Blood in the urine (haematuria) may be visible to the naked eye or it may be microscopic and detected only by dipstick testing or by microscopy.
Blood in the urine (haematuria) may be visible to the naked eye or it may be microscopic and detected only by dipstick testing or by microscopy. The presence on microscopy of 10 or more RBCs per high-power field is abnormal. Urinary dipsticks are very sensitive and can be positive at <5 RBCs per high-power field. Asymptomatic haematuria is found in about 0.5–2% of children.
- An episode of macroscopic haematuria (causes the alarm to child/family).
- Incidental finding of microscopic haematuria.
- Family screening and routine urinalysis.
Other causes of red urine
The following can usually be distinguished from haematuria by taking a careful history, and with urine dipstick testing and microscopy:
- Foods—colouring (e.g. beetroot).
- Drugs (e.g. rifampicin).
- Urate crystals (in young infants, usually ‘pink’ nappies).
- External source (e.g. menstrual blood losses).
- Fictitious—consider if no cause found.
Causes of haematuria
- Urinary tract infections:
o viral (e.g. adenovirus in outbreaks);
o schistosomiasis (history of foreign travel);
o post-infectious glomerulonephritis;
o Henoch–Schönlein purpura IgA nephropathy, SLE;
o hereditary—thin basement membrane, Alport’s syndrome.
- Urinary tract stones: e.g. due to hypercalciuria.
- Other renal tract pathology:
o renal tract tumour;
o polycystic kidney disease.
- renal vein thrombosis;
- Haematological: coagulopathy/sickle cell disease.
- Drugs: cyclophosphamide.
- UTI: fever/frequency/dysuria.
- Renal stones: colicky abdominal pain.
- Glomerular: sore throat/rashes.
- Coagulopathy: easy bruising.
- Family history: haematuria, deafness (Alport’s), sickle cell disease.
- Abdomen: palpable masses.
- Skin: rashes.
- Joints: pain/swelling.
It is important to identify serious, treatable, and progressive conditions. During an acute illness, exclude UTI by urine culture. Asymptomatic or ‘benign haematuria’ in children without growth failure, hypertension, oedema, proteinuria, urinary casts, or renal impairment is a frequent find-ing. Many such children require no immediate investigation but need to be checked in the outpatient clinic to see if the problem persists.
- microscopy (look for casts—suggestive of nephritis) and culture;
- protein:creatinine ratio (normal, <20mg/mmol);
- calcium:creatinine ratio (normal, <0.7mmol/mmol).
- complement—C3/C4, ASOT titres;
- US urinary tract.
- Urinalysis of parents (hereditary causes).
- Cystoscopy: rarely indicated in children.
- If the obvious cause (e.g. UTI), treat.
- If the complex diagnosis (impaired renal function, proteinuria, or family
- history) refer to paediatric nephrology unit.
- If no cause found and normal renal function, BP, and no proteinuria,
- monitor until resolves.
- If no resolution after 6mths or change in any of the above parameters
- refer to paediatric nephrology unit.