AKI CKD Flashcards
what is AKI
a rapid reduction in kidney function leading to an inability to maintain electrolyte acid base and fluid homeostasis
How is AKI defined based on creatinine
stage 1 increase by >26, or 1.5-1.9x the reference
stage 2 increase by 2.0 to 2.9 x the reference
stage 3 increase by >3 x the reference
why does pre renal AKI occur
poor perfusion - due to failure of normal adaptive mechanisms designed to maintain renal perfusion (baroceptors activated by low BP, activation of ras, release of vasopressin)
which drugs may predispose patients to develop pre-renal AKI
NSAIDS - decrease afferent arteriolar dilatation, calcineurin inhibitors - decrease afferent arteriolar dilation, ACEi or ARBs - decrease efferent arteriolar constriction, diuretics - affect tubular function, decrease preload
whats the difference between pre renal AKI and ATN with regards to responding to restoration of circulating volume
prerenal responds but AKI does not
name some causes of post renal AKI
hallmark is physical obstruction to urine flow, intrarenal, ureteric, prostatic, blocked catheter
what are some causes of intrinsic AKI
vascular disease, glomerular, tubular, interstitial disease e.g. analgesic nephropathy
direct tubular injury causes
ischaemic, endogenous toxins e.g. myoglobin, immunoglobulins, exogenous toxins e.g. aminoglycosides, amphotericin, acyclovir
why do same cases of AKI not improve
imbalance between scarring and remodelling
stages of CKD
Normal GFR >90 ml/min mild 60+ moderate 30+ severe 15+ endstage <15
commonest causes of CKD
diabetes, atherosclerotic, hypertension, glomerulonephritis, infective, PCKD
consequences of CKD
failure of homeostasis - acidosis, hyperkalaemia, progressive failure of hormonal function - anaemia (epO), renal bone disease, cardiovascular - uraemic cardiomyopathy, vascular calcification
how to treat anaemia of chronic renal disease
erythropoeitin stimulating agents like eprex
renal bone disease types
osteitis fibrosa (osteoclast resorption of calcified bone and replacement by fibrous tissue) osteomalacia, adynamic bone disease, mixed osteodystrophy
hyperparathyroidism in CKD
hypocalcaemia, leads to hyperparathyroidism, resistance to PTH and more hyperparathyroidism