Prevalence, correlates and impact of pain and cramps in anti-MAG neuropathy: a multicentre European study.

Abstract

The frequency of pain and cramps is uncertain in anti-myelin associated glycoprotein antibody (anti-MAG) neuropathy. Whether these symptoms may affect function/quality of life is unknown. A cross-sectional study of the prevalence, correlates and impact of pain, pain subtypes and cramps, their severity, frequency and anatomical distribution was performed for 55 clinically stable patients with anti-MAG neuropathy. Pain of any type was reported by 80% of subjects. The most common subtype was paraesthesiae and dysaesthesiae (70%). Cramps were reported by >60% of patients, with lower limb cramps in all and upper limb cramps in about 20%. Cramps affected daily activities in >30% of these subjects, sleep in 60%, ability to exercise in >30%. Total pain score correlated with several Short Form 36 health-related quality of life (SF-36 HR-QoL) measures (P<0.05), with Inflammatory Rasch-built Overall Disability Scale (I-RODS) (P=0.006) and 10-m timed walk (P=0.019). An independent association was ascertained with I-RODS (P=0.002). Different pain subtypes showed multiple associations with SF-36 HR-QoL measures and/or functional scales. Upper limb cramps had multiple SF-36 HR-QoL functional correlates, with an independent association with the Overall Neuropathy Limitation Score (ONLS) (P=0.004). Cramp severity correlated with ONLS (P=0.04) and I-RODS (P=0.028) and inversely with level of physiotherapy input (P=0.009). Cramp frequency was associated with tremor score (P=0.004) and multiple SF-36 HR-QoL subsections. Neuropathic pain and cramps may affect function and quality of life in anti-MAG neuropathy. Optimizing treatments of these symptoms, including by adequate levels of physiotherapy, may be beneficial in affected patients and requires further research.