A 26 year old suffers a motor vehicle accident

[kenneth masamaro]

Guys this should be easy...

After acute blood loss incurred during a motor vehicle accident,a 26 year old male remains hypotensive for several hours.Within the next week, his serum urea nitrogen concentration has risen to 48mg/dl and creatinine level to 5mg/dl, while his urine output is falling.He receives hemodialysis for the next 2 weeks, after which he has marked polyuria, with 2 to 3 L of urine output per day.His course is then complicated by bronchopneumonia.His renal function gradually returns to normal.The transient renal disease in this case is best characterized by which of the following histologic features?

A Glomerular crescents.
B Interstitial lymphocytic infiltrates.
C Arteriolar fibrinoid necrosis.
D Nodular glomerulosclerosis
E Rupture of the basement membrane.

[Oak]

A Glomerular crescents (Crescents are accumulations of macrophages, fibroblasts and fibrin within Bowman’s space which indicate active, and usually severe glomerular injury) - Rapidly progressive glomerulonephritis

B Interstitial lymphocytic infiltrates is seen in interstitial nephritis

C Arteriolar fibrinoid necrosis is seen in Malignant Hypertension

D Nodular glomerulosclerosis is seen in Diabetic Glomerulopathy

E Rupture of the basement membrane is seen in grannlomatous glomerular lesions, Antiglomerular Basement Membrane Disease and Immune

This is a case of Acute Tubuler Necrosis (ATN) as evidence by its course as ATN usually occurs after an acute ischemic or toxic event, and it has a well-defined sequence of events.

The initiation phase is characterized by an acute decrease in GFR to very low levels, with a sudden increase in serum creatinine and blood urea nitrogen (BUN) concentrations. The maintenance phase is characterized by a sustained severe reduction in GFR, and this phase continues for a variable length of time, most commonly 1-2 weeks. Because the filtration rate is so low during the maintenance phase, the creatinine and BUN continue to rise.

The recovery phase, in which tubular function is restored, is characterized by an increase in urine volume (if oliguria was present during the maintenance phase) and by a gradual decrease in BUN and serum creatinine to their preinjury levels.

Histologic Findings in ATN: In most circumstances, the histology demonstrates the loss of tubular cells or the denuded tubules, the tubular cells reveal swelling, formation of blebs over the cellular surface, and exfoliation of the tubular cells into the lumina. The earliest finding could be loss of the cellular brush border.

Disease progress and history suggest ATN, kenneth masamaro what is the correct answer ???

[kenneth masamaro]

The correct answer is E

Indeed oak you got the diagnosis correct.This is a typical history of ischaemic acute tubular necrosis.As you alluded ATN is characterized by loss of tubular cells or denudation of tthe tubules.BUT also remember that ATN is often accompanied by rupture of the basement membrane, a term referred to as TUBULORRHEXIS.As you correctly alluded to, rupture of the basement membrane may also be seen in RPGN(Rapidly Progressive Glomerulonephritis) especially type I of which goodpasture syndrome is an example.

The course of ATN is really what you said;initiation phase of a day or so,a maintenance phase during which there's progressive oliguria and rising blood urea and nitrogen levels with salt and water overload; and finally a recovery phase in which there's a steady increase in urinary output and hypokalemia.Eventually tubular function is restored.By treating this acute renal failure nearly all patients recover.