QUARTERLY BEAT / JULY 2025
VARIABILITY OF NEUROLOGIC SIGNS Now, you may wonder “Why do some dogs wag their tail with a blood glucose (BG) of 40 mg/dL (2.2 mmol/L) and others develop seizures?” The degree of neurologic impairment does not directly correlate with a specific blood glucose level. Individual responses will vary due to the following:
• magnitude of BG change • speed of BG change • duration of hypoglycemia
With gradual or mild BG changes, as seen in episodic hypoglycemia, clinical signs tend be subtle behavioral changes (e.g. confusion, weakness) and often resolve as BG normalized. These dogs may present with normal or low-normal BG, but more commonly, they will be hypoglycemic, which can be confirmed by running a quick BG on your handheld glucometer or in-house analyzer.
Image courtesy of Dr. Heidi Fay
This test is performed during periods of hypoglycemia and BEFORE administration of dextrose supplementation. What that means to you?
REMINDER Anemia falsely elevates BG on handheld glucometers (e.g., Alphatrak)!
REMEMBER Fill that extra red top tube BEFORE giving a dextrose bolus or starting a dextrose CRI!
On the other end of this spectrum, rapid, severe or persistent drops in BG can lead to more serious neurologic issues like tremors or seizures. HOW DO WE DIAGNOSE INSULINOMAS IN DOGS? First, we have to make sure we keep this differential on our radar for any dog presenting with subtle or episodic behavior changes. For emergency doctors, we might more commonly see these patients for seizures - so be sure to keep a glucometer handy when triaging those seizure patients!
Gold standard imaging for insulinomas is a contrast-enhanced CT scan to localize the tumor, check for metastasis, and help assign a TNM stage (TNM stands for tumor, node, and metastasis). Abdominal ultrasound may be more easily accessible and affordable, but is less reliable, identifying only about 1/3 of insulinomas. Ultrasound is still recommended for obtaining FNAs or biopsies of hepatic lesions or abdominal LN enlargements from local spread of insulinomas. Remember to also get a 3-view met check of the chest.
ARE INSULINOMAS TREATABLE? Ideally, complete removal with surgery (e.g., enucleation, partial
Next, we investigate whether the patient fulfills Whipple’s triad:
1. Hypoglycemia 2. Exhibits clinical signs related to hypoglycemia
pancreatectomy) is recommended and has been shown to prolong life expectancy by a few years. However, at the time of diagnosis, metastasis is present in about ½ of cases, resulting in a reduction in life expectancy even if the primary tumor is surgically removed. Medical management involves maintaining adequate glucose levels through medications, feeding adjustments, and exercise restriction. Diazoxide and glucocorticoids (i.e. prednisolone) are the primary medications used to reduce the frequency and severity of hypoglycemia. Diazoxide is a benzothiadiazine approved by the FDA for treatment of hyperinsulinism in people. It raises blood glucose levels by binding to the ATP-sensitive potassium (KATP) channels on pancreatic beta cells, causing excessive polarization, preventing their ability to release insulin. Additionally, diazoxide enhances hepatic glucose production while reducing hepatic glucose uptake. Side effects of diazoxide are not commonly seen in dogs, but may include anorexia, vomiting, and ptyalism. Glucocorticoids such as prednisone and
3. Demonstrates resolution of these clinical signs upon restoration of blood glucose levels (usually through IV dextrose or feeding)
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