Flashcards in Diabetes mellitus - general Deck (19)
What is diabetes mellitus?
Disorder that arises when the threshold of insulin required to maintain normal glucose levels is lost
Serum glucose levels rise
What happens normally in out body when glucose levels rise?
1. Insulin is released by beta cells
2. Promotes uptake of glucose by the liver, adipose tissue and muscles
3. Suppresses gluconeogeneis
4. Promotes glycogenesis and lipogenesis
What happens if blood glucose rises but insulin is not around?
Release of intermediates FFA and amino acids
Positively regulated by cortisol and growth hormone in stress situations
What are the characteristics of insulin?
Short acting if shot when eating
Longer acting if shot during the night - suppresses ketogenesis and promotes anabolic pathways
Short half life - extended by protamine and zinc
What are the symptoms of diabetes?
1. Polyuria and dehydration - increase in plasma glucose increases osmolarity of the urine in the tubules. More water is lost due to osmolar load
2. Recurrent infections - high glucose concentration stimulates growth of microbed
3. Blurred vision - osmolar load affects vision
4. Weight loss - glucose and carbohydrate stores are used ineffectively in the absence of insulin
What is ketoacidosis?
Since diabetic patients are unable to use carbohydrate stores effectively, patients get increase lipolysis
Lipolysis = increased beta oxidation of fatty acids
This liberates ketone bodies that are effective at generating energy, but in the process leads to acidosis
What is diabetic ketoacidosis?
Accumulation of ketone bodies from increased lipolysis and dehydration
Contributes to electrolyte problems
Intracellular potassium is exchanged for hydrogen ions that accumulate extracellularly in acidosis.
Dehydration drives potassium out of the body due to activation of renin-angiotensin system -> exchanges sodium for potassium
Patients present with very low potassium levels and loss of up to 10% of water
What is the treatment for diabetic ketoacidosis?
Insulin - stimulates active uptake of potassium into the cells
What does Diabetes Mellitus mean in Greek?
Much sweet urine
What kind of syndrome is Diabetes Mellitus?
Covers several syndromes of abnormal carbohydrate metabolism
What is the one characteristic shared by all the syndromes under the umbrella term DM?
What are the features of Type II diabetes mellitus?
Non-insulin dependent diabetes
Insulin resistance and pancreatic failure
Usually develops over 30 years of age
Most patients are overweight
What are the features of Type I diabetes mellitus?
Insulin dependent diabetes
Relative or absolute impairment of insulin secretion by the pancreas
Possible at any age
Autoimmune destruction of the pancreatic gland
What tests are commonly performed in a diabetic clinic?
Diagnostic criteria of diabetes?
Have to have diabetes symtoms PLUS test within diabetic range in clinical tests
What are diabetes symptoms?
Polyuria - large urine volume
Polydipsia - thirst
Unexplained weight loss - calories lost in urine
Whatr are clinical tests done to diagnose diabetes?
Fasting venous plasma more or equal to 7 mmol/L
Random venous plasma glucose more or equal to 11.1 mmol/L
HbALe - glycated haemoglobin
Oral glucose tolerance test - 2 hour plasma glucose more or equal to 11.1 after 75g of glucose
What is glycated haemoglobin?
Haemoglobin reacts with glucose in RBC becoming glycated
This is a non-enzymatic reaction
Enhanced when blood glucose is high for a long time
Clinicians are able to get overall picture of what average glucose levels have been for months/ years