Acute Kidney Injury Flashcards
What is the definition of acute kidney injury?
Increase in serum creatinine by at least 26.5 micromoles/litre within 48 hours
OR
Increase in serum creatinine to 1.5 times the baseline, which is known or presumed to have occured within the prior 7 days
OR
Urine volume less than 0.5 ml/kg/h for 6 hours
What are the immediately dangerous consequences of AKI?
Acidosis - can cause cardiac arrest
Electrolyte imbalance - can cause cardiac arrest (hyperkalaemia)
Intoxication TOXINS - opiates can cause respiratory and then cardiac arrest
Overload - with fluid and pulmonary oedema can cause cardiac arrest
Uraemic complications
What are the outcomes of AKI?
Short - term:
Death, dialysis, AEIOU
Intermediate:
Death, CKD, dialysis, CKD related CV events
Long term:
RRT, CKD
What are the divisions of causes of AKI?
Pre-renal (blood flow to the kidney)
Renal (intrinsic - damage to renal parenchyma)
Post - renal (obstruction to urine exit)
What are the pre-renal causes of AKI?
- Reduced vascular volume : haemorrhage / hypovolemia
- Reduced cardiac output: MI, cardiogenic shock
- systemic vasodilation: sepsis, drugs
- Renal vasoconstriction: drugs e.g. NSAIDs, ACE-I, hepatorenal syndrome
What are the intrinsic causes of acute renal injury?
- Acute tubular necrosis
- Toxin related: drugs, RADIOCONTRAST, Rhabdomyolisis (haem pigment)
Radiocontrast nephropathy: AKI could present after administration of the iodine dye
- Acute intersistial nephritis
- Acute glomerulonephritis
- MYELOMA
- Intra-renal vascular obstruction: vasculitis
What are the post - renal causes of AKI?
- Intraluminal: calculus, clot
- Intramural: malignancy, ureteric stricture, radiation fibrosis, prostate disease
- Extramural: malignancy , retro-peritoneal fibrosis
What is the most common cause of AKI?
Poor perfusion - established tubule damage
What is the effect of myeloma on blood cells?
Monoconal proliferation of plasma cells producing an excess of immunoglobulins and light chains
What are the investigations for AKI?
Urine dipstick
U and E’s
FBC (bicarb, LFT’s, Bone, clotting) - ANCA?
USS
Blood gas
Fancy blood tests if indicated
Renal Biopsy
Urine PCR?
Urine Bence Jones Protein - immunoglobulin light chain that may be suggestive of myeloma
What is the management of AKI?
Pre - renal - do they need fluid? BP support
Renal (intrinsic) - can you remove the precipitant
Post renal - do they need a catheter
STOPAKI
How do we manage fluid balance in AKI?
Volume resuscitation if volume deplete
Fluid restriction if volume overload
How do we optimise blood pressure in AKI?
Give fluid / vasopressors
Stop ACE i / antihypertensives
What are the sources of fluid intake?
Drinks
Food
Metabolic oxidation
