Question about Renal Functions

Renal Failure

Kidney Functions
:•Remove toxic waste products
•Remove excess water and salts
•Play a part in controlling blood pressure
•Produce erythropoetin (epo) which stimulates red cell production
•Helps to keep calcium and phosphate in balance for healthy bones
•Maintains proper pH for the blood

•Azotemia: Elevated blood urea nitrogen

(BUN>28mg/dL) & Creatinine (Cr>1.5mg/dL)

•Uremia: azotemia with symptoms or signs of renal failure
•End Stage Renal Disease (ESRD): uremia requiring transplantation or dialysis
•Chronic Renal Failure (CRF): irreversible kidney dysfunction with azotemia >3 mos.
•Creatinine Clearance (CCr): rate of filtration of creatinine by the kidney (marker for GFR)
•Glomerular Filtration Rate (GFR): the total rate of filtration of blood by the kidney.

Acute Renal Failure:
•Prerenal azotemia

An abnormally high level of nitrogen-type wastes in the bloodstream. It is caused by conditions that reduce blood flow to the kidneys.

•Postrenal azotemia

An obstruction of some kind (i.e., bladder cancer, uric acid crystals, urethral stricture etc)

•Intrinsic Renal Disease

Usually glomerular disease

Usually leads to End Stage Renal Disease

Stages of Chronic Renal Failure:
•Silent – GFR up to 50 ml/min.
•Renal insufficiency – GFR 25 to 50 ml/min.
•Renal failure – GFR 5 to 25 ml/min
•End-stage renal failure – GFR less than 5 ml/min.

Uremic Syndrome:
Uremia occurs in stage 3 & 4 of CRF. It means literally “urine in the blood”
•Symptomatic azotemia
•Fever, Malaise
•Anorexia, Nausea
•Mild neural dysfunction
•Uremic pruritus (itching)