S10) Diabetes Mellitus Flashcards
What is diabetes mellitus?
- Diabetes mellitus is a group of metabolic disorders in which there are high blood sugar levels over a prolonged period
- Over time, damage of small and large blood vessels causes premature death from cardiovascular diseases
What is a metabolic syndrome?
A metabolic syndrome is a cluster of the most dangerous risk factors associated with CVD – diabetes and raised fasting plasma glucose, abdominal obesity, high cholesterol and BP
Identify the requirements of a metabolic syndrome
- Waist measurement > 94cm (men) / > 80 cm (women)
- Any two of the following:
I. Raised triglyceride
II. Reduced HDL cholesterol
III. Raised blood pressure
IV. Raised fasting blood glucose
Identify some causes of a metabolic syndrome
- Insulin resistance
- Central obesity
- Genetics
- Physical inactivity
- Ageing
What are the two causes for hyperglycaemia seen in diabetes mellitus?
- Inability to produce insulin due to beta cell failure and
- Adequate insulin production but insulin resistance prevents insulin working effectively
Identify the following cell
Pancreatic islet cell
Outline the pathophysiology of Type I diabetes
Type I diabetes is due to autoimmune beta cell destruction:
- Beta cells secrete insulin
- Autoantibodies are directed against beta cells and insulin producing cells destroyed
Outline the pathophysiology of Type II diabetes
- Insulin deficiency – pancreas may not produce enough insulin
- Insulin resistance – cells do not use insulin properly i.e. insulin cannot fully “unlock” the cells to allow glucose to enter
How does Diabetes Mellitus present?
- Symptoms of hyperglycaemia – polyuria, polydipsia, blurring of vision, urogenital infections (thrush)
- Symptoms of inadequate energy utilisation – tiredness, weakness, lethargy, weight loss
Which tests are requested for in the diagnosis of a patient with suspected diabetes?
- Fasting glucose
- Oral glucose tolerance test
- HbA1c
What is required to diagnose diabetes mellitus in a patient?
- Symptoms & 1 abnormal test
- If asymptomatic, 2 abnormal tests
What is Type I Diabetes?
- Type I Diabetes is the absolute lack of insulin secondary to autoimmune destruction of β cells
- The aetiology not fully understood but the patient is usually young (< 30 years)
What are the symptoms of Type I Diabetes?
- Rapid onset (usually weeks)
- Weight loss
- Polyuria
- Polydipsia
- Vomiting due to ketoacidosis (late presentation)
Which blood results assist in diagnosing Type I Diabetes?
- Elevated venous plasma glucose (random > 11 mmol/L)
- Presence of ketones (breakdown products of fats)
How can one confirm the presence of ketones in a patient with suspected Type I Diabetes?
Most easily measured in urine using “ketostik” – signifies absolute lack of insulin
Describe the treatment of Type I Diabetes
Exogenous insulin – given by subcutaneous injection several times per day
What is Type II Diabetes?
- Type II Diabetes is a long-term metabolic disorder that is characterised by high blood sugar, insulin resistance, and relative lack of insulin
- 90% of patients are overweight/obese, over 40 years old and often asymptomatic (diagnosis made at routine health checks)
What causes insulin resistance to develop?
- Obesity (85% – central)
- Muscle and liver fat deposition
- Elevated circulating free fatty acids
- Physical inactivity
- Genetic influences
How can one prevent Type II Diabetes?
Maintain a healthy body weight – BMI of 20 to 25 kg/m2
Symptoms of Type II Diabetes are very variable as there is a slower rise in blood glucose.
Regardless, identify the usual presentations
- Polyuria
- Polydipsia
- Weight loss
- No urinary ketones
- May be asymptomatic
What are the consequences of uncontrolled Diabetes Type II?
- Gradual worsening of symptoms
- Hyperglycaemic
- Inadequate energy utilisation
- Onset of complications of diabetes
What are the consequences of uncontrolled Diabetes Type II on the NHS?
Significant morbidity, mortality and financial cost
How does one treat Diabetes Type II?
- Lifestyle
- Non-insulin therapies (drugs)
- Insulin
- Look for other vascular risk factors (BP, smoking, exercise, diet)
- Surveillance for chronic complications
Identify some acute complications of diabetes mellitus in terms of the following:
- Complications of hyperglycaemia
- Complications of hypoglycaemia
- Hyperglycaemia – diabetic ketoacidosis (type 1), hyperosmolar non-ketotic syndrome (type 2)
- Hypoglycaemia – coma due to hypoglycaemic therapy
Identify some chronic complications of diabetes mellitus in terms of the following:
- Macrovascular complications
- Microvascular complications
- Macrovascular – cerebrovascular, cardiovascular, peripheral vascular disease i.e. stroke, heart attack, intermittent claudication, gangrene
- Microvascular – retinopathy, nephropathy, neuropathy i.e. blindness, erectile dysfunction, foot ulceration, painful peripheral neuropathy
