Myasthenia gravis Flashcards

1
Q

What is myasthenia gravis

A

T2 Autoimmunity against nAch and MuSK receptors = poor muscle contraction (less ACh)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the clinical features of Myasthenia gravis

A
Muscle weakness (worse w/exertion)
Diplopia (CN4)
Ptosis (CN3)
Myaesthenic snarl/ weak jaw(CN5)
Bulbar weakness (dysphagia, can't swallow) (CN9/10)
Fatigued speech
Better with rest
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What features might a patient present with on examination

A

Bilateral ptosis
Myasthenic snarl
Nasal speech
Dysphagia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How will you investigate Myasthenia gravis

A
Serolgy = Anti Ach-r and Anti MUSK
Tensilon Test Positive (Power increase w/edotropium)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How is Myasthenia gravis managed

A
ACHASE Inhibitor (Neostigmine) with steroid
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the Tensilon test

A

Give Edotropium and power increases

Positive = Increased muscles strength after administration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How does Anti Ach-r cause myaesthenia gravis

A

Binds to post synaptic receptor = Comp. Inhibition of Ach
Exertion causes increased Anti-Ach-r binding
Activate complement = NMJ Destruction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How does Anti musk cause myaesthenia gravis

A

MUSK helps synthesise Ach-r so less MuSK = less Ach-r

-Anti-musk = decrease Ach-r expression at post synaptic membrane = Complement activation = NMJ Destruction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the differential of Myaesthenia gravis due to similar symptoms

A

Lamber Eaton syndrome

  • Autoimmunity against PRESYNAPTIC CA2+ Channel
  • Improve Sx with exertion
  • Assocaited w/ SCLC
  • Sx start at peripheral then head and neck
  • Tx = Steroids and IV Ig
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is thyroid asscoaition with myaesthenia gravis

A

Thymoma (Male)
Do Thymectomy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How does the symptom progression differ between MG and Lamber Eaton

A
MG = Sx worse w/ exertion
LE = Sx better w/exertion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How does the treatment of MG differ to its differential Lamber Eaton

A
MG = ACHASE Inhibitor( Nystigmine) w/ steroids
LE = Prednisolone w/ IV Ig
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is Myaesthenic Crisis

A

MG Complication

  • Sx worsening w/ Rapid Resp Weakness
  • Tx = Plasma exchange w/ IV Ig
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Thymoma is apparent in MG, what cancer is apparent in Lamber eaton

A

Small cell lung cancer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Where does the weakness start in Myaesthenia

A

Head to lower body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Where does the weakness start in lamber eaton

A

Extremities to head