NEURO: Part 8 Flashcards
What is Uhtoff’s phenomenon
A worsening of symptoms due to exposure to higher the n normal temperature - MS
What is Lhermitte’s sign
In MS, an electrical sensation that runs down the back when bending the neck - CHARACTERISTIC of MS
What factors increase risks of relapses in MS
COLD
Influenza
Gastroenteritis
Biomarkers for MS
- Oligoclonal bands (found in lumbar puncture - proteins present in the CNS but not the blood)
Signs of Myasthenia Gravis in the eyes
MUSCLES OF EYES AFFECTED INITIALLY:
- ptosis - levator palpeerde superioris
- diplopia - due to weakness of extra ocular muscles
- Symptoms worsen when watching television, reading or driving in bright conditions
Isolated symptoms to eye is called ocular myasthenia graves
Signs of Myasthenia Gravis when eating
- DYSPHAGIA (weakness of oesophageal muscles)
- Weakness of muscles of mastication
- Velopharyngeal insufficiency (regurgitation of food and liquids into nose than down the throat)
Signs of myasthenia graves when speaking
- Dysarthria
2. Hypophonia and nasal quality
Signs of myasthenia graves in the fcae
Weakness of facial expression muscles: Can’t keep mouth closed, dropping eye lids
THEY LOOK SAD
What is a dangerous red sign of myasthenia graves
Muscles that control breathing - dyspnea and limb movement is affected = takes years to occur
Results in myasthenic crisis
What is myasthenic crisis
When paralysis of res muscles occur
Pathophysiology of myasthenia graves
- Antibodies produced against nicotinic cholingeric receptor or muscle-specific kinase
- Deposition of complex anti-ACHr IgG and complement at post-synaptic membranes = destruction of receptors
What condition is MG in females associated with
THYMIC HYPERPLASIA
RA
SLE
pernicious anaemia
What conditions are associated in males with MG
THYMIC ATROPHY?TUMOUR
RA
SLE
What causes transient MG
D-PENICILLAMINE TREATMENT
WILSON’S DISEASE
Differential diagnosis of MG
- MS
- Hyperthyroidism
- Acute Guillain-Barre syndrome
- Lambert-Eaton myasthenic syndrome
What is Lambert-Eaton syndrome
- Causes defective ACh release at neuromuscular junction but weakness IMPROVES after exercise compared to MG
Physical examination done in MG
- Ask patient o do repetitive movements (allows us to see ptosis)
- Curtain sign : Holds a patient’s eye open which will lead to the other eye closing
FBC in MG
- autoantibody for AChR (not very sensitive in ocular myasthenia gravis)
- If negative, look for MUSK protein antibodies
Diagnostics for MG
- Electromyography
- ICE Test
- Edrophonium test
- CXR / CT/MRI
- Pulmonary function test
What do we look for in EMG for MG
- Repetitive nerve stimulation as muscle fibres are easily fatigued in MG
What do we look for in the ice test
- Apply ice for 4-5 mins to eyelids: ACh esterase is inhibited at lower temperatures
Positive if there is greater than 2mm rise in the eye lid after ice is removed
Role of CXR in myasthenia graves
- Mediastinum widening (thymoma or hyperplasia of thymus)
Role of MR in myasthenia graves
Eliminates lesions of cranial nerves and ocular muscles
Mediastinal widening
How are symptoms of MG controlled
ACh esterase inhibitor