Accepting prospective kidney donors with asymptomatic urinary abnormalities: Are we shooting in the dark?

Abstract

CASE PRESENTATIONA 53-year-old Caucasian lady was evaluated in our center as a potential kidney donor. She volunteered to donate a kidney to her brother with whom she shared a 6/6-antigen match. The exact etiology of her brother's end-stage renal disease (ESRD) could not be determined. On evaluation she was noted to be in good health and a review of systems was unremarkable. Family history was significant for functional pituitary tumor leading to acromegaly and diabetes in her father and renal cell carcinoma in her uncle. Physical examination revealed that she was overweight with a body mass index of 31.2 kg/m 2 . Her blood pressure was 120/68 mm Hg, her heart rate was 79 beats per minute and she was afebrile. The remainder of the systemic examination was unremarkable.A transplant donor workup was completed (Table 1). The pertinent abnormality was persistent microscopic hematuria with two out of three urine analyses positive for trace to 1 þ blood in dipstick and 1-4 red cells on microscopy. These urinalyses were performed on three separate occasions at least 1 month apart. Urine cultures were negative throughout. Gynecological examination, which included a papanicolaou (PAP) smear, was unremarkable.The differential diagnosis for the microhematuria was discussed with the patient. The patient was determined to be considered as a candidate for kidney donation and requested that we proceed to a percutaneous renal biopsy in order to definitively identify the cause of hematuria.

Persistent Glomerular Hematuria in Living Kidney Donors Confers a Risk of Progressive Kidney Disease in Donors After Heminephrectomy

“…The high 25.6% prevalence of occasional or persistent hematuria after donation means that hematuria is common in living kidney donation. Because extraglomerular bleeding can be excluded by evaluations such as computed tomography, sonography and urine cytology (20), isolated hematuria in pre-or postdonation donors is most likely to be of glomerular origin, suggesting the presence of glomerular diseases such as thin basement membrane nephropathy (TBMN), IgAN or AS, particularly if hematuria is dysmorphic. Although histological findings could not be evaluated in this study, we expect that light microscopy in many of the donors would have revealed minor glomerular abnormality, mild mesangial proliferative change, or partially global sclerosis in glomeruli, with either mesangial IgA and C3 deposition by immunofluorescence (IgAN), as well as thin glomerular basement membrane (GBM) and segmental attenuation of the lamina densa (TBMN), or thickening and lamellation of GBM (AS) on electron microscopy, as previously reported (19,20,29,30).…”

“…Although the paucity of evidence for the eligibility of candidates with isolated hematuria and their risk after donation has meant that the acceptability of glomerular hematuria in kidney donors remains controversial (19,20,29,31,32), our results clearly show that donors with persistent hematuria and d-RBC are at significant risk of developing persistent proteinuria or lower GFR, which also confer worse renal outcomes in patients with TBMN, IgAN or AS (31,(33)(34)(35)(36). The eligibility of potential donors with isolated but persistent dysmorphic hematuria should therefore be closely considered.…”

“…Similarly, no clear thresholds have been established for abnormal urinalysis. In particular, the risk of postdonation kidney disease with predonation persistent hematuria has not been well investigated (17)(18)(19)(20), albeit that it has been suggested (21).…”

“…Although the paucity of evidence for the eligibility of candidates with isolated hematuria and their risk after donation has meant that the acceptability of glomerular hematuria in kidney donors remains controversial (19,20,29,31,32) …”

Health Outcomes for Living Kidney Donors with Isolated Medical Abnormalities: A Systematic Review

“…Increasingly, individuals who would have previously been deemed unsuitable as living donors due to relative medical contraindications are being considered. Described variably as having ‘isolated medical abnormalities (IMAs)’ (1,2), ‘asymptomatic urinary abnormalities’ (3) or as ‘complex’, ‘marginal’ or ‘at incremental risk’ (4–6), these living donors have conditions such as older age, obesity, hypertension, microscopic hematuria, proteinuria, reduced glomerular filtration rate (GFR) or nephrolithiasis (7). They may also have more than one abnormality.…”