



Treatment is:

• IV methylprednisolone
• shortens relapses
• no effect on incidence of attacks
• beta interferon
• decreases relapses by 30%
• given if
• relapsing-remitting course and 2 relapses in 2 yrs and can walk 100m unaided
• secondary progressive and 2 relapses in 2 yrs and 100m aided
• side effect: flu-like
• baclofen
• decreases spascity

Now for the less heavy-going Menieres disease...

MRCP revision battle 31.4: Meniere's Disease

Meniere's Disease is a disorder of the inner ear causing vertigo and hearing loss.


Features include:

• vertigo
• tinnitus
• sesorineural hearing loss
• aural fullness

There may be nystagmus and a positive romberg's test


It is usually unilateral and is believed to be associated with endolymphatic hydrops (=increased fluid in ear)


Rarely it may be associated with drop attacks - no LOC or vertigo, but suddenly falling to one side.


Management:

• prochlorperazine
• inform DVLA and stop driving until controlled.

 Next up: that formally very topical topic CJD...

MRCP revision battle 31.5: CJD

Creutzfeldt-Jakob Disease (=CJD) is a prion disease which causes a rapidly progressive dementia with myoclonus.



The majority of cases are sporadic.  There is also an inherited form and an acquired form (=varient CJD, from meat infected with BSE)


CSF examination is usually normal but EEG shows characteristic biphasic high-amplitude sharp waves.


Death is usually within 6 months.


On a lighter note lets look at herpes zoster opthalmicus...

MRCP revision battle 31.6: Herpes Zoster Opthalmicus

Herpes zoster opthalmicus is the reactivation of varicella zoster in the area supplied by the opthalmic division of the trigeminal nerve.


It occurs in roughly 10% of cases of shingles.


There may be Hutchinson's sign = rash on the tip of nose, which indicates nasocillary involvement and is a strong risk factor for ocular involvement.


Treatment is oral antivirals for 7 to 10 days and urgent opthalmic review if there is ocular involvement.



On to the final revision battle of the day...

MRCP revision battle 31.7: Ramsey Hunt Syndrome

Ramsey Hunt Syndrome is the reactivation of varicella zoster in the geniculate ganglion of the facial nerve.  


It is characterised by:

• herpes zoster oticus (=herpetic eruption in external auditory meatus)
• facial nerve palsy
• +/- deafness, tinnitus and vertigo

Treatment is with oral antivirals

MRCP revision battle 30.1: Retinitis Pigmentosa

Today is the start of a 3 day neuro/opthalmology blitz, so hold on to your hats....


MRCP revision battle 30.1: Retinitis Pigmentosa
MRCP revision battle 30.2: Oculogyric Crisis
MRCP revision battle 30.3: Myotonic Dystrophy
MRCP revision battle 30.4: Trinucleotide repeat disorders
MRCP revision battle 30.5: Huntington's Chorea
MRCP revision battle 30.6: Friedreich's ataxia
MRCP revision battle 30.7: Alzheimer's Disease




MRCP revision battle 30.1: Retinitis Pigmentosa

Retinitis pigmentosa is a type of progressive retinal dystrophy which eventually leads to blindness.

It has a very characteristic fundoscopic appearence with black mottling of the retina and a pale optic disc, as illustrated below in an image by Christian Hammel (from wiki commons):

It can be inherited in an autosomal dominant, autosomal recessive or X linked recessive fashion.



Night blindness is often the first sign.
Later comes funnel/tunnel vision.


It is associated with many conditions, including:

• Kearns Sayre (remember battle 15.1?)
• Ushers syndrome = retinitis pigmentosa with sensorineural deafness
• congenital toxoplasmosis

There is no cure for retinitis pigmentosa but progression of the disease can be slowed by vitamin A.



On to the second battle of the day...

MRCP revision battle 30.2: Oculogyric Crisis

The key features of an oculogyric crisis are restlessness and upward deviation of the eyes (although this only occurs in severe cases).


Oculogyric crises may be precipitated by a range of drugs including:

• neuroleptics
• metoclopramide/domperidone
• nifedipine
• TCA
• carbamazepine

Several clinical conditions can also cause oculogyric crises, for example:

• parkinsons disease
• post encephalitis
• bilateral thalmic infarction
• MS

Treatment is with procyclidine, an anticholinergic.


On to the next battle...

MRCP revision battle 30.3: Myotonic Dystrophy

Myotonic dystrophy is an autosomal dominant condition in which there is muscle weakness and myotonia.  It is a trinucleotide repeat disorder.

Onset tends to be in the 30s.


There are 2 types:


Dystrophia myotonica (=DM) 1

• 98% of cases
• more severe
• distal muscle weakness
• chromosome 19

Dystrophia myotonica 2:

• 2% of cases
• less severe
• proximal muscle weakness
• chromosome 3

Features associated with myotonic dystrophy include:

• long faces
• frontal baldness
• myotonia and weakness
• testicular/ovarian atrophy
• bilateral ptosis
• cateract
• cardiomyopathy
• diabetes
• miotic pupils 
• mildly decreased IQ

It is incurable but phenytoin can improve the myotonia.


Lets move on to consider an overview of trinucleotide repeat disorders

MRCP revision battle 30.4: Trinucleotide repeat disorders

Trinucleotide repeat disorders are conditions in which 3 nucleotides in the DNA are expanded.

The most 'famous' are:

• Huntingtons chorea (CAG) - covered in next battle
• Fragile X (CGG)
• Myotonic dystrophy (CTG) - covered in previous battle
• Friedreichs ataxia (GAA) - covered in battle 30.6

Two concepts to be born in mind for trinucleotide repeat disorders are:

Anticipation = the disease presents earlier and is worse in successive generations

Somatic instability = expansion increases as patient gets older


So lets briefly cover the most famous, Huntingtons...

MRCP revision battle 30.5: Huntington's Chorea

Huntington's chorea is an autosomal dominant condition due to CAG repeats.

It is carried on chromosome 4.


Symptoms tend to start in the 40s with a progression from chorea to irritability to dementia and death.


There is no cure.  The chorea may be treated with a dopamine antagonist such as tetrabenazine.



Note that Hunington's has complete penetrance so a child of a sufferer has a 50% chance of being affected.  Due to anticipation if they are affected they are also likely to develop symptoms earlier.



Next up: Friedreich's ataxia...

MRCP revision battle 30.6: Friedreich's ataxia

Friedreichs ataxia is an autosomal recessive trinucleotide repeat disorder (GAA)


It causes degeneration of nerve tracts resulting in cerebellar ataxia, dysarthria, nystagmus and dysdiadocholokinesis.


Muscles are weak, reflexes are depressed but plantars are upgoing.


There is often scoliosis and high arches of the feet.

Cardiomyopathy is another complication.


There is no cure.


Lets now try and forget all these incurable diseases with a touch of Alzheimer's...