An insulinoma causing hypoglycaemia and seizures in a dog: case report and literature review

A nine-year-old mixed breed dog was presented with a history of mild generalized seizures, weakness, and muscle fasciculations, following periods of excitement and exercise. Investigative procedures included haematology, chemical pathology, faecal analysis, urinalysis, cerebrospinal fluid analysis, hormone assays, computerized axial tomography and scintigraphic imaging. Results of these investigations revealed hypoglycaemia (blood glucose 1.9 mmol l-1, hyperinsulinism (111 muu ml-1) and an amended insulin-glucose ratio of 2643. The glucagon tolerance test was typical for an insulin producing pancreatic islet cell tumour and pancreas scintigraphic imaging revealed focal lesions in the pancreas and liver. Seizures were initially controlled by dietary means and by limiting exercise. Eventual control was obtained by treatment with prednisolone (1 mg kg-1 on alternate days) and diazoxide (10 mg kg-1 in divided doses daily). Post mortem examination confirmed the presence of a pancreatic islet cell adenocarcinoma with hepatic metastasis.