Can multiple sclerosis cause bowel dysfunction and taste disturbances (dysgeusia)?

Can Multiple Sclerosis Cause Bowel Dysfunction and Taste Disturbances?

Yes, multiple sclerosis definitively causes both bowel dysfunction and taste disturbances (dysgeusia), though these manifestations occur through different mechanisms and with varying prevalence.

Bowel Dysfunction in MS

Prevalence and Clinical Impact

Bowel dysfunction is highly prevalent in MS patients, affecting the majority of those with the disease. Moderate-to-severe neurogenic bowel dysfunction (NBD) affects approximately 6.8% of MS patients, though milder symptoms are far more common 1. The 2018 ESPEN guideline on clinical nutrition in neurology acknowledges that dysphagia and bowel complications are among the most important issues affecting nutritional status in MS 2.

Key Clinical Determinants

The severity of bowel dysfunction correlates directly with:

• Disability level (EDSS score) - Each point increase in EDSS increases odds of moderate-to-severe NBD by 35% (OR 1.35) 1
• Bladder dysfunction severity - Neurogenic Bladder Symptom Score independently predicts bowel problems (OR 1.08 per point) 1
• Spinal cord involvement - Rectal compliance correlates with disability and reflects spinal cord disease burden 3

Notably, age, sex, disease duration, and MS subtype do not independently predict bowel dysfunction severity 1. This finding is clinically important because it means you should screen all MS patients regardless of disease duration, focusing instead on current disability level and bladder symptoms.

Clinical Manifestations

MS patients experience both constipation and fecal incontinence, which can coexist and alternate 4. The prevalence of mixed dysphagia reaches 71.4% in some cohorts 5. The pathophysiology is multifactorial, involving:

• Disruption of neurological pathways controlling bowel function
• Autonomic rectal dysfunction secondary to spinal cord lesions 3
• Reduced mobility and physical activity
• Polypharmacy effects
• Behavioral factors and toilet access limitations 4

Management Algorithm

For all MS patients with bowel symptoms:

1. Screen proactively using validated tools (NBD score, Wexner scales) - don't wait for patients to volunteer symptoms 1, 6

2. Assess bladder function concurrently - the two are closely linked and require integrated management 1, 7

3. First-line interventions:

   • Increase fiber and fluid intake
   • Establish regular bowel regime
   • Lifestyle modifications to improve colonic transit 2, 4

4. Second-line options when lifestyle measures fail:

   • Biofeedback therapy
   • Transanal irrigation
   • Consider probiotics (though evidence is primarily from Parkinson's disease studies) 4

5. Advanced interventions:

   • Antegrade colonic enemas
   • Stoma formation (not a last resort - can significantly improve quality of life) 4

Critical pitfall: Bowel dysfunction is multifactorial even within MS patient subgroups with similar symptom burden 3. Don't assume symptoms are solely due to neurological impairment - evaluate contributing factors including medications, mobility, and access issues.

Taste Disturbances (Dysgeusia) in MS

Prevalence

The pooled prevalence of gustatory dysfunction in MS patients is 16.4% (95% CI: 8.7-24.1%) based on systematic review and meta-analysis 8. When assessed using validated tools like the Taste Strip Test, prevalence reaches 18.8% 8.

Clinical Characteristics

MS patients demonstrate:

• Significantly lower gustatory test scores compared to healthy controls (standardized mean difference: -0.93) 8
• Sweet taste perception is most commonly affected - 78.6% of patients with taste alterations show impaired sweetness detection 5
• Taste alterations occur in 57.1% of MS patients with dysphagia 5

Clinical Consequences

Gustatory dysfunction leads to:

• Poor appetite
• Malnutrition and weight loss
• Decreased quality of life 8, 5

Notably, 66.7% of MS patients with dysphagia present with overweight or obesity despite inadequate dietary intake, suggesting complex nutritional disturbances 5. Over 70% have insufficient intake of energy, fiber, and key micronutrients (calcium, iron, potassium, magnesium) 5.

Assessment and Management

For MS patients, particularly those with dysphagia:

1. Assess taste perception using validated scales (Taste Strip Test preferred) 8

2. Evaluate nutritional status comprehensively:

   • Anthropometry and body composition
   • 3-day dietary recall and food frequency questionnaire
   • Micronutrient assessment 5

3. Implement multidisciplinary interventions:

   • Speech therapy for dysphagia management
   • Nutritional counseling to address inadequate intake
   • Modified food consistency when indicated 2, 5

Integrated Clinical Approach

Because gastrointestinal, urinary, and taste symptoms are closely interconnected in MS, assessment requires structured, proactive screening rather than reactive management 7. The 2018 ESPEN guidelines emphasize that dysphagia in MS typically results from brainstem involvement and is often accompanied by speech difficulties 2.

Key recommendation: Screen all MS patients with EDSS >3.5 or bladder symptoms for bowel dysfunction 1, and evaluate taste perception in any patient with dysphagia or nutritional concerns 8, 5. Early recognition prevents complications including aspiration pneumonia, severe malnutrition, urinary tract infections, and reduces healthcare costs 4, 7.