Nutritional Management: Refeeding Syndrome

Refeeding Syndrome

During starvation, mineral deficiencies cause phosphate, magnesium, calcium, and potassium to move out of cells and into plasma.
When refeeding begins, increased insulin levels lead to increased mineral and ion uptake into cells, causing dangerously low plasma concentrations of these ions.
This can result in hypophosphatemia, hypomagnesemia, hypokalemia, hyponatremia, and hypocalcemia.
Symptoms include congestive heart failure, cardiac dysrhythmias, muscle weakness, and death.
Prevention involves slowly initiating refeeding at approximately 20 kcal/kg/day for the first few days and closely monitoring plasma levels of phosphate, potassium, magnesium, and calcium.

Enteral Nutrition

Nutrition administration via the physiological pathway (mouth to stomach).
Simpler and cheaper than parenteral nutrition.
Usually involves tubes or stomas directing food to different parts of the gastrointestinal tract.
Used for:
- Severe dysphagia (e.g., head injury, stroke, motor neuron disease)
- Major, full-thickness burns
- Postoperative period when oral intake is limited
- Massive small bowel resection, in combination with parenteral nutrition
- Low-output enterocutaneous fistulae

Parenteral Nutrition

Supplying nutrients intravenously.
Used when enteral nutrition is not tolerated or efficient, or is contraindicated.
Disadvantage: Can lead to intestinal atrophy with decreased mucosal enzymes and disturbance of the mucous barrier.

Malnutrition Determination

Body mass index (BMI) below 18.5 kg/m²
Unintentional weight loss greater than 10% within 3-6 months
BMI less than 20 kg/m² and unintentional weight loss greater than 5% within 3-6 months

Malnutrition Indications

Malnutrition
Digestive disturbances
Malabsorption
Mental anorexia
Organic anorexia
Intestinal fistulae
Gastrointestinal stenosis
Ileus
Gastrointestinal operations
Ulcerative colitis
Multiple injuries
Head injuries
Fire injuries
Peritonitis
Sepsis
Renal failure
Liver failure
Pancreatitis
Crohn's disease

Parenteral Nutrition Administration

Peripheral veins: Short-term or middle-term parenteral nutrition.
Central vein:
- Long-lasting parenteral nutrition
- Intensive care: Parenteral nutrition plus electrolytic solutions
- Low capacity of peripheral veins
- When a functional cannula in the periphery cannot be guaranteed

Lipoprotein Metabolism Disorders

Dyslipidemia: Hyperlipoproteinemia (primary and secondary), hypolipoproteinemia, lipidosis.
Different types of lipoproteins have varying proportions of proteins, cholesterol, triglycerides, and phospholipids.

Protein Deficiency Effects

Liver: Reduced hepatic synthesis of serum proteins, leading to lowered serum protein levels, decreased immune cells, poor wound healing, and an inability to fight infections.
Gastrointestinal tract: Mucosal atrophy, loss of villi in the small intestine, leading to malabsorption.
Heart: Reduced myocardial contractility and cardiac output.
Respiration: Weakening of breathing muscles, compromising respiratory function as muscle proteins are used as fuel.

Malnutrition Indicators

Body mass index (BMI)
Bioelectric Impedance Analysis (BIA)

Anorexia Nervosa

Eating disorder characterized by determined dieting, often accompanied by compulsive exercise/vomiting and other purging behaviors, resulting in sustained low weight.
Usually begins in teenagers.
Causes are multifactorial, including genetic influence, personality traits (perfectionism), anxiety disorders, family history of depression and obesity.
Two types:
- Restricting: Eating small amounts of food.
- Binge/Purge: Eating large amounts and then vomiting.
Difference with bulimia: In anorexia nervosa, body weight is below normal, while in bulimia it can be normal.
Diagnostic criteria for anorexia nervosa:
- Body weight usually less than 85% of normal body weight.
- Refusal to maintain a minimal normal body weight for age and height.
- Intense fear of gaining weight or becoming fat.

Marasmus vs. Kwashiorkor

Marasmus:
- Severe deficiency of all nutrients (protein and calories).
- Etiology: Insufficient food intake, gastrointestinal disturbances, and malabsorption.
- Pathogenesis: Progressive loss of skeletal muscle and subcutaneous fat. Visceral protein is not depleted, serum albumin is normal or slightly decreased. Immune function is impaired, increasing the risk of infection.
- Symptoms: Underweight (BMI < 18), severe muscle wasting, dry and dull hair, wrinkled skin, diarrhea, cachexia, anorexia, extreme apathy, cold extremities, reduced cardiac output, tachycardia, anemia.
Kwashiorkor: (most common in hospitals)
- Severe protein deficiency with a high carbohydrate diet.
- Etiology: Transition from breast milk to solid food, usually lacking protein.
- Pathogenesis: Severe protein deficiency leads to hypoalbuminemia (loss of visceral protein), decreased oncotic pressure, and increased transudation, resulting in generalized edema. Lack of immune mediators due to protein deficiency.
- Symptoms: Ascites (very distended abdomen), large head compared to body, fatty liver due to insufficient apolipoprotein to transport fat, muscle wasting, discolored hair, desquamating skin, physical and mental retardation, growth retardation/failure.
The pathologic changes for both marasmus and kwashiorkor include humoral and cellular immunodeficiencies resulting from protein deficiencies and a lack of immune mediators.
Impaired synthesis of hair and skin pigments (hair color may change and the skin may become hyperpigmented) due to a lack of substrate (tyrosine) and coenzyme.

Stress Starvation (Secondary Malnutrition)

Protein-energy malnutrition most often occurs secondary to trauma or illness in industrialized societies.
Kwashiorkor-like protein malnutrition is most common in association with hypermetabolic acute illnesses, such as trauma, burns, and sepsis.
Marasmus-like secondary protein-energy malnutrition typically results from chronic illnesses such as chronic obstructive pulmonary disease (COPD), congestive heart failure, cancer, and HIV infection.
Net protein breakdown is accelerated and protein rebuilding is disrupted in individuals with severe injury or illness.