Chronic Kidney Disease Flashcards
If you detect a one-off finding of eGFR below 60 on a blood test, what are 4 things that need to be done?
- If otherwise well, repeat U+E in 2 weeks to check for resolution or deterioration
- Check urine for protein (ACR), haematuria (indicating renal disease) and dipped or sent for an MSU to rule out a UTI
- History to cover other medications that can trigger drop in eGFR and any recent illnesses that may have caused dehydration such as diarrhoea
What are 4 causes of a drop in eGFR?
- Acute/ secondary to dehydration (e.g. diarrhoea)
- Infection
- Nephrotoxic medications
- CKD
What are 6 criteria that can lead someone to be diagnosed with CKD?
- Markers of kidney damage such as proteinuria (urinary albumin:creatinine ratio [ACR] greater than 3 mg/mmol)
- urine sediment abnormalities
- electrolyte and other abnormalities due to tubular disorders
- abnormalities detected by histology
- structural abnormalities detected by imaging and a history of kidney transplantation, and/or
- A persistent reduction in renal function shown by a serum estimated glomerular filtration rate (eGFR) of less than 60 mL/min/1.73 m2.
Over what urinary ACR would CKD be diagnosed?
3 mg/mmol
What is the definition and minimum time frame of CKD?
Presence of abnormal kidney structure or function for >3 months
What are the 2 things that are used for classification of CKD?
- eGFR: G1-5
- Albuminuria: A1-3
What are the stages of chronic kidney disease as defined by eGFR?
- stage 1: >90
- stage 2: 60-89
- stage 3a: 45-59
- stage 3b: 30-44
- stage 4: 15-29
- stage 5: <15
Where is CKD generally managed and what are 7 exceptions?
Generally managed in primary care. Exceptions:
- uncontrolled hypertension: on 4 agents at therapeutic doses
- Polycystic kidneys, other rare of genetic causes
- Suspected renal artery stenosis
- Accelerated progression: drop of 25% in eGFR over 1 year AND hange in CKD category or drop of 15ml/min/1.73m2
- Renal anaemia
- Urinary ACR of >70mg/mmol (non-diabetic)
- ACR>30mg/mmol associated with haematuria
- eGFR<30
Should a statin be offered in CKD?
If eGFR<60, yes - offer statin to all these people regardless of QRISK score, as those with CKD 20x more likely to die from cariovascular disease than end stage renal failure
What regime of statin should patients with eGFR<60 be started on?
Atorvastatin 20mg, recheck in 3months
Aim for reduction in non-HDL cholesterol of 40% and titrate up
What are the blood pressure targets in CKD?
Based on protein levels
- If ACR <70mg/mmol aim for less than 140/90
- if >70 aim for <130/80
Make sure not too low, as once systolic <120 and diastolic <60 mortality and morbidity start to rise as eGFR decreases, and risk of end-stage renal failure increases
What is the recommended antihypertensive management in CKD?
If blood pressure within target, still recommend ACEi or AiiRA to reduce reduce progression of kidney disease IF ACR >30mg/mmol
What safety netting is needed when starting an ACEi? 3 things.
- Check U+E within 14 days to check for acute renal failure or renal artery stenosis (drop in eGFR, creatinine and/or potassium)
- BP: check it’s not too low and titrate ACEi up to best tolerated dose, checking bloods with each increase
- Advise to stop ACEi if used solely for CKD if diarrhoea/vomiting as can cause volume depletion, reducing flow to kidneys and may cause AKI
What are 5 things to warn a patient about with CKD regarding preventing AKI?
- Check U+Es 14 days after starting ACEi - check for drop in eGFR, creatinine and/or potassium
- Warn to stop if diarrhoea and vomiting due to dehydration risk if taking ACEi just for CKD
- Stop taking if you have a high fever
- Don’t use NSAIDs, not even topical
- Yearly influenza immunisations
What are 4 things that are used to calculate eGFR?
- Creatinine
- Age
- Gender
- Ethnicity
What are 3 scenarios when eGFR isn’t valid?
- <18 years
- Pregnancy
- Acute kidney injury (renal function changing rapidly)
What is an additional factor that can affect eGFR (other than creatinine, agen, gender, ethnicity)?
Extreme body mass: high or low, e.g. very obese and body builders
Why is serum creatinine no longer used to measure kidney function on its own?
When kidney function first declines, little change in serum creatinine so kidney disease could be missed
How is proteinuria now measured?
Using urinary albumin: creatinine ratio
What should patients be told before their ACR is calculate from a urine sample?
Should be told not to eat meat within 12 hours of having sample taken
What is the definition and time frame of chronic kidney disease?
Presence of abnormal kidney structure or function for >3 months
What are the boundaries for the 3 ACR categories in chronic kidney disease?
- A1: <3 [low]
- A2: 3-30
- A3: >30 [high]
What increases as ACR increases in CKD?
Risk of poor CKD outcome increases
How are eGFR and ACR used together to classify chronic kidney disease?
e.g. GFR of 35ml/min - CKD stage G3b, ACR or 20mg/mmol = A2
So: G3b A2, fall within high risk category (red area of table) for progression of chronic kidney disease
What proportion of the UK population is likely to have chronic kidney disease?
10% - relatively common
majority have 1, 2 o 3, small percentage 4 or 5
What is Stage 5 chronic kidney disease?
eGFR <15, end stage renal failure
Kidneys no longer sufficient to sustain life or health
Need haemodialysis, peritoneal dialysis, or transplantation
If too frail, palliative care
What are 6 key groups to think that chronic kidney disease may occur in?
- Hypertension
- Diabetes
- Multiple drugs especially NSAIDs
- Elderly
- Smokers - current o previous
- Poor education
What are the 2 commonest causes of chronic kidney disease in the UK?
Diabetes and renovascular disease
What are 2 examples of rarer causes of chronic kidney disease?
- Genetic e.g. autosomal dominant polycystic kidneys
- Vasculitis
- Glomulonephritis
How does chronic kidney disease relate to socioeconomic status?
Association between CKD and lower socio-economic status
What are 7 overall causes of chronic kidney disease?
- Systemic disease
- Immune mediated diseases
- Infectious diseases
- Genetic diseases
- Arterial disease
- Obstruction
- Drugs
What are 4 examples of systemic disease that can cause chronic kidney disease?
- Diabetes
- Hypertension
- SLE
- Vasculitis
What are 3 immune-mediated causes of chronic kidney disease?
- Membranous nephropathy
- IgA nephropathy
- Myeloma
What are 4 infectious diseases that can cause chronic kidney disease?
- HIV
- HBV
- HCV
- TB
What are 2 examples of genetic diseases which can cause chronic kidney disease?
- Polycystic kidneys
- Cystinosis
What are 2 examples of arterial disease that can cause chronic kidney disease?
- Atherosclerosis
- Fibromuscular dysplasia (impaired blood flow to kidneys)
What are 4 causes of obstruction that can cause chronic kidney disease?
- Tumours
- Benign prostate
- Stones
- Fibrosis
What are 2 examples of drugs which can cause chronic kidney disease?
- NSAIDs
- Calcineurin inhibitors e.g. tacrolimus and cyclosporin
In what proportion of patients with diabetes (type 1 and 2) does renal disease occur?
40%
What is diabetic nephorpathy usually seen in association with?
Associated with poor diabetes control and hypertension
In association with retinopathy, neuropathy - other diabetic complications
What is the pathology behind diabetic nephropathy? 5 elements
- Thickening of basement membrane
- Activation of renin-angiotensin system
- Mesangial expansion
- Glomerulosclerosis
- Proteinuria
What is the mechanism behind mesangial expansion?
- Hyperglycaemia stimulates increased matrix production by mesangial cells
- Stimulation of TGF-ß release
What is the mechanism of glomerulosclerosis in diabetes?
Intraglomerular hypertension or ischaemic damage
What causes proteinuria in diabetes?
Due to damage to the glomerulus; increases tubular damage and fibrosis
What can be seen on histology of kidneys in a diabetic patient with expansion of tissue in the glomerulus?
Kimmelstiel-Wilson nodules - amorphous pink material, loss of normal functioning glomerulus cells, los of open capillary loops
What are 3 key stages of the natural history of diabetic nephropathy?
- Onset of diabetes: raised GFR, reversible albuminuria, increased kidney size
- 5-15 years: increased glomerular basement membrane thickness, mesangial expansion. Rising BP, microalbuminuria
- 15-27 years: Inevitable decline in renal function, overt proteinuria, rise in creatinine and falling rGFR
What are 3 renal features likely to be seen at the onset of diabetes?
- Increased eGFR
- Reversible albuminuria
- Increased kidney size
What are 4 renal features likely to be seen 5-15 years after diagnosis of diabetes?
- Development of microalbuminuria in assoication with rising BP
- Rising BP
- Increased glomerular basement membrane thickness
- Mesangial expansion
What are 4 renal features seen in diabetes 15-27 years after onset, without treatment?
- Overt proteinuria
- Rise in creatinine
- Falling eGFR
- Inevitable decline over next 7-10 years, reaching ESRF
What are 2 things that can be done in diabetes to reverse or prevent renal changes?
- Early improvement of diabetic control
- Early BP control
What are 4 features of diabetic nephropathy?
- >10 years diabetes
- other microvascular complications (retinopathy, neuropathy)
- Progressive increase in urine protein excretion over years
- No evidence of other probable cause (no haemturia, no symptoms of obstruction, negative immunology and serology tests)
How is diabetic nephropathy diagnosed?
Has all the typical features in history → presumed diagnosis of diabetic nephropathy (without renal biopsy)
if doesn’t meet all criteria, may need further investigations such as a renal biopsy
What is a common cause of glomerular disease which leads to CKD?
IgA nephropathy
What happens histologically in IgA nephropathy?
- Mesangial proliferation of glomerulus (inrceased number of mesangial cells)
- IgA deposited in glomerulus
What are 2 ways that patients may present with IgA nephropathy?
- Usually present with incidental finding of haematuria (non-visible) and proteinuria
- May also present with visible haematuria and associated upper respiratory tract infections
What are 2 key kidney biopsy changes seen after a period of time with chronic glomerular disease?
- Glomeruli replaced with amorphous pink sclerotic material with a few scattered cells between
- Damage to tubules; atrophied, deposition of fibrous material and scarring in between
What is an infective disease that can cause typical glomerular disease? What is this called?
HIV: HIV associated collapsing glomerulopathy
How can HIV lead to HIV-associated collapsing glomerulonephropathy?
HIV virus directly infecting kidney cells causing nephropathy
How could HIV indirectly cause kidney damage?
Acute and chronic kidney damage due to HIV drugs
What is the inheritance pattern of polycystic kidey disease?
Autosomal dominant
What is one of the commonest genetic causes of chronic kidney disease?
Autosomal dominant polycystic kidney disease
When and how does screening occur for polycystic kidney disease?
Early 20s by USS
If negative in early 20s, can be confident pt doesn’t have disease
What are the 2 main genes affected in autosomal dominant polycystic kidney disease?
PKD1 and PKD2
Is there specific treatment available for polycystic kidney disease?
No specific treatment currently available
Drugs therapy currently in trials (Tolvaptan) - to slow down development of renal cysts
How can vascular disease impact on renal function?
Can often cause renal artery stenosis; seen in patients with atherosclerotic vascular disease elsewhere e.g. CVD, cerebral vascular disease, peripheral vascular disease
What is the screening test for vascular disease causing renal artery stenosis?
MR angiogram (sometimes conventional angiography)
see loss of lumen in right renal artery, small kidney due to ischaemia
What are 2 types of tumours that can cause CKD by obstruction?
- Intrinsic: obstruct ureteric orifices. can develop in bladder or ureter, obstructing ureter or orifice, causing hydronephrosis in kidney
- Extrinsic: colonic carcinoma with retroperitoneal spread or in women - cervical carcinoma, spread to obstruct ureters. Prostate cancer in men
What can cause fibrosis that may lead to obstruction, in turn leading to CKD?
Can be in relation to previous inflammation/ ifection, can cause obstruction in ureters or urethra