References
Canine insulinoma
Abstract
Hypoglycaemia is commonly seen in veterinary emergency rooms and may be caused by a multitude of disease processes. Patients with hypoglycaemia may display symptoms of weakness, ataxia and in severe cases, seizures. Hypoglycaemia is often described when serum blood glucose levels fall below 3.5 mmol/litre. The veterinarian must rule out potential causes of hypoglycaemia including sepsis, hepatic disease, hypoadrenocorticism, insulin overdose, cancer and toxin exposure. If the patient is sub-clinical it is important to rule out a lab or sampling error and consider the possibility of an insulinoma. Although rare in canines, the triage nurse should be familiar with the complications that can arise when treating these patients. This article will discuss the aetiology and physiology of a disease that may be overlooked in a busy emergency room.
Insulinoma is often described as a tumour of the pancreatic cells in the islets of Langerhans. It is best defined by the over production of insulin. The most common canine islet cell tumour affects the insulin-secreting beta cell. These beta cells comprise almost 70% of the cells located in the islets of Langerhans (Hess, 2010). Beta cells are primarily stimulated by an increase in circulating glucose, triggering the release of insulin. The islets of Langerhans also contain hormone producing alpha and delta cells. During times of hypoglycaemia the alpha cells release the hormone glucagon to antagonise or stop the release of insulin.
Although rare, insulinomas are most commonly seen in canine companions and rarely in felines. Signalment is not specific to a breed or gender, but has been mostly reported in older, medium to large breed canines (Hess, 2010). In contrast insulinoma is the most common neoplasm seen in pet ferrets (Pilney and Chen, 2004). Interestingly, 90% of insulinomas found in the human population are benign, but canine insulinoma has been shown to be predominately malignant (Fossum, 2002). A review of three studies compiling 179 dogs revealed a 45–64% rate of metastasis in canines with insulin secreting tumours. Metastasis was typically seen within the lymph nodes and liver, although there have been reports of metastasis to other organ systems (Hess, 2010).
Register now to continue reading
Thank you for visiting The Veterinary Nurse and reading some of our peer-reviewed content for veterinary professionals. To continue reading this article, please register today.