Haematuria: diagnostic approach — formative SAQs

SAQ 1 — The school-age child with cola-coloured urine (10 marks, 15 minutes)

A 7-year-old boy presents with cola-coloured urine, peri-orbital swelling and a headache. His blood pressure is at the ninety-fifth centile for his age, sex and height. Two weeks earlier he had a febrile sore throat. The urine dipstick is positive for blood and protein, and microscopy shows red-cell casts and dysmorphic red cells. [8]

a) State the most likely diagnosis, and explain how the timing and the urine findings distinguish it from IgA nephropathy. (3 marks) [8] [6]

b) Give the expected complement pattern and the single serological test that supports the diagnosis, and state when the complement should normalise. (3 marks) [8] [7]

c) Outline your immediate management, including the approach to his blood pressure and fluid status. (4 marks) [8]

SAQ 2 — The dipstick that lies (10 marks, 15 minutes)

An unwell 8-year-old child is found to have a urine dipstick strongly positive for blood, but the microscopy shows no red cells. The child is lethargic and has muscle aching after a viral illness. [1]

a) Explain why this is not haematuria, and name the two diagnoses that must be excluded. (4 marks) [1]

b) State the two blood tests that confirm each diagnosis, and the immediate danger of each condition. (3 marks) [1]

c) Describe how you would confirm true haematuria in a different child, giving the quantitative threshold for microscopic haematuria. (3 marks) [1]