Acute tubular necrosis
Classification and external resources
ICD-10	N17.0
ICD-9	584.5
DiseasesDB	11263
eMedicine	med/39 ped/28
MeSH	D007683

Acute tubular necrosis or (ATN) is a medical condition involving the death of tubular cells that form the tubule that transports urine to the ureters while reabsorbing 99% of the water (and highly concentrating the salts and metabolic byproducts). Tubular cells continually replace themselves and if the cause of ATN is removed then recovery is likely. ATN presents with acute renal failure (ARF) and is one of the most common causes of ARF.^[1] The presence of "muddy brown casts" of epithelial cells found in the urine during urinalysis is pathognomonic for ATN.^[2]

Contents 1 Classification 2 Diagnosis 3 Toxic ATN 4 Ischemic ATN 5 External links 6 References

[edit] Classification

It may be classified as either toxic or ischemic. Toxic ATN occurs when the tubular cells are exposed to a toxic substance (nephrotoxic ATN). Ischemic ATN occurs when the tubular cells do not get enough oxygen, a condition that they are highly sensitive and susceptible to, due to their very high metabolism.^[3]

[edit] Diagnosis

Acute Tubular Necrosis is classified as a "renal" (i.e. not pre-renal or post-renal) cause of Acute Renal Failure. Diagnosis is made by a FeNA (fractional excretion of sodium) > 3 and presence of muddy casts in urinalysis. Note that proximal tubule cells can shed with variable viability and not be purely "necrotic".^{[4][5][6][7][8]}

[edit] Toxic ATN

Toxic ATN can be caused by free hemoglobin or myoglobin, by medication such as antibiotics and cytostatic drugs, or by intoxication (ethylene glycol, "anti-freeze").

Histopathology: Toxic ATN is characterized by proximal tubular epithelium necrosis (no nuclei, intense eosinophilic homogeneous cytoplasm, but preserved shape) due to a toxic substance (poisons, organic solvents, drugs, heavy metals). Necrotic cells fall into the tubule lumen, obliterating it, and determining acute renal failure. Basement membrane is intact, so the tubular epithelium regeneration is possible. Glomeruli are not affected.^[1]

[edit] Ischemic ATN

Ischemic ATN can be caused when the kidneys are not sufficiently perfused for a long period of time (i.e. renal artery stenosis) or during shock. Hypoperfusion can also be caused by embolism of the renal arteries. Ischemic ATN specifically causes skip lesions through the tubules.^[2]

[edit] External links

• Photo at: Atlas of Pathology

[edit] References

v • d • e Urinary system · Pathology · Urologic disease / Uropathy (N00–N39, 580–599) Abdominal Nephropathy/ (nephritis+ nephrosis) Glomerulopathy/ glomerulitis/ (glomerulonephritis+ glomerulonephrosis) Primarily nephrotic Non-proliferative .0 Minimal change · .1 Focal segmental · .2 Membranous Proliferative .3 Mesangial proliferative · .4 Endocapillary proliferative .5/.6 Membranoproliferative/mesangiocapillary By condition Diabetic · Amyloidosis Primarily nephritic, .7 RPG Type I RPG/Type II hypersensitivity Goodpasture's syndrome Type II RPG/Type III hypersensitivity Post-streptococcal · Lupus (DPN) · IgA/Berger's Type III RPG/Pauci-immune Wegener's granulomatosis · Microscopic polyangiitis Tubulopathy/ tubulitis Proximal RTA (RTA 2) Thick ascending Bartter syndrome Distal convoluted Gitelman syndrome Collecting duct Liddle's syndrome · RTA (RTA 1) · Diabetes insipidus (Nephrogenic) Renal papilla Renal papillary necrosis Major calyx/pelvis Hydronephrosis · Pyonephrosis · Reflux nephropathy Any/all Acute tubular necrosis Interstitium Interstitial nephritis (Pyelonephritis, Danubian endemic familial nephropathy) Any/all General syndromes Renal failure (Acute renal failure, Chronic renal failure) · Uremic pericarditis · Uremia Vascular Renal artery stenosis · Hypertensive nephropathy · Renovascular hypertension Other Analgesic nephropathy · Renal osteodystrophy · Nephroptosis · Abderhalden-Kaufmann-Lignac syndrome Ureter Ureteritis · Ureterocele · Megaureter Pelvic Bladder Cystitis (Interstitial cystitis/painful bladder syndrome, Hunner's ulcer, Trigonitis, Hemorrhagic cystitis) · Neurogenic bladder · Vesicointestinal fistula · Vesicoureteral reflux Urethra Urethritis (Non-gonococcal urethritis) · Urethral syndrome · Urethral stricture/Meatal stenosis Any/all Obstructive uropathy · Urinary tract infection · Retroperitoneal fibrosis · Urolithiasis (Kidney stone, Renal colic) · Malacoplakia urinary system navs: anat/physio/dev, noncongen/acid+base/congen/neoplasia, symptoms+signs/eponymous, proc

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