Hypoglycemic Disorders

Question 1

What can cause artefactual BG readings?

Answer 1

BG may be lowered if the sample sits before being spun
BG lowered by very high white cell or red cell mass
Hand-held glucometers are less reliable if red cell count is out of reference range

Question 2

What are the two mechanisms for hypoglycemia?

Answer 2

Decreased glucose production and excessive glucose utilization

Question 3

What can cause decreased glucose production?

Answer 3

Puppies
Prolonged starvation
Impaired hepatic gluconeogenesis
Decreased glucose counter-regulatory hormones (cortisol deficiency)
Sepsis

Question 4

What can cause excessive glucose utilization?

Answer 4

Insulinoma
Hepatocellular carcinoma/hepatoma
Hemangiosarcoma
Leiomyosarcoma
Insulin overdose
Xylitol ingestion
Sepsis

Question 5

What clinical signs would you see in a hypoglycemic patient?

Answer 5

Chronic hypoglycemia is well tolerated
Weakness, tremors, collapse
Depressed neurologic status
Seizures

Question 6

If the cause is not obvious, what other further testing can you do for hypoglycemia?

Answer 6

Hepatic function tests, ACTH stim test, insulin to glucose ratio, imaging

Question 7

What is an insulinoma?

Answer 7

Tumor arising from pancreatic beta cells

Question 8

What type of dogs are most likely to have insulinomas?

Answer 8

Large breed, middle aged to older dogs

Question 9

How would you describe the insulin secretion of insulinomas?

Answer 9

Episodic

Question 10

Are insulinomas benign or malignant?

Answer 10

Malignant

Question 11

What are the clues a dog might have an insulinoma?

Answer 11

Weight gain
Appetite can be decreased

Question 12

How would you diagnose an insulinoma?

Answer 12

Measurement of insulin during a period of hypoglycemia - insulin may be above reference range or in upper half of range
Imaging - may be a small lesions, may see metastasis

Question 13

What is the treatment for insulinoma?

Answer 13

Frequent small meals
Surgical removal or debulking can be helpful but very unlikely to cure
Glucocorticoids to antagonize the effect of insulin
+/- diazoxide - decrease insulin secretion
+/- somatostatin analogues - inhibits insulin release
+/-streptozotocin - cytotoxic to pancreatic beta cells

Question 14

How do you manage emergent hypoglycemia?

Answer 14

Karo syrup rubbed on gums
Dextrose bolus - diluted
+/- dextrose infusion

Question 15

What should you be careful of when giving a dextrose bolus?

Answer 15

Need to dilute - 50% dextrose is caustic to the vein
May trigger more release of insulin from an insulinoma