**2.3 Quality of material/pathologist present**

A kidney biopsy is an important diagnostic tool and considered the "gold standard" for the best definition of the majority of nephropathies. It is capable of changing the clinical diagnosis approximately 50% of the time and changing the therapy to be administered approximately 40% of the time [16]. For this to happen, however, an adequate sample must be obtained.

A 19-gauge needle generally furnishes very small, narrow specimens that are often inadequate for the assessment of vessels. Thus, smaller needles, such as 18 or


#### **Table 1.**

*Conditions that impede a kidney biopsy.*

16 gauge, are advisable [17, 18]. Depending on the needle used, the difference in the obtainment of glomeruli can be as high as 300% [19]. The quantity of glomeruli needed for a secure diagnosis depends mainly on the diagnostic hypothesis and the clinical condition of the patient. For virtual exclusion (with greater than 95% certainty) of the diagnosis of focal segmental glomerulosclerosis, it is essential to have at least 25 glomeruli representing the juxtamedullary portion, as the focal disease affects some glomeruli while sparing others of morphological abnormalities seen with light microscopy and a good sample is important to the best definition of the disease [20]. In contrast, the diagnosis can be confirmed with a single glomerulus for other diseases, such as membranous glomerulopathy, in which diffuse morphological changes are similar in all glomeruli. For still other diseases, such as myeloma nephropathy, the diagnosis is essentially confirmed with representation of the medullary portion. In the analysis of transplanted kidney tissue, the aim is to achieve at least two core fragments exhibiting at least 7–10 glomeruli, two arteries, and the medullary portion (minimum assessment criteria defined by the Banff Meeting) [21].

In the evaluation of most glomerulopathies by light microscopy or immunofluorescence microscopy, 8–10 glomeruli are needed [22]. During the US-guided removal of the fragment, the evaluation of a pathologist is very important, as he/ she is capable of determining the adequacy of the sample. The examination of the fresh material determines its sufficiency (quantity of glomeruli) for testing the main clinical hypotheses and provides information on medullary representation as well as the representation of larger vessels (**Figure 1**).

After determining the ideal amount of material and its representation of the renal parenchyma, the pathologist stores the samples in specific solutions for different analyses. The solutions should not come into contact with each other, as this would render the subsequent analyses unviable. The largest portion of the fragments should be allocated to light microscopy analysis. The most widely used fixatives are

#### **Figure 1.**

*Ultrasound-guided kidney biopsy. Fragment stored in 0.9% NaCl and analyzed under a light microscope. Renal medulla with medullary rays and characteristic striation. Multiple small round structures (glomeruli) distributed in renal cortex—some paler, others congested with numerous red blood cells (details of two glomerular structures).*

**43**

**Table 2.**

*Major complications*

*Minor complications*

*Post-Biopsy Complications Associated with Percutaneous Kidney Biopsy*

immune deposits, which are lost if not fixed soon enough.

tract by clots. In such cases, management is normally necessary.

**Complications Management**

Arteriovenous fistula Conservative Hematuria Hydration

*Post-biopsy complication and proper management for each.*

**2.4 Complications and management**

10% neutral buffered formalin, paraformaldehyde, and Bouin's solution. In these media, the sample remains viable for analysis for several days. However, earlier histological processing results in analyses of better quality. For the analysis of antigens, such as IgG, IgM, IgA, complement components C3 and Cq1, fibrinogen as well as κ and λ chains, immunofluorescence microscopy should be used. Therefore, the sample should be stored in 0.9% saline solution—if the collection site is near the analysis site—and kept chilled (but not frozen) to obtain the best possible results. If rapid analysis (within several hours) is not possible, the sample should be placed in a transport solution, such as Michel's or Zeus solution. Although this solution preserves the sample for several days, better results are achieved the earlier the sample is taken for analysis, with poor or even impossible results if the sample is analyzed 5–7 days after being collected [23]. For transmission electron microscopy, a small portion is needed of the cortical parenchyma, with two glomeruli. This analysis is essential to the evaluation of podocytopathies, thin basement membrane disease, and metabolic disease. The fragments should be fixed within minutes after collection in a specific solution (glutaraldehyde or Karnovsky's solution). In the presence of a pathologist, a small portion may be acquired (1 and 2 mm) and fragmented until obtaining the quantity of glomeruli needed. This material should be placed in a buffered solution after fixation (1–2 days after collection), as the aim of the analysis is to examine the ultrastructure, such as the cytoplasmic membrane, reticulum, and

When a biopsy is performed without the presence of a nephropathologist, it is advisable to remove at least one fragment (if possible, two) from the renal parenchyma for each solution. Immunohistochemical analysis for the study of C4d, polyomavirus, adenovirus, cytomegalovirus, PLA2R, IgG4, etc. should be performed with material embedded in paraffin, which is preserved for light microscopy.

A kidney biopsy is considered a minimally invasive method but is not without complications. Depending on the severity, such events are classified as minor and major, which require different forms of treatment (**Table 2**). Minor complications include hematuria, small perirenal hematomas, arteriovenous fistulas, and pain, all of which normally resolve spontaneously [24]. Major complications include massive bleeding with hemodynamic instability, voluminous perirenal hematomas with refractory disabling pain, and important hematuria with obstruction of the urinary

Among all forms of complication, bleeding is the most frequent and occurs mainly within the first 12–24 hours after the procedure in nearly all patients [4, 25].

Disabling intense pain Optimization of analgesia (use of opioids) Hemodynamic instability with blood transfusion Endovascular treatment (embolization) Clot obstructing urinary tract Irrigation with three-way probe

*DOI: http://dx.doi.org/10.5772/intechopen.89226*

#### *Post-Biopsy Complications Associated with Percutaneous Kidney Biopsy DOI: http://dx.doi.org/10.5772/intechopen.89226*

*Renal Diseases*

Meeting) [21].

16 gauge, are advisable [17, 18]. Depending on the needle used, the difference in the obtainment of glomeruli can be as high as 300% [19]. The quantity of glomeruli needed for a secure diagnosis depends mainly on the diagnostic hypothesis and the clinical condition of the patient. For virtual exclusion (with greater than 95% certainty) of the diagnosis of focal segmental glomerulosclerosis, it is essential to have at least 25 glomeruli representing the juxtamedullary portion, as the focal disease affects some glomeruli while sparing others of morphological abnormalities seen with light microscopy and a good sample is important to the best definition of the disease [20]. In contrast, the diagnosis can be confirmed with a single glomerulus for other diseases, such as membranous glomerulopathy, in which diffuse morphological changes are similar in all glomeruli. For still other diseases, such as myeloma nephropathy, the diagnosis is essentially confirmed with representation of the medullary portion. In the analysis of transplanted kidney tissue, the aim is to achieve at least two core fragments exhibiting at least 7–10 glomeruli, two arteries, and the medullary portion (minimum assessment criteria defined by the Banff

In the evaluation of most glomerulopathies by light microscopy or immunofluorescence microscopy, 8–10 glomeruli are needed [22]. During the US-guided removal of the fragment, the evaluation of a pathologist is very important, as he/ she is capable of determining the adequacy of the sample. The examination of the fresh material determines its sufficiency (quantity of glomeruli) for testing the main clinical hypotheses and provides information on medullary representation as

After determining the ideal amount of material and its representation of the renal parenchyma, the pathologist stores the samples in specific solutions for different analyses. The solutions should not come into contact with each other, as this would render the subsequent analyses unviable. The largest portion of the fragments should be allocated to light microscopy analysis. The most widely used fixatives are

*Ultrasound-guided kidney biopsy. Fragment stored in 0.9% NaCl and analyzed under a light microscope. Renal medulla with medullary rays and characteristic striation. Multiple small round structures (glomeruli) distributed in renal cortex—some paler, others congested with numerous red blood cells (details of two* 

well as the representation of larger vessels (**Figure 1**).

**42**

**Figure 1.**

*glomerular structures).*

10% neutral buffered formalin, paraformaldehyde, and Bouin's solution. In these media, the sample remains viable for analysis for several days. However, earlier histological processing results in analyses of better quality. For the analysis of antigens, such as IgG, IgM, IgA, complement components C3 and Cq1, fibrinogen as well as κ and λ chains, immunofluorescence microscopy should be used. Therefore, the sample should be stored in 0.9% saline solution—if the collection site is near the analysis site—and kept chilled (but not frozen) to obtain the best possible results. If rapid analysis (within several hours) is not possible, the sample should be placed in a transport solution, such as Michel's or Zeus solution. Although this solution preserves the sample for several days, better results are achieved the earlier the sample is taken for analysis, with poor or even impossible results if the sample is analyzed 5–7 days after being collected [23]. For transmission electron microscopy, a small portion is needed of the cortical parenchyma, with two glomeruli. This analysis is essential to the evaluation of podocytopathies, thin basement membrane disease, and metabolic disease. The fragments should be fixed within minutes after collection in a specific solution (glutaraldehyde or Karnovsky's solution). In the presence of a pathologist, a small portion may be acquired (1 and 2 mm) and fragmented until obtaining the quantity of glomeruli needed. This material should be placed in a buffered solution after fixation (1–2 days after collection), as the aim of the analysis is to examine the ultrastructure, such as the cytoplasmic membrane, reticulum, and immune deposits, which are lost if not fixed soon enough.

When a biopsy is performed without the presence of a nephropathologist, it is advisable to remove at least one fragment (if possible, two) from the renal parenchyma for each solution. Immunohistochemical analysis for the study of C4d, polyomavirus, adenovirus, cytomegalovirus, PLA2R, IgG4, etc. should be performed with material embedded in paraffin, which is preserved for light microscopy.

## **2.4 Complications and management**

A kidney biopsy is considered a minimally invasive method but is not without complications. Depending on the severity, such events are classified as minor and major, which require different forms of treatment (**Table 2**). Minor complications include hematuria, small perirenal hematomas, arteriovenous fistulas, and pain, all of which normally resolve spontaneously [24]. Major complications include massive bleeding with hemodynamic instability, voluminous perirenal hematomas with refractory disabling pain, and important hematuria with obstruction of the urinary tract by clots. In such cases, management is normally necessary.

Among all forms of complication, bleeding is the most frequent and occurs mainly within the first 12–24 hours after the procedure in nearly all patients [4, 25].


**Table 2.**

*Post-biopsy complication and proper management for each.*
