Type 1 diabetes Flashcards
What are the presenting features of type 1 diabetes?
- Thirst
- Polyuria
- Weight loss and fatigue
- Hunger
- Pruritis vulvae and balanitis
- Blurred vision
Why is thirst a presenting feature?
osmotic activation of hypothalamus
Why is polyuria a presenting feature?
osmotic diuresis
Why is weight loss and fatigue a presenting feature?
lipid and muscle loss due to unrestrained gluconeogenesis
Why is hunger a presenting feature?
Lack of useable energy source
Why is pruritis vulvae and balanitis a presenting feature?
Because of
- Vaginal candidiasis
- Chest / skin infections
Why is blurred vision a presenting feature?
Altered acuity due to uptake of glucose/water into lens
What are suggestive features of type 1 diabetes?
- Onset in childhood / adolescence
- Lean body habitus
- Acute onset of osmotic symptoms
- Prone to ketoacidosis
- High levels of islet autoantibodies
What age can type 1 diabetes present?
Can occur at any age, the spectrum of presentation depends on the rate of b-cell destruction
What are clinical features of newly diagnosed Type 1 diabetes?
- Weight loss
- Urinary ketones
- Moderate or large urinary ketones
How many clinical features of newly diagnosed type 1 diabetes would call for immediate insulin treatment?
Any 2 of these three features
What are suggestive features of type 2 diabetes?
- Usually presents in over-30s
- Onset is gradual
- Almost 100% concordance in identical twins
- Diet, exercise and oral medication can often control hyperglycaemia; insulin may be required later in the disease
What makes diagnosing type 1 and 2 diabetes difficult?
- Type 2 is diagnosed in younger patients, including childhood
- Type 1 patients can be obese
- Uncontrolled Type 2 can present with weight loss and ketouria
- IF IN DOUBT – TREAT WITH INSULIN
What other autoimmune diseases is T1D associated with?
- Hypothyroidism
- Addisons
- Coeliac disease
What does reduced insulin lead to in fat metabolism?
leads to fat breakdown and formation of glycerol (a gluconeogenic precursor) and free fatty acids
What impact do free fatty acids have on glucose metabolism?
- Impair glucose uptake
- Are transported to the liver, providing ‘energy’ for gluconeogensis
- Are oxidised to form ketone bodies (beta hydroxy butyrate, acetoacetate and acetone)
What leads to a rise in ketones?
- Absence of insulin and rising counterregulatory hormones leads to increasing hyperglycaemia and rising ketones
- Glucose and ketones escape in the urine but lead to an osmotic diuresis and falling circulating blood volume
What do ketones cause?
cause anorexia and vomiting
What does cycle of increasing dehydration, hyperglycaemia and increasing acidosis eventually lead to?
circulatory collapse and death
Define Diabetic ketoacidosis (DKA)
- Hyperglycaemia (plasma glucose usually <50 mmol/l)
- Raised plasma ketones (urine ketones > 2+)
- Metabolic acidosis – plasma bicarbonate < 15 mmol/l
What does DKA cause?
- Intercurrent illness
- infection
- myocardial infarct
What is the triad of DKA?
- Hyperglycaemia
- Ketones
- Acidosis
What are symptoms of DKA?
- develop over days
- polyuria and polydipsia
- nausea and vomiting
- weight loss
- weakness
- abdominal pain (confused with surgical abdomen)
- Drowsiness / confusion
What are signs of DKA?
- hyperventilation (Kussmaul breathing)
- dehydration (average fluid loss 5-6 litres)
- hypotension
- Tachycardia
- coma
