AKI (1).docx

Acute Renal Failure Definition: Acute renal failure (ARF) is defined as an abrupt or rapid, reversible decline in renal function. A rise in serum blood urea nitrogen (BUN) or serum creatinine concentrations Causes of acute renal failure (ARF) Prerenal normal kidney that is responding to hypoperfusio...

Acute Renal Failure Definition: Acute renal failure (ARF) is defined as an abrupt or rapid, reversible decline in renal function. A rise in serum blood urea nitrogen (BUN) or serum creatinine concentrations Causes of acute renal failure (ARF) Prerenal normal kidney that is responding to hypoperfusion Renal Renal or intrinsic ARF refers to a condition in which the pathology lies within the kidney itself Postrenal caused by an obstruction of the urinary tract I- Pre-renal acute renal failure (50-60%)  Hemorrhage  myocardial infarction  Drugs (antihypertensive)  Anaphylaxis  Renal vasoconstriction (Norepinephrine ) II- Acute Intrinsic renal failure (35-40%)  Diseases involving large vessels (thrombosis, embolism)  Diseases of glomeruli such as Inflammatory Vasculitis Toxeamia of pregnancy, Radiocontrast agent antibiotics, anticancer,  Hematologic: Disseminated Intravascular Coagulopathy  Diseases of the tubules caused by hypoperfusion (per renal)  Infiltration (lymphoma,leukemia, III-Acute postrenal failure (5%) 1-Ureteric obstruction: ♠ Intraluminal: stone, clot, ♠ Extraureteric: Iatrogenic ligation. 2- Bladder neck obststruction: ♠ Intraluminal: stone, clot, ♠ neurogenic, drugs (ganglion blockers, tricyclic anti-deppresant). ♠ Extramural: prostatic hypertrophy, carcinoma. 3- Uretheral obststruction: ♠ Congenital valves, Stricture, Tumour. Course of acute renal failure 1- Initial phase. 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. Removal of the causative agents as early as possible can prevent the intrinsic renal changes. 2- Maintenance phase (oliguric phase): 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 and up to 6 weeks. Because the filtration rate is so low during the maintenance phase, the creatinine and BUN continue to rise. 3-Recovery phase (diuretic & post diuretic). characterized by regeneration of tubular epithelial cells. During recovery, an abnormal diuresis sometimes occurs, causing salt and water loss and volume depletion. Management of Acute Renal Failure Prevention Use smallest possible dosages of drugs Avoid radiocontrast agents to patients with diabetic nephropathy, chronic renal failure Volume repletion before surgery Initiation Phase Repair volume deficits Evaluate for postrenal obstruction (easy diagnosis and management ) Discontinue nephrotoxins Treat underlying disorders Consider use of furosemide (diuretics ) Maintenance Phase Maintain water and sodium balance Limit potassium intake Correct severe acidosis Optimize protein and caloric intake Monitor for signs and symptoms of uremia Monitor for infection Adjust medication dosages in relation to renal insufficiency Dialysis Diuretic Phase Monitor for major fluid and electrolyte shifts Monitor for infection Adjust medication dosages