Nephrology MRCP

Question 1

Proteinuria guidelines: ACR thresholds

Answer 1

Collecting an ACR sample
by collecting a ‘spot’ sample it avoids the need to collect urine over a 24 hour period in order to detect or quantify proteinuria
should be a first-pass morning urine specimen
if the initial ACR is between 3 mg/mmol and 70 mg/mmol, this should be confirmed by a subsequent early morning sample. If the initial ACR is 70 mg/mmol or more, a repeat sample need not be tested.

Question 2

Proteinuria guidelines: referral to nephrologist

Answer 2

NICE recommendations for referral to a nephrologist:
a urinary albumin:creatinine ratio (ACR) of 70 mg/mmol or more, unless known to be caused by diabetes and already appropriately treated
a urinary ACR of 30 mg/mmol or more, together with persistent haematuria (two out of three dipstick tests show 1+ or more of blood) after exclusion of a urinary tract infection
consider referral to a nephrologist for people with an ACR between 3-29 mg/mmol who have persistent haematuria and other risk factors such as a declining eGFR, or cardiovascular disease

Question 3

Thrombotic thrombocytopenic purpura (TTP): pathogenesis

Answer 3

abnormally large and sticky multimers of von Willebrand’s factor cause platelets to clump within vessels
in TTP there is a deficiency of ADAMTS13 (a metalloprotease enzyme) which breakdowns large multimers of von Willebrand’s factor
overlaps with haemolytic uraemic syndrome (HUS)

Question 4

Thrombotic thrombocytopenic purpura (TTP): features

Answer 4

rare, typically adult females
fever
fluctuating neuro signs (microemboli)
microangiopathic haemolytic anaemia
thrombocytopenia
renal failure

Question 5

Thrombotic thrombocytopenic purpura (TTP): causes

Answer 5

post-infection e.g. urinary, gastrointestinal
pregnancy
drugs: ciclosporin, oral contraceptive pill, penicillin, clopidogrel, aciclovir
tumours
SLE
HIV