Gabriele Guglielmetti

Radioisotopic Evaluation Glomerular Filtration Rate (GFR) before and after Kidney Donation

Background Because of the decrease of the nephron mass following nephrectomy, kidney donors (KD) develop a partial loss of renal function defined as Acute Kidney Injury (AKI) according to KDIGO criteria (Clinical Practice Guideline, 2012). The recovery of renal function following AKI is mainly ascribed to the concept of renal functional reserve (RFR), defined as the capacity of the kidney to increase glomerular filtration rate (GFR). However, only few studies correlated RFR in KD with long term functional outcomes. Aim of the Study The aim of the present study was to analyse 30 KD renal function before nephrectomy, in the immediate postoperative period and 1 year after the surgical procedure, developing the concept of estimated RFR (eRFR) for the long term follow-up of renal function in KD. Results KD mean age at the time of donation was 54.4 years (min-max, 30-78), mean serum creatinine 0.73 mg/dL (0.5-0.96), eGFR (CKD-EPI) 99 mL/min/1.73m2 (69-119) and radioisotope (51Cr-EDTA) GFR 101.4 mL/min (78-129). The split function was evaluated by concomitant scintigraphy using 99mTc-MAG: the mean percentage of renal function of right kidney was 48% (43-56) and left 52% (44-57), respectively. As expected, immediately after nephrectomy all KD worsened renal function: the mean percentage increase of serum creatinine was 79% (50-112.2%) within 72 hours post-surgery; most of KD (25/30) developed AKI stage 1, and 5 KD AKI stage 2 according to KDIGO criteria. Seven days after surgery, renal recovery was observed in all cases: the mean percentage increase of serum creatinine (50.6%) was significantly lower than the zenith of serum creatinine. These results suggest a potential gain of about 30% in comparison to the starting value of the right kidney. One year after nephrectomy (all KD were subjected to left nephrectomies), we studied KD renal function (GFR) by radioisotopic evaluation using 51Cr-EDTA and we then compared it with the split radioisotope (51Cr-EDTA) GFR of the right kidney at the first scintigraphic evaluation. Mean GFR was 68.8 mL/min (50-87) vs. 48.6 mL/min (39.7-60.4) before donation with an average GFR increase of 20 mL/min (0.8-45.6) and a percentage increase of the right renal function up to 110% (mean 42%, min 1.4%). Conclusions The results of this study show that radioisotopic evaluation is feasible and allows an estimated determination of RFR at different time points after nephrectomy in KD. We observed a compensatory hypertrophy due to RFR in all the 30 KD included in the study, independently from age and co-morbidities such as elevated BMI and hypertension. The limitation of this study is the evaluation of RFR only after the decrease of the nephron mass due to donation: we have now started a kidney stress test with a protein load to estimate RFR of KD before surgery with the aim of finding a correlation with radioisotpic GFR after nephrectomy. Figure. No caption available.

Membranous material in the urine: A diagnosis of cystic echinococcosis at first glance.

We herein report the case of a 19-year old woman who was referred to our unit for a large pale white-yellow, balloon-like, grape-sized “membranous material” measuring around 7 cm, with an uneven internal surface and a smooth external surface, which was expelled with urine. In the previous 3months she had a few episodes of urinary discharge of such “membranous material” associated with mild dysuria. Her previous medical history was uneventful and physical examination was normal. No major laboratory abnormalities were detectable: creatinine was 51.3mmol/L, wihte blood cells 9.6 ×10/L (neutrophils 68%), C-reactive protein 11mg/L, and urinalysis showed microscopic haematuria (++) and leukocyte esterase (+) without nitrites. Abdomen ultrasound showed multiple uncomplicated cysts in the left kidney, completely distorting the renal profile, which were confirmed by a contrast-enhanced CT scan and an MRI; these exams also excluded other abdominal lesions (Fig. 1). The gross characteristics of this material and the imaging are highly suggestive for cystic echinococcosis (CyEc). Indeed, the patient used to have a dog livingwith her formany years before the onset of symptoms. Microscopic examination of the material confirmed the diagnosis (laminated structure consistent with a hydatid cyst), and a chest and head CT excluded other metastatic lesions. She was treated with albendazole (4weeks) followed by left nephroureterectomy; right before surgery she was given one-shot of i.v. steroids to prevent allergic reaction. Serum creatinine has been stable thereafter (52.2mmol/L). CyEc occurs in humans as accidental intermediate hosts from direct contact with dogs or consumption of contaminated vegetables or water containing eggs of Echinococcus granulosus or multilocularis. The larval stage emerging from the eggs produces CyEc by haematogenous dissemination through the portal system mainly in liver and lungs. Renal CyEc is rare (2%)

Comment on: Think to prevent before than to treat renal impairment in multiple myeloma: do not forget tubular damage mimicking Fanconi syndrome

In a recent paper, renal impairment is correctly described as a common complication of symptomatic myeloma (20 -40%) needing dialysis. Significant improvement has been attributed to novel therapeutic chemotherapy regimens coupled with extrarenal free light chain removal obtained by plasma exchange or dialysis [1]. As nephrologists, we would like to stress the importance of recognizing early symptoms of renal impairment other than by measuring renal function as glomerular filtration rate (GFR) [2]. An increase in serum creatinine and/or a decrease in GFR are not the only markers of renal impairment in patients with multiple myeloma. Although a serum creatinine > 2 mg/dl is one of the hypercalcemia, renal impairment, anemia, bone disease (CRAB) diagnostic criteria for symptomatic myeloma requiring therapy, it has been stated that “a variety of other types of end-organ dysfunctions can occur and lead to a need for therapy. Such a dysfunction is sufficient to support classifications of myeloma if proven to be myeloma-related” [3]. Tubular dysfunctions, and mainly proximal tubular dysfunctions with the picture of complete or incomplete Fanconi syndrome, constitute such “other end-organ dysfunctions” [1-3]. As far as the kidney is concerned, it is important to have early indicators of tubular dysfunction. This includes hypophosphatemia, hypouricemia, hypokalemia and metabolic acidosis coupled with urine loss of phosphate, urate, potassium, bicarbonate, low-molecular-weight proteins and glycosuria (in the presence of normal blood glucose levels). Therefore, even if free light chains detected in the urine (Bence Jones proteinuria) is not a sign of renal damage by itself, its transcellular “traffic” may cause tubular damage, eventually leading to tubular crystal-storing histiocytosis and Fanconi syndrome. Subsequently, tubular casts precipitating in the distal tubule may cause acute renal failure of the classical ‘myeloma kidney’ [4,5]. Therefore, a delay in diagnosis could allow irreversible kidney damage to occur and might shorten patient survival.

PEComa of soft tissues can mimick lymph node relapse in patients with history of testicular seminoma

Perivascular Epithelioid Cell tumour (PEComa) is rare. We describe a 39-year-old man who underwent a left radical orchidectomy and adjuvant radiation therapy for a stage IA classical testicular seminoma. He was diagnosed with a mass lateral to the right common iliac artery that was considered suspicious for late lymph node relapse after 3 years of follow-up. Due to the unusual location of the mass and the equivocal findings of percutaneous biopsy, a laparoscopic pelvic lymphadenectomy was performed. Final pathology revealed PEComa of soft tissue. The patient is disease-free after 38 months of follow-up without adjuvant treatment. The presence of rare soft-tissue neoplasm should be considered in differential diagnosis of retroperitoneal masses during follow-up of germ cell tumours. Suspicious isolated recurrences of these neoplasms in unusual locations can require surgical excision to confirm diagnosis and avoid inappropriate treatment.