ACUTE KIDNEY INJURY Flashcards
WHAT IS ACUTE KIDNEY INJURY?
- decreased renal function that occurs over a period of days to weeks which is reversible
WHAT ARE THE RISK FACTORS FOR AKI?
1) older age
2) sepsis
3) prolonged immobilisation - rhabdomyolysis
4) diabetes
5) dehydration
WHY DOES SEPSIS INCREASE THE CHANCE OF DEVELOPING AKI?
systemic vasodilation leads to hypovolemia and hypoperfusion of the kidneys
WHAT ARE THE PRE-RENAL CAUSES OF AKI?
Hypoperfusion due to:
- medication - ACEI, ARBs and NSAIDS
- sepsis
- renal artery stenosis
- hypovolemia
- heart failure
- MI
WHAT ARE THE INTRAHEPATIC CAUSES OF AKI?
1) rhabdomyolysis
2) pyelonephritis - kidney infection
3) nephrotoxins - iodinated contrast, gentamycin, methotrexate
WHAT ARE THE POST-RENAL CAUSES OF AKI?
Factors that prevent urine leaving body
1) Benign prostatic hyperplasia
2) Prostate cancer
3) Renal stones
4) Strictures
5) Constipation
WHAT ARE THE SIGNS OF:
1) dehydration
2) fluid overload
1) dehydration - reduced skin tugor, dry mucous membrane, low urine output, negative fluid balance, increase capillary refill, low BP and high HR
2) fluid overload - signs of respiratory distress, pulmonary oedema (bi-basal crepitations), headaches, SOB, peripheral oedema (ankles and sacrum)
HOW MANY STAGES ARE THERE FOR AKI AND WHAT MEASUREMENTS DOES IT TAKE INTO ACCOUNT?
- 3 stages - stage 1 (50-100% from baseline), stage 2 (100%-200% from baseline), stage 3 (200% above baseline)
- serum creatinine and urine output
WHAT IS THE MANAGEMENT OF AKI?
STOP
1) SEPSIS
2) TOXINS - discontinue nephrotoxic drugs
3) OPTIMISE VOLUME STATUS- if dehydrated then give IV fluids, if overloaded give diuretics and aim for euvolaemia
4) PREVENT HARM - haemodynamic monitoring with central venous pressure and arterial line, monitor urine output and daily bloods, catheterise if necessary, avoid hyperglycaemia, drug dosing
WHICH 4 COMMON MEDICATIONS DECREASE RENAL FUNCTION?
1) NSAIDs
2) Diuretics
3) Aminoglycosides
4) ACE inhibitors
WHICH 4 COMMON MEDICATION CAUSE INCREASE TOXICITY IN KIDNEYS?
1) Opiates
2) Digoxin
3) Lithium
4) Metformin
WHAT INVESTIGATIONS WOULD YOU CARRY OUT FOR AKI?
1) Urine dip - proteinuria and haematuria (intrinsic damage)
2) ECG
3) Bloods: FBC (infection), U+E’s (increase urea, creatinine and potassium), creatine kinase (rhabdomyolysis), immunology (ANA, ANCA, anti-GBM)
4) Renal USS
5) CT KUB without contrast - renal stones and stricture
6) CXR (bog standard)- HF, cardiomegaly, effusion, chest infection
7) Abdominal X-ray
8) MRI - contrast not nephrotoxic
WHAT WILL U+E’s SHOW?
- increased urea and creatinine
WHY DO YOU NEEDS TO BE CAREFUL WHEN PRESCRIBING FLUIDS TO PATIENTS WITH RENAL AND CARDIAC IMPAIRMENT? AND HOW DO YOU MITIGATE THIS RISK?
- risk of fluid overload
- measure U and E before and during fluid prescription for evidence of electrolyte disturbance, fluid overloading and dehydration.
WHAT IS NEPHRITIC SYNDROME AND ITS SYMPTOMS?
- glomerular damage
- Haematuria, oedema (to a lesser extent compared to nephrotic syndrome),reduced urine output, hypertension, reduced GFR
WHAT IS NEPHROTIC SYNDROME AND ITS SYMPTOMS?
- podocyte damage leading to glomerular charge barrier disruption
- oedema, proteinuria, hypoalbuminaemia, hyperlipidaemia
WHAT ARE THE CAUSES OF NEPHRITIC SYNDROME?
- good pastures syndrome (anti-GBM disease)
- ANCA- associated vasculitis
- lupus
WHAT ELECTROLTE IMBALANCE CAN AKI CAUSE?
- hyperkalaemia due to reduce K+ secretion into tubules
WHY DOES PROLONGED IMMBOLISATION INCREASE THE CHANCE OF DEVELOPING AKI?
Leads to rhabdomyolysis, which is the release of myoglobin as a result of skeletal muscle degradation. Increase myoglobin leads to renal vasoconstriction and direct toxicity to kidney tubular cells.
WHY DOES DIABETES INCREASE THE CHANCE OF DEVELOPING AKI?
increase blood glucose and associated hypertension can damage kidney microvasculature leading to reduced renal function
WHY DOES DEHYDRATION INCREASE THE CHANCE OF DEVELOPING AKI?
hypovolemia leading to hypoperfusion to the kidneys.
WHAT FLUIDS IS GIVEN FOR PATIENT WITH AKI?
500 ml 0.9% NaCl
WHAT FLUIDS IS GIVEN FOR HEART FAILURE OR ELDERLY/FRAIL PATIENTS?
250ml 0.9% NaCl
