Refeeding syndrome Refeeding syndrome A condition of metabolic imbalance that is caused by complications of initially feeding a severely malnourished patient too aggressively. Usually occurring within the first 5 days of refeeding, this syndrome is characterized by water-electrolyte imbalance; glucose intolerance; cardiac arrhythmias; and diarrhea. Failure to Thrive (RFS) is a life-threatening complication marked by electrolyte and fluid shifts in malnourished patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship after reintroduction of nutrition. The hallmark is hypophosphatemia Hypophosphatemia A condition of an abnormally low level of phosphates in the blood. Bartter Syndrome, often with hypokalemia Hypokalemia Hypokalemia is defined as plasma potassium (K+) concentration < 3.5 mEq/L. Homeostatic mechanisms maintain plasma concentration between 3.5-5.2 mEq/L despite marked variation in dietary intake. Hypokalemia can be due to renal losses, GI losses, transcellular shifts, or poor dietary intake. Hypokalemia, hypomagnesemia Hypomagnesemia A nutritional condition produced by a deficiency of magnesium in the diet, characterized by anorexia, nausea, vomiting, lethargy, and weakness. Symptoms are paresthesias, muscle cramps, irritability, decreased attention span, and mental confusion, possibly requiring months to appear. Deficiency of body magnesium can exist even when serum values are normal. In addition, magnesium deficiency may be organ-selective, since certain tissues become deficient before others. Electrolytes, thiamine Thiamine Also known as thiamine or thiamin, it is a vitamin C12H17N4OSCl of the vitamin B complex that is essential to normal metabolism and nerve function and is widespread in plants and animals Water-soluble Vitamins and their Deficiencies deficiency, and fluid overload. RFS affects multiple organ systems and occurs with oral, enteral, or parenteral feeding. Early risk identification Identification Defense Mechanisms, careful monitoring, electrolyte correction, thiamine Thiamine Also known as thiamine or thiamin, it is a vitamin C12H17N4OSCl of the vitamin B complex that is essential to normal metabolism and nerve function and is widespread in plants and animals Water-soluble Vitamins and their Deficiencies supplementation, and gradual nutritional reintroduction are essential for prevention and management.
Last updated: Oct 10, 2025
The pathophysiology of RFS is best understood as a two-stage process involving the body’s adaptation to starvation and the subsequent abrupt metabolic shift during refeeding.
Identifying patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship at risk before initiating nutritional support is the most critical step in preventing RFS. The American Society for Parenteral and Enteral Nutrition Enteral nutrition Nutritional support given via the alimentary canal or any route connected to the gastrointestinal system (i.e., the enteral route). This includes oral feeding, sip feeding, and tube feeding using nasogastric, gastrostomy, and jejunostomy tubes. Short Bowel Syndrome (ASPEN) has developed a consensus criteria that is used to stratify risk for adult and pediatric patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship.
| Table: ASPEN Consensus Criteria for Adults – Refeeding Syndrome Refeeding syndrome A condition of metabolic imbalance that is caused by complications of initially feeding a severely malnourished patient too aggressively. Usually occurring within the first 5 days of refeeding, this syndrome is characterized by water-electrolyte imbalance; glucose intolerance; cardiac arrhythmias; and diarrhea. Failure to Thrive Risk | ||
| Risk Criteria | Moderate Risk (2 Criteria Needed) | Significant Risk (1 Criterion Needed) |
| BMI BMI An indicator of body density as determined by the relationship of body weight to body height. Bmi=weight (kg)/height squared (m2). Bmi correlates with body fat (adipose tissue). Their relationship varies with age and gender. For adults, bmi falls into these categories: below 18. 5 (underweight); 18. 5-24. 9 (normal); 25. 0-29. 9 (overweight); 30. 0 and above (obese). Obesity | <18.5 kg/m² | <16 kg/m² |
| Weight Loss Weight loss Decrease in existing body weight. Bariatric Surgery | 5% in 1 month | 7.5% in 3 months or >10% in 6 months |
| Caloric Intake | None or negligible oral intake for 5–6 days or <75% of estimated energy requirement for >1 month or <75% for >7 days during acute illness |
None or negligible oral intake for >7 days or <50% of estimated energy requirement for >1 month or <50% for >5 days during acute illness |
| Abnormal Prefeeding
Electrolytes
Electrolytes
Electrolytes are mineral salts that dissolve in water and dissociate into charged particles called ions, which can be either be positively (cations) or negatively (anions) charged. Electrolytes are distributed in the extracellular and intracellular compartments in different concentrations. Electrolytes are essential for various basic life-sustaining functions.
Electrolytes ( Potassium Potassium An element in the alkali group of metals with an atomic symbol k, atomic number 19, and atomic weight 39. 10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the water-electrolyte balance. Hyperkalemia, Phosphorus, Magnesium Magnesium A metallic element that has the atomic symbol mg, atomic number 12, and atomic weight 24. 31. It is important for the activity of many enzymes, especially those involved in oxidative phosphorylation. Electrolytes) |
Minimally low levels or normal levels with recent lows requiring minimal/single-dose supplementation | Moderately or significantly low levels or normal/minimally low levels with recent lows requiring significant/multiple-dose supplementation |
| Loss of Subcutaneous Fat Subcutaneous fat Fatty tissue under the skin throughout the body. Erythema Nodosum | Moderate loss | Severe loss |
| Loss of Muscle Mass Mass Three-dimensional lesion that occupies a space within the breast Imaging of the Breast | Mild or moderate loss | Severe loss |
| Higher-Risk Comorbidities Comorbidities The presence of co-existing or additional diseases with reference to an initial diagnosis or with reference to the index condition that is the subject of study. Comorbidity may affect the ability of affected individuals to function and also their survival; it may be used as a prognostic indicator for length of hospital stay, cost factors, and outcome or survival. St. Louis Encephalitis Virus | Moderate disease | Severe disease |
| Table: ASPEN Consensus Criteria for Children – Refeeding Syndrome Refeeding syndrome A condition of metabolic imbalance that is caused by complications of initially feeding a severely malnourished patient too aggressively. Usually occurring within the first 5 days of refeeding, this syndrome is characterized by water-electrolyte imbalance; glucose intolerance; cardiac arrhythmias; and diarrhea. Failure to Thrive Risk | |||
| Risk Criteria | Mild Risk (3 Categories Needed) | Moderate Risk (2 Categories Needed) | Significant Risk (1 Category Needed) |
| Weight-for-length
z-score
Z-score
Standard deviation difference between patient’s bone mass density and that of age-matched population.
Osteoporosis (1–24 months) or BMI-for-age z-score Z-score Standard deviation difference between patient’s bone mass density and that of age-matched population. Osteoporosis (2–20 years) |
−1 to −1.9 z-score Z-score Standard deviation difference between patient’s bone mass density and that of age-matched population. Osteoporosis that is a change from baseline | −2 to −2.9 z-score Z-score Standard deviation difference between patient’s bone mass density and that of age-matched population. Osteoporosis that is a change from baseline | −3 z-score Z-score Standard deviation difference between patient’s bone mass density and that of age-matched population. Osteoporosis or greater that is a change from baseline |
| Weight loss Weight loss Decrease in existing body weight. Bariatric Surgery | <75% of norm for expected weight gain | <50% of norm for expected weight gain | <25% of norm for expected weight gain |
| Energy Intake Energy intake Total number of calories taken in daily whether ingested or by parenteral routes. Energy Homeostasis | 3–5 consecutive days of protein or energy intake Energy intake Total number of calories taken in daily whether ingested or by parenteral routes. Energy Homeostasis <75% of estimated need |
5–7 consecutive days of protein or energy intake Energy intake Total number of calories taken in daily whether ingested or by parenteral routes. Energy Homeostasis <75% of estimated need |
>7 consecutive days of protein or energy intake Energy intake Total number of calories taken in daily whether ingested or by parenteral routes. Energy Homeostasis <75% of estimated need |
| Abnormal prefeeding
potassium
Potassium
An element in the alkali group of metals with an atomic symbol k, atomic number 19, and atomic weight 39. 10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the water-electrolyte balance.
Hyperkalemia, phosphorus, or magnesium Magnesium A metallic element that has the atomic symbol mg, atomic number 12, and atomic weight 24. 31. It is important for the activity of many enzymes, especially those involved in oxidative phosphorylation. Electrolytes serum concentrations |
Mildly abnormal or decreased to 25% below lower limit Limit A value (e.g., pressure or time) that should not be exceeded and which is specified by the operator to protect the lung Invasive Mechanical Ventilation of normal | Moderately/significantly abnormal or down to 25%–50% below lower limit Limit A value (e.g., pressure or time) that should not be exceeded and which is specified by the operator to protect the lung Invasive Mechanical Ventilation of normal |
Moderately/significantly abnormal or down to 25%–50% below lower limit Limit A value (e.g., pressure or time) that should not be exceeded and which is specified by the operator to protect the lung Invasive Mechanical Ventilation of normal |
| Loss of subcutaneous fat Subcutaneous fat Fatty tissue under the skin throughout the body. Erythema Nodosum | Evidence of mild loss or Mid-upper arm Arm The arm, or “upper arm” in common usage, is the region of the upper limb that extends from the shoulder to the elbow joint and connects inferiorly to the forearm through the cubital fossa. It is divided into 2 fascial compartments (anterior and posterior). Arm: Anatomy circumference z-score Z-score Standard deviation difference between patient’s bone mass density and that of age-matched population. Osteoporosis of −1 to −1.9 |
Evidence of moderate loss or Mid-upper arm Arm The arm, or “upper arm” in common usage, is the region of the upper limb that extends from the shoulder to the elbow joint and connects inferiorly to the forearm through the cubital fossa. It is divided into 2 fascial compartments (anterior and posterior). Arm: Anatomy circumference z-score Z-score Standard deviation difference between patient’s bone mass density and that of age-matched population. Osteoporosis of −2 to −2.9 |
Evidence of severe loss or Mid-upper arm Arm The arm, or “upper arm” in common usage, is the region of the upper limb that extends from the shoulder to the elbow joint and connects inferiorly to the forearm through the cubital fossa. It is divided into 2 fascial compartments (anterior and posterior). Arm: Anatomy circumference z-score Z-score Standard deviation difference between patient’s bone mass density and that of age-matched population. Osteoporosis of −3 or greater |
| Loss of muscle mass Mass Three-dimensional lesion that occupies a space within the breast Imaging of the Breast | — | Evidence of mild or moderate loss or Mid-upper arm Arm The arm, or “upper arm” in common usage, is the region of the upper limb that extends from the shoulder to the elbow joint and connects inferiorly to the forearm through the cubital fossa. It is divided into 2 fascial compartments (anterior and posterior). Arm: Anatomy circumference z-score Z-score Standard deviation difference between patient’s bone mass density and that of age-matched population. Osteoporosis of −2 to −2.9 |
Evidence of severe loss or Mid-upper arm Arm The arm, or “upper arm” in common usage, is the region of the upper limb that extends from the shoulder to the elbow joint and connects inferiorly to the forearm through the cubital fossa. It is divided into 2 fascial compartments (anterior and posterior). Arm: Anatomy circumference z-score Z-score Standard deviation difference between patient’s bone mass density and that of age-matched population. Osteoporosis of −3 or greater |
| Higher-risk comorbidities Comorbidities The presence of co-existing or additional diseases with reference to an initial diagnosis or with reference to the index condition that is the subject of study. Comorbidity may affect the ability of affected individuals to function and also their survival; it may be used as a prognostic indicator for length of hospital stay, cost factors, and outcome or survival. St. Louis Encephalitis Virus | Mild disease | Moderate disease | Severe disease |
The clinical manifestations of RFS are diverse and reflect the systemic effects of electrolyte depletion and fluid shifts. Symptoms typically appear within the first 5 days of refeeding.
The management of RFS is centered on prevention through careful and methodical nutritional rehabilitation.
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