Diabetes: Insulinoma and Hypoglycemia

Question 1

Glucose comes from three sources:

Answer 1

▫Intestinal absorption of glucose from digestion of carbohydrates
▫Breakdown of the storage form of glucose (glycogen) via glycogenolysis
▫Production of glucose from precursors lactate, pyruvate, amino acids, and glycerol via gluconeogenesis

Question 2

glucose-lowering
hormone

Answer 2

Insulin

Question 3

glucose-elevating
hormones

Answer 3

Glucagon
Epinephrine
Cortisol
Growth Hormone

Question 4

Central nervous system effects result in neurologic signs

Answer 4

Hypoglycemia Clinical Signs

Question 5

▫Severity of signs is based on the degree, rate of decline, and duration of hypoglycemia
- Chronic or episodic
▫Signs include altered mentation, dullness, sleepiness, weakness, recumbency, ataxia, blindness or altered vision, and seizure
▫Anxiety manifesting as pacing, vocalizing or restlessness, and shaking/trembling is also common

Answer 5

Hypoglycemia Clinical Signs

Question 6

symptoms of hypoglycemia, plasma glucose concentration<55 mg/dl (3.0 mmol/l), and resolution of those symptoms after the plasma glucose concentration is raised

Answer 6

Whipple’s triad

Question 7

▫Consistent clinical signs consistent
▫Hypoglycemia
▫Response to supplementation

Answer 7

Whipple’s triad

Question 8

• Artifact
• Excess insulin/insulin analogues
• Excess Glucose Utilization
• Decreased Glucose Production

Answer 8

Hypoglycemia Differentials

Question 9

Treatment:

Answer 9

▫Discontinue insulin therapy
▫Feed
▫Administer intravenous dextrose
▫Reconsider diabetic management (DOSE DECREASE)

Question 10

insulin-secreting, usually
malignant, tumors of the endocrine pancreas

Answer 10

Insulinoma

Question 11

▫Older dogs and less commonly cats
▫Other clinical pathology data are generally
unremarkable

Answer 11

Insulinoma

Question 12

_______________ can cause hypoglycemia via secretion of
insulin or insulin-like peptides, accelerated consumption of glucose by the tumor cells, or by failure of glycogenolysis or gluconeogenesis by the liver

Answer 12

Neoplasia

Question 13

• Oral glucose-lowering agents such as the sulfonylurea drugs chlorpropamide and glipizide
• Xylitol-sweetened products, such as sugar-free gum, can cause hypoglycemia in dogs via its stimulation of insulin release from β-cell

Answer 13

Toxins and Medications

Question 14

▫Inadequate substrate for glycolysis or gluconeogenesis
▫Glycogen stores are small and easily depleted in the face of inadequate food intake
▫Increased risk if concurrent:
- Infection, vaccinations, vigorous exercise, GI upset, hypothermia, poor nutrition, and extended fasting

Answer 14

Puppies and Toy Breeds

Question 15

• Any disease that causes liver dysfunction can cause hypoglycemia
  
  • Classic example: Liver synthetic failure
• Test: Confirm normal liver function – Step 1 Bile Acid Stimulation Test

Answer 15

Liver Disease

Question 16

Hypoglycemia via loss of cortisol-induced counter regulatory mechanisms
- Cortisol is produced by the adrenal gland
(hypo-adreno-corticism)
- Chronic, concurrent GI signs should raise suspicion
- Vague disease dubbed ‘The Great Pretender’ as it can look like
anything

Answer 16

Hypoadrenocorticism/Hypopituitarism

Question 17

• Infectious burden causes increased glucose consumption
• Patients with sepsis will be extremely ill
• Other clinical signs will depend on the type and location of infection
• Canine babesiosis particularly high rate of related hypoglycemia

Answer 17

Sepsis/Infection
(Common cause of hypoglycemia!)

Question 18

• Typically lean hunting or working dogs engaging in vigorous exercise
• Glycogen depletion in the face of increased glucose utilization

Answer 18

‘Hunting Dog Hypoglycemia’ (Exercise Induced)
(Consumptive Hypoglycemia)

Question 19

• Increased metabolism of glucose by the large red blood cell mass (similar phenomenon with severe leukocytosis)

Answer 19

Polycythemia/Leukocytosis
(Consumptive Hypoglycemia)