What are the risk complications of Therapeutic Plasma Exchange (TPE) in myasthenia crisis?

Risk Complications of Therapeutic Plasma Exchange in Myasthenia Crisis

Therapeutic plasma exchange (TPE) in myasthenic crisis carries a 3-4% incidence of serious adverse events, with the most significant risks being catheter-related complications (particularly when using central venous catheters), citrate toxicity, severe allergic reactions, arrhythmias, and vasovagal reactions, though the procedure is generally safe when performed with appropriate monitoring and peripheral venous access when feasible. 1

Serious Complications

Catheter-Related Complications (Most Significant Risk)

Central venous catheter insertion carries the highest risk of serious complications, including 1:

• Hemothorax, pneumothorax, hemomediastinum, hydromediastinum, hydrothorax 1
• Subcutaneous emphysema, retroperitoneal hemorrhage 1
• Embolism, nerve injury, arteriovenous fistula, tamponade, and death 1
• Line-related bacteremia 2

Central venous catheters are associated with significantly more complications than peripheral venous access (68% vs. 35% total complications; 41% vs. 4% serious complications), including 2 deaths in one institutional series 3. This represents the most preventable source of morbidity and mortality.

Direct TPE-Related Serious Complications

The procedure itself carries specific life-threatening risks 1:

• Citrate toxicity (from anticoagulation during exchange) 1
• Severe allergic reactions 1
• Arrhythmias 1
• Vasovagal reactions 1
• Hemodynamic shifts and coagulation disorders 2
• Electrolyte imbalances 2

Minor/Non-Serious Complications

These complications occur more frequently but are generally manageable and do not require procedure termination 1, 4, 5, 6:

• Hypotension (transient, judged non-serious) 1
• Hypocalcemia (from citrate binding calcium) 1
• Urticaria 1
• Citrate reactions (most common, easily treated) 3, 5
• Peripheral vascular access issues 3, 5
• Post-treatment hemoglobin drop 7

Overall Incidence Rates

The overall incidence of adverse reactions ranges from 21.7% to 33.3% across studies 4, 6, with:

• 55-78% of patients experiencing no complications 5, 6
• 45% experiencing mild-moderate reactions that do not require stopping treatment 5
• 3-4% experiencing serious adverse events 1, 8

Risk Mitigation Strategies

Venous Access Selection (Critical Decision Point)

Peripheral venous access should be attempted first whenever feasible, as it dramatically reduces complication rates 3:

• Peripheral access is successful in 75-83% of myasthenia gravis patients 3, 5
• Over 90% of patients improve with TPE regardless of access method 3
• Central venous catheters should be reserved only when peripheral access is not feasible 3

Monitoring Requirements

Patients require intensive monitoring during and after TPE 2:

• Careful monitoring for hemodynamic shifts, coagulation disorders, and electrolyte imbalances 2
• Minimum 24-hour monitoring in ICU, HDU, or recovery unit even after apparent stabilization 2
• Specialized equipment and expertise in apheresis procedures are essential 2

Medication Timing Considerations

Specific immunosuppressive medications require timing adjustments around TPE 2:

• Cyclophosphamide should be administered AFTER the plasma exchange session 2
• Plasma exchange should be held for 48-72 hours after rituximab infusion to prevent antibody removal 2

Special Populations and Comorbidities

Comorbid disease and age do not predict adverse reactions in myasthenia gravis patients 5. However, certain conditions increase procedural risk 1:

• Hepatic insufficiency dramatically impairs citrate metabolism 1
• Hypoperfusion states and hypothermia reduce citrate clearance 1
• Renal failure, hypercoagulable states, sepsis, and hemodynamic instability are contraindications to plasma exchange 1

Clinical Context and Outcomes

Despite these risks, TPE remains a safe and effective rapid therapy for myasthenic crisis 4, 5, 6:

• All patients demonstrate immediate benefits after each TPE cycle 4, 6
• Good acceptance of procedure occurs in 72-78% of patients 4, 6
• TPE reduces ICU stay length compared to IVIG (particularly in early response) 7
• The procedure is well-tolerated even in patients with moderate-severe myasthenia gravis 5

Common Pitfalls to Avoid

1. Defaulting to central venous access without attempting peripheral access first - this is the single most important modifiable risk factor 3
2. Inadequate monitoring for citrate toxicity in patients with liver disease or hypoperfusion 1
3. Failing to hold rituximab before TPE sessions (wastes expensive medication) 2
4. Insufficient post-procedure monitoring (minimum 24 hours required even when stable) 2
5. Performing TPE without specialized apheresis expertise and equipment 2