Neurogenic bowel problems in spinal cord Injury and multiple sclerosis: prevalence, dietary and gut microbiota interventions

Bowel dysfunction can lead to significant clinical complications, social isolation, and a reduced quality of life. Discussing such issues can be challenging for both patients and healthcare professionals. Among people with limited mobility, particularly those with spinal cord injury (SCI) or multiple sclerosis (MS), bowel problems, especially fecal incontinence, are often among the most distressing complications. Both SCI and MS can cause secondary health problems, with neurogenic bowel dysfunction (NBD) being one of the most prevalent and difficult to manage.

Chapter 1 provides an overview of SCI and MS, their associated secondary conditions, and introduces NBD. This chapter also presents the aims of this thesis: to study the prevalence of NBD in SCI and MS, assess dietary quality and its relationship with NBD, explore the gut microbiome in these patients, and evaluate the effects of probiotics on bowel function.

In Chapter 2, data from 1,210 patients in the Dutch Spinal Cord Injury Database were analyzed to assess bowel management during inpatient rehabilitation. Effective bowel management (EBM) was lacking in 68% of patients at admission and 38% at discharge. Those with complete or non-traumatic SCI were less likely to achieve EBM, highlighting the need for improved, individualized approaches.

Chapter 3 explored bladder and bowel problems in 1,082 patients with MS. Bladder issues were reported by 91% and bowel issues by 73% of respondents. Many patients consulted multiple healthcare professionals but often experienced delays or inadequate solutions. Sixty percent of those with bowel problems and 9% with bladder problems had not found satisfactory management, emphasizing gaps in care and the need for clearer referral pathways and greater professional expertise.

In Chapter 4, the relationship between diet and NBD in chronic SCI was studied. Patients showed poor dietary quality overall, with low vegetable and high salt intake in those with more severe NBD. Nearly half did not perceive a connection between diet and bowel symptoms, suggesting the need for better nutritional education and counseling during rehabilitation.

Chapter 5 reviewed 14 studies (479 patients) on gut microbiota in SCI and MS with NBD. Results indicated reduced microbial diversity in SCI but not in MS. However, findings were inconsistent, and most studies failed to adjust for factors such as diet or antibiotic use, indicating the need for more controlled research.

Chapters 6 and 7 described a double-blind, randomized, placebo-controlled trial investigating whether probiotics could prevent antibiotic-associated diarrhea (AAD) in SCI patients. Among 62 participants, no cases of AAD occurred, and there were no significant differences between the probiotic and placebo groups regarding stool consistency, nausea, or quality of life.

Chapter 8 describes the conclusion of this thesis: NBD is highly prevalent in SCI and MS, and current management is often insufficient. Many patients lack awareness of the link between their condition, diet, and bowel function. Improved education, early screening, structured dietary counseling, and continued research into gut microbiota and probiotics are essential to improve quality of life and clinical outcomes for these patients.