Refeeding Syndrome

Epidemiology

  • History
    • Refeeding was First Observed Following the Refeeding of WWII Prisoners

High-Risk Groups for Refeeding Syndrome

  • Anorexia Nervosa (see Anorexia Nervosa, [[Anorexia Nervosa]])
  • Chemotherapy Patients
  • Homeless/Alcoholic Patients Who Have Not Eaten for Many Days
  • Malnourished Elderly Patients
  • Specific Post-Operative Patients
  • Any Other Patient Who Has Not Received Significant Nutrition for >5 Days

Physiology

  • Carbohydrate Load Administered Orally (Oral Intake or Enteral Nutrition)/Intravenously (TPN) Following a Period of Starvation
    • During Starvation, Phosphate Stores are Depleted
    • With Refeeding
      • Insulin Secretion with Intracellular Shift of Phosphate, Magnesium, and Potassium
      • Insulin Secretion Leads to Renal Sodium Reabsorption and Retention, Followed by Fluid Retention
      • Enhanced Metabolism of Ketoacids Back to Bicarbonate

Diagnosis

  • xxx

Clinical Manifestations

General Comments

  • Most Fatalities are Due to Cardiac Complications

Cardiovascular Manifestations

  • Arrhythmias
    • Epidemiology: most common cause of death in refeeding syndrome
    • Clinical
      • Torsade (see Torsade, [[Torsade]]): may occur (due to hypomagnesemia)
  • Congestive Heart Failure (CHF) (see Congestive Heart Failure, [[Congestive Heart Failure]])
    • Physiologic Mechanisms
      • Impaired Myocardial Contractility: due to starvation-associated myocardial atrophy, hypophosphatemia, and thiamine deficiency
      • Sodium and Fluid Retention
  • Hypertension (see Hypertension, [[Hypertension]])
    • Epidemiology: may occur
  • Hypotension (see Hypotension, [[Hypotension]])
    • Epidemiology: may occur

Gastrointestinal/Hepatic Manifestations

  • Diarrhea (see Diarrhea, [[Diarrhea]])
    • Physiology: due to atrophy of intestinal mucosa and pancreatic impairment which occur during starvation
    • Treatment
      • May Require Decreasing the Rate of Nutritional Supplementation, Less Complex Carbohydrates, or Elemental Diet
      • Generally Resolves within Weeks
  • Elevated Liver Function Tests (LFT’s) (see xxxx, [[xxxx]])
    • Epidemiology: may occur during the first few weeks of refeeding
    • Physiology: due to excessive calories, fat deposition, or cell death-apoptosis from malnutrition
    • Clinical: mildly elevated
  • Hepatic Steatosis (Fatty Liver) (see Hepatic Steatosis, [[Hepatic Steatosis]])
  • Nausea/Vomiting (see Nausea and Vomiting, [[Nausea and Vomiting]])
    • Treatment: may require decreasing the rate of nutritional supplementation

Neurologic Manifestations

  • Central Pontine Myelinolysis (see Central Pontine Myelinolysis, [[Central Pontine Myelinolysis]])
    • Epidemiology: has been reported in refeeding syndrome associated with anorexia nervosa
  • Coma (see Obtundation-Coma, [[Obtundation-Coma]])
  • Delirium (see Delirium, [[Delirium]])
    • Physiology: due to electrolyte abnormalities
  • Exacerbation of Thiamine Deficiency (see Thiamine, [[Thiamine]])
    • Physiology: thiamine deficiency occurs during starvation, refeeding may exacerbate this deficiency
    • Clinical
      • Wernicke’s Encephalopathy (Encephalopathy, Oculomotor Dysfunction, and Ataxia): may occur
  • Parasthesias (see Parasthesias, [[Parasthesias]])
    • Physiology: due to electrolyte abnormalities
  • Seizures (see Seizures, [[Seizures]])
    • Physiology: due to electrolyte abnormalities
  • Weakness
    • Physiology: impaired muscular contractility (due to hypophosphatemia)
  • Tetany (see Tetany, [[Tetany]])
    • Physiology: due to hypophosphatemia

Pulmonary Manifestations

  • Respiratory Failure (see Respiratory Failure, [[Respiratory Failure]])
    • Epidemiology: rare
    • Physiology: impaired diaphragmatic contractility (due to atrophy and/or hypophosphatemia)

Renal Manifestations

  • Hypokalemia (see Hypokalemia, [[Hypokalemia]])
    • Physiology: glucose induces insulin release, resulting in intracellular shift of magnesium, phosphate, and potassium
  • Hypomagnesemia (see Hypomagnesemia, [[Hypomagnesemia]])
    • Physiology: glucose induces insulin release, resulting in intracellular shift of magnesium, phosphate, and potassium
  • Hypophosphatemia (see Hypophosphatemia, [[Hypophosphatemia]])
    • Physiology: hallmark and predominant cause of many of the clinical manifestations of the refeeding syndrome
      • Glucose induces insulin release, resulting in intracellular shift of magnesium, phosphate, and potassium
  • Metabolic Alkalosis (see Metabolic Alkalosis, [[Metabolic Alkalosis]])
    • Physiology: due to enhanced metabolism of ketoacids back to bicarbonate

Rheumatologic/Orthopedic Manifestations

  • Myalgias (see Myalgias, [[Myalgias]])
    • Physiology: due to hypophosphatemia
  • Peripheral Edema (see Peripheral Edema, [[Peripheral Edema]])
  • Rhabdomyolysis (see Rhabdomyolysis, [[Rhabdomyolysis]])
    • Epidemiology: may occur
    • Physiology: due to hypophosphatemia

Treatment

  • Decrease in the Rate of Initial Nutritional Support: as required
  • Correction of Electrolyte Abnormalities: in general, any pre-existing electrolyte abnormalities should be corrected prior to starting feeding

References

  • Refeeding syndrome: what it is, and how to prevent and treat it. BMJ. 2008;336(7659):1495 [MEDLINE]
  • Refeeding syndrome. Pediatr Clin North Am. 2009;56(5):1201 [MEDLINE]
  • Refeeding syndrome: treatment considerations based on collective analysis of literature case reports. Nutrition. 2010;26(2):156 [MEDLINE]
  • Refeeding hypophosphatemia in adolescents with anorexia nervosa: a systematic review. Nutr Clin Pract. 2013 Jun;28(3):358-64. Epub 2013 Mar 4 [MEDLINE]