Prerenal AKI
Causes
•Decreased cardiac output (cardiogenic shock, cardiac tamponade, arrhythmias, pulmonary embolism, congestive HF)
•Vasodilation (anaphylactic shock, sepsis, overdosing of antihypertensives)
•Low extracellular volume (bleeding, diarrhea, vomiting, polyuria, hypoalbuminemia)
•Other causes (hepato0renal syndrome)
Diagnosing pre-renal AKI
•Is the patient volume depleted?
•Is cardiac function good?
•Is the patient septic?
•History
•Examination
•Investigation
Signs of Hypovolaemia:
•Low BP( and reduced pulse pressure)
•Postural BP drop ( a fall in systolic BP > 10mmHg)
• Sinus tachycardia and postural increase in heart rate> 10 bpm
•Low JVP even when the patient is supine
•Cool peripheries and vasoconstriction
•Low diuresis
Renal AKI
Causes
•Exogenous toxins (poisons, insects and snakes venoms, drugs, iodine containing contrast medium)
•Acute infection with direct and indirect damage of the kidneys (hemorrhagic fever with renal syndrome, leptospirosis, glomerulonephritis)
•Vascular damage (hemolytic-uremic syndrome, systemic sclerosis, systemic vasculitidis, arterial or venous thrombosis, embolism)
•Trauma
•Post-ischemic AKI
•Intratubular blockage (casts, crystalls)
Further lab evaluation for renal AKI
•C3- and C4 complements
•ANA, ANCA, anti-GBM
•LDH, haptoglobin
•Biopsy
Postrenal AKI
Causes
•Extrarenal obstruction (concrements, tumors, necrotic papillitis, stricturas)
•Urinary retention (DM, spinal cord damage, use of ganglioblockers and M- cholinoblockers)
Urine Output and AKI
•Anuric
•< 50 cc / 24 hrs
•Oliguric
•< 500 cc / 24 hrs
•Non-oliguric
•Normal urine output, but inadequate clearance
•GFR 2 ml/min will produce ~3L of urine/day if there is no tubular reabsorption
Principles of AKI Management
•Identify AKI
•Avoid further nephrotoxic injury
•Optimize renal hemodynamics
•Treat complications
•Fluid balance, electrolytes, uremia
•Nutritional support
•Renal Support (RRT)
•Monitoring after AKI
Indications for urgent RRT
•Urea increase > 15-20 mg/24 h, increased hyperkalemia and metabolic acidosis
•Severe hyperhidration (risk of pulmonary and brain edema)
•Renal anuria
Principles of AKI Management
Acute kidney disease
•Acute kidney disease (AKD) describes acute or subacute damage and/or loss of kidney function for a duration of between 7 and 90 days after exposure to an acute kidney injury (AKI) initiating event
•Acute pyelonephritis
•Acute interstitial nephritis
•Acute glomerulonephritis
Chawla, L. S. et al. (2017) Acute kidney disease and renal recovery: consensus report of the Acute Disease Quality Initiative (ADQI) 16 Workgroup Nat. Rev. Nephrol. doi:10.1038/nrneph.2017.2
Chronic kidney disease (CKD)
CKD is defined as abnormalities of kidney structure or function, present for > 3 months, with implications for health and CKD is classified based on cause, GFR category, and albuminuria category