Renal biopsy practice: What is the gold standard?

Quantification of bleeding volume using computed tomography and clinical complications after percutaneous renal biopsy

Background: The aim of this study was to investigate specific bleeding volume after percutaneous renal biopsy (PRB) and the correlation between bleeding volume and clinical parameters.

Methods: A retrospective study of 252 consecutive patients (153 male patients and 99 female patients) who underwent PRB at the Department of Nephrology, Japanese Red Cross Ishinomaki Hospital, between July 2013 and January 2016 was conducted. PRB was performed under ultrasound guidance using an automated spring-loaded biopsy device and a 16-cm, 16-gauge needle. Patients underwent computed tomography (CT) the day after PRB. Bleeding volume after PRB was evaluated using reconstructed CT data.

Results: The median bleeding volume after PRB was 38 mL (25th–75th percentile, 18–85 mL), with ≥4 punctures identified as a risk factor for massive bleeding. The incidence rates of macrohematuria, transient hypotension and bladder obstruction were 14.3, 8.7 and 4.7%, respectively. Post-PRB blood transfusion and intervention were required in 4.7 and 0.8% of patients, respectively.

Conclusion: Although it is difficult to assess the risk for massive bleeding prior to PRB, we do provide evidence of a specific increased risk with ≥4 puncture attempts, and recommend careful follow-up of these patients.

HOW DO PATIENTS EXPERIENCE A KIDNEY BIOPSY?

BACKGROUND

Guidelines for care before, during and after a kidney biopsy vary nationally and internationally. A literature search has shown few studies about the care before, during and after a kidney biopsy and we found one study from the patients' perspective.

OBJECTIVES

The aim of the study is to gain knowledge about patients' experiences before, during and after a kidney biopsy.

METHODS

A qualitative study with a phenomenological and hermeneutic approach using 'observiews' of seven patients before, during and after a kidney biopsy. Data were analysed using Malterud's principles of systematic text condensation.

RESULTS

Three themes were found: The patients' basic needs, the patient's needs for information and the patients use humour as a coping strategy.

CONCLUSION AND APPLICATION TO PRACTICE

The patients' experiences were characterised by their need to fulfill self-care requirements, because they had to lie down for four to six hours after the biopsy procedure. There is a need to find evidence for the time the patient need to be bedbound to avoid bleeding complications. The patients' needs for information were different, which explains why information should be individualised. There is particular need for more information after discharge.

7 T renal MRI: challenges and promises

The progression to 7 Tesla (7 T) magnetic resonance imaging (MRI) yields promises of substantial increase in signal-to-noise (SNR) ratio. This increase can be traded off to increase image spatial resolution or to decrease acquisition time. However, renal 7 T MRI remains challenging due to inhomogeneity of the radiofrequency field and due to specific absorption rate (SAR) constraints. A number of studies has been published in the field of renal 7 T imaging. While the focus initially was on anatomic imaging and renal MR angiography, later studies have explored renal functional imaging. Although anatomic imaging remains somewhat limited by inhomogeneous excitation and SAR constraints, functional imaging results are promising. The increased SNR at 7 T has been particularly advantageous for blood oxygen level-dependent and arterial spin labelling MRI, as well as sodium MR imaging, thanks to changes in field-strength-dependent magnetic properties. Here, we provide an overview of the currently available literature on renal 7 T MRI. In addition, we provide a brief overview of challenges and opportunities in renal 7 T MR imaging.

Biomarkers for kidney involvement in pediatric lupus

Lupus nephritis (LN), the renal involvement in systemic lupus erythematosus, is currently diagnosed by histopathology obtained by percutaneous renal biopsy and is associated with increased morbidity and mortality in both adults and children. LN is more prevalent and severe in children, requiring aggressive and prolonged immunosuppression. The consequences of the diagnosis and its treatment have devastating long-term effects on the growth, well-being and quality of life of affected children. The paucity of reliable clinical indicators of the presence and severity of renal involvement have contributed to a halt in the reduction of progression to end-stage renal disease in recent years. Here, we discuss the recent development of biomarkers in the management of LN and their role as therapeutic targets.

The use of gallium-67 scintigraphy in the diagnosis of acute interstitial nephritis

Background

Gallium-67 scintigraphy has been suggested as a noninvasive method to diagnose acute interstitial nephritis (AIN). However, its diagnostic performance and usefulness remain controversial.

Methods

We retrospectively reviewed the charts of 76 patients who underwent gallium-67 scintigraphy for a suspicion of AIN. Patients were classified based on kidney biopsy and/or clinical probability of AIN. Gallium-67 scintigraphy results were reinterpreted blindly using both posterior planar and single photon emission computed tomography (SPECT) imaging. Intensity of radioisotope uptake in the kidney was graded from 0 to 5.

Results

The diagnosis of AIN was confirmed in 23 patients and excluded in 44. Nine patients with an uncertain diagnosis were excluded from subsequent analysis. A gallium-67 kidney uptake cutoff of 1 gave a negative predictive value of 100%, whereas a cutoff of 5 had an excellent specificity and positive predictive value for the diagnosis of AIN. When using a cutoff of 3, which had previously been used in the literature, we obtained a sensitivity of 61% and a specificity of 75% with posterior planar imaging. The results of both SPECT and posterior planar imaging modalities were comparable.

Conclusions

Gallium-67 scintigraphy may be of interest in patients with a clinical suspicion of AIN, especially in those who are unable to undergo kidney biopsy. However, results need to be interpreted with caution and depend on the intensity of gallium-67 kidney uptake.