Simple renal cyst and renal dysfunction: A pilot study using dimercaptosuccinic acid renal Scan

Influence of a simple cyst on kidney function

Introduction

The aim of the study was to estimate the influence of a simple kidney cyst on kidney function and to determine indications for surgical treatment.

Materials and methods

In this prospective cohort study, we analyze data on 109 patients who sought counseling with a simple kidney cyst. Patients with solitary cyst of the right or left kidney, grade I-IIF according to the Bosniak classification, were included. Split glomerular filtration rate (sGFR) was calculated. The maximum size of the cyst, single kidney volumes (SKV) and the volume of the lost (atrophied) parenchyma were estimated with computed tomography (CT) scan of the urinary tract with contrast.

Results

The average difference between the sGFR of a healthy and affected kidney cyst was 11 [8.70; 13.44] ml/min, which is a statistically significant value (p = 0.001). Correlation analysis revealed a statistically significant relationship between the proportion of lost parenchyma and the maximum cyst size: p = 0.37 with 95% CI [0.20; 0.52] (p = 0). A multivariate logistic regression model showed that a statistically significant factor influencing the likelihood of a significant decrease in sGFR is the percentage of lost kidney parenchyma (OR = 1.13; p = 0).

Conclusion

The growth of kidney cyst causes atrophy of the renal parenchyma and a decrease in the sGFR of the affected kidney. An increase in the volume of the atrophied parenchyma leads to a decrease in the sGFR of the affected kidney.

Decline in measured glomerular filtration rate is associated with simple renal cyst in Chinese patients with type 2 diabetes

AIMS/INTRODUCTION

Simple renal cysts (SRC) are associated with age, hypertension and hyperuricemia, which are risk factors of renal impairment. This study aimed to investigate the prevalence of SRC and its association with measured glomerular filtration rate (mGFR) in patients with type 2 diabetes mellitus in China.

METHODS

A total of 3,552 patients with type 2 diabetes mellitus admitted to Shanghai Sixth People's Hospital from January 2012 to December 2016 were investigated. All participants were diagnosed as SRC by color Doppler, and all participants were measured for GFR by using dynamic renal scintigraphy with technetium-99m-diethylene triamine peta-acetic acid.

RESULTS

The prevalence of SRC was 17.4% (619 cases). Participants with SRC had significantly lower mGFR values than those without SRC (86.16 ± 26.20 vs 94.88 ± 23.98 mL/min/1.73 m2 , P < 0.001). In 478 participants with unilateral renal cyst, the mGFR of the kidney affected by SRC was significantly lower than that of the unaffected kidney (43.32 ± 13.74 vs 44.18 ± 13.34 mL/min/1.73 m2 , P = 0.014). The participants were divided into four groups according to the quartiles of mGFR level (≥109.50, 93.80-109.49, 76.90-93.79 and <76.90 mL/min/1.73 m2 ). The prevalence of SRC gradually increased with decreasing mGFR level (12.9, 13.9, 16.6 and 27.8%, respectively; P trend <0.01). After adjusting for age, sex, duration of diabetes, hypertension and other potential confounders, the logistic regression showed that SRC was an independent risk factor for impaired GFR (<60 mL/min/1.73 m2 ; odds ratio 1.656; 95% confidence interval 1.451-1.890, P < 0.001).

CONCLUSION

SRC is an independent risk factor for the decrease of mGFR in Chinese diabetes patients, and could affect the renal GFR measured by dynamic renal scintigraphy on the SRC side.

Association between serum uric acid levels and simple renal cyst risk in a nondiabetic population: A nested case-control study

BACKGROUND

Previous studies have found a relationship between hypertension or cardiovascular disease and simple renal cysts (SRCs) in health check-up population, but SRCs incidence is still controversially associated with serum uric acid (SUA) concentration in the nondiabetic participants. In this single-centre nest case-control study, serum uric acid levels were examined in relation to the incidence of SRCs in nondiabetic individuals.

METHOD

Participants who underwent at least two renal ultrasound examinations with an interval of more than 12 months were enrolled. The results of clinical examinations, laboratory tests and abdominal ultrasound tests were recorded for each participant and analysed in this retrospective observation study.

RESULT

A total of 144 control and 144 SRC patients were ultimately confirmed and included in further analysis. Hyperuricaemia (OR 2.846, 95% CI 1.519-5.332, p = 0.001) was significantly correlated with SRC formation according to multivariable analysis. In both the male and female groups, SRC patients had significantly higher serum uric acid levels compared with control subjects. In 54 SRC patients with cyst puncture, the serum uric acid concentration was positively correlated with the uric acid concentration in cyst fluid (r = 0.6144, p < 0.0001). The serum uric acid concentration was positively correlated with the maximum cyst diameter in the SRC patients (r = 0.4531, p < 0.0001).

CONCLUSION

In a nondiabetic population, hyperuricaemia was significantly independently associated with a higher SRCs incidence. In SRC participants with cyst puncture, the SUA level had a significantly positive correlation with the uric acid level in cyst fluid. In SRC patients, the SUA level had a significantly positive correlation with cyst maximum diameter.

Does the simple renal cyst treatment improve renal function: A pilot study

Background:

The current study aims to assess the effects of the large simple renal cyst (SRC) surgery on renal function for the first time.

Materials and Methods:

This case-series study included 22 patients with larger than 50 mm single SRC who underwent laparoscopic cyst unroofing surgery. Twenty-four-hour urinary protein, creatinine, and volume along with plasma creatinine and estimated glomerular filtration rate (GFR) were measured in patients before and 1 month after surgery. Patients underwent abdominopelvic computed tomography-scan without contrast and parenchymal thickness diameter adjacent to the cyst was measured before and after surgery.

Results:

Mean age and weight of patients were 52.2 ± 8.9 years and 77 ± 10.9 akg, respectively. There was no significant difference between plasma creatinine and GFR before and after surgery (P = 0.25 and 0.37, respectively). Twenty-four-hour urinary volume, creatinine, and protein before and after surgery revealed no significant changes (P = 0.37, 0.08, and 0.31, respectively). The mean improvement of parenchymal thickness diameter after surgery was 10.4 ± 0.7 mm which was statistically significant (P = 0.001). However, it was not correlated with the mean estimated GFR change (r = 0.349, P = 0.13).

Conclusions:

Although laparoscopic unroofing of renal cyst recovered renal parenchymal thickness noticeably, it did not improve renal function significantly; therefore, the latter factor lonely should not be considered a reason for surgery decision. Observation can be chosen as a safe treatment strategy in large SRCs without concern about renal function.

Relationship Between Sporadic Renal Cysts and Renal Function Detected by Isotope Renography in Type 2 Diabetes

PURPOSE

This study aimed to reveal the relationship between the volume of sporadic renal cysts and renal function in patients with type 2 diabetes (T2D).

MATERIALS AND METHODS

One hundred and seventy-one patients that underwent renal imaging and other routine examinations at the Shanghai Pudong Hospital were included in this study. The Gates' method of glomerular filtration rate (GFR) was measured by ^99mTc-DTPA renal dynamic imaging in addition to the eGFR, calculated by the Chronic Kidney Disease Epidemiology Collaboration equation (CKD-EPI).

RESULTS

Our results showed that BMI, total iGFR, and eGFR showed significant differences between patients with T2D with or without SRC (p < 0.05). Spearman correlation analysis showed that cyst volume was positively correlated with Scr and gender but not iGFR (p > 0.05). The total iGFR positively correlated with eGFR (r = 0.83, p < 0.0001) and negatively with Scr (r = -0.78, p < 0.0001), age (r = -0.43, p < 0.0001), duration of T2D (r = -0.25, p = 0.001), and BMI (r = -0.21, p = 0.006) but not gender (r = -0.03, p = 0.668). The multilinear regression model revealed that gender (β = 0.346, p < 0.001), iGFR (β = -0.705, p < 0.001), and serum uric acid (β = 0.195, p = 0.032) were independent predictors of Scr. Moreover, we observed a significant increase in Scr in males (p < 0.05). Finally, we found that the split kidney function reflected by iGFR and related parameters such as time to peak (PTT) and half time of excretion (excrete t1/2) did not mutually distinguish from each other significantly whether they are measured in patients with renal cysts or in those without renal cysts (p > 0.05).

CONCLUSION

Our preliminary results suggest that in T2D, SRCs may be a renal complication of diabetic nephropathy. Although we found that the patients with renal cysts may display reduced iGFR, the volume of simple cysts seems not to exacerbate renal insufficiency. Isotope renography is a useful tool to evaluate the split kidney functions in diabetic patients who acquire single-side cysts.

Prevalence, risk factors and clinical characteristics of renal dysfunction in Chinese outpatients with growth simple renal cysts

Background

Researchers have proved that simple renal cysts (SRCs) might be correlated with renal dysfunction, but it is still controversial. Thus, we conducted clinical research study with large sample size and long-term follow-up to clarify the relationship between SRCs and renal dysfunction.

Methods

A total of 571 SRCs patients in outpatients of nephrology department were included, we investigated the clinical characteristics of growth SRCs compared with non-growth SRCs, evaluated the incidence of renal dysfunction in SRCs and explored the risk factors of renal dysfunction in growth SRCs.

Results

The mean baseline age was 51.31 ± 14.37 years in the whole cohort, ranging from 19 to 79 years, and 57.6% of them were male. The median follow-up duration was 3 years, ranging from 1 to 10 years. In addition, the final maximum diameter increased 1 mm (2.74%) per year. Patients in growth SRCs group tented to have higher percentage of hypertension, hematuria, large cyst and multiple cysts compared with non-growth SRCs group. The prevalence of renal dysfunction was 15.6% after the follow-up, and the prevalence of renal dysfunction was about 10 times higher in growth SRCs group than non-growth SRCs group (23.3% vs. 2.4%). Renal dysfunction was significantly associated with age, female, total cholesterol, diastolic blood pressure, final maximum diameter and yearly change in maximum diameter in growth SRCs.

Conclusions

SRCs were closely related to the decline of renal function, we recommend close follow-up for growth SRCs.

Single-Incision Laparoscopic Deroofing and Omentalization of a Cystic Renal Adenoma in a Dog

A 12 yr old 13.5 kg male castrated Pembroke Welsh corgi was presented for evaluation of a suspected renal cyst following multiple episodes of lethargy and abdominal pain. Abdominal imaging revealed a large, thin-walled, hypoechoic cystic lesion associated with the cranial pole of the left kidney and a second smaller cystic lesion on the caudal pole. The larger cystic lesion was repeatedly drained percutaneously, but the lesion returned to initial size and clinical signs returned within weeks. Percutaneous ethanol sclerotherapy achieved only transient improvement in lesion size and abdominal discomfort. Laparoscopic deroofing and omentalization of the larger left renal cystic lesion was performed. The resected cystic wall was histopathologically consistent with a renal adenoma. Abdominal ultrasonography performed 1 mo postoperatively found no recurrence of the cystic renal adenoma. Repeated ultrasonography at 3 mo postoperatively detected a small cystic lesion at the cranial pole of the left kidney, which remained static in appearance at 11 and 18 mo postoperatively. During all follow-up visits, the dog was reported to be doing well with no recurrence of clinical signs. Renal cysts causing clinical signs and renal adenomas are rare in veterinary medicine; laparoscopic deroofing and omentalization provides a minimally invasive treatment approach.

Long-term renal function in living kidney donors with simple renal cysts: A retrospective cohort study

Simple (Bosniak I) renal cysts are considered acceptable in living kidney donor selection in terms of cancer risk. However, they tend to increase in number and size over time and might compromise renal function in donors. To clarify their implications for long-term renal function, we characterized the prevalence of renal cysts in 454 individuals who donated at our center from 2000 to 2007. We estimated the association between the presence of cysts in the kidney remaining after nephrectomy (ie, retained cysts) and postdonation eGFR trajectory using mixed-effects linear regression. Donors with retained cysts (N = 86) were older (P < .001) and had slightly lower predonation eGFR (median 94 vs 98 mL/min/1.73 m2 , P < .01) than those without cysts. Over a median 7.8 years, donors with retained cysts had lower baseline eGFR (-8.7 -5.6 -2.3  mL/min/1.73 m2 , P < .01) but similar yearly change in eGFR (-0.4 0.02 0.4  mL/min/1.73 m2 , P = .2) compared to those without retained cysts. Adjusting for predonation characteristics, there was no difference in baseline eGFR (P = .6) or yearly change in eGFR (P > .9). There continued to be no evidence of an association when we considered retained cyst(s) ≥10 mm or multiple retained cysts (all P > .05). These findings reaffirm current practices of accepting candidates with simple renal cysts for donor nephrectomy.

Hyperuricemia and overexcretion of uric acid increase the risk of simple renal cysts in type 2 diabetes

Previous studies have discussed the relationship between simple renal cysts (SRC) and serum uric acid level in healthy individuals. We performed a cross-sectional study to evaluate the association between serum uric acid level and fractional excretion of uric acid (FEUA) and simple renal cysts in males and postmenopausal females with type 2 diabetes. The overall prevalence of SRC was 18.1% in our population. SRC prevalence was significantly higher in hyperuricemic than normouricemic subjects (27.3% vs. 16.8%, P < 0.001). Subjects who overexcreted uric acid had a higher prevalence of SRC than underexcretors (total population: 21.6% vs. 16.3%; normouricemic subjects: 19.8% vs. 13.7%; hyperuricemic subjects: 50.0% vs. 22.7%, all P-values < 0.05). Hyperuricemia (odds ratio [OR] 1.824, 95% confidence interval [CI] 1.332-2.498, P < 0.001); FEUA (OR 1.046, 95% CI 1.002-1.091, P < 0.05); male gender (OR 1.922, 95% CI 1.489-2.480, P < 0.001); age (OR 1.049, 95% CI 1.035-1.064, P < 0.001); and albuminuria (OR 1.492, 95% CI 1.176-1.892, P < 0.01) were independent risk factors for SRC development. These findings suggested that hyperuricemia and high level of FEUA were both independent risk factors for SRC development in males and postmenopausal females with type 2 diabetes. Half of overproduction hyperuricemic patients had SRC.