Renal puncture, or renal biopsy, is also known as renal puncture biopsy.
Clinical significance In addition, the histopathological changes in kidney disease are not consistent across different periods of its development. For example, the same IgA nephropathy can manifest pathologically in almost all stages of development from near normal renal tissue to sclerosis of most glomeruli. Therefore, understanding the histomorphological alterations of the kidney provides an important basis for clinicians in judging the condition, treating the disease and estimating the prognosis. It can be said that the development of renal pathology examination is a leap forward in the development of nephrology. At present, the results of renal pathology examination have become the golden indicator for the diagnosis of kidney diseases. To summarize, the clinical significance of renal puncture examination mainly includes the following points.
(1) Clear diagnosis: The clinical diagnosis of more than one-third of patients can be revised through renal puncture biopsy.
(2) Guidance of treatment: The clinical treatment plan of nearly one third of patients can be modified by renal puncture biopsy.
(3) Estimation of prognosis: The prognosis of patients with kidney disease can be more accurately evaluated by renal puncture biopsy.
In addition, repeat renal pathology is sometimes required to understand the effectiveness of treatment or to understand the progression of pathology (e.g., crescentic nephritis, lupus nephritis, and IgA nephropathy).
In order to clarify the diagnosis, guide the treatment or judge the prognosis, and when there is no contraindication to puncture, renal puncture can be performed for various primary, secondary and hereditary renal parenchymal diseases (especially diffuse lesions) in internal medicine.
(1) Primary renal diseases: ①Acute nephritis syndrome, when renal function is rapidly deteriorating and acute nephritis is suspected, kidney puncture should be done as soon as possible; kidney puncture should be done when the condition does not improve according to the treatment of acute nephritis for 2 to 3 months. ② primary nephrotic syndrome, treatment first, renal puncture when hormone rule treatment is ineffective for 8 weeks; or puncture first, differentiated treatment according to the type of pathology. (③ asymptomatic hematuria, deformed red blood cell hematuria when the clinical diagnosis is unclear, asymptomatic proteinuria, proteinuria persist >1g/d when the diagnosis is unclear should do renal puncture.
(2) Secondary or hereditary renal disease: renal puncture should be done when the clinical suspicion is undiagnosed, when the clinical diagnosis has been confirmed, but the renal pathological information is important for guiding the treatment or judging the prognosis.
(3) Acute renal failure: puncture should be performed promptly when the cause cannot be determined by clinical and laboratory tests (including chronic kidney patients with rapid deterioration of renal function).
(4) Transplanted kidney: (1) when the cause of significant renal function deterioration is unclear, (2) when severe rejection reaction determines whether to remove the transplanted kidney, and (3) when the original renal disease is suspected to recur in the transplanted kidney.
Contraindications Renal puncture is an invasive test. When selecting a puncture case, it is necessary to master not only the indications but also to carefully exclude the contraindications.
(1) Absolute contraindications: (1) obvious bleeding tendency, (2) severe hypertension, (3) mental illness or uncooperative operation, (4) isolated kidney, (5) small kidney.
(2) Relative contraindications: ① active pyelonephritis, renal tuberculosis, hydronephrosis or pus accumulation in the renal pelvis, renal abscess or perirenal abscess. ② Renal tumor or renal aneurysm. ③Polycystic kidney or large cysts in the kidney. ④Kidney position is too high (the lower pole of the kidney does not reach below the twelfth rib even with deep inspiration) or wandering kidney. ⑤ chronic renal failure. ⑥Excessive obesity. ⑦Severe ascites. (viii) Cardiac failure, severe anemia, hypovolemia, pregnancy or old age.
Preoperative preparation A good preparation for renal puncture is an important part of reducing complications. The following tasks should be done before surgery.
(1) Explain to the patient and family the necessity and safety of renal biopsy and possible complications, and obtain consent from the patient and family. Explain the operation of renal puncture to the patient and relieve the patient’s fear to obtain the patient’s cooperation. Let them practice breath-holding (brief breath-holding is required during renal puncture) and bed-resting for urination (bed-resting is required for 24 hours after renal puncture) to facilitate close cooperation.
(2) Check the bleeding and clotting time, platelet count and prothrombin time to find out whether there is any bleeding tendency.
(3) Check creatinine clearance, blood creatinine and urea nitrogen to understand renal function, check isotope renogram to understand fractional renal function, and make ultrasound to understand kidney size, location and activity.
(4) Check blood type and blood preparation, and routinely clean the skin of the kidney area before surgery.
(5) Take vitamin K orally or intramuscularly 2 to 3 days before surgery.
(6) Before renal puncture in patients with acute renal failure, in addition to the prothrombin time, the leukotocin partial thromboplastin time should be measured. In addition to checking the platelet count, platelet function (aggregation, adhesion and release function) should be checked from time to time, and if abnormalities are found, they should all be corrected before surgery. Abnormal platelet count and function can be corrected by preoperative transfusion of fresh platelets on the day of puncture. Prolonged bleeding time can be corrected by transfusion of cold precipitates rich in clotting factors. Patients with severe renal failure should preferably undergo hemodialysis several times before the kidney puncture, stop dialysis 24 hours before the kidney puncture, neutralize heparin with fisetin at the end of dialysis, and review the clotting time of the test tube method before the kidney puncture to confirm that the effect of heparin has disappeared.
(7) Empty the bladder before the procedure. Renal biopsy is usually divided into three categories: (1) transdermal puncture renal biopsy, which is a widely recognized and applied renal biopsy method in clinical practice; (2) surgical direct-view open renal biopsy; and (3) transrenal venous puncture renal biopsy.
Puncture site localization: the lateral margin of the lower level of the right kidney is mostly selected. The methods of localization are: (1) anatomical localization; (2) X-ray localization; (3) isotope renal scan localization; and (4) ultrasound localization, which is the most commonly used and safer method at present.
Currently, our department adopts ultrasound-guided renal puncture biopsy, which is safe to operate and has a high success rate of puncture.
Operation steps.
Specific operation steps: the patient lies prone on the examination table after urination, a pillow of 10-15 cm in diameter and 50-6-cm in length is placed on the abdomen, the kidney is pushed to the dorsal side and fixed, the arms are extended forward and the head is tilted to the side. The lower level of the right kidney is usually chosen as the puncture site, and the skin of the back is disinfected with the puncture site as the center, and a sterile towel is laid. The sterile ultrasound puncture probe is imaged and local anesthesia is applied with 1-2% lidocaine. A 10-cm-long intracardiac injection needle was taken to pierce the renal capsule vertically from the puncture point and injected with a small amount of local anesthetic drug. The puncture needle was inserted vertically to reach the renal capsule, and the movement of the kidney up and down with breathing was observed. When the lower pole of the kidney moved to the best position for puncture, the patient was asked to exhale, and the puncture needle was immediately and rapidly inserted 2-3 cm into the kidney, and the puncture needle was withdrawn, and the patient was asked to breathe normally. Check whether kidney tissue is taken and measure its length. After observing more than 5 glomeruli under dissecting microscope, send light microscope, electron microscope and immunofluorescence. If there is no kidney tissue, the above steps can be repeated. Generally 2-3 times is appropriate.
Postoperatively: advise the patient to lie flat for 24 hours, drink more water, and closely observe the changes in blood pressure, pulse and urine color. Those with sarcoid hematuria should be kept in bed for longer.
Complications
(1) Hematuria: the incidence of inferior hematuria is almost 100%, which often disappears 1-5 days after surgery and does not need to be treated. When the renal puncture needle penetrates the renal calyces or renal pelvis, hematuria of the sarcoid can occur, mostly disappearing in 1-3 days. When sarcoid hematuria with blood clots appears, it can usually be relieved after intravenous VitK1 or posterior pituitary hormone, and it is important not to use hemostatic drugs at this time to avoid serious consequences of urinary tract obstruction. Encourage patients to drink more water to ensure smooth urinary tract. Patients with renal insufficiency should avoid excessive water consumption causing heart failure, and pay attention to urination. In rare patients with severe bleeding, blood or fluid transfusion should be given, and blood pressure and hemoglobin should be monitored. If the blood pressure cannot be maintained after resuscitation, selective renal arteriography should be considered to clarify the site of bleeding and decide to treat with arterial embolization or take surgical procedures.
(2) Perirenal hematoma: The incidence of perirenal hematoma is about 60-90%, which is usually small, without clinical symptoms, and mostly absorbed within 1-2 weeks. Larger hematomas are rare, mostly caused by kidney tears or penetration to large and medium-sized vessels, especially arteries, mostly occurring on the day of puncture, manifested as abdominal pain, lumbago, pressure pain at the puncture site or slightly inflated compared to the opposite side, pressure pain and rebound pain in the abdomen on the puncture side, blood pressure drops in severe cases, and the pressure product of red blood cells drops, which can be further confirmed by ultrasound or X-ray examination, and are generally treated conservatively.
(3) Low back pain: the incidence of about 17-60%, mostly disappear within a week.
(4) Arteriovenous fistula: 15-19% incidence, most patients are asymptomatic. The typical presentation is severe hematuria and/or perirenal hematoma, intractable hypertension, progressive heart failure, and lumbar and abdominal vascular murmurs. Definitive diagnosis requires renal angiography, and most heal on their own in 3-30 months, with timely surgery in severe cases.
(5) Injury to other organs: Most of the organs are damaged by improper puncture points or too deep needle entry, and serious cases require surgery.
(6) Infection: The incidence of infection is low, mostly due to poor aseptic measures, perirenal infection or associated pyelonephritis, such as fever, severe back pain, high white blood cells need to be treated with antibiotics.
(7) Death: the incidence is 0-0.1%, due to severe haemorrhage, infection, organ damage or the appearance of other systemic complications.
Post-puncture care
(1) General care ①After the patient’s renal biopsy, local wound pressure is applied for several minutes and then pushed into the ward on a flat cart.
②Take blood pressure and pulse every half hour, and stop measuring after 4 hours when blood pressure is stable. If the patient’s blood pressure fluctuates or is low, it should be measured until it is stable and symptomatic treatment should be given.
③After 20 hours of lying down, if the condition is stable and there is no sarcoid hematuria, you can go down to the floor. If the patient develops sarcoid hematuria, bed rest should be extended until the sarcoid hematuria disappears or is significantly reduced. Give intravenous hemostatic drugs or blood transfusion if necessary.
④After surgery, the patient should be advised to drink more water to expel a small amount of clot as soon as possible. At the same time, urine specimens were taken 3 times for routine examination.
⑤ During the bed rest period, ask the patient to rest quietly and reduce the movement of the body to avoid wound bleeding, and at the same time, carefully observe whether the patient’s wound is bleeding and strengthen life care.
⑥Patients should be closely observed for changes in vital signs, asked if there are complaints of discomfort, and abnormalities should be handled in a timely manner.
(2) Care of complications
In order to make a small amount of bleeding discharged from the kidney as soon as possible, in addition to absolute bed rest, the patient should be asked to drink a lot of water, and the change of urine color should be observed each time to determine whether the hematuria is gradually aggravated or reduced. In case of obvious hematuria, bed rest should be prolonged, and hemostatic drugs should be given intravenously in time, and blood transfusion should be given if necessary.
② Perirenal hematoma: absolute bed rest should be provided within 24 hours after renal biopsy. If the patient cannot tolerate it, the importance of absolute bed rest and the possible complications of strenuous activities should be explained to the patient in a timely manner. To obtain the patient’s cooperation. After 24 hours of bed rest without visual hematuria, the patient should start to move gradually and should not increase the activity suddenly to avoid rebleeding of the wound that has not completely healed. At this time, the patient’s activities should be limited and appropriate care should be given. Patients with perirenal hematoma detected by postoperative ultrasound should be kept in bed for a longer period of time.
③Lumbar pain and lumbar discomfort: Most patients have mild ipsilateral lumbar pain or lumbar discomfort, which usually lasts about 1 week. Most patients can reduce pain by taking general painkillers, but patients with combined perirenal hematoma have severe back pain and can be given narcotic painkillers for pain relief.
④ Abdominal pain and distension: abdominal pain occurs in individual patients after renal biopsy and lasts from 1 to 7 days, and a few patients may have pressure pain and rebound pain. Due to the change of living habits plus the compression of the lap band, the patient drinks a lot of water or may have abdominal distension, which generally does not require special treatment, and lactase and antispasmodics can be given to those with obvious abdominal distension and abdominal pain to relieve the symptoms.
⑤ Fever: Patients with perirenal hematoma may have moderate fever due to the absorption of the hematoma, and should be cared for as febrile patients and given appropriate medication.
Components
The kidney is an important organ of the human body with a complex structure and multiple functions. The pathological diagnosis of renal puncture biopsy is an important component of nephrology today, an important branch of pathology, and an essential tool for the diagnosis of renal diseases. The development of renal puncture biopsy can help clinicians to formulate treatment plans; it can determine the presence, type and severity of rejection in transplanted kidneys, and make a clear pathological diagnosis of acute tubular necrosis, cyclosporine toxicity, recurrent and relapsing glomerulonephritis in transplanted kidneys.
1 Kidney specimen processing and preparation Kidney biopsy specimens are usually obtained by percutaneous renal puncture, open renal puncture biopsy, or nephrectomy, and the kidney biopsy specimen should be divided into three for LM, IF, and EM examination. A 1 mm piece is taken from each end of the biopsy specimen for EM, a 2 mm piece is cut from the cortical end for IF, and the rest is routinely paraffin-embedded for LM. The tissues for LM should be fixed in 10% formaldehyde fixative with buffer, and after fixation, they can be embedded in paraffin or plastic and made into ultrathin sections with a thickness of 2 μm to 3 μm for routine hematoxylin 2 eosin (HE) staining, periodic acid 2 Schiff (PAS) staining, hexagonal silver (PASM) staining and Masson trichrome staining.
The tissues for IF examination should be frozen and placed first in OCT embedding solution for frozen sectioning and then in the cold chamber of the frozen sectioning machine. for EM examination, it is best to cut the tissues into 1 mm cubes with a sharp razor blade (wash the oil with alcohol or xylene) and then place them in cold glutaraldehyde or carson formaldehyde fixative as soon as possible.
Generally, 10 or more glomeruli are required for LM, 5 or more glomeruli for IF, and 1 glomerulus for EM.
2 Pathological observation methods and points of renal diseases According to the main parts of lesions, renal diseases are basically divided into glomerular diseases, tubular diseases, interstitial diseases and renal vascular diseases. According to the pathogenesis, renal diseases are basically divided into metabolic inflammation, inflammation directly caused by pathogenic microorganisms, metabolic diseases, congenital developmental abnormalities, hereditary diseases, tumors, etc. Therefore, pathological methods such as light microscopy, immunopathological examination and electron microscopy are often indispensable. The diagnosis of renal diseases is often the result of the application of the above pathological methods, comprehensive observation and analysis of lesions in various parts of the kidney, combined with clinical manifestations, and comprehensive judgment, and the main points of observation of renal diseases are summarized below.
2. 1 Glomerular examination
2. 1. 1 Light microscopy Volume and distribution of capillary collaterals (lobulated, luminal dilatation), cell proliferation status, lesion distribution (diffuse, focal, globular, segmental), thylakoid width and composition, leukocyte infiltration, fibrinoid necrosis and distribution, GBM and vessel wall, microthrombus, deposits or eosinophilia (site and type), crescent (type and percentage), sclerosis (distribution and percentage). 2. 1. 2 Immunopathy
2. 1. 2 Immunopathology Positive or negative reactions, types, sites, images (linear, granular and clumped), intensity of immunoglobulins, complement and fibrin.
2. 1. 3 Electron microscopy GBM (thickness, density and contour, etc.), morphology and lesions of various cells, characteristics of fine membrane areas, electron dense material (type and site), special structures and special substances.
2. 2. 2 Renal tubular examination
2. 2. 1 Light microscopy necrosis, regeneration, lumen expansion, tubular pattern (type), crystallization, intracellular inclusion, cellular degeneration, basement membrane.
2. 2. 2 Immunopathology, immune response (type site and intensity).
2. 2. 3 Electron microscopy of cell morphology and lesions, inclusion, basement membrane, electron dense material (type, site).
2. 3 Interstitial examination of the kidney
2. 3. 1 Light microscopy Edema, inflammatory cell infiltration (type and area), fibrosis. 2. 3. 2 Immunopathy.
2. 3. 2 Immunopathology, immune response (type of site and intensity). 2. 3. 3 Electron microscopy
2. 3. 3 Electron microscopy Cellular infiltration (type of site), electron dense material (type of site).
2. 4 Renal vascular examination
2. 4. 1 Light microscopy Endothelial lesions, elastic membrane lesions, mesothelial lesions, vitreous degeneration, thrombosis, inflammatory lesions, glomerular paraglomerular lesions.
2. 4. 2 Immunopathology Immune response (type site and intensity) .
2. 4. 3 Electron microscopy Endothelial lesions, elastic membrane lesions, mesothelial lesions, electron dense material (type site).
3 General rules for the diagnosis of primary and secondary glomerular diseases 3. 1 Different morphologic manifestations of renal pathology can lead to the same clinical syndrome Nephrotic syndrome and hematuria can be caused by the following diseases: hereditary nephropathy, membranoproliferative GN, IgA nephropathy, acute proliferative GN, etc.; nephrotic syndrome can be caused by the following diseases: microscopic lesions, focal segmental glomerulosclerosis, membranous nephropathy, diabetic Nephrotic syndrome can be caused by microscopic lesions, focal segmental glomerulosclerosis, membranous nephropathy, diabetic nephropathy, or amyloidosis.
3. 2 A clinical syndrome can produce different types of nephropathy, such as lupus nephritis, with different prognoses.
3. 3 The same pathological type or disease process can present with many different diseases.
3. 4 Only a few renal biopsies, such as Alport’s hereditary nephropathy, are diagnosed pathologically by a single pathological method (EM examination), whereas most renal pathology is a comprehensive process that requires the analysis and comparison of all clinical data and the results of LM, EM and IF examinations to arrive at a correct pathological diagnosis.