CKD Flashcards
What range does a normal GFR have?
~ 90-120ml/min (in 1.73m person)
note: using 100ml/min allows % values to be used
What are some of the signs and symptoms of chronic kidney disease?
Slow, progressive renal impairment: no symptoms until GFR falls below 30ml/min
Dialysis required at 8-10ml/min
- tiredness & lethargy
- breathlessness
- nausea & vomiting
- aches and pains
- sleep reversal
- nocturia
- restless legs
- itching
- chest pains
- seizures & coma
- pale
- pruritis
Define chronic kidney disease.
Irreversible and sometimes progressive loss of renal function over a period of months to years
What are some of the causes of CKD?
COMMON:
- vascular
- systemic disease e.g. diabetes, myeloma
- idiopathic (most common in those who require dialysis)
- immunological e.g. glomerulonephritis
- polycystic kidney disease
- obstruction reflux nephropathy
- hypertension
What are some of the histological features of CKD?
Atrophy of cortex
Shrunken kidney
Irregular outline
Kidney scarring
note: renal injury causes renal tissue to be replaced by fibrin
How can CKD be classified?
GFR (ml/min/1.73m^2):
G1 = >90ml/min (therefore it is possible to have kidney disease but have a normal GFR)
G2-G4 = decreased GFR relative to young adult level
G5 = kidney failure
ACR (albumin:creatinine) (mg/mmol):
A1-A3 = increased ACR relative to young adult level
What proportion of the population have CKD?
~12% have CKD G1-G3
Outline the prognosis of CKD.
- associated with substantial cardiovascular morbidity & mortality (often before requiring dialysis)
- some patients inevitably lose renal function despite treatment
- greatly shortened life expectancy with renal failure (renal transplant > dialysis)
- at ~75% GFR renal function decline accelerates
- dialysis required at ~2%-10% GFR
- proteinuria indicates worse prognosis/increased risk of CVD
What are some of the problems in measuring GFR?
Serum creatinine = ~80-120umol/l
INACCURATE - GFR can decline to 60% before [creatinine]serum is abnormal
eGFR (applies modifiers for age, sex, race)
- only accurate in adults
- not useful in AKI, intermittent illness, haemodynamic problems (as eGFR relies on the GFR being stable)
How can the cause of CKD be assessed?
Blood e.g. autoantibody screen, complement, Ig, ANCA, CRP, etc. (if glomerulonephritis is suspected)
Imaging - ultrasound (size, ?hydronephrosis), CT, MRI (structural abnormalities)
Angiography (?renal artery stenosis)
Renal biopsy (if kidneys are normal size & cause of CKD is not obvious)
What is polycystic kidney disease?
Can be autosomal dominant or recessive
Multiple cysts develop on the kidney, eventually replacing normal kidney tissue
Do not develop kidney failure until ~50-60yrs
note: one or two cysts on kidneys normal and usually harmless
What are some of the complications of CKD?
Acidosis = affects muscle, bone, renal function (treat with NaHCO3 tablets)
Anaemia due to:
- reduced EPO production
- resistance to EPO (uraemic environment)
- reduced RBC survival (releases urea -> uraemic environment)
- blood loss (reduced platelet function)
Bone disorders due to reduced GFR:
- reduces active vit. D (kidney cannot hydroxylate) —> osteomalacia
- increases phosphate (reduced excretion) —> reduces calcium (maintenance of calcium phosphate product)
- reduced calcium & reduced active vit. D —> increases PTH —> osteitis fibrosa cystica
+ abnormal bone turnover, mineralisation, volume, linear growth, and strength of bones (renal osteodystrophy)
+ bone cysts, erosion to terminal phalanges, sclerosis of end plates (“rugger jersey spine”)
+ vascular/soft tissue calcification e.g. aorta, extra-articular, calciphylaxis (calcification of vessels & skin necrosis)
What are some considerations which need to be made in giving drugs to CKD patients?
Dose alteration required due to reduced metabolism/elimination
Drug sensitivity can be increased even if elimination is unaffected ——–> side-effects more likely
e.g. statins (even though they are metabolised by the liver)
How is CKD treated?
- lifestyle (to reduce CVD risk) e.g. stop smoking, lose weight, exercise
- treat diabetes if present (to reduce CVD risk)
- treat hypertension if present (to reduce CVD risk)
- ACE inhibitors/angiotensin receptor blockers in proteinuria (reduces CVD risk, reduces proteinuria, slows renal function decline)
- renal therapy (dialysis/transplant) = indicated when eGFR <8-10ml/min
When is dialysis indicated?
eGFR =< 8-10ml/min
- uraemic symptoms e.g. reduced appetite, nausea/vomiting, pruritis
- acidosis —> bone disease/muscle wasting
- pericarditis
- fluid overload
- hyperkalaemia
