Botulism sequelae: A Systematic Review

Background Botulism is a life-threatening neuroparalytic disease caused by botulinum neurotoxins. While its acute phase has been extensively studied, long-term sequelae following recovery remain insufficiently explored. This systematic review aims to comprehensively assess and synthesise available evidence on post-botulism sequelae to improve understanding and guide future research. Methods A systematic search was conducted in MEDLINE, EMBASE via Ovid, and Web of Science from inception to June 24, 2024. Eligible studies included observational studies, case series, and case reports describing post-recovery symptoms in individuals diagnosed with foodborne, wound, or infant botulism, excluding iatrogenic cases. The risk of bias was assessed using the Critical Appraisal Skills Programme (CASP) checklists. Results Out of 340 screened records, nine studies met inclusion criteria, comprising two case-control studies (n=230 botulism cases, n=669 controls) and seven cohort studies (n=185 botulism cases). Most studies reported some short- and/or long-term consequences of botulism. Among three studies homogeneously reporting sequelae symptomatology, the most frequently reported long-term symptoms included fatigue (66.2%, range 47.9–84.6%), limitations in vigorous activities (55.8%, range 47.6–64.0%), general weakness (57.1%, range 43.1–76.9%), and dyspnoea (42.9%, range 18.0–92.3%). In some patients, psychosocial dysfunction persisted longer than physical impairments, over the six-year period post intoxication. Two studies provided comparative data with control groups, demonstrating significantly higher prevalence of fatigue, weakness, and impaired health perception in botulism survivors. Additionally, 14 case reports and case series (n=43 individuals) reported similar patterns with dyspnoea, fatigue, and autonomic dysfunction among the most reported sequelae. Conclusions This systematic review highlights significant long-term sequelae among botulism survivors, particularly fatigue, respiratory impairment, and psychosocial dysfunction. While recovery trajectories suggest improvement over time, persistent symptoms may impact quality of life. Standardised outcome measures and longitudinal studies are needed to elucidate the burden of post-botulism sequelae further and inform clinical management strategies.