ChemPath: Diabetes CPC Flashcards
Define diabetes based on:
- Fasting plasma glucose
- 2-hour oral glucose tolerance test
- HbA1c
-
Fasting plasma glucose
- > 7 mmol/L
-
2-hour oral glucose tolerance test
- > 11.1 mmol/L
-
HbA1c
- More than 48 mmol/mo (6.5%)
List some causes of metabolic alkalosis.
- H+ loss (e.g. vomiting)
- Hypokalaemia
- Ingestion of bicarbonate
Why is respiratory compensation for alkalosis usually quite poor?
Metabolic alkalosis inhibits ventilation but ventilation must remain sufficient to maintain good oxygen levels
State the equation for plasma osmolality.
Osmolality = 2(Na + K) + Urea + Glucose
Equation of anion gap
Na + K - Cl - bicarb
List some causes of hypokalaemic alkalosis.
- Intestinal loss (diarrhoea, vomiting, fistula)
- Renal loss (minerlocorticoid excess, diuretics, renal tubular disease, osmotic diuresis, increased sodium delivery to distal nephron)
- Redistribution (insulin, alkalosis, beta-agonists)
- Rare (renal tubular acidosis type 1 and 2, hypomagnesaemia)
i.e. causes of hypokalaemia
Outline the relationship between hypokalaemia and alkalosis.
- Low K+ leads to a shift of H+ into cells
- This causes alkalosis
- Similarly, low H+ will result in a shift of K+ into cells
Complications of hypo and hyper kalaemia
Hypokalaemia - VF
Hyper - Asystole
How can ectopic ACTH be distinguished from other causes of Cushing’s syndrome?
Ectopic ACTH cannot be suppressed by high-dose dexamethasone suppression test
Which cause of Cushing’s syndrome is most commonly associated with hypokalaemia?
Ectopic ACTH
Causes of ectopic ACTH
Cancers
Why might a patient with Cushing’s syndrome be hypotensive?
Diuresis can lead to dehydration and hypotension
What is the only definitive way of distinguishing acute renal failure from chronic renal failure?
Renal biopsy
How might ATN due to dehydration be treated?
3 weeks of dialysis
What treatment might diabetic glomerular kidney disease require?
This can result in end-stage renal failure requiring dialysis.
