Acute tubular necrosis (ATN) is the most common cause of acute kidney injury (AKI) seen in clinical practice. Necrosis of renal tubular epithelial cells severely affects the functioning of the kidney. In the early stages ATN is reversible if the cause if removed.

There are two main causes of ATN; ischaemia and nephrotoxins:

• ischaemia

  • shock
  • sepsis
  • dehydration

• nephrotoxins

  • aminoglycosides
  • acetazolamide
  • myoglobin secondary to rhabdomyolysis
  • radiocontrast agents
  • lead

  Other risk factors:

  • CKD
  • Chronic HTN
  • Diabetes mellitus
  • Advanced age

PC

• Oliguria or anuria
• Hypotension
• Tachycardia
• Poor oral intake and anorexia
• Malaise

Investigations

• Urinalysis for sediment - muddy brown casts in the urine
• U and E - Elavated creatinine, urea.
• Urea:Creatinine ratio - 10:1 supports ATN
• ABG - Metabolic acidosis
• Elavated urine sodium
• Urine osmolality <450
• Fractional excretion of urea - over 35% supports ATN
• Fractional excretion of sodium - Over 2% supports ATN