renal failure

DEFINITION:

The inability of a kidney to excrete metabolites at normal plasma levels under conditions of normal loading or the inability to retain electrolytes under conditions of normal intake. In the acute form, it is marked by uremia and usually by oliguria or anuria, with hyperkalemia and pulmonary edema. Chronic forms result from a wide variety of conditions and may require hemodialysis or transplantation.

nephrogenic diabetes insipidus

DEFINITION:

A syndrome of polyuria and hyposthenuria caused by the failure of the renal tubules to reabsorb water in response to antidiuretic hormone, without disturbance in the renal filtration and solute excretion rates; the condition does not respond to exogenous vasopressin. It may be inherited as a rare X-linked trait or be acquired as a result of drug therapy or systemic disease.

renal biopsy

DEFINITION:

A procedure in which a small portion of kidney tissue is removed and examined under a microscope. Renal biopsy is usually performed as part of the investigation and diagnosis of various kidney disorders, such as glomerulonephritis, proteinuria, nephrotic syndrome, or acute renal failure. It may also be used to assess the status of a kidney transplant. Percutaneous (through the skin) needle biopsy of the kidney may not be performed if the person has a bleeding disorder, only one functioning kidney, or chronic renal failure with small, contracted kidneys.

How It Is Done
A percutaneous needle biopsy of the kidney is performed with a local anesthetic injected into the skin and tissues over the kidney; it is virtually painless. There is a risk of bleeding from the kidney into the abdominal cavity.

1. The kidney must be accurately located, usually by an ultrasound scan. Local anesthetic is then injected.

2. A core of tissue is taken by means of a hollow biopsy needle passed through the skin into the kidney.

3. The core of the kidney tissue is embedded in wax and cut into thin slices, which are mounted on slides for staining and microscopic examination.

If a percutaneous needle biopsy is not advisable, an open end renal biopsy may be performed. Using general anesthesia, the surgeon makes a small incision in the flank to visualize the kidney and then cuts a small wedge of renal cortex (the biopsy specimen).

In both cases, the renal tissue is sent to a pathologist for examination under a light microscope, electron microscope, or immunofluorescent microscope.

Recovery Period

The patient may have slight pain in the back for some hours after the biopsy and a small amount of blood may be passed in the urine. Provided there are no complications (such as severe bleeding), the patient can return home the following day.

tubular

DEFINITION:

Shaped like a tube; of or pertaining to a tubule.

necrosis

DEFINITION:

Localized death of living tissue.

nuclear

DEFINITION:

Pertaining to the nucleus.

acidosis

DEFINITION:

1. The accumulation of acid and hydrogen ions or depletion of the alkaline reserve (bicarbonate content) in the blood and body tissues, resulting in a decrease in pH.

2. The pathologic condition resulting from this process.

proteinuria

DEFINITION:

The presence of an excess of serum proteins in the urine; called also albuminuria .