Assessing asymmetrical kidney function in living donors:a retrospective cohort study on CT metrics

Background: Live donor kidney transplantation is the preferred kidney replacement therapy for eligible patients but requires thorough donor evaluation to minimise risks. Contemporary guidelines recommend split kidney function measurement in living donors only when there is a significant kidney size discrepancy, yet the evidence for this is poor, and practice varies nationally. This study evaluates the efficacy of CT-derived kidney metrics in detecting significant functional asymmetry. Methods: We conducted a retrospective cohort analysis of 123 prospective living kidney donors at a regional transplant centre from June 2011 to October 2014, utilising CT to determine kidney and cortical volumes and lengths. Asymmetric kidney function (AKF), defined by > 10% function difference on DMSA scans, was correlated with CT measurements to calculate the diagnostic accuracy of current guidelines. Results: Among the prospective donors, the median age was 42 years, and 59.3% were female. The median split kidney function difference was 4%, with 25 individuals exhibiting > 10% AKF. Kidney length discrepancy proved to be a poor indicator of AKF (sensitivity: 28%, specificity: 84%). While negative predictive values for cortical and kidney volumes were high (96% and 93%, respectively), sensitivity was low, and specificity and positive predictive value did not meet satisfactory thresholds. Conclusions: CT-derived metrics of kidney length, cortical, and total volume show limited sensitivity and specificity in identifying significant AKF. These findings provide evidence to support revised guideline development in the assessment of living kidney donors

Cocaine-induced granulomatosis with polyangiitis—an under-recognized condition

Objectives: Cocaine and cocaine mixed with levamisole are increasingly used in the UK and result in significant direct nasal damage in addition to promoting vasculitis. Our aims were as follows: (1) to identify the main symptoms and presentation of cocaine-induced vasculitis; (2) to provide evidence regarding the best practice for the investigation and diagnosis of cocaine-induced vasculitis; and (3) to analyse the clinical outcomes of patients in order to understand the optimal management for the condition./ Methods: We performed a retrospective case series analysis of patients presenting with cocaine-induced midline destructive lesions or vasculitis compatible with granulomatosis with polyangiitis (GPA) from two large tertiary vasculitis clinics between 2016 and 2021./ Results: Forty-two patients (29 Birmingham, 13 London) with cocaine-induced midline lesions or systemic disease were identified. The median age was 41 years (range 23–66 years). Current cocaine use was common, and 20 of 23 samples provided were positive when routine urine toxicology was performed; 9 patients who denied ever using cocaine were identified as using cocaine based on urine toxicology analysis, and 11 who stated they were ex-users still tested positive. There was a high incidence of septal perforation (75%) and oronasal fistula (15%). Systemic manifestations were less common (27%), and only one patient had acute kidney injury. Fifty-six per cent of our patients were PR3-ANCA positive, with none testing positive for MPO-ANCA. Symptom remission required cocaine discontinuation even when immunosuppression was administered./ Conclusion: Patients with destructive nasal lesions, especially young patients, should have urine toxicology performed for cocaine before diagnosing GPA and considering immunosuppressive therapy. The ANCA pattern is not specific for cocaine-induced midline destructive lesions. Treatment should be focused on cocaine cessation and conservative management in the first instance in the absence of organ-threatening disease