Management of Myasthenic Crisis in ER

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Management of Myasthenic Crisis in ER

• Jiann-Horng Yeh, M.D.Department of Neurology
  Blood Purification Center
• Shin-Kong WHS Memorial Hospital

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Clinical pattern - MG

• Ocular
• Ptosis ophthalmoplegia
• Usually asymmetric bilateral

• Bulbar
• Dysarthria, dysphagia, weak mastication
• Complicated with aspiration pneumonia
• Facial gt 95

• Respiratory failure
• Life-threatening
• Etiology
• diaphragmatic intercostal muscle weakness
• vocal cord paralysis

• Systemic
• Typical symmetric
• Proximal gt distal
• Arms gt legs
• Selective weakness
• Posterior neck

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Severity classification of MG
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Clinical manifestation of MG
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Clinical grade of MG
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Diagnosis - MG

• 3 mainstays of diagnostic testing
• Pharmacological (Tensilon test)
• Serological (acetylcholine receptor antibody)
• Electrodiagnostic (RNS SFEMG)
• Diagnosis
• a characteristic history /PE
• two positive diagnostic tests, preferably
  serological and electrodiagnostic.

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• Adults with generalized MG 85 to 90
• Childhood MG 50
• Ocular MG 50 to 70
• MG with thymoma nearly 100
• Some patients taking penicillamine /- MG

AchRAb Positive

• Thymoma without MG
• Immune liver disorders
• Lambert-Eaton syndrome (13)
• Primary lung cancer 3
• Older patients (gt 70 years) 1 to 3
• Neuromyotonia

AchRAb False
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AchRAb titers in Osserman stages (n699)
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Myasthenic crisis - clinical data
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Onset to 1st crisis (n61, Cohen Younger)
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Treatment - MG

• Pyridostigmine the first line treatment
• Prednisone the most effective Tx for ocular MG
• Thymectomy aged 8 to 55 with generalized MG
• Immunosuppressant
• Azathioprine
• Cyclosporine
• Cyclophosphamide
• Acute immune therapy
• Plasmapheresis
• Intravenous immunoglobulin

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MG ?
SFEMG AchRAb
MG
Mediastinal CT
Thymoma
?
V
Thymomectomy
Ocular
?
V
AchEI
Generalized
V
Effective
CT
?
Thymic hyperplasia
Effective
?
V
?
V
V
Thymectomy
Immunotherapy
?
Effective
Effective
?
Plasmapheresis
V
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Management of myasthenic crisis

• Treat underlying precipitants
• Keep adequate airway
• Aggressive immune therapy
• Adjuvant therapy
• Psychological support

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Precipitants (n20)
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Complications (n20)
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Drugs interfere NM transmission
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Management of myasthenic crisis

• Treat underlying precipitants
• Keep adequate airway
• Aggressive immune therapy
• Adjuvant therapy
• Psychological support

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MUSCLE WEAKNESS
Effective cough?
Vital capacity?
Resp volume?
Airway patency?
Sigh?
Fatique
Resp load?
ATELECTASIS
AV shunting
HYPOXIA
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AIRWAY MANAGEMENT Evaluate s/s of impending
respiratory failure

• Orthopnea, interrupted speech
• Shallow rapid respiration
• Paradoxical respiration
• Breathing sound
• Reduced BS, sputum, crackle
• Arterial blood gas
• Hypoxemia, CO2 narcosis, respiratory acidosis

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AIRWAY MANAGEMENTMonitor the changes of
pulmonary function

• Criteria for intubation
• VClt15 mL/kg Pimax lt -25 cmH2O
• Paired VC test supine sitting position
• Normal Supine VC gt 80 Sitting VC
• Weakness Supine VC lt 40 Sitting VC
• Digit count at one breath
• Count lt25 VC lt 20 mL/kg

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AIRWAY MANAGEMENT Appropriate chest care

• Chest physical therapy
• Percussion, postural drainage
• Education for effective respiration/coughing
• Elective intubation
• Impaired swallowing
• Signs of aspiration pneumonia
• Hypoxemia
• Critical level of lung function

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Management of myasthenic crisis

• Treat underlying precipitants
• Keep adequate airway
• Aggressive immune therapy
• Adjuvant therapy
• Psychological support

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Time to produce a 50 AchRAb ?(m)
Tindall RSA/1982
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Blood pump
Plasma separator
Plasma pump
Plasma fractionator
Drain pump

• Plasma exchange
• Plasma modification
• Cascade filtrationDouble filtration
  Cryofiltration
• Plasma perfusion Biological Non-biological

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Blood
Plasma
Purified P
Double-filtration plasmapheresis
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?????????

• ???? ???? gt ????
• ?? ???????,??5?
• ?? 2 ??
• ????? 1 ????? (2.5-3L)
• ????? 10 ?????
• ??? ?? 2-3000 ??
• ???????30????????
• ????? ??????

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????
Poor Fair Good 0 2 212 53 1
5 38 62 48 gt5
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????
?? ?? ?? ??

• Dau-81 60 ???? 74
• Fornasari-85 33 ???? 61
• Mantegazza-87 37 ???? 87
• Antozzi-91 70 ???? 70
• Kornfeld-92 43 ???? 91

Shibuya-94 20 ???? 55
Yeh-99 45 ???? 84
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???????????????????
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???????????AchRAb??
0.78
0.71
0.61
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????????????????
1.86
1.49
1.40
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IVIG - MG

• Dose 2 grams/kg (over 2 to 5 days)
• Indication acutely ill MG patient
• Advantages
• Easily administered
• Rare serious side effects
• Short onset of action
• Disadvantages
• Benefits not well demonstrated
• High cost
• Benefit only short-term
• Probably less effective in crisis

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IVIG in MG (overall efficacy 69)
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PP-14 / IVIG-7
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Management of myasthenic crisis

• Treat underlying precipitants
• Keep adequate airway
• Aggressive immune therapy
• Adjuvant therapy
• Psychological support

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Fluid nutrition

• N/S infusion ? amount during fever
• NG feeding in severe bulbar dysfunction
• Sucralfate or antacid when steroid use
• 3rd generation cephalosporin if pneumonia

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Management of myasthenic crisis

• Treat underlying precipitants
• Keep adequate airway
• Aggressive immune therapy
• Adjuvant therapy
• Psychological support

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Keynotes

• Be patient confident
• Fatigability fluctuation
• Avoid NM blocking agents
• Keep adequate airway
• Elective intubation