Acute and chronic renal failure Flashcards
(42 cards)
define acute kidney injury?
Abrupt decline in GFR
inability to maintain electrolyte, acid-base and fluid homeostasis
Potentially reversible
define chronic kidney injury?
Longstanding decline in GFR
Irreversible
which serum protein measurement is used to classify AKI?
creatinine
what are the different stages of AKI and the KDIGO classification?
AKI Stage 1: Inc sCr by ≥26 µmol/L, or by 1.5 - 1.9x
AKI Stage 2: Inc sCr by 2.0 -2.9x
AKI Stage 3: Inc sCr by ≥3x
or inc ≥354 µmol/L
types of AKI?
1) pre-renal - most important
2] intrinsic renal
3] post-renal
in the Renin Angiotensin Aldosterone pathway, which hormone stimulates vasopressin?
Angiotensin II
what is the Normal response to reduced circulating volume?
○ Activation of central baroreceptors ○ Activation of RAS ○ Release of vasopressin ○ Activation of sympathetic system ○ This results in: § Vasoconstriction § Increased cardiac output § Renal sodium retention
causes of pre-renal AKI?
True volume depletion - haemorrhage Hypotension Oedematous states Selective renal ischaemia - renal artery stenosis Drugs affecting glomerular blood flow
Renal blood flow is able to stay constant over a huge range of pressures due to which TWO main mechanisms?
Myogenic stretch:
- arterioles constrict to reduce effect of high BP
Tubuloglomerular feedback:
- (Cl- )in DCT causing constriction of afferent arterioles
Name 4 drug groups affecting glomerular blood flow?
§ NSAIDs - decrease afferent arteriolar dilatation
§ Calcineurin inhibitors - decrease afferent arteriolar dilatation
§ ACE inhibitors/ ARBs - reduce efferent arteriolar constriction
Diuretics - affect tubular function, decrease preload
what is the difference between Pre-Renal AKI v Acute Tubular Necrosis?
Pre-Renal AKI is not associated with structural renal damage and responds immediately to restoration of circulating volume
ATN does not respond to restoration of circulating volume
Ischaemic injury
-> Epithelial cell casts
causes of post renal AKI?
physical obstruction to urine flow
(Intra-renal obstruction) Ureteric obstruction (bilateral) Prostatic / Urethral obstruction Blocked urinary catheter
What causes reduced gfr in obstructive uropathy?
GFR is dependent on hydraulic pressure gradient
Obstruction results in INCREASED renal TUBULAR pressure
Immediate decline in GFR = long term consequences if unresolved
causes of intrinsic AKI?
which part of kidney affected
abnormality of any part of Nephron:
Vascular Disease e.g. vasculitis
Glomerular Disease e.g. glomerulonephritis
Tubular Disease e.g. ATN
Interstitial Disease e.g. analgesic nephropathy
causes of direct TUBULAR injury?
Endogenous toxins: Myoglobin, Immunoglobulins
Exogenous toxins - contrast, drugs: acyclovir
why can rhabdomyolysis lead to AKI?
Rhabdomyolysis – myoglobin leak has clogged up renal TUBULES
which conditions cause renal injury via Infiltration / Abnormal protein deposition?
Amyloidosis
Lymphoma
Myeloma-related renal disease
which conditions cause renal injury via
Immune dysfunction causing renal inflammation
Glomerulonephritis
Vasculitis
What two measures do we use to define severity of acute kidney injury?
Serum creatinine and urine output
4 phases of wound healing?
Haemostasis
Inflammation
Proliferation
Remodeling
Why do some cases of AKI resolve? And some not?
wound healing:
Replacement of renal tissue by scar tissue results in chronic disease
How many Stages of CKD?
what is the last stage?
5 stages
stage 5 - end stage renal failure egfr < 15
what is stage 1 ckd?
Kidney damage with normal GFR
above 90
CKD is determined based on?
GFR
