CHEMPATH: Diabetes CPC Flashcards
first and last are correct
4th is incorrect because it needs to be 11.1
What is the criteria for diabetes diagnosis?
Symptoms + 1 diabetes test result
No symptoms + 2 diabetes test results
- Fasting ≥7.0mmol/L [whole fasted blood ≥6.1mmol/L]
- OGTT ≥11.1mmol>L
- HbA1c >6.5% / >48mmol/mol
- Random ≥11.1mmol/L
What is the cut off for IGT and IFG?
Impaired Glucose Tolerance (IGT) = OGTT, random = 7.8-11.1 mmol/L
Impaired Fasting Glucose (IFG) = Fasting = 6.1-7.0 mmol/L
What is the aBG abnormality?
pH 7.65; pCO2 6.1kPa (4.7-6.0); pO2 15kPa
Metabolic acidosis with partial respiratory compensation
Compensation makes the pH better and the CO2 worse
What are the causes of metabolc alkalosis?
Causes of metabolic alkalosis:
- H+ loss (i.e. vomiting)
- Hypokalaemia (and alkalosis)
- Ingestion of bicarbonate (i.e. lots of rennie
What is the osmolality formula?
2(Na + K) + U + G
In addition to bicarb, and all the others in the osmolality formula, what other result is needed to calculate anion gap?
Anion gap = Na + K – Cl – bicarb
What is the osmolality and anion gap?
- Bicarbonate = 55mM (20-24)
- Na = 145 ;
- K = 2.5
- U = 40
- pH = 7.65
- Glucose = 46
- Chloride = 80
- Osmolality = 2(Na + K) + U + G = 2(145+2.5) + 40 + 46 = 381 mOsm/kg
- Anion gap = Na + K – Cl – bicarb = 145 + 2.5 – 80 – 55 = 12
Is this DKA?
- Bicarbonate = 55mM (20-24)
- Na = 145 ;
- K = 2.5
- U = 40
- pH = 7.65
- Glucose = 46
- Chloride = 80
No - this is hypokalaemic alkalosis
What are the causes of hypokalaemia?
- GI losses (diarrhoea > vomiting, fistulas)
-
Renal losses –> low K+ + alkalosis
- MR excess
- Hyperaldosteronism/Conn’s
- Cushing’s
- Increased Na+ delivery to DCT
- Osmotic diuresis
- MR excess
-
Redistribution into cells
- Beta-agonists - think hyperkalaemia tx
- Insulin / insulinomas - think hyperkalaemia tx
- Alkalosis
-
Rare causes
- RTA T1, T2
- Hypomagnesaemia
- Low Mg2+ means you won’t be able to bring back up a ¯ K+ and so you have to correct the Mg2+ before you attempt to correct any ¯ K+
Where do thizide diuretics/loop diuretics affect the renal tubule?
- Triple- or co-transporter is blocked à less Na+ is resorbed in the ascending LoH –> more goes to DCT
- Triple = Loop diuretics (furosemide)
- Co-transporter = Thiazides (bendroflumethiazide)
- More Na+ reaches and is absorbed in the DCT à a more electronegative nephron
- This results in loss of K+ down the electrochemical gradient through ROMK channels
Blood results:
- ACTH = 250 (very high); Cortisol 3220nM (very high)
- Dexamethasone failed to suppress the axis
- Low dose; cortisol = 3100nM
- High dose; cortisol = 2990nM (i.e. totally failed to suppress)
What is the cause? Ectopic/adrenal tumour/pituitary disease?
Ectopic
- Pituitary disease would be suppressed by a high-dose test
- Adrenal tumours would suppress ACTH
What is a cause of ectopic ACTH?
Lung cancer (SCLS)
Respiratory exam shows this:
- Dull percussion on right side
- Vocal resonance increased on right side
What is the cause?
Suggests right-side collapse and consolidation
How can you distinguish between acute and chronic renal failure?
Biopsy
What is shown on this renal biopsy of the patient? What is the management of ATN?
- Shows very dehydrated tubules
- Tubules are necrosed but glomeruli intact
- This indicated ATN
- If ATN, dialyse for 3 weeks and they will recover
- If diabetic glomerular kidney disease (i.e. end-stage renal failure), they need lifelong dialysis
What is shown on this ECG?
II, III, aVF = inferior MI
