renal biopsy

renal biopsy,

the removal of kidney tissue for microscopic examination. It is conducted to establish the diagnosis of a renal disorder and to aid in determining the stage of the disease, the appropriate therapy, and the prognosis. An open biopsy involves an incision, permits better visualization of the kidney, and carries a lower risk of hemorrhage. A closed or percutaneous biopsy performed by aspirating a specimen of tissue with a needle requires a shorter period of recovery and is less likely to cause infection. Contraindications to percutaneous biopsy include bleeding disorders, uncontrolled hypertension, and presence of a single kidney.

method Before biopsy, the procedure is explained and the patient is medically evaluated and tested for bleeding or coagulation time. Aspirin or coumadin therapy is discontinued for a period of time determined by the physician. Informed consent is obtained. The patient's blood is usually typed and crossmatched with two units of donor blood that are held for a possible transfusion until there is no threat of bleeding after the procedure. An open biopsy is generally carried out in the operating room, but the percutaneous procedure may be performed in the radiology department or the patient's room. The location of the kidney, determined by a plain x-ray film, dye contrast study, or fluoroscopic or ultrasound examination, is marked on the patient's skin in ink for a needle biopsy. The patient is then placed prone over a sandbag and soft pillow with the body bent at the level of the diaphragm, the shoulders on the bed, and the spine in straight alignment. A local anesthetic is injected, and the physician inserts the biopsy needle in the lower pole of the kidney, because this area contains the smallest number of large renal vessels. The needle is quickly withdrawn, and, after pressure is applied to the site for 30 to 60 minutes, a pressure bandage is applied. The patient is turned and kept supine and motionless for the next 4 hours. The dressing, blood pressure, and pulse are checked every 5 to 10 minutes for the first hour, then at frequency determined by institutional protocols. Excessive drainage, decreased blood pressure, tachycardia, or elevated temperature is reported to the physician. Fluids are forced to the maximum allotted for the patient's condition. The amount and character of urinary output are noted, and the physician is informed if hematuria occurs. The patient is kept in bed for at least 24 hours and is cautioned not to lift any heavy objects for 10 days or to take any anticoagulants until the physician gives permission.

interventions The nurse offers an explanation of the procedure, prepares and positions the patient for the percutaneous procedure, and, on its completion, provides care and emotional support.

outcome criteria A biopsy is the most accurate measure for determining the nature and stage of a renal pathologic condition.

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renal

pertaining to the kidney. See also kidney.

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renal abscess

results from infected emboli and infarcts. Usually without localizing signs unless they are very large and palpable, or when they extend into the renal pelvis and cause pyelonephritis.

renal adenoma

rare, incidental necropsy finding.

renal agenesis

failure of the renal tissue to develop; unilateral agenesis causes compensatory hypertrophy in the single kidney; bilateral is fatal. Commonly accompanies genital tract malformation.

renal artery

see Table 9.

avian renal hemorrhage

sporadic unexplained disease of turkeys; sudden death is common.

renal biopsy

is conducted usually with a biopsy needle introduced percutaneously through the flank. In food animals it is possible to fix the left kidney via a rectal manipulation, but the right kidney can be impossible to reach.

renal calculus

see urolithiasis.

renal capsular cyst

see feline perirenal cysts.

renal carcinoma

commonest in old male dogs. They are very large, spread locally and metastasize widely.

renal casts

see urinary cast.

renal clearance tests

laboratory tests that determine the ability of the kidney to remove certain substances from the blood. See also phenolsulfonphthalein clearance test, inulin clearance.

renal cortical fissures

external fissures created by the lobar structure of the large ruminant kidney.

renal cortical hypoplasia

see renal dysplasia (below).

renal cortical necrosis

results from patchy or complete renal ischemia and is part of the terminal state of many diseases, e.g. severe metritis, grain overload in cattle, azoturia in horses.

renal countercurrent system

see countercurrent.

renal cyst

incidental necropsy finding except for polycystic kidney disease. See also feline perirenal cysts.

renal cystadenoma

inherited as an autosomal dominant trait in middle-aged German shepherd bitches with generalized nodular dermatofibrosis.

renal diabetes insipidus

see nephrogenic diabetes insipidus.

renal dialysis

the application of the principles of dialysis for treatment of renal failure (below). See also hemodialysis and peritoneal dialysis.

renal diverticuli

diverticuli of the renal pelvis.

renal dysfunction

reduced capacity to excrete metabolic products which accumulate systemically and are detectable clinicopathologically by renal function tests. The early stage of uremia.

renal dysplasia

small, misshapen kidneys at birth. May be caused by intrauterine infection of the fetus by virus, but numerous inherited renal dysplasias occur in dogs. They occur in several breeds and are manifested by signs of chronic renal insufficiency, e.g. polyuria, polydypsia, poor growth and weight gain, pale mucous membranes, and renal secondary osteodystrophia fibrosa, from an early age.

renal ectopia

see pelvic kidney, horseshoe kidney.

renal erythropoietic factor

erythropoietin.

renal failure

inability of the kidney to maintain normal function. Impairment of kidney function affects most of the body's systems because of its important role in maintaining fluid balance, regulating the electrochemical composition of body fluids, providing constant protection against acid-base imbalance, and controlling blood pressure. See also kidney.

renal function tests

include blood urea nitrogen and serum creatinine estimations, tests of concentrating ability, tests of ability to excrete test substances, e.g. phenolsulfonphthalein (PSP) clearance test. Of the urine tests, only specific gravity (SG) has any significance in terms of a function test but abnormalities of urine should lead to a function test being conducted.

renal hilus

a fissure on the medial border of the kidney through which arteries, veins and ureter enter.

renal hypophosphatemic rickets

inherited as an X-linked dominant trait in children and mice; characterized by hypophosphatemia and normocalcemia due to failure of phosphate resorption in renal tubules, and skeletal deformities. Called also vitamin-resistant rickets.

renal infarct

results from embolic or thrombotic occlusion of renal arteries or branches. Clinical signs are those of renal colic initially followed by toxemia if the infarct is infected.

renal insufficiency

see renal dysfunction (above).

renal ischemia

a significant cause of renal dysfunction and cortical and medullary necrosis. Is usually part of a general state of shock, dehydration and severe toxemia.

renal lobe

a large mass of a kidney, comprising the tissue contributing to each pyramid; kidneys may be unilobar (unipyramidal), e.g. cats, dogs, small ruminants, horses, or multilobar (multipyramidal), e.g. cattle, pigs.

renal lobule

small masses of kidney tissue comprising a medullary ray and its associated nephrons.

renal medullary necrosis

necrosis of the renal medulla due to restriction of blood flow in medullary vessels, usually due to venous occlusion.

renal medullary washout

see medullary solute washout.

renal mineralization

see nephrocalcinosis.

renal osteodystrophy, renal osteitis fibrosa, renal osteitis fibrosa cystica

see renal secondary hyperparathyroidism.

renal oxalosis

deposition of oxalate crystals in renal tubules of patients poisoned by dietary oxalate, usually in poisonous plants.

renal papillae

see renal papilla.

renal papillary necrosis

necrosis of renal papillae due usually to obstruction to urinary flow or poisoning or dehydration.

renal pelvis

the chamber in the kidney into which the collecting tubules discharge urine and from which urine is voided into the ureter.

renal plasma flow

the effective rate of blood flow through the kidneys; the determining factor relative to the rate of glomerular filtration.

renal portal system

a system unique to birds; half to two thirds of the blood supply to the kidney comes from the hindlimbs via veins and terminates in peritubular capillaries where it is mixed with arteriolar blood coming from the glomeruli.

renal rickets

see renal secondary hyperparathyroidism.

renal shutdown

cessation of the excretory function of the kidney; oliguria.

renal spongiform encephalopathy

spongiform encephalopathy associated with renal failure.

renal tubular casts

see urinary cast.

renal vein thrombosis

commonly associated with renal amyloidosis in dogs.

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renal biopsy

Kidney biopsy A Bx guided by ultrasonography of a core of renal tissue to be examined by LM, immunofluorescence, EM Indications Nephrotic syndrome, idiopathic proteinuria, proteinuria with 'glomerular' hematuria, acute renal failure, lupus nephritis, rapidly progressive glomerulonephritis, transplant rejection, renal vasculitis Complications Microscopic hematuria–which occurs with most renal biopsies, and thus is regarded by some authors as normal, perineal hematoma, pain, worsened HTN, AV fistula formation, renal laceration, puncture or laceration of aorta or arteries, pancreas, spleen, liver, GI tract, and death, which occurs in 1:3000 Pts