Autoimmune nerve Conditions Flashcards
What is MS?
Chronic T-cell autoimmune attack of myelin leading to sensory & motor impairment
What is the pathophysiology of MS?
T-cell mediated attack of myelin
Leads to plaques of demyelination of CNS neurons = sclerosis
Reduces/blocks transmission of signals from CNS
Impairment of sensory & motor functions
What are the types of MS? Describe them
- Relapsing & remitting: 80% poor demyelination but periods of good health
- Primary progressive: From onset Sx are progressive
- Secondary progressive: 50% w/relapsing & remitting disease. Prolonged demyelination causes axonal loss + clinically progressive Sx
- Progressive & relapsing
What is the main trigger of primary progressive MS?
Infection
What are the RFs for MS?
Western world
30yo
Female
Vit D Deficiency
What type of hypersensitivity is MS?
Type 4
How does MS present?
Monosymptomatic initially Sx WORSE AFTER HOT SHOWER Charcot's triad: Dysarthria + Intention tremor + Nystagmus U/L Optic neuritis Paraesthesia + Numbness Brainstem/cerebellar Sx Fatigue Autonomic effects
What are the Sx of optic neuritis?
Demyelination of optic nerve
Pain on eye movement
Rapid ↓central vision & ↓acuity → hemianopia/blindness
Red desaturation (colours not as vibrant)
Nystagmus
CN6 palsy
What are the Sx of paraesthesia in someone with MS?
Tingling/itching/burning
Numbness
OFTEN LEGS: Acute leg weakness & incontinence= transverse myelitis
What are the Sx of brainstem & cerebellar MS?
Cerebellar = DANISH Diplopia & Nystagmus Trunk & limb ataxia Trigeminal neuralgia Deafness & BPPV Headache Facial weakness- Bell's palsy, dysarthria
What are the autonomic effects of MS?
Bladder: Urgency, frequency, incontinence
Sexual: Impotence, altered sensation
How is MS investigated?
Prior to referral =
Bloods: FBC, ESR/CRP, LFTs, U&E, Ca2+, Glucose, TFT, B12, HIV
REFER to neurologist post-bloods
MRI: Multiple disseminated lesions
LP: Oligoclonal IgG bands in CSF or ↑IgG index
Other than suspecting MS when else should someone be referred to a neurologist for ?MS ?
Ophthalmologist confirms optic neuritis
How is MS diagnosed?
Can only be done by consultant neurologist
>2 episodes at 2 SEPARATE SITES at 2 DIFFERENT POINTS IN TIME
What advice is given to someone with MS?
Stop smoking
Exercise
Vit D: Cholecalciferol aim >50 of 25(OH)D levels
How is MS managed?
Methylprednisolone: 0.5-1g PO OD shortens acute relapses- use sparingly + PPI
DMARDs: Alemtuzumab (R&R)
How are the Sx of MS treated?
Spasticity: Baclofen Tremor: Botulinum toxin Urgency/frequency: Catheterisation Neuro pain: TCA, Pregabalin Emotions: TCA
What are the complications of MS?
Transverse myelitis: Urgent hospital admission
Relapse: Over 12-24hours
Pressure ulcers
Cognitive decline = 50%
What is myasthenia gravis?
Autoimmune disorder of neuromuscular transmission leading to muscle fatigue
What is the pathophysiology of myasthenia?
Auto antibodies bind to postsynaptic Ach receptors
Deficiency of nicotinic acetylcholine receptors
What is myasthenia associated with?
<50yo women: Thymic hyperplasia
>50yo men: Thymic atrophy, tumour, RA, SLE
Other: thymoma, pernicious anaemia, AI thyroid disorders
What are the Sx of myasthenia?
Bilateral, symmetrical Sx
Increasing muscle fatigue WITH ACTIVITY
Slow improvement with rest
Proximal weakness of muscles
Extraocular muscle weakness: Diplopia & ptosis
Bulbar weakness: Dysphagia, dysarthria, dysphonia
What are the triggers for weakness in myasthenia?
Pregnancy Infection Climate change Emotion Exercise Drugs
Which drugs can exacerbate myasthenia?
BB Abx: Gentamicin, Ciprofloxacin, tetracyclines Anti-Arrhythmias: Verapamil Opiates Lithium Statins Quinine GA- neuromuscular blockers
In what order does weakness occur in myasthenia?
extra-occular → bulbar (swallowing, chewing) → face → neck → limb girdle → trunk
How is myasthenia investigated?
90% have auto-Ab:
Anti-AchR Ab = DIAGNOSTIC
Anti-MuSK Ab = DIAGNOSTIC
CXR/CT thorax: ESSENTIAL (exclude thymoma)
Neurophysiology
Count to 50: Voice weakens due to fatigue
How is myasthenia managed?
Pyridostigmine
Relapse: Prednisolone 5mg or DMARD (Azathioprine) if steroids not covering it
Crisis: Plasma exchange + IV immunoglobulin
What is a myasthenic crisis?
Respiratory compromise
Weak muscles of ventilation = acute respiratory failure
Weak pharyngeal muscles = compromise airways
REGULAR PO2 + FVC
Tx: Plasma exchange + IV immunoglobulin
What is Lambert-Eaton myasthenic syndrome?
Paraneoplastic syndrome causing muscle weakness IMPROVING w/exercise
CXR: LUNG CANCER
Patho: Autoimmune destruction of Ca2+ channels on presynaptic terminal
What are the Sx of Guillain Barre?
Symmetrical ascending muscle weakness
AND
Paraesthesia (glove-stocking)
↓Reflexes depressed/absent
How is Guillain Barre treated?
IV Immunoglobulins 400mg/kg/24hr
How is Guillain Barre investigated?
LP: ↑PROTEIN
Nerve conduction: Slow
