Renal 1 - Acute renal failure and Glomerulonephritis Flashcards
What are the definitions of CKD stages?
Stage 1 - Kidney damage, GFR >90 (albuminuria, haem, scar) Stage 2 - Kidney damage, GFR 60-90 Stage 3 - Moderate, GFR 30-59 Stage 4 - Severe GFR 15-29 Stage 5 - ESKD, GFR
What are problems with CG and MDRD in estimating GFR?
Accuracy significantly reduces as GFR increases.
What is the most prevalent stage of CKD in Australia?
Stage 3/3a
What is the importance of microalbuminuria in diabetes?
Heralds diabetic nephropathy.
Treating this slows the progression of DM.
What factors drive progression of CKD?
Proteinuria +++
Hypertension
Hyperglycaemia
Smoking
What is associated with increased CV mortality and overall mortality in CKD?
Reducing GFR
Increasing ACR
What are features of AKI?
Acidosis, hyperkalaemia common
Urine volume variable
Features of CRF - anaemia, PO4, PTH, Small Kidneys
What are causes of AKI?
Prerenal - hypovolaemia, CCF, sepsis, ACEi, NSAIDs, hepatorenal.
Nephrotoxins, contrast, atheroembolism
Obstruction - prostatic, others
What are risk factors for AKI?
elderly
Pre-existing CKD
What is the prognosis of AKI?
> 50% mortality if sepsis induced AKI requiring ICU
Recovery common if survival.
If dialysis dependent >60 days, ESKD
What is the RIFLE classification of AKI?
Risk – 1.5-fold increase in the serum creatinine, or glomerular filtration rate (GFR) decrease by 25 percent, or urine output
What is the AKIN staging system for AKI?
Stage 1 = serum creatinine increase >=26.5 OR increase to 1.5-2x from baseline, UO 2.0-3.0x from baseline, 3.0x from baseline OR serum creatinine >=354 with an acute increase of at least 44, or need for RRT.
What are some new biomarkers in AKI?
Urine NGAL
Plasma NGAL
Serum cystatin C
(others include IL-18 and KIM-1)
What area is the most sensitive to hypoperfusion in the kidney?
The thick ascending loop of henle - most metabolically active.
What are causes of acute tubular necrosis?
Ischaemic: - prolonged pre-renal - hypotension, shock - CCF - CP bypass Sepsis Nephrotoxic Drugs - Radiocontrast - Aminoglycosides - Cisplatin - Others Pigment nephropathy - Haemoglobin - Myoglobin - Bilirubin
What are urine indices in ATN?
50% are polyuric
Urinary Na wasting
Sediment
What is the mortality rate in ARF vs ESRF?
50% in critically ill patients requiring HD
10% in ESRD patients requring HD
Significantly poorer outcomes in ATN requiring RRT
What is released in tumor lysis syndrome?
K+
PO4-
Ca2+
Largely in lymphoproliferative and leukaemic malignancies
What are risk factors for TLS?
LDH
Bone marrow disease
High chemosensitivity
What are methods of preventing TLS?
Hydration Allopurinol Urinary alkalinisation OR Rasburicase - recombinant urate oxidase - AEs - haemolysis, allergy
What are the 3 phases of hepatorenal syndrome?
1) pre-ascitic - compensated Na+ retention
2) AScities - sodium retention, mostly DCT with urinary Na
How is a Dx of Hepatorenal syndrome made?
Urinary Na
What are the types of hepatorenal syndrome?
Type I - worse than type 2, idiopathic
Type II - better prognosis than type 1 - has correctable cause
If requirement for HD for 3/12 - indication for kidney and liver transplant.
What is the timeframe for radio-contrast nephropathy?
Acute rise in serum creat 24-48hrs post contrast. Peaks in day 5-7, resolves by day 14.
3-5% post PTCA, associated with increased mortality.
What are clinical features/risk factors of radio-contrast nephropathy?
DDx = ATN, atheroembolism (weeks post insult)
Non-oliguric.
RFs =
- dye volume and type - hypo>iso osmolar
- heart failure, dehydration, diuretics (not ACEi)
- CKD, diabetes, myeloma
How does one prevent radio-contrast nephropathy?
Hydration with N/S
Hydration with NaHCO3 if acidotic
N-Acetyl cysteine
What is useful in management of Contrast nephropathy?
Supportative
Haemofiltration may help