Refeeding syndrome

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Parenteral nutrition - the cornerstone of treatment for refeeeding syndrome
Cachexia in an Abyssinian associated with hyperthyroidism

Refeeding syndrome occurs secondary to reintroduction of nutrition to the chronically starved patient. Although severe weight loss (cachexia) is related to malnutrition, cachexia associated with malignant diseases differs from starvation cachexia in that it is more recalcitrant to nutritional therapy. All cachexia responds to judicious nutritional support; however, cancer cachexia worsens autonomously as the disease advances and cannot be arrested or reversed by any known form of nutrition, hormonal, or pharmacologic therapy. Cachexia must be treated cautiously to avoid overfeeding syndrome, which may result in serious or dangerous complications or death[1].

Refeeding syndrome usually presents as a constellation of metabolic challenges termed 'refeeding syndrome'. The consequences of this syndrome-principally hypophosphatemia-may be life threatening[2].

Refeeding syndrome is defined as the constellation of metabolic and physiologic derangements associated with caloric depletion of the starved feline patient[3]. Classically, refeeding syndrome is characterised by the development of severe hypophosphatemia following the introduction of enteral or parenteral nutrition. Refeeding syndromes in cats can also include hypokalemia, hypomagnesemia, vitamin deficiency, fluid intolerance and glucose intolerance[4]. In response to anabolism and heightened by the release of insulin, cellular uptake of phosphorus and inorganic phosphorus occurs, leading to hypophosphatemia. Phosphorus depletion leads to a reduction in erythrocyte ATP concentration, failure of actin and myosin, altered erythrocyte membrane lipids and consequently, hemolytic anaemia. Hypokalemia may provoke glucose intolerance, neuromuscular weakness, ileus, polyuria and polydipsia[5].

Cases in cats have been recorded secondary to hepatic lipidosis and following gastrointestinal disease in older cats such as is seen with inflammatory bowel disease, Giardia spp and lymphoma.

It is believed that refeeding syndrome is a consequence of the cat's inability to rapidly adapt from a chronically catabolic state to an anabolic state. Starvation can lead to villous atrophy and compromised absorptive capacity may lead to diarrhoea in some patients.

Treatment is based on nutritional replacement strategies. The notion of 'starting low and going slow' with the prescription of daily calories seems unlikely to be important in preventing refeeding syndrome. Recent publications suggest this approach does not necessarily add to safety in the refeeding process but rather the contrary. It typically results in weight loss and protracts hospitalization and nutritional recovery. Rather, the composition of macronutrients, in particular avoiding a high proportion of calories from carbohydrates, appears to be more important than the absolute number of calories[6].

A cat's resting energy requirements (RER) can be calculated by using a standard formulation:

RER (kcal) = 30 x body weight (kg) + 70[7]

References

  1. Palesty JA & Dudrick SJ (2011) Cachexia, malnutrition, the refeeding syndrome, and lessons from Goldilocks. Surg Clin North Am 91(3):653-673
  2. Ní Bhraonáin S & Lawton LD (2011) Chronic Malnutrition May In Fact Be an Acute emergency. J Emerg Med Jul 8
  3. Solomon, S & Kirby D (1990) The refeeding syndrome: a review. J Parenter Enteral Nutr 14:90-97
  4. Brenner K et al (2011) Refeeding syndrome in a cat with hepatic lipidosis. J Feline Med Surg 13(8):614-617
  5. Boateng, AA et al (2010) Refeeding syndrome; treatment considerations based on collective analysis of literature case reports. Nutrition 26:156-157
  6. Kohn MR et al (2011) Refeeding in anorexia nervosa: increased safety and efficiency through understanding the pathophysiology of protein calorie malnutrition. Curr Opin Pediatr 23(4):390-394
  7. Gross, KL et al (2010) Macronutrients. In: Hand, MS et al, eds. Small animal clinical nutrition. 5th edn. Topeka: Mark Morris Institute, pp:60-133