Endocrine pancreas 1 + 2 Flashcards
Pancreatic insulin secretion is stimulated by?
Circulating glucose and amino acid levels.
What is the role of insulin?
To reduce serum glucose levels and increase glucose uptake by tissues
Reduce gluconeogenesis and glycogenolysis in the liver
Describe the aetiology of Diabetes mellitus in dogs
- Immune mediated disease with gradual destruction of beta cells
- Slow progression so most islets are lost before diabetes occurs
What are the predisposing factors for diabetes in dogs?
Genetics
Chronic pancreatitis
Obesity
Medication induced
Females 3x more likely
Middle aged
Describe the aetiology of Diabetes mellitus in cats
- Beta cell function fails to meet demand due to insulin resistance
- This effect is mediated by islet cell amyloid deposition
What are the predisposing factors for diabetes in cats?
- Obesity
- Pancreatitis
- Endocrinopathies
- Burmese cats predisposed
- Males > females
- Middle aged
What are the consequences of insulin deficiency?
- Increased Glucagon
- Increased Gluconeogenesis
- Decreased cellular uptake of glucose
- Osmotic diuresis
- Fatty acid mobilisation -> ketoacid production
What are the clinical signs of diabetes mellitus?
- PUPD
- Glucosuria
- Polyphagia
- Weight loss
- Cataracts
- Neuropathies
List some DDx of diabetes
Hyperthyroidism (in cats)
Gastrointestinal lymphoma
Hepatic disease
Renal disease
Pancreatitis
Hyperadrenocorticism
Acromegaly
How is diabetes diagnosed?
History
Clinical signs
Haematology/ Biochemistry
Urinalysis
Describe the haematology and biochemistry findings in patients with diabetes
- Hyperglycaemia
- Elevated ALT, ALKP – due to mobilisation of fat
- Hypertriglyceridemia
- Urinary Ketones
Describe the urinalysis findings in patients with diabetes
Low USG
Glycosuria
Ketonuria
Active sediment
Based on the findings how can diabetes be clinically diagnosed?
DIABETES = appropriate clinical signs + persistent fasting hyperglycaemia + glycosuria
Therapy for diabetes centres of which 4 main areas?
- Treatment of concurrent illness (UTI, pyodermas, etc.)
- Oral hypoglycemic agents
- Insulin therapy
- Dietary management
Describe the main differences when considering diabetes treatments for cats and dogs
Dogs - life long
- Life-style change for dog and owner
- Insulin, Diet, Routine
Cats - May go into remission
Describe insulin treatment for a dog with diabetes
- Twice daily.
- Feed half ration and then administer insulin
- Starting dose 0.25-0.5iu/Kg, usually end up on about 0.8u/Kg
Legacy Protocol: - Intermediate acting insulin
- Feed twice daily, with insulin injection
- 6-8 hours later - Second part of ration - larger portion
Describe insulin treatment for a cat with diabetes
Mostly use twice daily injection
Caninsulin® or Prozinc®
Describe dietary therapy in dogs
Fibre/Complex CHO - avoid diets with simple sugars
Low fat
Ideally, the feeding schedule should be coordinated with the onset of action of the insulin. The most important component of the dietary plan is to stress consistency in the diet
Describe dietary therapy in cats
High protein, low carbohydrate
These diets may result in remission of the diabetes and elimination of the need for exogenous insulin and/or oral hypoglycemic agents.
Name the oral hypoglycaemic drug used in practice
Sulfonylureas (glipizide)
How should diabetic patients be monitored
- Clinical Signs: Thirst, Appetite, Weight Gain
- Urine Glucose: Afternoon sample, Do not adjust insulin based on this
- Glucose Curve - NB 5-7 days for adaptation
- Fructosamine (~2wks)
- Glycosylated Hb (2-3months)
What are the signs of an insulin overdose?
Ataxia, collapse, seizure
How can you treat hypoglycaemia due to an insulin overdose?
Give sugary substance under tongue
Feed ASAP
Avoid insulin dose if imminent
What should you do if a diabetic animal stops eating?
- Basal insulin always needed to control glucose entry into cells
- If not eating (ill or requiring procedure such as GA)
- Reduce insulin dose by 50%
- Do not stop insulin – will lead to ketoacidosis
Describe the use of pin prick glucose monitors
Some owners can be trained to perform glucose monitoring at home using patient side glucometers, sampling using ear or lip-prick. This may provide a more representative measure of the performance of the insulin treatment in any given animal.
What are some issue with serial blood glucose curves?
- Prolonged insulin antagonistic effects of counter-regulatory hormones
- Poor appetite
- Stress
What factors/situations could lead to recurrence of clinical signs of diabetes?
- Administration technique and insulin activity problems
- Insulin overdose and glucose counter-regulation
- Short duration of insulin effect
- Inadequate insulin absorption
- Circulating insulin binding antibodies
- Concurrent disorders causing insulin resistance
List the chronic complications of diabetes mellitus
Ketoacidosis
Infections
Lens induced uveitis
Diabetic neuropathy
Cataracts
Diabetic retinopathy
If your diabetic patient is unstable, what questions should be asked?
Is insulin effective at lowering blood glucose?
How quickly does the insulin act
What is the glucose nadir?
What is the duration of insulin action?
How can you rule out some obvious causes of unstable diabetic patients?
- Is the owner giving the injections correctly?
- Is the owner using the correct dose and syringes?
- Is the insulin being handled/stored appropriately?
- Is the insulin out of date?
- What is the feeding regime?
Describe Insulin induced hyperglycemia (Somogyi phenomenon)
The Somogyi phenomenon occurs when there is hypoglycaemia (<3.5 mmol/l) followed by hyperglycaemia (>17 mmol/l) within 24 hours of insulin injection
When should the Somogyi phenomenon be suspected?
When insulin requirements exceed 2 U/kg and clinical signs persist or when the animals show clinical signs of hypoglycaemia in the afternoon.
The diagnosis of the Somogyi phenomenon is done with blood glucose curves
What should be done following diagnosis of the Somogyi phenomenon?
The dose of insulin should be reduced by 25-50%.
Describe rapid insulin metabolism as a problem of insulin therapy
This occurs when the duration of the insulin effect is less than 18 hours.
Diagnosed by performing a blood glucose curve and identifying hyperglycaemia (>14 mmol/l) within 18 hours of insulin injection WITHOUT previous hypoglycaemia.
Indicated to switch to a longer acting insulin (if administering insulin once daily) or to administer insulin twice daily
Define insulin resistance
The presence of hyperglycaemia (>17 mmol/l) throughout the day, despite insulin dosages > 2 U/kg
What are some potential causes of insulin resistance?
Hyperadrenocorticism
Steroid or progestagen administrationdiestrus or pregnancy
Acromegaly
Concurrent illness
Infection
Hypothyroidism (dogs), hyperthyroidism (cats).
Hypoglycaemia usually occurs due to?
Insulin overdose
What are the clinical signs of hypoglycaemia?
Weakness, shaking, ataxia or seizures at the time of the peak effect of the insulin
The owners should be warned about these clinical signs and asked to feed the patient as soon as possible
Describe the aetiology of diabetic ketoacidosis
- Medical emergency
- Occurs as a consequence of imbalance between insulin and counter- regulatory hormones -> increase in lipolysis and free fatty acids (FFA).
- The FFA are metabolized in the liver to ketone bodies.
- When the ketone production exceeds peripheral utilization of ketones, ketonemia results
- Ketone bodies are acidic and the build-up of ketones in the body causes metabolic acidosis
List the clinical signs of diabetic ketoacidosis
The presence of severe academia, electrolyte imbalances and dehydration lead to vomiting, diarrhoea and anorexia, which contributes to the water and electrolyte loss.
What are the effects of azotaemia in the body?
Cause an increase in plasma osmolarity which leads to cellular dehydration
How is diabetic ketoacidosis diagnosed?
Diabetes + ketonuria
What are the goals of therpay for ketoacidosis?
Provide adequate amounts of insulin
Restore water and electrolyte losses
Correct acidosis
Identify any concurrent illness
Provide carbohydrate substrate
Describe the minimum database needed for diabetic ketoacidosis patients
Urinalysis
Haematocrit
Plasma protein concentration
Blood glucose concentration
Urea and creatinine
Serum electrolytes
Describe fluid therpay for diabetic ketoacidosis patients
Fluids are the most crucial aspect to treating DKA.
Rehydration alone will lower blood glucose concentrations.
Often beneficial therefore to start patients on fluids for a few hours prior to giving insulin
Dehydration should be corrected over 24 hours
The serum levels of which ion need to be monitored in diabetic ketoacidosis patients - why?
Potassium and phosphate
Most DKA’s are moderately to severely hypokalaemic, due to urinary and gastro- intestinal potassium loss
As treatment begins to correct the acidosis, the serum K+ concentration will drop. Insulin also causes K+ to move intracellularly
Describe insulin therpay for diabetic ketoacidosis patients
- Intermittent intramuscular regime
- Initial loading dose of regular crystalline insulin im, measure glucose every hour
- Maintained until glucose levels are normal and patient has started eating - Constant low dose insulin infusion
What is an insulinoma?
Functional tumour of pancreatic islet β-cells.
Produce insulin resulting in hypoglycaemia
What are the clinical signs of an insulinoma?
Often episodic: include lethargy, weakness, trembling, ataxia, collapse, seizures, or bizarre behaviour.
Signs often precipitated by fasting, exercise, or excitement.
Episodes can be short.
Physical exam may be normal, there may be weight gain as insulin is anabolic.
May have neurological deficits if hypoglycaemic at the time.
How is an insulinoma diagnosed?
- Hypoglycaemia (persistent: beware of lab error)
- Normal glucose doesn’t rule it out: can fluctuate. Sometimes need to fast the patient for a few hours under observation, with hourly samples.
- Elevated insulin at a time of low blood glucose
- Pancreatic mass +/- metastasis – detected by palpation, radiography, ultrasound, exploratory laparotomy. Can be very small: easily missed.
How is an insulinoma treated?
- IV glucose if needed
- Avoid excess stimulation of insulin by giving: Frequent small meals - Avoid simple sugars, Use diet high in complex carbohydrates, protein and fat
- Prednisolone
- Oral hyperglycaemics (expensive, not licensed)
- Surgery (pancreatitis)
Describe the prognosis of an insulinoma
Long-term prognosis is guarded, as metastasis is common
leading to eventual recurrence of signs
What is a gastrinoma?
Functional pancreatic islet α2 or δ- cell tumour producing gastrin
This results in gastric hyperacidity and risk of ulceration
What are the clinical signs of a gastrinoma?
Vomiting, haematemesis, diarrhoea, melaena, pain, anorexia, weight loss, pallor, pyrexia, cranial abdominal pain, dehydration, shock and tachycardia
