Acute Renal Failure

Acute Renal Failure

Problem: A man arrives at a clinic with complaints of asthenia, malaise, headache, weight gain, and a decrease in urination. A tentative diagnosis of acute renal failure is made.

The generic term for an abrupt and sustained decrease in renal function is called acute renal failure. This is the retention of urea, creatinine, and waste products. Prerenal, intrarenal and postrenal are sub classification for acute renal failure.

Prerenal is the most common form of kidney failure. Blood flow to the kidney that is reduce/interrupted may cause damage to the tissues and recue the ability of the kidney to function. This includes burns, loss of blood volume, heart failure, shock, long-term vomiting/diarrhea/bleeding, injury to the kidney, and certain types of surgery. Prerenal failure if identified early and treated correctly may be reversible.

Intrarenal failure is the actual damage to the nephrons and renal parenchyma . This can be categorized as acute tubular necrosis and is a common type of acute renal failure in critically ill patients. This is a reversible type of renal failure but may take weeks or months before adequate renal function return.

The condition that causes obstruction to urine flow is postrenal failure. Any conditions as in tumors, benign prostatic hypertrophy, kidney stones and bladder neck obstruction may cause this type of acute kidney failure. Untreated the result is actual nephron damage and intrarenal failure.

A patient with kidney disease will have laboratory tests done but first a full and complete history will be taken. Physically the patient’s body will show swelling caused by fluid retention and murmur in the heart, crackles in the lungs or any abnormal sounds in the heart or lungs can be found. These tests include BUN (normal range 6-20 mg/dl), creatinine clearance (compares the levels of creatinine in urine and blood), serum creatinine, serum potassium and urinalysis. The preferred test for diagnosing a blockage in the urinary tract would be an ultrasound. X-ray or MRI can also tell if there is a blockage, and the blood test will help reveal the underlying cause of kidney failure.

Insufficient filtering of the blood by the kidney causing high levels of compounds containing nitrogen and other waste products is called azotemia. This waste product is normally excreted in the urine and can lead to uremia. In Uremia the waste products now show in the blood. With oliguria the body gets reed of an abnormally small amount of urine.