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Myasthenia Gravis and

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AskTheNeurologist.Com. Myasthenia Gravis and. Guillan Barre Syndrome ... Guillan Barre Syndrome ' Acute Demyelinating Polyneuropathy' AXON. MYELIN ... – PowerPoint PPT presentation

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Title: Myasthenia Gravis and


1
Myasthenia Gravis and Guillan Barre Syndrome
Submitted to AskTheNeurologist.Com in
2007 Author Anon.
2
Myaesthenia Gravis
A disease consisting of muscle weakness due to
a variable block of neuromuscular transmission in
which there is an immune-mediated decrease in the
number or function of acetylcholine receptors
3
(No Transcript)
4
Neuromuscular transmission
  • Action potential arrives at synapse
  • Calcium enters via Ca channels (LEMS)
  • ACh vesicles released
  • ACh binds to postsynaptic receptors
  • Muscle AP resulting in contraction
  • Enzyme ( ACHE ) breaks down ACh

5
Associated factors
  • Female gt Male
  • Often associated conditions
  • - Thymoma
  • - Thyrotoxicosis
  • - SLE
  • - RA
  • - Other autoimmune conditions

6
Symptoms
  • Diplopia
  • Ptosis
  • Dysarthria
  • Dysphagia
  • Limb weakness
  • Fluctuative fatiguability is hallmark
  • NO SENSORY SYMPTOMS

7
Examination
  • Weakness of EOMs
  • Ptosis
  • Limb weakness
  • Fatiguability
  • SENSATION IN TACT

8
Exacerbating factors
  • Infection
  • Hypothyroidism
  • Poor compliance
  • Drugs - Aminoglycosides
  • - Beta Blockers
  • - Many others!
  • IV CONTRAST

9
Diagnostic tests
  • Tensilon ( edrophonium )
  • EMG ( decrement )
  • Ach receptor Abs

10
Further Investigations
  • Chest CT scan
  • Monitoring of Ach R Ab level
  • VITAL CAPACITY during exacerbations

11
Treatment
  • Anticholinesterase drugs
  • - Pyridostigmine ( Mestinon)
  • Thymectomy
  • Steroids ( may worsen initially)
  • Azathioprine ( Imuran)
  • Cyclosporine
  • IVIG or plasmapharesis

12
Prognosis
  • Most patients can be managed successfully with
    drug treatment
  • Occasionally fatal due to respiratory
    complications including aspiration pneumonia

13
Case 1
  • 75 year old man with malignant thymoma and
    metastasis
  • Seropositive MG for 2 years ( controlled with
    pyridostigmine only)
  • Hospitalised in ITU because of aspiration
    pneumonia
  • Severe deterioration, family consulted regarding
    intubation

14
Case 2
  • 19 year old male soldier, admitted to ER with 3
    hour history of worsening diplopia, dysphagia and
    general weakness.
  • On examination BP 70 / 30, Pulse 40
  • blurred vision when each eye examined separately
  • Pupils dilated and not reactive

15
Case 2 continued
  • 2 hours later, another soldier admitted with a
    similar problem ( from same base)

16
Guillan Barre Syndrome
  • Acute Demyelinating Polyneuropathy

MYELIN
AXON
17
Guillan Barre Syndrome
Acute Demyelinating Polyneuropathy
MYELIN
AXON
18
History
  • Often follows minor infection
  • - URTI
  • - Diarrhoea ( Campylobacter)
  • Progressive symmetrical limb weakness
  • Usually affects legs first and ascends
  • Proximal gt Distal weakness
  • Frequent sensory complaints
  • Progresses over no more than 4 weeks

19
Examination
  • Limb weakness
  • May ascend to affect facial muscles
  • Decreased or absent reflexes
  • In severe cases where there is axonal damage
    muscle wasting may occur

20
Autonomic instability
  • Tachycardia
  • Other cardiac irregularities
  • Labile blood pressure
  • Sweating
  • Pulmonary dysfunction
  • Sphincter disturbances
  • Paralytic ileus

21
Investigations
  • LP High protein with normal cell count
  • Nerve conduction studies reveal slowing of nerve
    conduction
  • Both abnormalities may lag behind clinical course

22
Treatment
  • IVIG and plasmapharesis
  • Steroids contraversial
  • Respiratory support if necessary
  • General supportive care e.g. s.c heparin

23
Monitoring
  • Neurological examination
  • Complaints of dyspnea
  • Cardiac monitor
  • Blood pressure
  • Vital capacity

24
Prognosis
  • Self limiting
  • Improvement expected to begin by 4 weeks
  • About ¾ recover completely
  • 20 remain with mild deficits
  • 5 die - Respiratory failure
  • - Autonomic instability

25
Submitted to AskTheNeurologist.Com in
2007 Author Anon.
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