AKI, CKD, RRT Flashcards
What are the main functions of the kidney?
Homeostasis - fluid, electrolytes and acid-base balance
Hormone production - renin/angiotensin, vitamin D metabolites, EPO
Excretion of metabolites - organic acids, phosphates, urea/creatinine etc
What is AKI?
Acute kidney injury = a significant deterioration in renal function, which is potentially reversible, over a period of hours/days
How can an AKI be recognised?
RIFLE criteria = RISK, INJURY, FAILURE, LOSS, ESRD. Recognising change in creatinine, GFR and urine output. Graded (RIFLE) based on how much it has changed.
AKIN criteria = graded stage 1, 2, 3 based on creatinine and urine.
What are the 3 main causes of AKI/renal damage? Which are most common?
Pre-renal failure (85%)
Intrinsic renal failure (5%)
Post-renal failure (10%)
Give examples of Pre-renal failure
Renal hypoperfusion
- Systemic hypotension - hypovolaemia (bleeding/haemorrhage, massive dehydration, XS N+V)
- Local - renal artery stenosis (narrowing bf’s), drugs affecting perfusion to kidney (ACEi, NSAIDs)
Give examples of Intrinsic renal failure
- Primary renal disease - glomerulonephritis
- Secondary renal disease - diabetes, SLE, myeloma etc (all due to systemic conditions)
- Interstitial nephritis - usually drugs (allergic type reactions)
- Secondary acute tubular necrosis (ATN) - established after pre-renal failure that has extended over long period of time
Give examples of post-renal failure (what should always be considered?)
Obstruction/blockage of drainage from kidney:
- Prostate enlargement
- Cancer
- Kidney stones in ureter/bladder
- Compression
Always consider: where in relation to bladder? what can cause it?
What are the tests for renal dysfunction?
Blood tests:
Biochem = creatinine, eGFR, Na/K, HCO3-, Ca/Phos/PTH, CRP, creatine kinase
Haematology = Hb
Immunology = ANA, ANCA, anti-GBM, complement (C3,4) electrophoresis (IgA/G/M), serum free light chains (not all these are done, depends on location of systemic cause)
Urine tests: Urine dipstick (blood, proteins), urine output, MSU, Albumin Creatine ratio (ACR)/Protein Creatinine ratio (PCR), 24h creatinine clearance, urine creatinine/electrolytes/calcium
Radiological tests: Renal tract USS CXR (fluid assessment, pulmonary oedema in young) CT renal angiogram CT KUB Renogram
What is the initial management for AKI?
Keep patient alive
Review meds, close observation, fluid management
Diagnose cause + treat
What is CKD?
Chronic kidney disease: >90days kidney disease, often no specific innate disease of kidney more just co-morbidities affecting it, irreversible
What are the complications of CKD?
CVD (CAD), hypertension, anaemia, bone-mineral metabolism, poor nutritional + functional status, progression of CKD, AKI
How to measure CKD?
Test for renal excretory function: creatinine, cystitis C, eGFR,
Test for albuminuria (proteinuria)
Test for complications: Hb, K+, sBic, cCa, PTH
Diagnostic blood tests: ANCA, electrophoresis, Glc
Radiological tests: USS, CT, DMSA
What is significant progression?
Most patients with CKD will not progress to ERF but accelerated progression of CKD as sustained decrease in GFR of 25%< and change in CFR category within 12 months or sustained decrease in GFR of 15ml/min/1.73m2 per year.
What risk factors are associated with CKD progression?
Hypertension, DM, albuminuria, CVD, smoking, ethnicity, NSAIDs (ibuprofen - long term)
Why is progressive CKD important?
Consequences = high mortality, morbidity, hospital stay, cost etc
