13 Diabetes Mellitus Flashcards
What does glucagon do to blood glucose
raises blood glucose
What is diabetes characterized by
loss of insulin or decreased insulin responsiveness
*major disease in animals and people
What are 3 metabolic characteristics of diabetes
Decrease glucose uptake
Increase protein catabolism
Increase lipolysis
What are the 2 major forms of diabetes
Insulin dependent (IDDM) Insulin independent (NIDDM)
What are diabetes mellitus clinical signs
hyperglycemia, glycosuria
polydipsia, polyuria hyperphagia
in severe cases:
weight loss
cataracts in dogs
plantigrade posture in cats
vascular changes, microangiopathies
What are some predisposing factors to diabetes
genetic factors
dogs: females > males
cats: neutered males slightly more common
pancreatitis
immune -mediated destruction (dogs?)
amyloidosis (cats)
obesity (decreased receptors > down-regulation)
Why does PU/PD occur
Excess glucose spills into urine and osmotically drags water with it > polyuria, polydipsia, weight loss
What is the more common diabetes in dogs
IDDM
What is the more common diabetus in cats
NIDDM and IDDM
1/3 of cats are NIDDM
What are the 4 risk factors for diabetes in the cat
Age, obesity, neutering, gender (male more common)
What drugs can you give to cats instead of insulin
Drugs that increase insulin receptors or sensitivity of the receptors
What does insulin do to blood glucose
Lowers blood glucose
- moves glucose intracellularly
- causes liver to store glycogen
- facilitates fat deposition in adipose tissue
What is the result of decreased glucose uptake?
hyperglycemia (increased blood sugar) causes:
decreased glyconeogenesis
increased polyuria, polydipsia, polyphagia
What is the result of increased protein catabolism?
increased plasma aa
increased weight loss > decrease in growth
increased negative nitrogen balance
What is the result of increased lipolysis?
increased free fatty acids
ketosis
acidocis
Insulin-dependent diabetes (IDDM)
Type I (often autoimmune)
- destruction or loss of function of pancreatic beta cells leads to low insulin levels
- animals often have relatively high glucagon and are prone to ketosis
- most severe form of the disease
- etiology is unclear but can involve genetics, pancreatitis, autoimmunity, obesity, and viral causes
non-insulin-dependent diabetes (NIDDM)
Type II
- decreased number or responsiveness of insulin RECEPTORS
- less severe than IDDM
- can progress to IDDM
- results from insulin resistance secondary to obesity r other causes
Diabetes-species differences
carnivores are relatively susceptible; herbivores less so
diabetes mellitus - most common endocrine malady
incidence varies with age, breed etc
major illness in both dogs and cats
renal threshold
dogs: 180-220 mg/dl (more like humans)
cats: 240-300 mg/dl
cat has amazing capacity to absorb glucose from the kidney so just bc no glucose in urine does NOT mean there are no metabolic changes
consequences of insulin deprivation on lipid & protein metabolism?
loss of calories > weight loss
compensatory effect > hyperphagia
diabetic ketoacidosis
insulin deficiency + dehydration + stress →
mobilization of fat →
ketone body formation →
ketone accumulation in blood →
acidosis, dehydration, hypotension, depression
glucose and ketones spill over into urine →
worsens dehydration
diabetes mellitus diagnostics
baseline glucose values - street hyperglycemia in cats - postprandial (after a meal) hyperglycemia urinalysis - glucose present in urine (glucosuria)
diabetes in the dog
IDDM much more common
disease of older dogs (7-9yrs)
treatment: insulin
diabetes in the cat
NIDDM and IDDM
1/3 of cats are NIDDM
treatment: insulin and/or drugs
cat very different than dog
transient diabetes
reversible suppression of the pancreatic β-cells
waxing and waning of clinical signs
may progress to permanent diabetes
20% of cats will stop being diabetic all on their own
dogs can show transient diabetes during pregnancy or progesterone treatment
Who purified insulin?
1921 xmas day
Banting > nobel prize
Best
