Diabetes Mellitus Flashcards
What is diabetes mellitus?
A group of metabolic disorders characterised by chronic hyperglycaemia
What is diabetes mellitus due to?
Insulin deficiency, insulin resistance, or both
At what age is type 1 diabetes onset most common?
Teenage years
Describe the age related rate of type 1 diabetes after teenage years?
It is mostly similar up until old
Does the rate of diabetes mellitus type 1 vary between countries?
Yes, substantially
What does the strong seasonal variation of type 1 diabetes onset suggest?
A link with viral infection acting as a trigger
What is the mechanism of onset of type 1 diabetes?
- Genetic predisposition to the disease interacts with environmental triggers to produce immune activation
- Immune activation leads to the production of killer lymphocytes, macrophages and antibodies that attack and progressively destroy ß-cells
What is the genetic predisposition to type 1 diabetes associated with?
The genetic markers HLA DR2 and HLA DR4
How does a patient present with type 1 diabetes?
- Polyuria
- Polydipsia
- Weight loss
What is polyuria?
Excess urine production
What produces the polyuria in type 1 diabetes?
Large quantities of glucose in the blood are filtered by the kidney, so not all of it is reabsorbed. The extra glucose in the nephron places an extra osmotic load on it, meaning that less water is reabsorbed to maintain osmotic pressure
What is polydipsia?
Thirst and drinking a lot, due to polyuria
Why does type 1 diabetes cause weight loss?
Fat and protein are metabolised because insulin is absent
Describe the typical patient presenting with type 1 diabetes
A lean young person with a recent history of viral infection
How can type 1 diabetes be diagnosed?
By measurement of plasma glucose levels
Why is blood glucose raised in type 1 diabetes?
Due to lack of insulin