Kidney biopsy

Biopsy - a morphological study of tissue in vivo.

A kidney biopsy is used to diagnose kidney disease and determine the tactics of therapy. A diagnostic biopsy of the kidney is used after the possibilities of other, less invasive instrumental methods have been exhausted, including a biopsy of the rectal mucosa, nasopharynx, skin, lymph node.

[1], [2], [3], [4], [5], [6], [7]

Indications for kidney biopsy

It is necessary to clarify the causes of massive organic proteinuria, primarily - nephrotic syndrome, renal hematuria, hypertension, tubulopathy. Biopsy allows to distinguish between primary (bright) nephritis and nephropathy within the framework of systemic and metabolic diseases, vasculitis, amyloidosis, to establish the type of amyloid, which is important in connection with differentiated therapy of primary and secondary amyloidosis. With kidney damage (microhematuria, nephrotic, acute nephritic syndrome ), who joined the insulin-dependent diabetes mellitus in the first years of the disease , a kidney biopsy is usually necessary. The prognosis of hypertension persisting after severe nephropathy in pregnant women depends largely on the morphological variant of nephropathy: endotheliosis, focal segmental glomerulosclerosis, sclerosis of interlobular arteries.

A kidney biopsy is indicated in renal acute renal failure of an unclear etiology. At the same time, it radically changes the diagnosis and therapeutic tactics in more than half of the patients with renal acute renal insufficiency, revealing the need for immunosuppressive therapy of fast-progressive glomerulonephritis (14%), allergic acute tubulointerstitial nephritis (11%), necrotizing vasculitis (20%). Of great practical importance is the delineation of drug acute tubulointerstitial nephritis, requiring glucocorticoid therapy, and drug prerenal acute renal failure, drug acute tubular and cortical necrosis, intracanalular blockade.

A kidney biopsy largely determines the overall strategy of renal therapy. With ischemic kidney disease and other renovascular hypertension, the results of kidney biopsy allow you to choose the tactics of surgical treatment - angioplasty of the renal artery or nephrectomy. Nephrobiopsy can detect relative contraindications to kidney transplantation, it is performed in patients with chronic kidney failure in HD in preparation for kidney transplantation. Often relapse and early damage to the transplant is an antibody chronic glomerulonephritis, hemolytic-uremic syndrome, focal-segmental glomerulosclerosis, mesangiocapillary glomerulonephritis. In liver-kidney failure, liver transplantation is effective when a kidney biopsy confirms the diagnosis of hepatorenal syndrome or acute tubular necrosis (OCN). In the event that a background of active chronic hepatitis with replication of HBV (HCV) shows signs of diffuse fibroplastic nephritis, a liver transplant is required along with the kidney.

Diagnostic indications for kidney biopsy

Disease	Indications for kidney biopsy
Nephropathies Renal acute kidney failure Kidney transplant diseases	Organic proteinuria, nephrotic syndrome, glomerular hematuria, renal hypertension of unknown origin, tubulopathy of unknown origin Unclear etiology, with systemic manifestation, symptoms of glomerulonephritis and vasculitis, anuria more than 3 weeks Acute discontinuation and rapid decrease in function, an increase in proteinuria and hypertension

Diagnostic biopsy of the kidney transplant is widespread, the reasons for the violation of its function are manifold. The crisis of acute renal rejection is differentiated from acute drug nephrotoxicity caused by calcineurin inhibitors, antibiotics, NSAIDs, posttransplantation lymphoproliferative syndrome, viral acute tubulointerstitial nephritis ( cytomegalovirus ), recurrence of glomerulonephritis in the transplant. In 30% of cases, a subclinical variant of an acute rejection crisis is developed, diagnosed mainly with the help of kidney biopsy, while the morphological variant of the crisis (interstitial, vascular) largely determines the prognosis and tactics of treatment.

A kidney biopsy for the purpose of choosing therapy and monitoring the effectiveness of treatment should be carried out in the first 2 years of chronic glomerulonephritis with mandatory use of immunoluminescent and electron microscopic methods of analysis. The establishment of a morphological variant of chronic glomerulonephritis with an assessment of the activity of the kidney process and the severity of fibroplastic transformation makes it possible to select the optimal method of immunosuppressive therapy and to predict its effectiveness (Glomerulonephritis). Repeated biopsies that control the effectiveness of therapy are performed in patients with active chronic glomerulonephritis (fast-progressive glomerulonephritis) and in recipients of the kidney transplant; are performed from one to 4-6 times a year, depending on the severity of the course of the kidney process and the features of the therapy. With an effective treatment of the rejection crisis, positive morphological changes in the biopsy for several days outstrip the development of biochemical dynamics.

Preparing for a kidney biopsy

Before biopsy it is necessary:

• assess the state of the coagulating system of blood (bleeding time, the number of blood platelets, coagulogram );
• determine the blood group and Rh factor;
• determine the total and separate functional capacity of the kidneys, their location, mobility (intravenous urography).

Conduct an intravenous urofafia in the position of the patient lying and standing.

In the presence of contraindications to intravenous urofacii, dynamic renoscintiphaphy, as well as echophaphy, are used. Ultrasound can determine the depth of the location of the kidneys and diagnoses such contraindications to nephrobiopsy, as polycystic disease, nephrocalcinosis, roentgenogenous renal concretions.

Before biopsy, anemia (Ht greater than 35%) and blood pressure should be adjusted. With severe arterial hypertension at the time of biopsy and within 2-3 days after it, controlled hypotension is used by intravenous drip diazoxide, sodium nitroprusside or trimethofan kamsilate. In a dialysis patient, a kidney biopsy should be performed at least 6 hours after the next HD; The next GD session is allowed to be performed no earlier than a day after the biopsy.

Technique for carrying out a kidney biopsy

A kidney biopsy is performed with a closed (percutaneous puncture) or operative (open, semi-open biopsy) method.

Since the beginning of the 1980s, the technique of closed kidney biopsy using a real-time monitoring of sectoral ultrasound scanning has been used. With kidney biopsy in patients with overweight, ultrasound control is more effective than computed tomography.

If a complete correction of hypertension, hemorrhagic syndrome and hypocoagulation can not be achieved, a transgular endoscopic kidney biopsy or an open kidney biopsy is used. The method of obtaining a biopsy specimen depends on the structure of the puncture needle. Along with the traditional manual method, automatic biopsy needles are increasingly being used.

Ultrasonic monitoring of the state of the punctured kidney is performed immediately after a biopsy. To prevent complications of the patient for 3 hours after the puncture lies on the ice bladder, in the next 2 days - a strict bed rest. Assign haemostatic drugs (menadione sodium bisulfite, calcium chloride) and antibiotics (macrolides or semi-synthetic penicillins).

Contraindications to kidney biopsy

Absolute contraindications to kidney biopsy and methods for their diagnosis are reflected in the table.

Relative contraindications:

• uncontrollable hypertension;
• marked renal failure (creatinine of blood more than 0.44 mmol / l);
• hypocoagulation;
• thrombocytopenia;
• common atherosclerosis;
• severe nephrocalcinosis;
• nodular periarteritis;
• myeloma nephropathy;
• pathological mobility of the kidney;
• days preceding menstruation in women.

Absolute contraindications to kidney biopsy and methods of their diagnosis

Contraindications

Diagnostic Methods

The only functioning kidney Hydronephrosis, polycystosis Tumor of the kidney, swelling of the pelvis Aneurysm of the renal artery Thrombosis of renal veins Chronic heart failure Novocain Intolerance Mental inadequacy

Chromocystoscopy, dynamic scintigraphy, intravenous urography Ultrasound, intravenous urography, computed tomography Ultrasound, intravenous urography, computed tomography Ultrasonic dopplerography, renal angiography US-dopplerography, renal venography Echocardiography (Echocardiography), measurement of central venous pressure, blood flow velocity Allergic anamnesis Consultation of the psychoneurologist

[8], [9], [10], [11], [12], [13],

Complications of kidney biopsy

The frequency of serious complications after a kidney biopsy is 3.6%, the frequency of nephrectomy is 0.06%, the mortality rate is 0.1%.

• In 20-30% of cases, microhematuria is observed , which lasts for the first 2 days after biopsy.
• Macrogematuria is observed in 5-7% of cases. Usually it is short-term, it is asymptomatic. Prolonged macrohematuria, usually due to a kidney infarction, is often accompanied by renal colic, bladder tamponade with blood clots, which requires urological care.
• For massive bleeding under the capsule of the kidney or paranephric fiber with the formation of perirenal hematoma characterized by intense permanent pain in the lower back, lower blood pressure and hemoglobin levels of blood. Perhaps a transient cessation of kidney function, squeezed by a hematoma. Hematoma is diagnosed with ultrasound and CT. The choice of a method for treating perirenal hematoma (surgical or conservative haemostatic therapy) is carried out together with the urologist.
• To rare, extremely difficult complications of a biopsy of a kidney carry:
  • infection of the hematoma with the development of purulent post-biopsy paranephritis;
  • kidney rupture;
  • injuries of other organs (liver, spleen, pancreas);
  • damage to large vessels (aorta, lower hollow vein).

[14], [15], [16], [17], [18]