A 44 year old man with previous interstitial nephritis (22)

This man was diagnosed with interstitial nephritis secondary to mesalazine (prescribed for ulcerative colitis) in 2009.  His eGFR has remained stable since and is curently 42.  Last year he was started on lisinopril for hypertension but this was stopped some months later as his BP was too low.  The plan then was to reintroduce if BP over 130/80 or if proteinuria worsened.  Urinary PCR was 15 mg/mmol.

His PCR has increased a bit to 20; blood pressure on his last two visits 123/83, 124/96.  I just wanted to check that we should add in lisinopril 2.5mg in vew of this.

I also note that his cholesterol was recently 6.1, LDL 4.2, chol/HDL ratio 4.2.  I wonder if we should be starting a statin also?  He has no significant family history of heart disease and is an ex-smoker.  Other therapy is azathioprine (only) for ulcerative colitis.

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That level of proteinuria, just outside the normal range, wouldn’t trigger me in his case.  Any threshold is going to be arbitrary, but 50 is sometimes uesd.  Consistently over 50 maybe.  His BP is well within limits. His CV risk is low (see Further Info)

Proteinuria is in general a strong marker for progression of renal disease, with higher levels indicating much higher risk.  Mostly we are talking about glomerular leaking of protein.  He actually had tubulointerstitial disease rather than glomerular, which is associated iwth lower levels of proteinuria in general, and lower risk of progression if the cause is removed (as it is in him).

If he showed any signs of long term deterioration I’d be stricter but he seems to have experience a small fall in creatinine over the last couple of years.

Further info

  • CV risk calculator gives him a 10y risk of CV events of 3.6% – this does not include proteinuria however, which would ‘usually’ probably at least double risk, though this is contentious in this patient’s unusual circumstances.
  • Interstitial nephritis (Edren Textbook)
  • The Edrep Glomerulonephritis page has a link to a 10 min lecture on Interstitial nephritis (requires Flash).  The Resources page there has more links