Editing Acute renal failure (section)

== Pathophysiology: ==

* GFR can be estimated from serum creatinine, BMI and gender
**
* Pre-renal injuries:
** Systemic hypoperfusion leads to increased sympathetic neural tone and release of renin and ADH
** Leads to arteriolar vasoconstriction primarily in the renal, splanchnic and musculocutaneous circulations to preserve blood flow to the heart and brain
** Renal vasoconstriction leads to reduced blood flow and GFR
* Acute tubular necrosis
** Occurs in the setting of prolonged or severe ischaemia
** Renal tubular cells are more vulnerable than the cortex due to their position deep in the medulla
** May lead to necrosis, with denuding of the epithelium and occlusion of the tubular lumen by casts and cell debris
* Urine output
** Normal urine output is 0.5-2mL/kg/hr
** Oliguria is <0.5mL/kg/hr
** Anuria is <100mL/day (approx 0.1mL/kg/hr)