B76 Acute tubular necrosis Flashcards
What are the 3 types of ATN?
Ischemic
Nephrotoxic
Pigment ATN, crush syndrome
What is the clinical presentation of ATN?
Acute renal failure. ATN is the most common cause of acute renal failure.
- oliguria/anuria
- RAS activation
- hypertension
- azotemia
- brown epithelial casts in urine
- FENa is increased
- inability to concentrate urine
What can cause ischemic ATN?
Any kind of heart decompensation causing hypovolemia or redistribution and ischemia to the kidneys can cause ATN.
What is the progression of changes in acute tubular necrosis?
How is it treated and its prognosis?
Ischemia or toxin exposure
Cell swelling
Loss of polarity and loss of tubular function.
Necrosis and detachment
Epethilial cell sloughing into the tubules, obstruction
Decreased GFR, exacerbated ischemia
Increased back-pressure and peritubular edema, causing collapse of the tubules.
Acute renal failure.
It should be treated by dialysis, the tubular epithelium will spontaneously regenerate in 2-3 weeks if the source of ischemia is resolved and renal function will be restored.
What can cause nephrotoxin ATN?
Aminoglycosides
Radiocontrast dye
Heavy metals, mercury
Organic solvents, ethylene glycol -> oxalate crystals cause damage
Myoglobinuria, tumor lysis syndrome, extreme hemolysis (discussed separately in Robbins as Pigment ATP
What causes Pigment ATN
Myoglobin during crush syndrome
Severe hemolysis and hemoglobin
Tumor lysis syndrome and severe uric acidemia
What is the difference in the histology for ischemic and nephrotoxic ATN?
Ischemic ATN causes the most damage to the proximal tubule and thick ascending limb of the loops of henle.
Nephrotoxic agents primarily damage the proximal tubule.
