Renal biopsy is usually called renal puncture. Due to the wide variety of kidney diseases, complex etiology and pathogenesis, the clinical manifestations of many kidney diseases are not completely consistent with the histological changes of the kidney. In order to clarify the etiology of the disease and further diagnose the specific type of disease the patient is suffering from, a kidney puncture biopsy is needed! In recent years, with the development of science and technology, the update of imaging equipment and the improvement of operational skills, percutaneous renal biopsy technique has been carried out more widely, which can directly observe the morphological changes of the kidney in kidney disease and allow for a series of observations. The quality of its diagnosis has also been greatly improved due to the improvement of puncture techniques, immunohistochemistry techniques and the application of electron microscopy. It has become an important tool for diagnosis, guiding treatment and prognosis determination of renal diseases. It has also contributed to the etiology and development trend of many glomerular diseases. A renal biopsy is required in the following cases.
1, nephrotic syndrome: when the etiology of nephrotic syndrome is unknown and those who consider whether it is secondary to systemic diseases.
2, glomerulonephritis with rapid renal decompensation, a renal biopsy is required to determine the pathological type of their renal damage.
3. In acute nephritis syndrome, renal biopsy can reveal the morphology of inflammation and immune deposits and their extent, which is important for the early diagnosis and treatment of acute nephritis. Primary acute nephritis with atypical clinical manifestations or acute nephritis that does not heal after several months or decreased renal function.
4, primary nephrotic syndrome seen in adults is best to do a kidney biopsy to determine its tissue type before using hormones to avoid side effects caused by the blind use of hormones, especially for those who are ineffective in treatment.
5, patients with hematuria can be considered for renal biopsy after various examinations to exclude non-glomerular hematuria, and those who fail to establish the diagnosis can be considered for renal biopsy, and those with persistent hematuria without clinical manifestations and hematuria with proteinuria and 24-hour urine protein quantification greater than 1 gram should have renal biopsy.
6.For those who have proteinuria for a long time without any symptoms, kidney biopsy can clarify the pathological type to facilitate the use of drugs and prognosis.
7. Lupus nephritis, renal hypertension, acute renal failure and chronic renal failure of unknown origin can be diagnosed by kidney biopsy to help diagnosis.
When the above conditions occur, patients had better go to the hospital for kidney biopsy to make a clear diagnosis.
It is mainly used to diagnose lupus nephritis in rheumatic immune system diseases and is an important tool to understand the pathological type of lupus nephritis. In recent years, due to the improvement of renal biopsy technology, trans-B ultrasound-guided renal biopsy has been gradually carried out more widely. Renal biopsy is the main basis for determining the diagnosis, adjusting the treatment plan and judging the prognosis. One of the main roles of renal biopsy in lupus nephritis is to determine the activity and chronicity of the lesion in order to understand the prognosis and guide the treatment.
Active lesions in lupus nephritis have been recognized as an indicator to guide aggressive and intensive treatment. It is an important indicator for the aggressive administration of corticosteroids and cytotoxic drugs. For example, (1) segmental glomerular necrosis; (2) marked proliferation of glomerular cells; (3) wire loop-like changes in the basement membrane; (4) electron microscopic findings of more electron-dense deposits in the subendothelial and thylakoid areas, more nuclear fragments and hematoxylin vesicles; (5) cellular crescent; (6) small renal vascular lesions; (7) extensive interstitial edema and mononuclear cell infiltration.
However, if lupus nephritis is dominated by chronic lesions, the outcome is poor. Evidence of chronic lesions are: (1) glomerulosclerosis; (2) fibrous crescent; (3) tubular atrophy; (4) interstitial fibrosis; (5) capsular adhesions; and (6) tubular sclerosis. The 5-year survival rate of the kidney is significantly lower in those with a predominance of the above chronicity indicators.
Significance of renal biopsy
Understanding the histomorphological changes 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 is 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 decompensation is unclear, (2) severe rejection reaction to decide whether to remove the transplanted kidney, and (3) suspected recurrence of the original renal disease in the transplanted kidney.
Contraindications to renal biopsy
Renal biopsy is an invasive test, so when selecting a biopsy case, it is necessary not only to master the indications, but also to carefully exclude the contraindications.
(1) absolute contraindications: ① obvious bleeding tendency, ② severe hypertension, ③ psychiatric 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) Heart failure, severe anemia, hypovolemia, pregnancy or old age.
Post-operative care of renal biopsy
(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 rate 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.
Indications for renal biopsy
1. erythrocyte tubular pattern in the urine sediment.
2, clinical or laboratory manifestations with autoimmune diseases or other systemic diseases.
3, no retinopathy or only mild lesions, and those with diabetes mellitus of more than 10 years duration.
The basic lesions: glomerular basement membrane thickening and increased thylakoid stroma with glomerular nodular and diffuse lesions and small arterial vitelliform lesions, glomerulosclerosis.