Spinal Muscular Atrophy: Fluids and Hydration

Patients with Spinal Muscular Atrophy (SMA) have nutritional needs that vary depending on their ages, the severity of their weakness (non-sitter versus sitter), and the acuity of their situation.1 

Chronic Hydration Needs

SMA is associated with dysphagia and gastric dysmotility, and the most severe forms of SMA will necessitate gastrostomy tube placement because oral feeding is unsafe due to aspiration risk.2,3 A consortium of SMA experts recommends that patients with SMA undergo regular, at least annual, assessments of their dietary needs.1 A comprehensive diet evaluation will assess fluid intake and perform nutrition labs to ascertain if electrolyte imbalances are present with patients’ current fluid regimen.1 There are no published evaluations of particular formula or fluid regimens with particular benefit in SMA.4 Experts advise an individualized approach to fluid management in patients with SMA.5 Sitters or more mobile patients will have more dynamic fluid needs than less mobile or non-sitter status patients.1

Acute (Sick) Needs

Because of their baseline illness, patients with SMA are at risk of dehydration during periods of acute illness because increased metabolic expenditures due to illness will commensurately increase insensible fluid losses, especially in debilitated non-sitter patients.6 Electrolyte monitoring and repletion should be appropriately aggressive in all patients with SMA.1 Practitioners should consider administering standard age appropriate fluids with carbohydrate (dextrose) intravenously to acutely ill or hospitalized patients with SMA to avoid prolonged fasting which may induce ketoacidosis.7 Subcutaneous fluids can be used if intravenous access is problematic.8 Careful fluid management of ill patients with SMA, especially medically fragile patients with new respiratory needs, can achieve good outcomes.9  

End-of-Life Needs

SMA can be a fatal disease, and future palliative care needs should be considered from diagnosis to maximize quality of life.10 The provision of fluids is a consideration in end-of-life care and as can be done in a humane way to minimize patient and observer distress.11,12


1. Mercuri E, Finkel RS, Muntoni F, et al. Diagnosis and management of spinal muscular atrophy: Part 1: Recommendations for diagnosis, rehabilitation, orthopedic and nutritional care. Neuromuscular disorders : NMD. 2018;28(2):103-115.

2. Birnkrant DJ, Pope JF, Martin JE, Repucci AH, Eiben RM. Treatment of type i spinal muscular atrophy with noninvasive ventilation and gastrostomy feeding. Pediatr Neurol. 1998;18(5):407-410.

3. Durkin ET, Schroth MK, Helin M, Shaaban AF. Early laparoscopic fundoplication and gastrostomy in infants with spinal muscular atrophy type i. J Pediatr Surg. 2008;43(11):2031-2037.

4. Moore GE, Lindenmayer AW, McConchie GA, Ryan MM, Davidson ZE. Describing nutrition in spinal muscular atrophy: A systematic review. Neuromuscular disorders : NMD. 2016;26(7):395-404.

5. Martinez EE, Quinn N, Arouchon K, et al. Comprehensive nutritional and metabolic assessment in patients with spinal muscular atrophy: Opportunity for an individualized approach. Neuromuscular disorders : NMD. 2018;28(6):512-519.

6. Finkel RS, Mercuri E, Meyer OH, et al. Diagnosis and management of spinal muscular atrophy: Part 2: Pulmonary and acute care; medications, supplements and immunizations; other organ systems; and ethics. Neuromuscular disorders : NMD. 2018;28(3):197-207.

7. Mulroy E, Gleeson S, Furlong MJ. Stress-induced ketoacidosis in spinal muscular atrophy: An under-recognized complication. J Neuromuscul Dis. 2016;3(3):419-423.

8. Caccialanza R, Constans T, Cotogni P, Zaloga GP, Pontes-Arruda A. Subcutaneous infusion of fluids for hydration or nutrition: A review. JPEN Journal of parenteral and enteral nutrition. 2018;42(2):296-307.

9. Wampole A, Schroth M, Boriosi J. Survival of a child with spinal muscular atrophy and acute respiratory distress syndrome. Pediatric pulmonology. 2015;50(8):E29-31.

10. de Visser M, Oliver DJ. Palliative care in neuromuscular diseases. Current opinion in neurology. 2017;30(6):686-691.

11. Del Rio MI, Shand B, Bonati P, et al. Hydration and nutrition at the end of life: A systematic review of emotional impact, perceptions, and decision-making among patients, family, and health care staff. Psycho-oncology. 2012;21(9):913-921.

12. Dev R, Dalal S, Bruera E. Is there a role for parenteral nutrition or hydration at the end of life? Current opinion in supportive and palliative care. 2012;6(3):365-370.