What are the management considerations for an elderly patient with a history of neurological disorders and a jejunostomy, who is potentially on Dimethyl Fumarate (DMF) for a condition such as multiple sclerosis?

Management of Jejunostomy in a Patient on Dimethyl Fumarate (DMF)

Continue DMF therapy in this patient with a jejunostomy, as the medication can be administered effectively through the feeding tube with appropriate crushing or liquid formulation, and there are no contraindications to jejunal feeding in patients on DMF. 1

Jejunostomy Management Fundamentals

The primary concern with jejunostomy patients is salt and water depletion, as each liter of jejunostomy fluid contains approximately 100 mmol/L of sodium. 1 This is critical because:

• Reduce oral hypotonic fluids to 500 ml/day maximum - this is the single most important intervention 1
• Provide glucose/saline solution with sodium concentration of at least 90 mmol/L for sipping, as stomal losses contain ~100 mmol/L sodium 1
• Monitor urinary sodium - concentrations <10 mmol/L indicate sodium depletion requiring immediate correction 1
• Track daily weights - abrupt weight loss signals water/sodium deficiency before laboratory abnormalities appear 1

Electrolyte Management Specific to Jejunostomy

Hypomagnesemia is extremely common and requires aggressive treatment: 1

• Initiate intravenous magnesium sulfate for acute correction 1
• Transition to oral magnesium oxide and/or 1-alpha cholecalciferol for maintenance 1
• Monitor serum magnesium every 1-2 days initially, then weekly, as levels <0.6 mmol/L cause symptoms 1
• Hypokalaemia is typically secondary to sodium depletion with hyperaldosteronism - correct sodium and magnesium first before potassium supplementation 1

Motility-Reducing Medications

Administer loperamide 2-8 mg before food (non-sedative, non-addictive) to reduce stomal output. 1 If output exceeds 3 L/24 hours, add:

• H2 antagonists or proton pump inhibitors to reduce gastric acid secretion 1
• Octreotide if unable to absorb oral medications, which can reduce output by 1-2 L/24 hours 1

DMF Administration Through Jejunostomy

DMF can be safely administered through jejunostomy tubes with the following considerations:

• The delayed-release capsules can be opened and the contents mixed with water for administration through the tube 2, 3
• Flush the tube with 30-50 mL water before and after medication administration to prevent clogging 1
• Administer DMF at the standard dose of 240 mg twice daily after the initial titration period 2, 3
• Separate DMF administration from enteral feeding by 1 hour if possible to optimize absorption 1

Monitoring for DMF-Specific Complications

Lymphopenia monitoring is critical in DMF-treated patients, particularly those with additional risk factors: 4

• Check absolute lymphocyte count (ALC) every 3 months during the first year, then every 6 months 4, 2
• Discontinue DMF if ALC remains <0.5 × 10⁹/L for >6 months due to progressive multifocal leukoencephalopathy (PML) risk 4
• Older age appears to increase PML risk, though cases have occurred in younger patients without severe lymphopenia 4
• Monitor for gastrointestinal side effects (flushing, diarrhea, nausea) which occur in 9% of patients and may complicate jejunostomy management 3

Neurological Disorder Considerations

For patients with multiple sclerosis requiring jejunostomy (due to dysphagia from bulbar involvement or other neurological complications): 1, 5

• Percutaneous endoscopic gastrostomy (PEG) is preferred over jejunostomy when gastric feeding is safe, as it has lower complication rates 1
• Jejunal feeding is specifically indicated when gastric emptying is delayed or when patients must be nursed flat 5
• The American Gastroenterological Association identifies MS as a primary indication for feeding tube placement when dysphagia is expected to persist >4-6 weeks 5

DMF Efficacy in Stable MS Patients

Do not discontinue DMF in clinically stable patients, as this exposes them to unnecessary disease reactivation risk: 6

• DMF reduces relapse rate by 39% and disability progression by 40% at 96 weeks 6
• The medication has demonstrated safety over ≥7.5 years of continuous treatment 6
• Switching therapies requires a washout period that risks breakthrough disease activity 6
• Adjusted annualized relapse rate declines by 90% with DMF treatment in real-world studies 3

Critical Pitfalls to Avoid

Do not allow the patient to drink large volumes of hypotonic fluids (water, tea, juice) as this paradoxically worsens dehydration by increasing stomal sodium losses. 1 The 500 mL/day limit on hypotonic fluids is non-negotiable.

Do not assume normal potassium supplementation will correct hypokalaemia - always address sodium depletion and hypomagnesemia first, as these are the underlying causes. 1

Do not delay intravenous rehydration if the patient shows signs of dehydration (rising creatinine, low urine output, postural hypotension) - initiate IV normal saline immediately while maintaining NPO status for 24-48 hours. 1

Do not continue DMF without regular lymphocyte monitoring - PML has occurred in DMF-treated patients, including some without severe lymphopenia, making surveillance essential. 4

Do not crush or open DMF capsules without flushing the tube adequately - the medication can cause tube obstruction if not properly administered with sufficient water. 1