Hyperglycaemia

Question 1

What are the 2 types of DM and how would you determine which type was the problem in this case (provide a diagnostic plan)?

Answer 1

Type 1: Insufficient insulin secretion; usually autoimmune destruction of beta cells. Diagnostic plan: Should be very sensitive to insulin, so inject exogenous insulin and assess response. Can also measure insulin concentration and it should be lower than expected.

Type 2: Insulin resistance; sometimes with secondary pancreatic insulin insufficiency. Determine if the animal is insulin resistant with insulin tolerance test (ITT) or combined glucose-insulin test (CGIT). An oral sugar test can be used for both. Glucose response will be high for both and the insulin curve will be low for Type 1 and high for Type 2

Question 2

High plasma creatinine concentrations (azotaemia) and haemoconcentration were detected after surgery, despite aggressive isotonic intravenous fluid therapy. How can you explain this finding?

Answer 2

• Diabetes mellitus is causing glucosuria which causes free water loss due to osmotic diuresis
• Glucosuria and loss of free water leads to dehydration and pre-renal azotaemia

Question 3

We now recognise that horses that already suffer from insulin dysregulation and then develop pituitary pars intermedia dysfunction (PPID) are at risk for diabetes mellitus. We recently treated a 22-year-old Quarter Horse with colic and detected a blood glucose concentration of 18.3 mmol/L (330 mg/dL) at presentation.

A pedunculated lipoma was found at surgery and approximately 7 meters of small intestine was resected. Insulin was administered before surgery and plasma triglyceride concentrations were above normal range. A blood glucose of 22.5 mmol/L (405 mg/dL) was detected after surgery. Hyperlipidaemia also became more severe after surgery.

High plasma creatinine concentrations (azotaemia) and haemoconcentration were detected after surgery, despite aggressive isotonic intravenous fluid therapy.

How would you manage this patient medically?

Answer 3

Administer insulin as a continuous rate infusion or via subcutaneous injections

Question 4

You are asked to give a second opinion on a 21-year-old Morgan horse gelding that had an episode of diarrhoea approximately 4 weeks ago that lasted 3 days. Another veterinary surgeon attended the horse at that time. Since the diarrhoea episode, the horse has had a poor appetite and there have been two episodes of mild colic, characterised by kicking at the abdomen.

Physical examination reveals fever 101.5 °F (38.6 °C), but no other abnormalities. However, the horse has a higher body condition score of 4/5, a thick neck crest, and fat pads close to the base of the tail. He has a history of equine metabolic syndrome (EMS), including previous episodes of laminitis.

Complete blood count (CBC) and plasma biochemical analysis (PBA) values are within reference range, with the exception of a markedly elevated plasma glucose concentration and hyperbilirubinemia. Glucosuria is detected.

Why is hyperlipaemia developing in this patient and what would you do to address this problem?

Answer 4

• Lack of insulin plus stress.
• Insulin output from the pancreas is low, so insulin is not inhibiting hormone-sensitive lipase

Question 5

You are asked to give a second opinion on a 21-year-old Morgan horse gelding that had an episode of diarrhoea approximately 4 weeks ago that lasted 3 days. Another veterinary surgeon attended the horse at that time. Since the diarrhoea episode, the horse has had a poor appetite and there have been two episodes of mild colic, characterised by kicking at the abdomen.

Physical examination reveals fever 101.5 °F (38.6 °C), but no other abnormalities. However, the horse has a higher body condition score of 4/5, a thick neck crest, and fat pads close to the base of the tail. He has a history of equine metabolic syndrome (EMS), including previous episodes of laminitis.

Complete blood count (CBC) and plasma biochemical analysis (PBA) values are within reference range, with the exception of a markedly elevated plasma glucose concentration and hyperbilirubinemia. Glucosuria is detected.

Generate a problem list for this patient and try to identify a medical condition that would connect all of the current problems?

Answer 5

• Physical characteristics of EMS
• Laminitis (historical)
• Hyperglycaemia
• Glucosuria
• Hyperinsulinaemia (historical)
• Relative insulin deficiency (current)
• Colic (historical)
• Diarrhoea (historical)
• Reduced appetite (current)
• Fever (current)
• Hyperbilirubinaemia (current – attributed to anorexia)
• Hypertriglyceridemia

Medical condition: Underlying EMS with pancreatitis (may have been secondary to intestinal disease)

Question 6

Patient has underlying EMS with pancreatitis (may have been secondary to intestinal disease). What additional testing would you perform to assess this patient?

Answer 6

• Peritoneal fluid and blood amylase and lipase activities
• Results:
• Amylase: < 3 IU/L (reference range: 0 to 100 IU/L)
• Lipase: 1,970 IU/L (reference range: 0 to 50 IU/L)
• Interpretation: Results consistent with pancreatitis. Not clear why amylase activity is within reference range.

Question 7

Formulate a treatment plan for this patient: Underlying EMS with pancreatitis (may have been secondary to intestinal disease)?

Answer 7

• Pancreatitis: Antibiotics and supportive care
• Type 2 diabetes mellitus and hyperlipaemia: Insulin therapy