Acute Tubular Necrosis

This PPT contains only a brief summery about ATN.
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1. BY JOSEPH NDANJI MULEBA ACUTE TUBULAR NECROSIS

2. Definition This is a disorder characterized by destruction of tubular epithelial cells resulting in renal function loss…. NOTE: ATF is the most common and most important cause of ARF characterized by sudden cessation of renal outflow or 24hrs urine <400ml

3. Types of ATN Based on etiology and morphology, they are two types of Acute Tubular Necrosis (ATN)…. Ischemic ATN Toxic ATN

4. ISCHEMIC ATN Its also known as ANOXIC NECROSIS or SHOCK KIDNEY. It occurs due to hypo perfusion of the kidney resulting in focal damage to the distal part of the convoluted tubules.. ETIOLOGY SHOCK(post-traumatic, surgical, burns, dehydration CRUSH INJURIES Non-traumatic rhabdomyolysis induced by alcohol, coma, muscle diseases etc Mismatched blood transfusion, black-water fever (haemoglobinuric nephrosis)

5. TOXIC ATN Its also known as NEPHRONTOXIC ATN or TOXIC NEPHROSIS It occurs as a results of direct damage to tubular, more marked in PCT of nephrons, its caused by ingestion, injection or inhalation of number of toxic agents ETIOLOGY General poison e.g. mercuric, chloride, mushroom poisoning, insecticides etc Heavy metals (mercury, lead, arsenic, gold etc ) Drugs e.g. anesthetic agents, certain antibiotics Radiographic contrast material

6. Pathogenesis of ATN Tubular damage in ischemic or toxic ATN Debris of the desquamated epithelium due to necrosis cause tubular obstruction and may block the urinary outflow and drop in GFR & produce casts in urine. This events cause increases in intratubular pressure resulting to damage to tubular basement membrane Further increase in the pressure result to rupture of the tubular and haematuria is seen With the rupture of the tubular there is linkage of fluid into the interstitium causing interstitial oedema . leakage of tubular fluid in interstitium ( oedema) increases the interstitial pressure and may incites host inflammatory response The Increased interstitial pressure causes compression of tubules and blood vessels and setting up a cycle of accentuated ischemia and necrosis Ultimately, leads to reduced GFR and Oliguria

7. Difference Feature Ischemic ATN Toxic ANT Synonym Frequency More common ( about 80% of cases) Less common Etiology Shock Crush injury Mismatch blood transfusion Poison Heavy metal Certain drugs Grossly Kidney enlarged Swollen Cortex pale and dark medulla Same Prognosis Becomes worse in most cases Becomes better in most cases

8. Clinical features of ATN INITIATION PHASE : lasts for about 36hrs and is characterized by decreased in urine out put and increase in BUN. MAINTENCE PHASE : characterized by uriguria, salt &water overload, hyperkalemia and increase in BUN RECOVERY PHASE : Steady increase in urine volume (up to 3l/d), hypokalemia and increase vulnerability to infections

9. Acute Renal Failure due to ATN (ischemic)

10. Complications of ATN Electrolyte abnormalities Intravascular volume overload Hypertension Uremic syndromes Anemia Infections

11. Diagnosis of ATN URINALYSIS to look for abnormal cells, color and signs of infection. BUN &CREATININE URINE TEST both increases in kidney failure BIOPY to examine the kidney tissues BLOOD SODIUM & CREATINE MEASURE CT Scans

12. Reference : HARSH MOHAN text book of pathology 8 th edition www.pathology.jcu.edu.au

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