Scoring Systems for Evaluating GBS During TPE Treatment
The GBS Disability Scale (also called Hughes Functional Grading Scale) is the primary scoring system used to evaluate treatment effectiveness in Guillain-Barré Syndrome patients receiving therapeutic plasma exchange (TPE). 1
Primary Assessment Tool: GBS Disability Scale
The GBS Disability Scale is a widely used tool for documenting GBS disease course and monitoring treatment response during TPE. 1 This scale ranges from 0 (healthy) to 6 (death) and provides a standardized method to track functional disability throughout treatment. 2
Clinical application during TPE:
- Assess the Hughes score before initiating TPE and on the first day post-TPE for early clinical evaluation 2
- The scale effectively captures clinically meaningful changes, with studies showing median Hughes scores decreasing from grade 4 pre-TPE to grade 1 post-TPE 2
- Serial measurements allow clinicians to identify treatment responders versus non-responders 2
Complementary Assessment: Medical Research Council (MRC) Sum Score
Muscle strength should be assessed using the Medical Research Council grading scale to complement functional disability assessment. 1 The MRC sum score evaluates muscle strength in the neck, arms, and legs, providing objective data on motor recovery during TPE treatment. 1
Prognostic Scoring Systems
While not specifically for evaluating TPE effectiveness, two prognostic tools are valuable for clinical decision-making:
Modified Erasmus GBS Outcome Score (mEGOS):
- Predicts the probability of regaining walking ability at 6 months 1, 3
- Helps identify patients who may need more intensive treatment 4
- Incorporates age, preceding diarrhea, and MRC sum score at admission 1
Modified Erasmus GBS Respiratory Insufficiency Score (mEGRIS):
- Calculates probability of requiring mechanical ventilation within 1 week 5, 3
- Critical for determining appropriate monitoring intensity during TPE 5
- Scores range from 0-7 based on clinical parameters 1
Monitoring Frequency During TPE
Regular assessment is required to monitor disease progression and treatment response. 1 The nature and frequency of monitoring depends on the rate of deterioration, presence of autonomic dysfunction, disease phase, and healthcare setting. 1
Key monitoring parameters beyond disability scales:
- Respiratory function using the "20/30/40 rule" (vital capacity <20 ml/kg, maximum inspiratory pressure <30 cmH₂O, or maximum expiratory pressure <40 cmH₂O indicates respiratory failure risk) 1, 5
- Autonomic dysfunction via electrocardiography and monitoring of heart rate and blood pressure 1
- Swallowing and coughing difficulties 1
Clinical Pitfall to Avoid
Do not assume lack of improvement in Hughes score during the first 4 weeks indicates TPE failure. 1 About 40% of patients treated with TPE do not improve in the first 4 weeks following treatment, but this does not imply treatment ineffectiveness—progression might have been worse without therapy. 1