Clinical Aspects of Diabetes Flashcards
What indicates diabetes / how can diabetes be diagnosed?
- Glycated Haemoglobin > 48 mmol/mol
- Fasting blood glucose > 7 mmol/l
- 2 hour blood glucose > 11.1 mmol/l following OGTT
- Random blood glucose > 11.1 mmol/l in presence of symptoms
What can type 2 diabetes be classified into?
- Insulin resistance with relative insulin deficiency
- Secretory defect with insulin resistance
What are other types of diabetes? (outside of type 1 and 2)
- Genetic (MODY etc)
- Pancreatic disease (alcohol, gallstones)
- Endocrine disease (acromegaly)
- Drugs
What percentage of diabetes patients are not type 1 or 2?
~ 5%
What is gestational diabetes?
Feto-placental unit tries to push glucose towards baby - mother is relatively insulin resistant so glucose moves towards baby
What do black dots represent on B-cell histology?
Lymphocytes
What autoantibodies are involved in diabetes?
- Iselt cell
- Insulin
- GAD (GAD65)
- Tyrosine phsophatases
- Positive in 85-90%
What does GAD stand for?
Glutamic acid decarboxylase
What genes is HLA associated with in the development of type 1 diabetes?
- DQA and DQB genes
- Influenced by the DRB genes
How do patients monitor blood glucose?
Capillary blood glucose
What is a “basal bolus” regime?
- Bolus of long-acting insulin taken once a day (usually night time) adjusted nased on morning blood sugar
- Then vary amount of insulin given before main meals based on pre-test blood sugar
What is CS 2?
- Pump therapy
- Continous subcutaneous infusion of insulin therapy - permenant glucose monitor measures blood glucose
What genetic factors lead to type 2 diabetes?
- Defect of Beta cell
- Insulin resistance
What environmental factors lead to type 2 diabetes?
- Obesity
- Stress
- Reduced physical activity
How can type 2 diabetes classically present itself?
- Thirst, polyuria
- Malaise, fatigue
- Infections (e.g candidiasis)
- Blurred vision
- Complications
- Incidental finding
What type of drug is metformin?
Biguanide
What are examples of sulphonylureas?
- Chlorpropamide
- Glipizide
- Gliclazide
What are the acute complications of diabetes mellitus?
- Diabetic ketoacidosis
- Hypoglycaemia
- Other emergencies
What are the chronic complications of diabetes mellitus?
Microvascular - Eyes - Kidneys - Nerves (feet) Macrovascular - Hear - Brain - Feet
What does low Na+, low bicarbonate and high glucose indicate on a blood sample in a ward?
Diabetic ketoacidosis
What are the clinical features of diabetic Ketoacidosis?
Hyperglycaemia - dehydration - Tachycardia - Hypotension - Clouding of consciousness Acidosis - Kussmaul's respiration - Acetone on breath - Abdominal pain - Vomitting SEPSIS?
How does the body create ketones?
Amino acids (leucine, lysine) and adipose tissue (free fatty acids) liver breaks down into ketones
What are examples of ketone bodies in the blood whcih the liver has created?
- Acetoacetate (acetone + carboxyl group)
- 3 Beta - Hydroxybutyrate
- Acetone
They are organic acids
What electrolyte loss is most concerning in ketoacidosis?
K+ (200-700 mmol loss) can lead to arrhythmias and death
How many litres of water can be lost in diabetic ketoacidosis?
5 - 10 litres
What ketone levels are worrying?
Anything above 1 mmol/L
How is DKA treated?
- Insulin IV 6U/hour then by sliding scale
- IV sailine (4-6 L)
- Dextrose subsequently to replace water loss
- K+ monitored and replaced as required
What are symptoms of hypoglycemia?
Adrenergic - Tachycardia - Palpitations - Sweating - Tremor - Hunger Neuroglycopaenic - Dizziness - Confusion - Sleepiness - Coma - Seizure
What are neuroglycopaenic symptoms of hypoglycemia?
Lack of glucose to brain
What are the causes of hypoglycaemia?
- Too much insulin
- Too little food
- Unusual exercise
What is the formal definition of hypoglycemia?
Blood glucose <= 2.2 mmol/l
What blood glucose is considered low?
4 mmol/L
- Aim to keep blood glucose above 4
What mechanisms cause an increase in blood glucose in response to hypoglycaemia?
Parasympathetic glucagon release and sympathetic adrenaline release whcih both stimulate glycogen release by the liver
How is hypoglycaemia treated?
- IV 50% dextrose (by expert, can cause sclerosis in subcutaneous tissue)
- Glucogel
What other emergencies other than DKA and hypoglycaemia are involved with diabetes mellitus?
- HyperOsmolar Hyperglycemic state or Hyper osmolar Non-Ketonic coma (HONK)
- Metformin Associated Lactic Acidosis (MALA)
What is HyperOsmolar Hyperglycemic state (HONK)?
Enough insulin to produce ketones but not enough to stop them becomeing hypoglycaemic (become dehydrated)
- Elderly patients (MI and Chest infection associated)
What does Metformin Associated Lactic Acidosis (MALA) cause?
- Have renal impairment
- Metformin builds up and uncouples mitochondria causes build up of lactic acid
When should metformin be avoided?
In patients with kidney disease (can cause MALA
What is glycation?
- Non-enzymatic binding of glucose to proteins (can cause rearrangement and cross linking, proteins become stick and brown)
- Amadori rearrangement
- Schiff base
- Ketoamine
- 5_hydroxy-methylfurfural
What is a classic nephropathy as a result of diabetes?
Kimmelsteil-Wilson lesion
Kimmelsteil-Wilson lesion on histology
Extra purpal staining
What are the different stages of nephropathy?
- Hyperfiltration
- Normal
- Microalbinuria
- Overt Nephropathy
- Chronic renal failure
How is nephropathy managed?
- Screening (albustix, microalbinuria, creatinine)
- BP (ACEi, ARBs) (130/80 or lower)
- Hyperlipidaemia (statins)
- Good glycaemic control
- Diet
How does diabetes effect nerves?
Lumen more closed over ischaemic nerve
What should be examined on the foot?
- General appearence
- Architecture
- Pulses
- Sensation (monofilament, neurosthesiometer)
How is diabetic retinopathy managed?
- Screening (once a year)
- Opthalmascope or retinal camera
- Blindess audit
What is maculopathy?
Protein and fat deposition around macula (migrates on to macula causing loss of fine vision and vision)
How is diabetic maculopathy treated?
- Periphery of retina burned with laser reducing ischaemic area
- Preserves macula vision
What does a pre-retinal haemorrhage look like?
Huge black area on retina