Weakness Flashcards
isolated progressive weakness, involving a number of limbs progressively, with muscle wasting
ALS
name 3 causes of subacute/acute onset of weakness
- Guillian Barre syndrome
- Cauda equina
- Transverse myelitis
condition that can present with both peripheral weakness + loss of peripheral sensation
GBS
investigations for a patient presenting with peripheral weakness + loss of sensation
FBC, U+E, Ca, LFTs, Phosphate, Magnesium, CRP, ESR, CXR
How can GBS affect breathing?
by causing neuromuscular ventilatory failure by causing muscular weakness of diaphragm
what position makes neuromuscular ventilatory failure worse?
lying down
examination signs of worsening GBS
- worsening neck weakness
- SoB worse on lying flat
- reduced chest excursion on deep inspiration
- CO2 retention flap
signs of GBS related autonomic instability
tachycardia
BP changes
investigation for GBS
LP
landmarks for LP
between lateral aspects of iliac crest at L4
complications of LP
- cerebellar herniation
- pain
- headache
- bleeding
- infection
- CSF leakage
- subarachnoid epidermal cyst
CSF finding in GBS
normal cell count + elevated protein level
= cytoalbuminologic dissociation
Presentation of transverse myelitis
rapid onset of weakness, bladder/bowel and sensory alterations
frequency of FVC measurements in GBS
4-hourly
GBS is…
immune mediated demyelination of the peripheral nervous system
antibody found in 25% patients with GBS
Anti-GM1 antibody
autonomic involvement in GBS
urinary retention \+ labile BP \+ constipation
Poss CN involvement in GBS
- diplopia
- ophthalmoplegia
- facial weakness
triggers of GBS
- EBV, HIV, CMV,
- Campylobacter jejuni
- E. Coli
- Hodgkin’s disease
- Pregnancy
examination findings in GBS
- ascending weakness
- areflexia
- distal paraesthesia
- slurred speech (if oropharyngeal muscle weakness)
Investigations for ascending weakness:
- Nerve conduction studies
- LP
- LFTs
- Spirometry
- Antibody
Management of GBS
- Thromboprophylaxis
- IVIG or Plasma exchange
- FVC monitoring
- Neurorehabilitation
Triad in Miller fisher syndrome
- ophthalmoplegia
- ataxia
- areflexia
CIDP is …
chronic, progressive relapsing remitting course of GBS; if the symptoms progress after 6 weeks
when do symptoms in GBS peak?
1-4 weeks after starting
how does plasma exchange hep to treat GBS?
In GBS your plasma contains harmful proteins, this treatment removes your blood, separates out the plasma and combines your remaining blood with a donors plasma which is then put back into you
majority fully recover by how long?
6-12 months
Myasthenia Gravis is …
chronic autoimmune disorder of the post-synaptic membrane at the NMJ in skeletal muscle
MG antibodies ?
antibodies to Acetylcholine receptors
Differentials of weakness?
- Lambert-Eaton syndrome
- GBS
- Transverse Myelitis
often the first symptoms to appear in MG are?
ocular symptoms
Muscle weakness in MG is dependant on what?
fatiguability
what is muscle fatiguability?
muscles become progressively weaker through periods of activity
+
diurnal variation
Levator palpebrae superioris weakness in MG causes
ptosis/dopping eyelids
double vision in MG is caused by>
extraocular muscle weakness
speech changes in MG and why?
nasal speech: dysarthria; due to bulbar muscle weakness
transverse smile in MG caused by
facial muscle weakness
difficulty getting out a chair in MG caused by
proximal muscle weakness
specific examination tests in MG (2)
asking patient to count to 50 and listen to voice become quiter (positive finding)
+
ask patient to stare at your finger held above their forehead
investigations for MG
- CT thorax (thyoma)
- EMG
- autoantibodies
- Pulmonary function tests
symptomatic treatment of MG
pyridostigmine
1st line treatment of MG
- Pyridostigmine
- Thymectomy
+/- Immunosuppressants: corticosteroids, rituximab
Pyridostigmine is a…
anticholinesterase
Myasthenic crisis is…
complication of MG: characterised by worsening muscle weakness resulting in respiratory failure requiring intubation + mechanical ventilation
management of Myasthenic Crisis
IVIG or plasmaphoresis
indication for mechanical ventilation
FVC < 15 ml/kg
complications of MG
- respiratory failure
- impaired swallowing (following mechanical ventilation)
- acute aspiration
- secondary pneumonia
- plasma exchange induced adverse reactions
Cauda equina examination findings
- reduced perianal sensation
- reduced anal tone
- urinary retention
- bilateral leg weakness
- areflexia
what FVC is an indication for intubation>
< 15 ml/kg
