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Flashcards in AKI Deck (21):
1

What is AKI

abrupt sustained rise in serum urea and creatinine due to a rapid decline in GFR leading to loss of normal water and solute homeostatis

usually reversible

2

What is CKD

Long standing and usually progressive impairment in renal function

3

classification of AKI

renal failure results in reduced excretion of nitrogenous waste of which urea is most commonly measured. A raised serum conc (uraemia) is classified (i) pre renal (ii) renal - instrinsic (iii) post renal

4

pre renal failure

impaired perfusion of the kidneys due to hypovolaemia, hypotension, impaired cardiac pump efficiency or vasc disease limiting renal blood flow

5

what is autoregulation

the kidney is usually able to maintain glomerular filtration in spite of a wide variation in the renal perfusion pressure and volume status

6

in the face of a decreased systemic pressure what does maintenance of a normal GFR depend on

the intrarenal production of prostaglandins and Angiotensin II

7

what drugs impair renal autoregulation

ACEi and NSAIDs
they inc tendency to develop pre renal failure

8

rx pre renal failure

prompt fluid replacement

9

post renal uraemia

both urinary outflow tracts are obstructed or when the tract is obstructed in a pt with a single functional kidney - quickly reversed if obstruction removed

10

investigations post renal uraemia

all pts with AKI should be examined for evidence of obstruction: enlarged palpable kidneys or bladder, large prostate
and undergo renal US to look for hydronephrosis and dilated ureters

11

how is bladder outflow obstruction ruled out in post renal uraemia

flushing a catheter

12

rx of post renal uraemia

by a temp measure eg urethral / supra pubic catheter or percutaneous nephrostomy until definitive rx of the obstructing lesion can be undertaken

13

Acute uraemia due to renal parenchymal disease - most common cause?

tubular necrosis as a result of renal ischaemia or renal toxins
also acute glomerulonephritis

14

AKI clinical features

early = asymptomatic
1 - altered urine volume, initially oliguria then increase
2 - hyperkalaemia, metabolic acidosis, hyponatraemia, hypocalcaemia & hyperphosphataemia
3 - symps of uraemia

15

What is the cause of the following abnormalities in AKI:
hyponatraemia
hypocalcaemia
hyperphosphataemia

hyponatraemia - water overload from continued drinking after the onset of oliguria
hypocalcaemia - reduced renal production of 1,25-dihydroxycholecalciferol
hyperphosphataemia - phosphate retention

16

What are the symptoms of uraemia experienced in AKI?

Weakness, fatigue, anorexia, nausea, vomiting followed by mental confusion, seizures & coma.
May be pruritis & bruising
Breathlessness from anaemia & pulmonary oedema secondary to volume overload
Pericarditis w severe untreated uraemia

17

what would you be looking for in blood count in AKI?

anaemia and inc ESR = myeloma or vasculitis as underlying cause

18

why would you do urine and blood cultures in AKI?

to exclude infection

19

what looking for in urine dipstick and microscopy AKI?

haematuria & proteinuria on dipstick and red cell casts on microscopy = glomerulonephritis as cause

20

when should renal biopsy be performed in AKI?

when AKI is unexplained

21

management AKI

emergency resuscitation
establish aetiology and treat underlying cause
prevention of further damage (if infec, abx. AVOID: hypovolaemia, nephrotic drugs, NSAIDs and ACEi)
Frequent review for dialysis
Careful fluid and electrolyte balance