Science News: Monitoring Clinical Course and Treatment Response in Chronic Inflammatory Demyelinating Polyneuropathy During Routine Care

Submitted by: Niranjan N. Singh, MD, DM
Edited by: Shan Chen, MD

Allen JA, Merkies ISJ, Lewis RA. Monitoring clinical course and treatment response in chronic inflammatory demyelinating polyneuropathy during routine care: A review of clinical and laboratory assessment measures. JAMA Neurol. 2020;77(9):1159-1166. doi:10.1001/jamaneurol.2020.0781

Summary: Chronic inflammatory demyelinating polyneuropathy (CIDP) is without a disease activity biomarker and has broad clinical heterogeneity. There are several different metrics used in research trials, but we do not have a standard parameter to use in clinical practice to monitor the response to treatment. We do not have characteristic-defining clinical response or relapse by standard methods. Most of time, the clinical decision to treat the patient is based on clinician’s interpretation of patient's subjective experience. This review article summarizes clinical and diagnostic tools which can be used in clinical practice to help the clinician to just the outcome of the patient and determine if the treatment is effective or not.
 
1. Among the scales, INCAT disability score 0-10, 0 normal and 10 wheelchair-bound, higher score meaning more disability, I-RODS question constructed using Rasch patient's ability to complete a task, 0-complete disability to 48 no disability generated on 24 item response.

2. Grip strength is a reliable assessment of strength measured using a dynamometer-Jamar/Martin and correlates with overall neurologic status, a change of 8kPa  has been considered to discriminate between treatment and placebo in trials. Combined with muscle strength testing using MRC is recommended.

3. Time Up and Go (TUG) assessment may be the best to assess gait in CIDP. It provides information on patient's ability to rise from a seated position, accelerate, turn and sit down in addition to gait.

4. There are several evidence based quality of life tools which can be used to assess the effectiveness of treatment, one of such-PGIC-patient global assessment of change where participants are asked to indicate how you feel now compared with how you felt before receiving treatment on a 7 point scale ranging from +3 very much improved to -3 very much worsened can be used.

5. Electrodiagnostic studies have no value in monitoring of the treatment in routine typical cases.

6. CSF study is not needed for all patient with suspected CIDP but may provide supportive diagnostic data when electrophysiological findings are equivocal.

7. Neuro imaging including MRI and ultrasound may be useful where electrodiagnostic studies are equivocal.

Comments: Diagnosis and treatment of CIDP is complex, expensive, and not free from side effects. Treatment strategy should not solely based on the subjective responses from patients. However, we do not have a standard protocol for treatment response monitoring. This article summarized several parameters, which can be utilized in practice, and would be very useful for both validity, safety as well as cost effectiveness.