Type 1 diabetes Flashcards
What is latent autoimmune diabetes in adults (LADA)?
Autoimmune diabetes (type 1) leading to insulin deficiency that presents late (decades)
Which three endocrine diseases does diabetes particularly present after?
Phaeochromocytoma
Cushing’s
Acromegaly
What is the aetiology of type 1 diabetes?
Normally there is an environmental trigger that occurs in the background of a genetic component which leads to autoimmune destruction of islet cells
What is the aetiology of type 2 diabetes in comparison?
There is a much bigger genetic component in type 2, it is also caused by obesity which will lead to insulin resistance so the beta cells will fail
What is a good marker of insulin function?
C peptide- it can be measured in blood and is linked with insulin production
Why do some people believe that type 1 diabetes is a relapsing-remitting disease?
Over time beta cells reduce then stabilise then reduce again, some believe this is due to an imbalance between effector T cells and regulatory T cells (effectors cause destruction, regulatory control), over time effectors increase and regulatory decrease
What are the histological features of T1DM?
There is a lot of lymphocyte infiltration of the beta cells which destroys it so it can no longer release insulin
Where is human leukocyte antigen (HLA) located?
Chromosome 6
Which HLA DR alleles confer a particular risk of T1DM?
DR3 and DR4
Throughout the year, when does T1DM increase in prevalence?
Autumn
Why is T1DM thought to increase in autumn?
A pathogen in the air around this time of the year that triggers diabetes
What are the two most significant antibody markers for T1DM?
Islet cell antibodies (ICA)- group O human pancreas
Glutamic acid decarboxylase antibodies (GADA)- widespread neurotransmitter
What are the symptoms and signs of T1DM?
Symptoms: Polyuria Nocturia Polydipsia Blurring of vision Thrush Weight loss Fatigue
Signs: Dehydration Cachexia Hyperventilation Smell of ketones Glycosuria Ketonuria
Why do people with type 1 DM have hyperventilation?
They have metabolic acidosis so their body tries to get rid of acid by blowing out CO2- this is called Kussmaul breathing
What are the effects of insulin?
Decrease:
Hepatic glucose output
Protein breakdown in muscle
Glycerol being taken out from the fatty tissue into the periphery
Increase:
Glucose being taken up by muscle
What happens in insulin deficiency?
Lot of glucose goes into circulation but isn’t taken up by tissues
What hormones increase hepatic glucose output?
Catecholamines
Cortisol
Glucagon
Growth hormone
How does diabetic ketoacidosis occur?
Glucose isn’t taken up by cells so a lot of our energy comes from fatty acids so the lipid in adipocytes is broken down to fatty acids which enters circulation and are converted to ketones in the liver (this process is normally inhibited by insulin)
Wha defines insulin deficiency?
Ketones
What are the long term complications of T1DM?
Retinopathy
Nephropathy
Neuropathy
Vascular disease
What sort of diet is recommended for someone with type 1 DM?
Reduce calories as fat
Reduce calories as refined carbohydrates
Increase calories as complex carbohydrates
Increase soluble fibre
Balance food distribution throughout the day
Apart from insulin treatment, how can T1DM be treated?
Islet cell transplants-
Cells are isolated, harvested and injected into liver
Risk of rejection so on immunosuppressants for life
How are glucose levels in a diabetes patient often measured?
Capillary blood glucose levels can be measured using a finger prick test which is reflective of venous blood glucose and patients can use this to titrate their own insulin
What is HbA1c used for?
HbA1c is used as a long term blood glucose control marker over the last 3 months (as red cell lifespan is about 120 days)
What HbA1c should you aim for in T1DM?
<7% (lower=less risk of complication particularly microvascular)
When would HbA1c be inaccurate?
If anything causes increased turnover of haemoglobin (e.g. haemolytic anaemia or haemoglobinopathy)
What is the main acute complication of T1DM?
Hyperglycaemia
What are other acute complications of T1DM?
Metabolic acidosis
Circulating acetoacetate and hydroxybutyrate
Osmotic dehydration and poor tissue perfusion
What is the definition of hypoglycaemia?
Plasma glucose < 3.6mmol/l
What is severe hypoglycaemia?
Anything that requires someone to treat it
What happens when blood glucose is < 3mmol/l?
Most mental processes impaired
What happens when blood glucose is < 2mmol/l?
Consciousness impaired
What happens with recurrent hypos?
Loss of warnings- hypoglycaemia unawareness
What is the main risk factor of hypoglycaemia in T1DM patients?
Quality of glycemic control- most frequent in patients with low HbA1c
When are hypos most common?
Pre lunch and nocturnal
Why do T1DM patients become hypoglycaemic?
Unaccustomed exercise Missed meals Inadequate snacks Alcohol Poor insulin regime
What are the signs and symptoms of hypoglycaemia?
Palpitations Tremor Sweating Pallor/cold extremities Anxiety Drowsiness Confusion Altered behaviour Focal neurology Coma
How do you treat hypoglycaemia?
Oral- feed the patient:
Glucose- rapidly absorbed as solution or tablets
Complex carbohydrates- maintain blood glucose after treatment
Parenteral- if consciousness impaired:
IV dextrose- 10% glucose infusion
1mg glucagon IM
