ChemPath: Diabetes CPC

Question 1

What would you see on ABG with metabolic alkalosis?

Answer 1

High pH
High pCO2

Question 2

List causes of metabolic alkalosis

Answer 2

1. H+ loss (vomiting)
2. Hypokalaemia
   - T2DM (high insulin drives K+ into cells)
   - Cushing’s (high cortisol activates aldosterone receptor)
3. Ingestion of bicarb (antacids)

Question 3

How are potassium and H+ related?

Answer 3

Hypokalaemia and alkalosis are related, they cause each other

Low K+ -> K+ out of cells to compensate -> H+ has to go in -> alkalosis

Low H+ -> H+ out of cells to compensate -> K+ has to go in -> hypokalaemia

Question 4

Which cause of Cushing’s is most commonly associated with hypokalaemia? (And why?)

Answer 4

Ectopic (SCLC)

As only very high levels of cortisol can induce the aldosterone receptor

Question 5

What is the only definitive way of distinguishing acute and chronic renal failure?

Answer 5

Renal biopsy

Question 6

HDDST - how does it differentiate between pituitary and ectopic Cushing’s?

Answer 6

Pituitary: cortisol suppressed to half
Ectopic: cortisol not suppressed at all

*however not used anymore due to high rate of false positives

Question 7

What does increased vocal resonance (resp exam) suggest?

Answer 7

Increased vocal resonance: Solids e.g. consolidation/tumour

Decreased vocal resonance:
Liquids e.g. effusion

Question 8

What’s the treatment for ATN?

Answer 8

3 weeks dialysis

Question 9

What does hypotension in a diabetic patient suggest?

Answer 9

Polyuria, dehydration (osmotic diuresis).

If acute -> HHS