Monday, 8 November 2010

MRCP revision battle 43.4: Haematuria

When considering haematuria you need to subdivide into microscopic and macroscopic.

Causes of transient, non-visible/microscopic haematuria include:
  • UTI/pyelonephritis
  • menstrual period
  • vigorous exercise
  • sex

Causes of persistent, non-visible/microscopic haematuria include:
  • renal stones
  • prostatitis
  • urethritis
  • stones
  • cancer
  • benign prostatic hypertrophy
  • IgA nephropathy
  • benign familial haematuria

Macroscopic haematuria can be caused by:
  • infection: UTI
  • renal disease: renal papillary necrosis, IgA nephropathy, glomerulonephritis
  • malignancy- although note just 4% of cases of bladder cancer will be asymptomatic except for haematuria
  • renal stones
  • prostatic hypertrophy

NICE guidelines demand urgent referral for:
  • patients of any age with painless macroscopic haematuria
  • patients aged 40+ with recurrent/persistent UTI and haematuria
  • patients aged 50+ with unexplained microhaematuria

And as always consider whether the result could be spurious;  false positive blood on dipstick can occur with:
  • beetroot
  • porphyria
  • alkaptonuria
  • rifampicin

Just a brief note at the end of this battle on benign familial haematuria.  This accounts for around 25% of patients referred to nephrologists with microscopic haematuria.  It is associated with the basement membrane being thinner than normal (<250nm compared with normal 450nm).   Patients generally have a normal BP and normal renal function.  They are however followed up as there is a small risk of renal failure.

Now on to a battle I fight daily in my current job... renal stones...