An Observational Study on Factors Causing Variable Response to Therapeutic Doses of Intravenous Immunoglobulin in Acute Immune-Mediated Polyneuropathy: A Tertiary Care Center Experience

Abstract

Context: Immune-mediated neuropathies, notably Guillain–Barré syndrome (GBS) and its subtypes, exhibit diverse clinical presentations. Intravenous immunoglobulin (IVIG) is a standard treatment for these conditions, but the variable clinical course complicates outcome prediction. Despite standard IVIG dosing, some patients continue to deteriorate. Aim: The aim of this study was to assess the factors responsible for variable response to therapeutic doses of immunoglobulins in acute immune-mediated polyneuropathy. Settings and Design: This was a prospective, observational study. Materials and Methods: Acute immune-mediated polyneuropathy cases within 14 days of symptom onset and receiving IVIG were recruited. Hughes disability score (HDS), modified Erasmus GBS outcome score (mEGOS), and modified Rankin score (mRS) were assessed before IVIG, immediately after IVIG, and 4 weeks thereafter. Statistical Analysis Used: Categorical variables are expressed as percentages, and continuous variables are presented as mean ± standard deviation. Relationships between parameters were assessed using analysis of variance and multivariate analysis of covariance. Correlations were measured using Pearson’s correlation, and proportions were compared using the Chi-square test or Fisher’s exact test. Results: Among 60 GBS patients, the median age was 38 years, with upper respiratory tract infection as the most common antecedent infection (60%). The most common variant was pure motor type, while demyelinating (88.33%) was the most common electrophysiological subtype. Outcome correlated with post-IVIG scores of HDS and mRS. Linear regression analysis showed a positive correlation between onset-to-treatment duration and HDS and mEGOS scores after 4 weeks of IVIG, while mRS showed minimal correlation. No significant correlations were found between antecedent infection, gender, nerve conduction study pattern, GBS variant, and scores of HDS, mEGOS, and mRS. Conclusions: The study highlights the significance of onset-to-treatment duration. Factors with unfavorable course were age, delay in receiving IVIG, respiratory involvement, dysautonomia, cranial nerve involvement, and those with higher mEGOS scores at the 7th day of admission. Seasonal trends should not be overlooked. Serial evaluation of disability scores can predict the varying response to IVIG.