Renal Flashcards
ADPKD
-How common is this?
-What disease loci have been identified?
Autosomal dominant polycystic kidney disease (ADPKD) is the most common inherited cause of kidney disease, affecting 1 in 1,000 Caucasians. Two disease loci have been identified, PKD1 and PKD2, which code for polycystin-1 and polycystin-2 respectively
ADPKD type 1 and type 2
-Which is more common?
-Which chromosome corresponds to which type?
-Which presents with renal failure earlier
ADPKD type 1 ADPKD type 2
85% of cases 15% of cases
Chromosome 16 Chromosome 4
Type 1 - Presents with renal failure earlier
What is the screening investigation for ADPKD?
The screening investigation for relatives is abdominal ultrasound
What is the ultrasound diagnostic criteria for ADPKD
-if aged <30
-If aged 30-59
-If aged >60
Ultrasound diagnostic criteria (in patients with positive family history)
two cysts, unilateral or bilateral, if aged < 30 years two cysts in both kidneys if aged 30-59 years four cysts in both kidneys if aged > 60 years
What can be used for treatment in ADPKD? what are the criteria for treatment 3?
For select patients, tolvaptan (vasopressin receptor 2 antagonist) may be an option. NICE recommended it as an option for treating ADPKD in adults to slow the progression of cyst development and renal insufficiency only if:
they have chronic kidney disease stage 2 or 3 at the start of treatment there is evidence of rapidly progressing disease and the company provides it with the discount agreed in the patient access scheme.
What are 7 features of ADPKD?
Features
hypertension recurrent UTIs flank pain haematuria palpable kidneys renal impairment renal stones
What are 4 extra renal manifestations of ADPKD?
Extra-renal manifestations
liver cysts (70% - the commonest extra-renal manifestation): may cause hepatomegaly berry aneurysms (8%): rupture can cause subarachnoid haemorrhage cardiovascular system: mitral valve prolapse, mitral/tricuspid incompetence, aortic root dilation, aortic dissection cysts in other organs: pancreas, spleen; very rarely: thyroid, oesophagus, ovary
Give 5 causes of chronic kidney disease?
diabetic nephropathy
chronic glomerulonephritis
chronic pyelonephritis
hypertension
adult polycystic kidney disease
What may affect eGFR? 3
Factors which may affect the result
pregnancy muscle mass (e.g. amputees, body-builders) eating red meat 12 hours prior to the sample being taken
What CKD stage corresponds to what eGFR range?
1
2
3
4
5
CKD stage GFR range
1 Greater than 90 ml/min, with some sign of kidney damage on other tests (if all the kidney tests* are normal, there is no CKD)
2 60-90 ml/min with some sign of kidney damage (if kidney tests* are normal, there is no CKD)
3a 45-59 ml/min, a moderate reduction in kidney function
3b 30-44 ml/min, a moderate reduction in kidney function
4 15-29 ml/min, a severe reduction in kidney function
5 Less than 15 ml/min, established kidney failure - dialysis or a kidney transplant may be needed
give 8 possible features of CKD
Possible features include:
oedema: e.g. ankle swelling, weight gain polyuria lethargy pruritus (secondary to uraemia) anorexia, which may result in weight loss insomnia nausea and vomiting hypertension
Describe the pathophysiology of CKD and bone disease?
Basic problems in chronic kidney disease (CKD):
1-alpha hydroxylation normally occurs in the kidneys → CKD leads to low vitamin D the kidneys normally excrete phosphate → CKD leads to high phosphate
This, in turn, causes other problems:
the high phosphate level 'drags' calcium from the bones, resulting in osteomalacia low calcium: due to lack of vitamin D, high phosphate secondary hyperparathyroidism: due to low calcium, high phosphate and low vitamin D
What is the aim in management of renal bone disease?
The aim is to reduce phosphate and parathyroid hormone levels.
Overview
reduced dietary intake of phosphate is the first-line management phosphate binders vitamin D: alfacalcidol, calcitriol parathyroidectomy may be needed in some cases
What phosphate binders can be used for patients with renal bone disease?
Phosphate binders
aluminium-based binders are less commonly used now
calcium-based binders
problems include hypercalcemia and vascular calcification
sevelamer
a non-calcium based binder that is now increasingly used
binds to dietary phosphate and prevents its absorption
also appears to have other beneficial effects including reducing uric acid levels and improving the lipid profiles of patients with chronic kidney disease
What does ACR 30 / 70 correspond to in terms of PCR and total protein?
ACR 30 - PCR 50 - urinary protein exc. 0.5
ACR 70 - PCR 100 - urinary protein exc 1
How is ACR sample collected?
When would you need a repeat early morning sample?
What is a significant ACR?
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.
Interpreting the ACR results
the NICE guidelines state ‘regard a confirmed ACR of 3 mg/mmol or more as clinically important proteinuria’
In what 3 situations would you refer to a nephrologist ?
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
Haematuria
-What is used to test for this?
-What is persistent, non-visible haematuria defined as?
-what other 3 things should be checked when haematuria is found?
Testing
urine dipstick is the test of choice for detecting haematuria
persistent non-visible haematuria is often defined as blood being present in 2 out of 3 samples tested 2-3 weeks apart
renal function, albumin:creatinine (ACR) or protein:creatinine ratio (PCR) and blood pressure should also be checked
urine microscopy may be used but time to analysis significantly affects the number of red blood cells detected
in what 2 situations does haematuria require urgent referral within 2 weeks?
Aged >= 45 years AND:
unexplained visible haematuria without urinary tract infection, or
visible haematuria that persists or recurs after successful treatment of urinary tract infection
Aged >= 60 years AND have unexplained nonvisible haematuria and either dysuria or a raised white cell count on a blood test
What requires a routine referral to urology?
Aged 60 >= 60 years with recurrent or persistent unexplained urinary tract infection
Since the investigation (or not) of non-visible haematuria is such as a common dilemma a number of guidelines have been published. They generally agree with NICE guidance, of note:
patients under the age of 40 years with normal renal function, no proteinuria and who are normotensive do not need to be referred and may be managed in primary care
what is nephritic syndrome?
haematuria and hypertension
What is nephrotic syndrome?
proteinuria, oedema
What accounts for 80% of nephrotic syndrome?
Primary glomerulonephritis accounts for around 80% of cases
minimal change glomerulonephritis (causes 80% in children, 30% in adults)
membranous glomerulonephritis
focal segmental glomerulosclerosis
membranoproliferative glomerulonephritis
What systemic disease can cause nephrotic syndrome?
Systemic disease (about 20%)
diabetes mellitus
systemic lupus erythematosus
amyloidosis
