MND, MS, MG Flashcards
What are the 4 clinical patterns of motor neurone disease?
1) Amytrophic lateral sclerosis -motor cortex and anterior horn of spinal cord. (UMN and LMN signs)
2) Progressive Bulbar Palsy - Nuclei of CN9-12 in the medulla. (LMN lesion of tongue and swallowing muscles - flaccid and fascinating tongue, jaw jerk and quiet/hoarse/nasal speech)
3) Progressive Muscle atrophy - Anterior horn lesion (LMN signs affecting distal before proximal)
4) Pseudo-bulbar palsy - Motor cortex + loss of Betz cells (UMN signs - spastic leg weakness, slow tongue, speech, jaw jerk, unprovoked weeping and giggling)
How is motor neurone disease diagnosed?
1) EMG/nerve conduction
2) Rule out other causes through bloods, MRI, LP, muscle biopsy
Treatment for MND?
1) Riluzole to prolong life by 3 months.
2) MDT
3) Symptomatic - baclofen for spasms, amitriptyline for drooling, anti-convulsive, non-invasive ventilation/PEG tubes
Aetiology for multiple sclerosis?
1) Chronic inflammatory disorder of CNS, immune mediated demyelination at multiple CNS sites - discrete plaques. Antibodies against myelin.
What are the clinical patterns for MS?
Relapse remitting, secondary progressive or primary progressive.
What are the signs/symptoms for MS?
1) Unilateral Optic Neuritis - pain on eye movement and reduced central vision.
2) Motor signs - leg weakness, spasticity and UMN signs.
3) Sensory disturbance - numbness/tingling
4) Autonomic function - Bladder and sexual dysfunction
5) Lhermitte’s sign - neck flexion causing electric sensation down spine
6) Brainstem features - nystagmus, dysarthria, vertigo, diplopia
7) Cerebellar features - limb and trunk ataxia, intention tremor, falls.
How do you diagnose MS?
1) Exclude differentials through FBC, ESR/CRP, LFT, TFT, U & E, glucose, calcium, B12)
2) Electrophysiology - visual evoked potential studies show delayed nerve conduction.
3) MRI shows paraventricular lesions and discrete white matter abnormalities.
4) Lumbar Puncture and CSF studies diagnostic - Increased protein and oligoclonal bands of immunoglobulins on electrophoresis.
2 or more CNS lesions disseminated in time and space.
Treatment of MS
1) Relapse treatment - Oral methylprednisolone (500mg OD for 5 days or IV if severe)
2) Disease-modifying agents - Alemtuzumab/Natalizumab (IV monoclonal antibodies)
3) Symptomatic control - Baclofen for spasticity, diazepam, dantrolene, Tizonidine.
Aetiology of myasthenia gravis
Autoimmune disease mediated by antibodies to nicotinic acetylcholine receptors, and MuSK receptors - affecting neuromuscular junction.
Clinical presentation of myasthenia gravis?
1) Muscular fatigue in extra-ocular, bulbar (swallowing and chewing), face, neck, trunk, limb girdle.
2) Ptosis
3) Diplopia
4) Myasthenia Snarl
5) Weakness of respiratory muscles
6) Voice deteriorates on counting to 50 and cannot keep eye raised and fixed on high finger.
7) NO PAIN NO SENSORY CHANGE, normal tone and no wasting.
How to diagnose MG?
1) Serum antibodies - anti-AChR and anti-MuSK.
2) Tensilon test - give IV edrophonium (short-acting acetylcholinesterase inhibitor, power should increase within seconds)
3) Thymus CT
4) Neurophysiology - decreased evoked muscle action potentials during repeat nerve stimulation.
How do you manage MG?
1) Symptom control - with anticholinesterase pyridostigmine/neostigmine.
2) Immunosuppression - with steroids (Prednisolone +/- methotrexate or azathioprine)
3) Thymectomy if patient is <50yo or if thymoma is found on CT.
Myasthenia Crisis summary:
MuSK +ve people are more likely to develop myasthenia crisis (weakness of respiratory muscles leading to respiratory failure). Can be triggered by anaemia, infection, stress, botox, and drugs (anti-HT and arrhythmic, anaesthetics). Treated with acetylcholinesterase, steroid, ventilatory support and plasmapheresis or IV Ig.
