Despite our best efforts to raise awareness, cases of toxic ingestion and dietary indiscretion remain common during the Christmas season. Deciding what and when to feed these patients as they recover is one of the key challenges, especially those who are showing very little interest in food. More severe cases will often receive intravenous fluid therapy, but clinics could also be benefitting from adopting early enteral nutrition as part of their routine protocol.
Feed, don’t fast, this festive season
Specific treatment advice – such as whether induction of vomiting is appropriate, use of medications and the need for IV fluids – depends on individual case presentation and varies by the toxin ingested. The Veterinary Poisons Information Service offers very useful support directly to member vet practices. In the past, classic dietary advice for any cases that lead to gastrointestinal (GI) symptoms was to fast for 24 to 72 hours until symptoms subsided. However, we now know that fasting can be very damaging to the integrity of the GI tract, adding to any negative effects of toxin ingestion.
This is partly due to atrophy of enterocytes, which occurs without sufficient levels of the correct microenteral nutrition to support their healthy functioning (Mohr et al., 2003). Enterocytes are simple, column-shaped epithelial cells that are continuously being replenished by the stem cells in the crypts of Lieberkühn at the base of the villi within the GI tract. The enterocytes have an absorptive function – taking up sugars, amino acids, water and electrolytes – as well as a defensive function by acting as a physical barrier. This barrier is achieved due to their tight adherence to neighbouring enterocytes. Thus, when atrophy occurs, there is increased risk of bacterial translocation.
Once a patient has been appropriately stabilised, and is no longer vomiting, enteral nutrition is recommended if it can be tolerated by the patient. Therapeutic diets have been designed to support patients during recovery from gastrointestinal symptoms. However, inappetence during recovery is common, especially during the first 24 hours.
Enteral nutrition for critical care
Isotonic solutions (such as Oralade®, Macahl Animal Health) are a useful option for encouraging initial uptake of enteral nutrition, as these will usually be low in fat, be easy to digest and contain the right balance of suitable amino acids, electrolytes and prebiotics. The absence of citrate also improves palatability and voluntary intake. A suggested critical care protocol is 0.5ml per kg every two hours, given by mouth or offered in a bowl for voluntary intake increasing by 50 percent every four to eight hours (Macahl Animal Health, 2020). This is in addition to access to fresh water and is also suitable as a post-operative protocol for patients following gastrointestinal surgery such as Christmas foreign body removal.
After the first 24 hours of recovery, an isotonic solution can then be offered alongside a therapeutic diet, and can be continued for two weeks. Another benefit of isotonic solutions is the increased fluid intake, which can be 70 percent more than patients offered solely water (Macahl Animal Health, 2020) This can help to reduce the reliance on intravenous fluids and studies have shown that electrolyte solutions can be effective at helping to correct mild to moderate cases of dehydration in dogs (Reineke et al., 2013). Longer term, in cases where toxin ingestion has led to ongoing compromised kidney function, these solutions can form part of a multimodal management approach, by helping to maintain levels of fluid intake.
Pancreatitis and poisonings
Some toxins are directly associated with acute pancreatitis, as of course are titbits from fatty Christmas meals. However, pancreatitis can also occur secondary to poison ingestion due to generalised inflammation of the GI tract. These cases pose additional dietary considerations and the need for low-fat options. A zero fat, isotonic formula for microenteral nutrition can work well in these patients. Research in people and veterinary patients has shown very positive findings in cases that receive early enteral nutrition, including improved return to appetite and decreased levels of gastrointestinal intolerance (Jensen and Chan, 2014; Harris et al., 2017).
