RED URINE
History
Fiona is a 6-year-old girl who presents to the A&E department where her mother states that Fiona’s urine has turned red. She has brought a jar of urine which contains what appears to be reddish-brown urine. She has no dysuria, frequency or abdominal pain and there is no history of trauma. She is otherwise well but she and the rest of the family have recently had colds. There have been no nosebleeds or abnormal bruising. She has had no problems with her joints. She had a urinary tract infection at the age of 4 years, but following a normal renal ultrasound she was discharged from clinic. She is on no medication. There is no family history of renal problems but her grandmother has hypertension.
Examination
There is no anaemia. She is apyrexial. There is no skin rash or bruising. There is no oedema of the legs. There are no abdominal signs or joint abnormalities. Blood pressure is 124/80 mmHg. There are no other signs.
INVESTIGATIONS
Normal
Haemoglobin 11.7 g/dL 11.5–15.5 g/dL
White cell count 8.7 109/L 4.0–11.0 109/L
Platelets 372 109/L 150–400 109/L
Sodium 137 mmol/L 135–145 mmol/L
Potassium 4.1 mmol/L 3.5–5.0 mmol/L
Urea 11.3 mmol/L 1.8–6.4 mmol/L
Creatinine 145 mol/L 27–62 mol/L
Alkaline phosphatase 372 U/L 145–420 U/L
Bilirubin 16 mol/L 2–26 mol/L
Alanine aminotransferase (ALT) 32 U/L 10–40 U/L
Albumin 41 g/L 37–50 g/L
Clotting Normal Urine dipstick Blood 4+
Protein 2+
Leucocytes 1+
Nitrites Nil
Microscopy – red blood cells and red blood cell casts seen
Questions
• What further investigations should be performed?
• What is the most likely diagnosis?
• What is the treatment?
Medicine
The following investigations should be performed:
• throat swab
• anti-streptolysin O titre (ASOT), C3 and C4 – ASOT is raised and C3 is reduced in post-streptococcal glomerulonephritis
• ESR and ANA – will be abnormal in vasculitides, e.g. SLE
• abdominal X-ray and renal US – will demonstrate normality of kidneys and help exclude calculi. The most likely diagnosis is a post-streptococcal glomerulonephritis. This condition typically occurs approximately 2 weeks after a streptococcal upper respiratory tract infection (it may also follow a streptococcal skin infection). It can be associated with varying degrees of oliguria and renal failure (in this case there is mild renal failure). The casts indicate renal involvement. In cases of red urine or blood in the nappy, one should first ensure the blood is from the urinary tract and not from the rectum (e.g. due to constipation) or from the vagina (e.g. periods or abuse). Foods such as beetroot can lead to red urine. Haemoglobinuria due to haemolysis will also lead to red urine which will be dipstick-positive for blood but there will be no red blood cells on microscopy.
The causes of haematuria are:
• urinary tract infection
• nephritis – post-streptococcal glomerulonephritis – Henoch–Schönlein purpura – IgA nephropathy – nephrotic syndrome (20 per cent have haematuria at presentation)
• calculi
• trauma
• haematological – clotting disorders, haemolytic uraemic syndrome
• anatomical causes – polycystic kidneys, hydronephrosis
• tumours, e.g. Wilms’ tumour
• drugs, e.g. cyclophosphamide, aspirin
• factitious illness
• recurrent benign haematuria (a diagnosis by elimination).
Treatment is primarily symptomatic. A 10-day course of oral penicillin should be given but this will not alter the natural history of the glomerulonephritis. Fluids should be restricted to 1 L/day and the diet should have no added salt. Frusemide is helpful in cases of hypertension (this girl’s blood pressure is greater than the 95th centile for a 6-year-old girl) or oedema and will increase urine output. If hypertension persists, a calcium channel blocker such as amlodipine may be helpful. If heavy proteinuria develops or if renal function deteriorates, a renal opinion should be sought. Indications for dialysis include life-threatening hyperkalaemia and the clinical manifestations of uraemia. Outpatient follow-up will necessitate the monitoring of blood pressure, urea and electrolytes/creatinine and urine dipstick. More than 95 per cent of patients make a complete recovery. Complications include nephrotic range proteinuria and renal failure.
KEY POINTS
• Urinary tract infections, post-streptococcal glomerulonephritis and Henoch– Schönlein purpura account for the majority of cases of haematuria.
• Post-streptococcal glomerulonephritis has a very good prognosis.
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