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