neuro bottom tier Flashcards
huntingtons prognosis
poor. no cure. progressive decline
death within 15y, usually from infection
huntingtons management
- Nothing prevents progression
- Counselling to patient and family
- Chorea management:
- –Benzodiazepines - valium (enhances GABA)
- –Sulprode (depresses nerve function)
- –Tetrabenazine (depletes dopamine)
- –Sodium valporate (blocks Na channels and increases GABA)
- SSRI antidepressants - seroxate
- Antipsychotic neuroleptic medication (depresses nerve function) - haloperidol
- Aggression treated with risperidone
huntingtons investigations
- Genetic testing- see over 35 CAG repeats (genetic counselling required)
- CT/MRI (not useful early on)
Caudate nucleus atrophy
Increased size in frontal horns of lateral ventricles (brain destruction)
huntingtons symptoms
Prodromal phase = mild psychotic and behavioural symptoms
Chorea
- -Relentless progression
- -Jerky, explosive rigidity involuntary movements
- -May begin as restlessness, unintentionally initiated movements and lack of coordination
- -Flits from one part of the body to another
- -May interfere with voluntary movements
- -Ceases during sleep
- Dysarthria
- Dysphagia
- Abnormal eye movements
- Psychiatric - Depression, anxiety, behaviour change - (aggression, addictive behaviour, apathy, self-neglect)
- Dementia (impaired cognitive abilities and memory)= later
- Parkinsonism
- Associated with seizures
huntingtons pathophysiology
Characterised by lack of GABA (inhibitory neurotransmitter
a cause of chorea
Progressive caudate nucleus atrophy
Marked loss of GABA-nergic and cholinergic neurons is the caudate nucleus and the putamen of the basal ganglia. This causes decreased ACh and GABA synthesis
GABA is the main inhibitory neurotransmitter so this results in decreased inhibition of dopamine. So excessive stimulation and thus excessive movements
causes of chorea
huntingtons Rheumatic fever = sydenham’s chorea Creutzfeldt-jakob disease Wilson’s disease SLE Stroke of basal ganglia
huntingtons cause
Genetic
Autosomal dominant
Full penetrance. 50% from parent
Mutation on chromosome 4 – repeated expression of CAG sequence. The more CAG repeats, the earlier the onset of symptoms. Adult onset = 36-55 repeats. Early onset (child)= 60+
huntingtons onset age
middle aged
complications of guillian barre syndrome
Respiratory failure- life threatening– involvement of respiratory muscles
LMN issues
Most make complete recovery
management of guillian barre
IV immunoglobulin
Plasma exchange possible
Mechanical ventilation if necessary (complication of resp failure)
Low molecular weight heparin and compression stockings to reduce risk of venous thrombosis
investigations into guillian barre
- Antibody screen : anti-ganglioside antibodies
- Nerve conduction studies - slow conductions (diagnostic)
- Lumbar puncture
- –At L4
- –CSF: raised protein level (IgG anti-ganglioside antibodies) with normal white cell count
- Monitor FVC for respiratory involvement (serious complication)
symptoms of guillian barre
Rapid onset
Sensory and motor symptoms
- Sensory less common
- Glove and stocking – distal disturbance = ascending limb symptoms. Usually symmetrical
- Weakness (but no muscle wasting)- paralysis
- Lost reflexes
- Paraesthesia
- pain- proximal muscles
Autonomic dysfunction
- Sweating
- Increased pulse
- BP changs
- Arrhythmias
guillian barre pathophysiology
Primary damage to axons or myelin sheath → progressive ascending neuropathy - ‘acute inflammatory demyelinating polyneuropathy’
In the peripheral nervous system ! = schwann cells
Antibodies from infection attack myelin = theory
Molecular mimicry = antigens on pathogen are same as on schwann cells
Demyelination results in reduction in peripheral nerve conduction
Type 4 hypersensitivity
causes of guillian barre + risk factors
Most have preceding infection - usually GI, respiratory 1-3w prior - Camplyobacter jejuni = main - CMV - HIV - Mycoplasma - EBV In some cases, no infection is found Antibodies to infection also attack peripheral nerves Vaccination maybe
so risk factors = infection, vaccination, post pregnancy
what gender is guillian barre more common in
m
