Myasthenia Gravis Flashcards
Myasthenia Gravis is a disease of the neuromuscular junction that can affect ……… …….
Nicotinic acetylcholine receptors
MuSK Muscle-specific kinase
What is MG
It is an autoimmune disorder that affects the neuromuscular junction at the postsynaptic region
It is characterized by fluctuating fatigable weakness of the voluntary muscle
The first peak of MG occurs at ……… and it’s common in ……….
2nd and 3rd decade
Females
The target site of autoimmune AB in Achr in MG is …..
Immunogenic region
The three effector mechanisms by which autoimmune AB induces muscle change in MG are ……
- Effector mechanism 1: blockade
- X- linking adjacent nAchr
- Ab induces inflammatory and destructive changes leading to decreased Achr and morphological changes in the entire postsynaptic membrane
An immune system abnormality which MG is commonly associated with is…
Thymic abnormality
2nd peak of MG occurs at………. period and it’s common in ………
6th -7th
Males
………..% of patients have a thymic abnormality and the thymic abnormality distribution is …..
75 %
15% thymoma
85% thymic hyperplasia
…….. % of Generalised and ocular myasthenia Gravis are seronegative
10% generalized
50% ocular
The tensilon test is carried out using
Iv edrophonium 2mg or as much as 10 mg
Alternatively
IM neostigmine 1.5 mg
The onset of action of edrophonium is ……….. in tensilon test and can last ……..
30 secs
<10 mins
…………. is the most sensitive and specific test for MG
Laboratory investigation of Achr Ab
Electrodiagnostic test in MG include
Repetitive nerve stimulation shows >10% decreased response
Nerve conduction test is usually normal
Single fibre electromyography increased jitter most sensitive test for NM conduction but not specific
The most sensitive test for NM conduction is ……..
Electromyography
The side effects of symptomatic treatment of MG with anticholinesterase is
Nicotinic : fasciculations, cholinergic crisis
Muscarinic: hypermotility,bradycardia, excessive respiratory amd GI secretions
