Corrections - Renal

Question 1

What is next step in management of a kidney stone with an obstructed, infected system?

Answer 1

This is an indication for urgent decompression –> often percutaneous nephrostomy.

Also IV Abx

Question 2

What size renal stones can be considered for extracorporeal shock wave lithotripsy (ESWL)?

Answer 2

Total volume of <2cm

Question 3

Management of large, proximal renal stones?

Answer 3

Percutaneous nephrolithotomy.

Question 4

What does a percutaneous nephrolithotomy involve?

Answer 4

1) Access is gained to the renal collecting system

2) Intra corporeal lithotripsy or stone fragmentation is performed and stone fragments removed.

Question 5

Define lithotripsy

Answer 5

A treatment, typically using US shock waves, by which a kidney stone is broken into small particles that can be passed out by the body.

Question 6

What is a normal anion gap?

Answer 6

8-14 mmol/L

Question 7

How is the anion gap calculated?

Answer 7

(Na+ + K+) - (Cl- + HCO3-) = anion gap

Question 8

What are some causes of a raised anion gap metabolic acidosis?

Answer 8

1) Lactate: shock, hypoxia

2) Ketones: DKA, alcohol

3) Urate: renal failure

4) Acid poisoning: salicylates, methanol

5) 5-oxoproline: chronic paracetamol use

Question 9

What are some causes of a normal anion gap or hyperchloraemic metabolic acidosis?

Answer 9

1) GI bicarb loss: diarrhoea, ureterosigmoidostomy, fistula

2) Renal tubular acidosis

3) Drugs e.g. acetazolamide

4) Ammonium chloride injection

5) Addison’s disease

Question 10

What type of acid base disturbance does renal tubular acidosis cause?

Answer 10

Hyperchloraemic metabolic acidosis with a normal anion gap

Question 11

Management of patients with obstructive urinary calculi and signs of infection?

Answer 11

Urgent renal decompression and IV antibiotics due to the risk of sepsis

Question 12

What is the imaging of choice in suspected renal colic?

Answer 12

Non-contrast CT KUB

Question 13

What does fat stranding indicate on a CT scan in renal colic?

Answer 13

Fat stranding can occur beside the ureter (periureteric fat stranding) –> this can indicate recent stone passage if a ureteric calculus is not present.

Fat stranding can also occur beside the kidney –> this can indicate pyelonephritis

Question 14

What can periureteric fat stranding on a CT indicate if a ureteric calculus is not present?

Answer 14

Recent stone passage

Question 15

What analgesia can be given in renal colic if NSAIDs are contraindicated?

Answer 15

IV paracetamol

Question 16

What electrolyte abnormality is seen in renal tubular acidosis type 1 & 2?

Answer 16

Hypokalaemia