14 - Diabetes Mellitus Flashcards
What is type 1 diabetes?
- Absolute insulin deficiency by autoimmune destruction of B-cells
- Mainly in the young
- Rapidly fatal if not treated
What is type 2 diabetes?
- Slow progressive loss of beta cells along with issues of insulin secretion and tissue resistance to insulin
- May be present for long time before diagnosis
- May not need treatment initially
What will blood results from a type 1 diabetic show?
- HLA markers
- Autoantibodies
What is the staging of type 1 diabetes?
- HLA and autoantibodies in blood with no insulin or glucose issues
- Impaired glucose tolerance
- Diabetes
- Insulin dependent
What is the staging of type 2 diabetes?
- Insulin resistance
- Impaired glucose tolerance
- Diabetes
How is type 2 diabetes initially treated?
- Diet
- Tablets
- Insulin
What is diabetes?
What are the two different mechanisms of diabetes?
- Inability to produce insulin due to beta cell failur
and/or
- Insulin production adequate but insulin resistance prevents insulin working effectively
What is the genetic predisposition of type 1 diabetes?
- Genetic marker: HLA DR3 and HLA DR4
- Strong seasonal variation suggesting link with viral trigger
What is the classic picture of type 1 diabetes?
- Lean young person
- Triad of symptoms: polyuria, thirst, weight loss
- Glycosuria
Why do the triad of symptoms occur in type 1 diabetes?
- Polyuria: not all glucose reabsorbe so less water reabsorbed in the nephron
- Thirst: excess water loss in urine
- Weight loss: fat and protein metabolised by tissues because insulin absent
Why does diabetic ketoacidosis occur and how can it be spotted?
- Excess beta oxidation of fats in liver and low insulin/glucagon ratio stimulates ketogenesis
- Large amount of ketones produced and H+
Features: prostration, hyperventilation, nausea, vomiting, dehydration, abdominal pain, fruity breath
Why is it essential to diagnose type 1 diabetes quickly?
Prevent ketoacidosis which is fatal
At diagnosis of type 2 diabetes where are the beta cells at?
- Around 50% functioning and progressively less as time goes on
What are some typical symptoms of type 2 diabetes?
- Triad of symptoms
- Tiredness, weakness, lethargy and weight loss due to inadequate energy utilisation
- Blurring of vision
- Persistent infections, mainly genitalia thrush and feet
- Slow healing
How do you diagnose diabetes?
- Symptoms PLUS
- Random venous plasma glucose conc >11.1 mmol/L
- Fasting plasma glucose conc > 7mmol/L
- Plasma glucose >11.1 mmol/L 2 hours after 75g anhydrous glucose in OGTT
(don’t use finger prick test for diagnosis)
How is type 1 diabetes treated?
- Exogenous insulin subcutaneous several times per day
- Educate patients for times and doses, exercise and diet
- Finger prick BM stick and reader to check sugar levels
When might you change a type 1 diabetic’s insulin dosage?
- Patient suffered trauma or infection need to increase dosage to prevent ketoacidosis
What are some drugs used in the treatment of type 2 diabetes and what else can be used in management of this disease?
- Sulphonylureas: increase insuline release from remaining B cells and reduces insulin resistance
- Metformin: Reduces gluconeogenesis
- Diet and exercise
How can you prevent type 2 diabetes?
- Diet
- Exercise
- Prevent obesity
What is HbA1c?
- Glycated Hb
- Glucose in blood will react with terminal valine of Hb to form glycated Hb
- Healthy 4-6% HbA1c, diabetics 10%
What is the issue with glycation of plasma proteins?
- Glucose reacting with free amino acids to form stable covalent linkages
- Changes net charge and 3D structure of protein so affects function
What are the differences in the urine of type 1 and type 2 diabetics?
Type 2 have no ketones in urine
What are some macrovascular complications of diabetes?
- Increased risk of stroke
- Increased risk of MI
- Poor circulation to peripheries
How can diabetes lead to oxidative stress in the body, what tissues are most susceptible and why?
- Peripheral nerves, eye and kidney most susceptible as do not require insulin to uptake glucose
- During hyperglycaemia glucose conc in these tissues increases so glucose is metabolised by aldose reductase
- Reaction uses NADPH and accumulation of sorbitol causes osmotic damage to cells
What are some microvascular complications of diabetes and why?
- Diabetic eye disease: osmotic effects of glucose, so cataracts, or retinopathy damaging blood vessels causing them to leak and alow protein exudates to form on retina
- Diabetic kidney disease: Poor blood supply or damage from infections of urinary tract, protein in urine
- Diabetic neuropathy: peripheral nerve damage, loss of sensation due to alternation of ANS
- Diabetic feet: poor blood supply, damage to nerves and increased risk of infection
What is dyslipidemia?
- Increased VLDL and LDL
- Decreased HDL
What is metabolic syndrome?
A group of symptoms associated with central adiposity
- Insulin resistance
- Dyslipidaemia
- Glucose intolerance
- Hypertension
What is the WHO requirements for metabolic syndrome?
- Hip ratio >0.85 women >0.9 men
- BMI > 30kgm2
- Blood pressure > 140/90 mmHg
- Triglycerides > 1.7 mmol/L
- HDL <0.9mmol/L men and <1mmol/L women
- Glucose fasting or 2h after glucose load >7.8mmol/L
What can metabolic syndrome be a risk factor for?
- Type 2 diabetes
- Cardiovascular disease
- Obesity
Why is the use of BMI in metabolic syndrome questioned?
Does not allow for large muscle bulk and it is central fat, not fully body fat, associated with insulin resistance and fatty liver
What groups is obesity more prevalent in?
- South Asians then Europeans then African-carribbeans
Why does type 1 diabetes have to be treated immediately?
Can lead to ketoneacidosis which can put someone into coma
What are the signs of untreated Type 1 diabetes?
What are some quick tests you can do to diagnose untreated type I diabetes?
When treating type 1 diabetes what should you teach the patient?
What are the differences between type 1 and type 2 diabetes?
What is the treatment ladder for type 2 diabetes?
