Acute Kidney Injury

Acute Kidney Injury

1. Pre-Renal (decreased blood flow into kidneys)

   • Hypovolaemia (absolute loss of intravascular volume)
     • Diuresis, diarrhoea, dehydration, haemmorhage, severe burns
   • Relative decrease in of intravascular volume (total body fluid stays the same)
     • Distributive shock
       • Anaphylaxis, neurological injury, septic shock
     • Cardiogenic
       • Congestive heart failure (venous pooling --> less blood sent to kidneys
       • Cardiogenic shock (MI, heart failure, arrhythmias)
   • Obstructive
     • Renal artery stenosis (narrowing of renal artery)
     • Renal artery thrombus

2. Intra-renal

   • ATN (acute tubular necrosis) *** most common for hospitilised pts Tubular epithelial cells necrose, slough off, causing obstruction in tubular flow, leading to back- flow of filtrate, further increasing blood waste products (nitrogenous wastes). Casts seen in urine.
     • Ischaemic - prolonged hypoperfusion (prolonged pre-renal failure)
     • Neophrotoxic
       • Nephrotoxic drugs
         • Vancomycin (glycopeptide antibiotic) Aminoglycoside (gentamicin) Chemotherapeutic agents Contrast dye NSAIDs Sulfonamides (trimethoprim, bactrim) Chemical exposure: ethylene glycol, lead, arsenic, carbon tetrachloride
       • Haemolytic blood transfusion reaction (Haemoglobin release from RBCs)
         • Block tubules, causing renal vasoconstriction
         • Blood transfused is destroyed by patients immune system
       • Myoglobin release from necrotic muscle cells
     • Pts at risk: Major surgery, shock, sepsis, blood transfusion reaction, muslce injury from trauma, prolonged hypotension, nephrotoxic agents
     • Sepsis
       • Bacterial infections (acute pyelonephritis (viral or fungal cause))
     • Interstitial nephritis due to an allergic / hypersensitive reaction
       • Penicillin, NSAIDs
       • Immune reaction that damages the cells in glomerulus

3. Post-renal

   • Obstruction (renal calculi)
   • BPH enlarged prostate
     • benign prostatic hyperplasia
   • neuromuscular disorders
   • spinal cord disease
   • strictures
   • prostate cancer

4. Decrease in GFR - normal = 100% kidney function

   • How much blood is filtered via the glomeruli per minute
   • Stage 1 90-100% function
   • Stage 2 60-89% kidney function
   • Stage 3 30-59% kidney function
   • Stage 4 15-29% kidney function
   • Stage 5 less than 15% kidney function

5. Azotemia (accumulation of nitrogenous containing wastes in blood)

   • Urea & Creatinine
     • Creatinine 45-85 micromol/L Urea 3.o-8.5mmol/L

6. Decrease in urine output (oliguria less than 400mLs/day)

7. Activation of the RAAS

   • Reabsorption of H20 and Salt
     • Fluid retention --> HTN, bounding pulse, heart failure, pulmonary oedema, peripheral oedema, pleural effusions.
       • Monitoring?
       • Assessments?

8. hyperkalaemia

   • Complications?
     • Resonium, insulin
     • Which blood test?
   • 3.5-5.5mmol/L

9. Metabolic acidosis due to H+ accumulation in blood

10. Increased mortality

11. Medical management

    • Dialysis

12. Nursing Diagnosis At risk of

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