Sun28November0628PM 13

You are asked to review a 45-year-old man with type 2 diabetes who has been treated with IV co-amoxiclav for an ulcer on his left foot. In total he has received three days of oral therapy and is on his fourth day of intravenous medication.

The nurses are concerned as he has developed a generalised erythematous rash and a fever. He is pyrexial 38.4°C. It appears that the foot ulcer is clean and healing well. His BP is 135/72 mmHg, pulse is 80 and regular.

Investigations reveal:

Hb 105 g/L (115-160)

WCC 11.5 ×109/L (4-10)

Eosinophils 2.5 ×109/L (0.04-0.4)

PLT 222 ×109/L (130-400)

Na 137 mmol/L (135-145)

K 5.6 mmol/L (3.5-5.5)

Urea 12.4 mmol/L (2.5-8)

Cr 255 µmol/L (70-120)

(increased from 155 on admission)

Urine blood +

protein +

Eosinophils seen on urine microscopy

Which of the following is the most appropriate next intervention?

(Please select 1 option)

Start IV methylprednisolone

Start oral prednisolone

Start IV cyclophosphamide

Start IV normal saline

Discontinue co-amoxiclav Correct

Explanation

This patient has acute interstitial nephritis as a result of penicillin therapy. The principal mechanism in acute tubulointerstitial nephritis is a hypersensitivity reaction to drugs such as penicillins, non-steroidal anti-inflammatory drugs (NSAIDs), and sulphonamides. It can also occur as a result of acute cellular injury caused by infection, both viral and bacterial.

Unlike chronic interstitial nephritis it appears that tubular damage is reversible on cessation of medication. In total acute tubulointerstitial nephritis is thought to account for up to 15% of patients presenting with acute kidney injury.

Corticosteroids are generally initiated within a few days if symptoms have not improved on cessation of the causative agent. There are no randomised controlled trials, although evidence from case series suggests they accelerate recovery.

IV rehydration will not remove the cause of the hypersensitivity reaction and as such is an ineffective option here.

Answer Statistics

1

14%

2

11%

3

1%

4

4%

5

72%

Times answered: 284