Cardiac ultrasound when shock or unexplained dyspnea
LV dysfunction alternative cause
Pericardial effusion assessment
Disposition
Level of care
ICU criteria
Any ventilatory support requirement
Invasive mechanical ventilation
Noninvasive ventilation with close monitoring
Rapidly progressive bulbar symptoms
Inability to manage secretions
Aspiration events
Respiratory mechanics decline
Forced vital capacity less than 20 mL/kg
PaCO2 greater than 45 mmHg
Stepdown criteria
Stable respiratory mechanics for 24 hours
Improving forced vital capacity trend
No NIV requirement
Bulbar symptoms controlled
Safe swallow plan in place
Transfer and consults
Neurology involvement
Rescue therapy selection
Plasma exchange versus IVIG decision
Long term immunotherapy planning
Steroid strategy
Steroid sparing agent timing
Critical care involvement
Ventilator management and weaning strategy
Tracheostomy consideration for prolonged ventilation
Treatment
Respiratory support
Oxygenation and ventilation support
Noninvasive ventilation pathway
BiPAP trial criteria
Alert and cooperative patient
Minimal secretion burden
No severe bulbar dysfunction
BiPAP failure predictors
PaCO2 greater than 45 mmHg
Inability to clear secretions
Invasive ventilation pathway
Intubation triggers
Forced vital capacity less than 20 mL/kg
Rapid respiratory mechanics decline
Bulbar failure with aspiration risk
Airway secretion strategy
Chest physiotherapy
Suctioning plan
Humidification
Nutrition and aspiration prevention
NPO status during unsafe swallow
Speech language pathology evaluation when feasible
Enteral feeding route planning
Nasogastric or post pyloric tube based on aspiration risk
Rapid immunomodulation
Plasma exchange
Standard course
5 exchanges over 7 to 14 days
1.0 to 1.5 plasma volumes per exchange
Albumin replacement typical
Contraindications and risks
Hemodynamic instability risk
Central line complications
Coagulopathy monitoring
Intravenous immunoglobulin
Standard dosing
0.4 g/kg/day for 5 days
Ideal or adjusted body weight per local protocol
Contraindications and risks
Thrombosis risk assessment
Renal dysfunction risk monitoring
Aseptic meningitis risk counseling
Symptomatic therapy and steroid strategy
Acetylcholinesterase inhibitors
Pyridostigmine oral
Typical outpatient dosing range 30 to 60 mg every 4 to 6 hours
Dose adjustment for side effects
Intubated patient approach
Temporary hold strategy
Reduced secretion burden goal
Cholinergic crisis avoidance
Corticosteroids
Continuation strategy
Continue home dose when already on chronic therapy
Stress dose consideration when septic shock physiology
Initiation strategy
Early neurology guided initiation
Risk of transient worsening with high dose initiation
Long term immunosuppressants
Continuation considerations
Azathioprine continuation when stable and no contraindication
Mycophenolate continuation when stable and no contraindication
Infection and cytopenia precautions
Hold strategy in severe sepsis based on multidisciplinary decision
Trigger treatment and avoidance
Infection management
Early antibiotics when infection suspected
Avoid high risk MG worsening antibiotics when alternatives exist
Aspiration pneumonia pathway
Airway clearance measures
Appropriate anaerobic and oral flora coverage per local guidance
Medication avoidance list in crisis
Neuromuscular transmission impairing agents
Magnesium salts
Aminoglycosides
Fluoroquinolones
Macrolides
Beta blockers
Sedation minimization strategy
Avoid oversedation masking hypercapnia
Cholinergic crisis management
Recognition and differentiation
Muscarinic features
Diarrhea
Sweating
Salivation
Bradycardia
Overmedication history
Recent pyridostigmine dose escalation
Management approach
Anticholinesterase hold
Symptom improvement monitoring
Atropine for severe muscarinic symptoms
Titrated dosing based on bradycardia and bronchorrhea
Special Populations
Pregnancy
Maternal considerations
Increased aspiration risk with bulbar weakness
Early obstetric and anesthesia involvement
Rescue therapy compatibility
Plasma exchange use when indicated
IVIG use when indicated
Medication considerations
Pyridostigmine compatibility in pregnancy
Dose based on symptom control and side effects
Corticosteroid considerations
Gestational diabetes monitoring
Hypertension monitoring
Neonatal considerations
Transient neonatal myasthenia risk
Neonatal observation plan after delivery
Geriatric
Presentation differences
Reduced reserve and rapid fatigue
Earlier ventilatory failure despite subtle signs
Delirium and hypercapnia interaction
Altered mental status from CO2 retention
Therapy risks
IVIG thrombosis risk higher
VTE risk mitigation plan
Plasma exchange access complications higher
Line complication monitoring
Pediatrics
Juvenile MG considerations
Weight based thresholds for respiratory mechanics
Forced vital capacity mL/kg trend tracking
Rescue therapy dosing
IVIG 0.4 g/kg/day for 5 days
Plasma exchange with pediatric apheresis expertise
Safety considerations
Sedation sensitivity
Hypercapnia risk with minimal sedation
Family education
Trigger medication avoidance list reinforcement
Background
Epidemiology
Frequency and burden
Myasthenic crisis occurrence in generalized MG
Highest risk early in disease course
Common triggers
Infection as leading precipitant
Medication exposure as preventable trigger
Pathophysiology
Neuromuscular junction failure
Autoantibody mediated impaired transmission
AChR antibodies reducing receptor availability
MuSK antibodies disrupting receptor clustering
Fatigable weakness mechanism
Decrement with repetitive activation
Respiratory failure mechanisms
Diaphragm and intercostal weakness
Hypoventilation and CO2 retention
Upper airway muscle weakness
Airway collapse and secretion retention
Bulbar weakness
Aspiration and pneumonia cycle
Therapeutic Considerations
Rescue therapy rationale
Plasma exchange mechanism
Rapid removal of pathogenic antibodies
IVIG mechanism
Immune modulation and antibody neutralization
Clinical effect timing
Plasma exchange often faster onset than IVIG
Both used as short term bridging therapies
Steroid initiation risk
Early transient worsening possible
ICU capable monitoring preferred when starting high dose
Extubation and weaning principles
Improvement in respiratory mechanics guiding weaning
Forced vital capacity trend upward
Adequate cough and secretion handling
Patient Discharge Instructions
copy discharge instructions
Myasthenia flare education
Symptoms needing urgent reassessment
New or worsening shortness of breath
Trouble swallowing or choking on liquids
Weak cough or inability to clear secretions
Rapidly worsening weakness or inability to hold head up
Blue lips or confusion
Medication safety
Do not stop MG medicines without clinician guidance
Avoid new medicines without checking MG safety list
Infection precautions
Early assessment for fever or cough
Hydration and rest during viral illness
Follow up plan
Neurology follow up timing
Within 1 week after ED visit for exacerbation
Return to ED criteria
Any breathing difficulty
Any swallowing difficulty
Any rapid symptom progression
References
Clinical guidelines and consensus
International Consensus Guidance for Management of Myasthenia Gravis 2016 Neurology
IVIG and plasma exchange for impending and manifest myasthenic crisis
Expert consensus guidance for global MG management
International Consensus Guidance for Management of Myasthenia Gravis 2020 update published 2021
Updated recommendations across MG subtypes and therapies
Expert consensus for crisis level care and rescue therapies
Evidence based sources
JAMA Neurology 2008 noninvasive ventilation in myasthenic crisis
Hypercapnia association with BiPAP failure
Patient selection importance for NIV success
Practical approach review 2020 in open access neurology literature
Symptomatic and immunotherapy sequencing overview
Steroid related transient worsening considerations
Muscle and Nerve 2023 myasthenic crisis review
Neuromuscular blocker sensitivity considerations
ICU management and complications overview
Peer reviewed open access review 2024 pitfalls in respiratory failure evaluation in myasthenic crisis
Limited distress signs despite CO2 retention
Need for ABG and clinical correlation
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