Rebecca Egan, Margaret Stalker, Murray Hazlett

Animal Health Laboratory, University of Guelph, Guelph, ON

AHL Newsletter 2021;25(1):20.

Hepatic lipidosis/microvesicular degeneration is seen in puppies in the AHL caseload, and small and toy breed dogs are over-represented (Table 1).  Primary hypoglycemia in neonatal and juvenile small and toy breed puppies is a recognized syndrome, and a connection between anorexia, fasting hypoglycemia and fatty liver syndrome has been suggested.  The inciting cause can be difficult to determine, but stressful events including chilling, malnutrition, dehydration, internal parasitism, illness, injury, weaning, and re-homing are some of the recognized triggers.  Neonatal and juvenile toy and small breed puppies have relatively high metabolic needs and are at increased risk of developing hypoglycemia because of their propensity for rapid depletion of blood glucose in combination with their lower muscle mass and glycogen reserves.  These puppies therefore rely more heavily on fat mobilization in the face of hypoglycemia, which can lead to substantial microvesicular hepatic lipidosis (Fig. 1). AHL

Table 1.  Hepatic lipidosis diagnoses in toy/small breed puppies under 6 months of age, AHL 2007-2021.

Figure 1. A. Hepatic lipidosis (arrow) in a toy breed dog.  The liver is tan, greasy, and will often float in water or formalin.  B and C are histologic sections showing hepatocellular microvesicular lipidosis. (H&E)

References
1. Van der Linde-Sipman JS, Ingh TVD, Van Toor AJ. Fatty liver syndrome in puppies. JAAHA 1990;26(1):9-12.
2. Bartner  L. Hepatic Lipidosis in Toy Breed Dogs. Quarterly Newsletter from the Animal Disease Diagnostic Laboratory Purdue University. 2008; 18 (1).
3. Idowu O, Heading K. Hypoglycemia in dogs: Causes, management, and diagnosis. Can Vet J 2018;59(6):642-649.