Acute Kidney Injury Flashcards
Define Oliguria
< 500mls urine output /24hours or < 20mls/ hour
Define Anuria
No urine output or < 100mls/24 hours
Define polyuria
> 2.5L urine output / 24hours
Define Acute Kidney Injury (AKI)
Inability of kidney to maintain homeostasis leading to a buildup of nitrogenous wastes
What are the 3 types of acute renal failure (ARF)?
Pre-renal (functional), renal-intrinsic (structural) and post-renal (obstruction)
Discuss pre-renal kidney injury
Decreased renal perfusion w/o cellular injury
Often reversible upon restoration of renal blood flow and glomerular perfusion pressure
KIDNEYS ARE NORMAL
Causes: hypovolaemia, low CO, systemic dilation or selective nitrate all vasoconstriction
Results in: decreased renal blood flow and GFR, increase Na and H2O reabsorption, Oliguria, high Uosm, low Una, elevated BUN/Cr ratio
Discuss intrinsic AKI
Structural injury in the kidney
Causes: acute tubular necrosis (ischaemia, toxin, tubular factors), acute interstitial necrosis (inflammation, oedema), glomerulonephritis (damage to filtering mechanisms), drugs
What is contrast-induced AKI?
Risk factors: renal insufficiency, diabetes, multiple myeloma and high osmolar contrast media
Clinical characteristics: onset 24-48hrs after exposure, duration 5-7 days, non-Oliguric (majority), urinary sediment (variable), low fractional excretion of Na
Discuss post-renal AKI
Causes: intra-renal obstruction (drugs, acute runic acid nephropathy), extra-renal obstruction (renal, pelvis or ureter, bladder, urethra)
What are the common signs of AKI? Rationale these..
Weight gain, peripheral oedema, hypertension, hyperkalaemia, pulmonary oedema, ascites, asterixis encephalopathy, rise in BUN and serum creatinine, acidosis, increase in phosphate levels, low serum calcium levels, anaemic (from blood loss)
What diagnostic tests would you perform for AKI and what will the results show?
Tests: FBC, ABGs, Radiography, urinary sediments (U&Es, creatinine), urine volume, aortorenal angiography,
Findings: increased creatinine and urea, increased potassium, decreased Hb, Acidosis, hyponaturaemia, hupocalcaemia
What are the indications for acute dialysis (AEIOU)?
Acidosis, Electrolytes, Ingestion of drugs/ischaemia, Overload (fluid), Uraemia
Discuss the treatment of AKI
Immediate treatment if pulmonary oedema and hyperkalaemia
Treat cause
Dialysis as required
Adjustment if drug regimen
Usually restriction of water, Na, and K intake; provision of adequate protein
Possibly phosphate binders and Na polystyrene sulfonate
What type of patient is at risk for a reduced renal reserve?
Pre-existing chronic renal failure, age > 60, hypertension, diabetes
What type of patient is at risk for a reduced intra-vascular volume?
Diuretics, sepsis, cirrhosis, nephrosis
Describe in brief the pathophysiology of AKI
Abrupt loss of kidney function, resulting in:
retention of urea and nitrogenous waste products
dysregulation of extracellular volume and electrolytes
Define Azotemia
A rise in BUN concentration
What are the manifestations of AKI? Rationale these..
Lethargy w/ persistence nausea and diarrhoea, DMM and skin, CNS manifestations (drowsiness, headache, muscle twitching, seizures), low urine output
What might you find upon skin examination of a pt w/ AKI?
Digital ischaemia, butterfly rash, palpable purpura (rash), systemic vasculitis, maculopapular rash, allergic interstitial nephritis, track marks (IV drug abusers)
What might you find upon eye examination of a pt w/ AKI?
Dry conjunctivae, autoimmune vasculitis, jaundice, liver disease, hypercalcaemia, retinopathy
What might you find upon ear examination of a pt w/ AKI?
Hearing loss, aminoglycoside toxicity, mucosal or cartilaginous ulcerations
What might you find upon CVS examination of a pt w/ AKI?
Irregular rhythms (AF), thromboemboli, murmurs, endocarditis, pericardial friction rub, uraemic pericarditis, inc jugulovenous distension, rales (crackles), S3 heart failure
What might you find upon abdominal examination of a pt w/ AKI?
Pulsatile mass or bruit (artheroemboli), abdominal or costovertebral angle tenderness, nephrolithiasis, papillary necrosis, renal artery thrombosis, renal vein thrombosis, pelvic/rectal masses, prostatic hypertrophy, distended bladder, urinary obstruction, oedema, rhabdomyolysis (breakdown of muscle tissue)
What might you find upon pulmonary examination of a pt w/ AKI?
Rales, haemoptysis (coughing blood)
Discuss the routine nursing care for a pt w/ AKI
FBC (input and output), monitor urine SG, daily weights, vitals, auscultation of heart and lung sounds, GCS, oral fluid replacement w/ restrictions, correct reversible causes of AKI, skin integrity, infection control, psychological support, mouth care, comfort, medications, catheter care, dialysis as indicated
What are the complications of AKI?
Fluid buildup (pulmonary oedema), chest pain (endocarditis), muscle weakness (hypercalcaemia), permanent kidney damage, death
What are the 3 different types of dialysis and give a brief explanation of each
Haemodialysis: Pts blood pumped through blood compartment of dialyzer (water/wastes removed) and blood returned to the body
Peritoneal dialysis: sterile solution containing glucose (dialysate) run through tube into peritoneal cavity, diffusion and osmosis drive waste products and excess fluid through peritoneum into dialysate, dialysate drained, discarded and replaced w/ fresh dialysate
Heamofiltration: same process as haemodialysis but no dialysate used, works by applying pressure gradient
