AKI & CKD Flashcards
What is the definition of AKI?
A clinical syndrome characterised by an abrupt reduction in kidney function in a previous normal kidney
What are the different stages of AKI?
STAGE 1: Absolute ↑Creatinine >26 within 48hours OR >50%↑ in Creatinine from baseline in 7d OR 25%↓ in eGFR in 7days OR UO <0.5ml/kg/hr for >6hours
STAGE 2: Creatinine >2-3x baseline OR eGFR >50% or UO <0.5ml/kg/hr for >12hrs
STAGE 3: Cr >354 OR >x3 baseline OR eGFR >70% OR UO < 0.3ml/kg/hr for 24hours OR use of RRT
What signs can show the severity of an AKI?
- Fluid overload: Pulmonary crackles, ↑JVP, peripheral oedema, gallop rhythm
- Fluid depletion: Postural hypoT (<90/60), tissue turgor, dry mucous membranes, sunken eyes
- Urine output: Oligo/anuria
- HyperK
- Acidosis
What are the signs of hyperK on an ECG?
Tall tented T-waves Flat P waves Broad QRS Sliping ST Sine wave ECG
How are 80% of cases of AKI resolved?
Fluid assessment & replacement
Tx acidosis
Tx sepsis
STOP nephrotoxic drugs
What are the pre-renal causes of AKI?
Hypovolaemia (HF, blood/fluid loss, D&V) Sepsis RAS (worse w/ACEi) Nephrotic syndrome Nephrotoxic drugs
Which drugs are nephrotoxic?
Vasomotor nephropathy: ACEi, ARB, NSAIDs
Allergy: NSAIDs, Abx: Trimethoprim, Vancomycin, ahminoglycosides
Direct nephrotoxicity: Gentamicin, Contrast
Diuretics
↑risk of toxicity: Metformin, Lithium, Digoxin
What are the renal/intrinsic causes of AKI?
GN Acute tubular necrosis Acute interstitial nephritis Thrombotic microangiopathy Rhabdomyolysis Tumour lysis Myeloma
What are the post-renal causes of AKI?
Ureteric stones
Ureteric retroperitoneal fibrosis/tumour
BPH
RTA
What are the indication for dialysis?
AEIOU A: Metabolic acidosis E: Electrolyte disturbance I: Intoxication O: Overload U: Uraemia (pericarditis, encephalopathy, bleeding)
How is an AKI investigated?
Bloods: FBC, U&E, LFT (↑ALP), ESR/CRP, Ca2+, CK, Coag, K+
Urine dip: Protein, blood, leukocytes, nitrates +/- MC&S
ABG: Metabolic acidosis
Immunology screen: ANCA, ANA, anti-GBM, ASO titre, Complements
ECG: HyperK
USS: In 24hrs if obstruction
How is AKI treated?
HOLD nephrotoxic drugs
HOLD K+ supplements
How is hyperkalaemia treated?
Calcium gluconate: 30ml in 10% bolus IV REPEAT every 20mins until ECG normalises
Insulin: Actrapid 10u in 50ml of 50% Dextrose
Salbutamol: 5mg news x4
Calcium resonium: 15g PO TDS
Haemodialysis
In AKI how is acidosis treated?
IV Bicarb: 50-100ml 8.4% in 30mins
How is an obstructive AKI treated?
Catheter- monitor UO
USS ASAP
What are the complications of dialysis?
HypoK
Intravascular hypoV
Alkalosis
Air embolism
What are the SE of dialysis?
Headache Arrhythmia HypoT Muscle cramps Line complications (obstruction, infection)
How does haemodialysis work?
Semipermeable membrane
Blood flows on one side & solution of crystalloid on other side
Diffuse across
Removal of small molecules (urea)
What are the Sx of uraemia?
Tremor Cognitive impairment Coma Fits Urea >45
How does haemofiltration work?
Blood filtered out of body
Plasma, water & water-soluble substances move across semi-permeable membrane
Later fresh electrolytes replaced
What are the complications of peritoneal dialysis?
Peritonitis Catheter infection Protein loss Breathing problems Back pain Hyperglycaemia Hernia
How does peritoneal dialysis work?
Hypertonic solution
Draws fluid & solutes across peritoneum
Via peritoneal catheter
Define CKD?
AKA Chronic renal failure;
Permanently impaired renal function/structure for >3months
OR
eGFR <60 for >3mo leads to inability to maintain homeostasis of fluids/U&Es/acid-base
What are the causes of CKD?
Diabetes
HTN
GN
Idiopathic
Other: RAS, chronic pyelonephritis, reflux nephropathy, PCKD
Systemic: SLE, Vasculitis, myeloma, amyloid
