Day 1 - Acute Kidney Injury

Acute Kidney Injury.jpg

KDIGO definition: Rise in serum creatinine >1.5x baseline (presumed creatinine in past week), or >27 micromol/L over past 48 hours, or <0.5ml/kg/h of urine output for at least 6 hours

Indications for Dialysis:

Acidosis, Electrolyte abnormalities (Severe hyperkalemia), Intoxication (specifically toxic alcohols, aspirin), Overload, Uremia (Uremic encephalitis, pericarditis)

Work-Up:

  1. Electrolytes, Bicarbonate, Urea, VBG, Urinalysis

  2. Renal ultrasound

  3. Urine electrolytes including urine urea may be helpful if indeterminate etiology

General Treatment Considerations:

  1. Hold nephrotoxic medications

  2. Monitor urinary output

  3. Monitor for indications for dialysis

Post-Renal

  • Obstructive mechanisms

    • Consider in patients with BPH, obstructive intra-abdominal mass, intra-abdominal compartment syndrome

  • Neurogenic bladder

  • Treatment: Treat underlying cause, Foley for patients with urinary retention (neurogenic or obstructive)

Etiologies:

Pre-Renal:

  • Hypovolemia

  • Cardiorenal or hepatorenal states (Decreased effective circulating volume)

  • Medications: NSAIDs, ACE inhibitors, ARBs

  • UNa < 20

  • Treatment:

    • Hypovolemic states - Fluid resuscitation

    • Hypervolemic states - Diuresis

Renal:

Broad categories can be remembered with - Thank God It’s Vriday

Tubular:

  • ATN - most common cause of tubular AKI

  • Drug induced

  • Treatment:

    • Supportive care

    • Monitor for post-ATN diuresis

    • Dialysis if required

Glomerular:

  • Glomerulonephirits

    • ‘Active’ urine with proteinuria, hematuria

    • Patients can also present with AKI, hypertension, pulmonary infilitrates, hemoptysis and other systemic manifestations of underlying ethology of GN

  • Glomerulonephropathy

    • Tends to have very mild creatinine elevation, but has significant proteinuria, defined as >3.5g / 24 hours

  • Treatment is targeted to underlying cause - Nephrology consultation recommended

Interstitial:

  • Acute interstitial Nephritis

    • May present with peripheral eosinophilia

    • Urine eosinophils helpful for diagnosis but may not be readily available

  • Treatment: Remove offending drug

Vascular

  • Reno-vascular occlusion including MAHA, renal vein thrombosis

  • Treatment: Targeted to underlying cause



The Intern at Work -