Genetic and radiological aspects of pediatric renal cystic disease: A case series / Aspectos genéticos e imagenológicos de la enfermedad quística renal en pediatría: serie de casos

Renal cystic diseases are common conditions whose etiology can be highly heterogeneous. They require a correct approach for adequate diagnosis and management. We aimed to illustrate part of the spectrum of renal cystic diseases through some clinical cases managed in our service. We describe 11 clinical cases including clinical entities such as renal multicystic dysplasia, and autosomal dominant and autosomal recessive polycystic renal disease, among other pathologies. Renal cystic diseases are heterogeneous in their clinical presentation, natural history, radiological findings, and genetic and pathophysiological basis. An integral clinical approach is needed to get a clear etiological diagnosis and offer adequate individualized care and follow-up for patients.

Las enfermedades quísticas renales son condiciones frecuentes cuya etiología puede ser muy heterogénea, por lo que se requiere un adecuado abordaje para su diagnóstico y manejo. El objetivo de este trabajo fue ilustrar parte del espectro de la enfermedad renal quística por medio de casos clínicos manejados en la Fundación Valle del Lili. Se describen 11 casos clínicos que incluyen enfermedades como displasia multiquística renal, enfermedad poliquística renal autosómica dominante y autosómica recesiva, entre otras. Las enfermedades quísticas renales varían en su presentación clínica, historia natural, hallazgos imagenológicos, bases genéticas y fisiopatológicas, por consiguiente, el enfoque diagnóstico y el manejo integral se debe realizar de forma individualizada y con un abordaje multidisciplinario.

Anomalías nefro-urologicas en el riñón contralateral de pacientes con displasia renal multiquística unilateral / Urological and nephrological abnormalities in the contralateral kidney in patients with unilateral multicystic dysplastic kidney

La displasia renal multiquística unilateral (DRMU) es la enfermedad quística renal más frecuente en pediatría. En estos pacientes, la función renal depende exclusivamente del riñón único funcionante contralateral. El objetivo de este trabajo retrospectivo fue determinar la prevalencia y tipo de anomalías nefro-urológicas en el riñón contralateral funcionante de 103 pacientes con DRMU atendidos en el Hospital Nacional de Pediatría Prof. Dr. Juan P. Garrahan entre 1995-2008. Se analizaron sólo aquellos niños que tenían ecografía renal y vesical, cistouretrografía miccional (CUGM) y centellograma renal con ácido dimercaptosuccínico (DMSA-Tc99m). Por ecografía se encontraron anomalías en el riñón contralateral funcionante en el 18.5%. Las más frecuentes fueron dilatación de la vía urinaria (6.8%) y aumento de la ecogenicidad (6.8%). La CUGM detectó la presencia de reflujo vesicoureteral en el riñón contralateral en 11 niños (10.7%), la mayoría leve a moderado. El centellograma renal con DMSA-Tc99m demostró escaras en 12 niños (11.6%). Los resultados muestran que el 23.3% de los pacientes con DRMU tienen alguna anomalía nefro-urológica en el riñón único funcionante contralateral. (AU)

Segmental multicystic dysplastic kidney: a rare situation.

Segmental multicystic dysplastic kidney is a rare subtype, found in only about 4% of children diagnosed with MCDK. To the best of our knowledge, we describe the 36th reported case of segmental multicystic kidney disease.

Horseshoe kidney with cysts and a single ureter: a case report.

Horseshoe kidney is the most common of all renal fusion anomalies, occurring in approximately 0.25% of the general population. Horseshoe kidney with only a single ureter is a rare anomaly. A 60-year-old man was admitted to hospital for routine health screening. His family history was negative for kidney diseases, and there was no abnormality in his physical examination. A computed tomography (CT) scan revealed an atypical horseshoe kidney with cysts and three-dimensional spiral CT reconstruction showed the presence of a single ureter. The patient has since been followed up for two years without any signs of clinical disease. We report a rare case of a patient with a horseshoe kidney with cysts and a single ureter that was diagnosed incidentally.

[A clinical approach to renal cysts]. / Quistes renales, manifestación de diversas patologías.

Many diseases can be associated with kidney cysts and they may be classified as hereditary and non-hereditary renal cystic disease. The first group can be sub-classified as autosomal recessive cystic disease, such as autosomal recessive polycystic kidney disease and nephronophthisis, as autosomal dominant kidney disease such as autosomal dominant polycystic kidney disease, glomerulocystic disease and tuberous sclerosis, and as cysts associated with syndromes. Cystic dysplasia, multicystic dysplastic kidney, simple cyst, multilocular cysts, Wilm's tumor and acquired cystic kidney disease are classified in the second group. The genetic study of renal cysts is becoming increasingly important, due to the possible therapeutic interventions that could be devised in the future. The aim of this review is to provide a fast and easy clinical approach to renal cysts.

Ultrasound progression of prenatally detected multicystic dysplastic kidney.

OBJECTIVES: To evaluate the sonographic involution of prenatally detected multicystic dysplastic kidney (MCDK). METHODS: A total of 53 children with unilateral MCDK detected by prenatal ultrasonography between 1989 and 2004 were included in this analysis. All children received conservative management with follow-up visits every 6 months. Follow-up ultrasound examinations were performed at 6-month intervals during the first 2 years after birth and yearly thereafter. A linear mixed effect model was constructed, including MCDK length as the dependent variable and body size parameters and contralateral renal dimensions as independent variables. RESULTS: The mean follow-up time was 68 months. A total of 334 ultrasound scans were analyzed. The ultrasound scan demonstrated partial or total involution of the MCDK in 48 cases (91%). A consistent negative correlation was found among MCDK length, patient age, and body size parameters. As a whole, the MCDK length reduction was estimated to be 0.29 mm/mo. The rate of reduction was not constant over time and was intense during the first 30 months of age. According to the regression model, MCKD reduced in length by 0.80 mm/mo during the first 30 months of age, 0.26 mm between 30 and 84 months old, and 0.30 mm in children older than 84 months. CONCLUSIONS: Our results suggest a clear tendency of MCDK to decrease in size, with the rate of the involution greater during the first 30 months than the rate in older children.

[Conservative management of multicystic dysplastic kidney: clinical course and ultrasound outcome]. / Tratamento conservador do rim displásico multicístico: curso clínico e ultra-sonográfico.

OBJECTIVE: The aim of this study was to describe the clinical course and ultrasound outcome of prenatally detected multicystic dysplastic kidney. METHODS: Fifty-three children with unilateral multicystic dysplastic kidney detected by prenatal ultrasound between 1989 and 2004 were included in the analysis. All children were submitted to conservative management with follow-up visits every six months. Follow-up ultrasound examinations were performed at six-month intervals during the first two years of life and yearly thereafter. The following clinical parameters were evaluated: blood pressure, urinary tract infection, renal function, and growth. The following ultrasound parameters were evaluated: involution of multicystic dysplastic kidney and contralateral renal growth. RESULTS: The mean follow-up time was 68 months. Two children presented hypertension during follow-up and five had urinary tract infection (only one with recurrent episodes). There was no malignant degeneration of multicystic dysplastic kidney. A total of 334 ultrasound scans were analyzed. US scan demonstrated involution of the multicystic dysplastic kidney in 48 (90%) cases, including complete involution in nine (17%). The involution rate was faster in the first 30 months of life. There was progressive compensatory renal hypertrophy of the contralateral renal unit; the rate of growth was greater in the first 24 months of life. CONCLUSION: The results of prolonged follow-up of children with conservatively managed multicystic dysplastic kidney suggest that clinical approach is safe, the incidence of complications is small, and that there is a clear tendency for multicystic dysplastic kidney to decrease in size. Our data also suggest that the involution rate of multicystic dysplastic kidney as well as the growth of the contralateral kidney is greater in the first 24 months of life.

Routine voiding cystourethrography is of no value in neonates with unilateral multicystic dysplastic kidney.

OBJECTIVES: To determine if two successive ultrasound examinations could rule out the presence of clinically significant contralateral anomalies in neonates with multicystic dysplastic kidney (MCDK), thereby avoiding unnecessary voiding cystourethrography (VCUG). STUDY DESIGN: We followed 76 newborn infants with antenatally discovered MCDK. Two successive neonatal renal ultrasound examinations were performed, one within the first week and one at around 1 month of life. VCUG and isotopic studies were performed in all infants. RESULTS: Urologic anomalies of the contralateral kidney were present in 19 of 76 children (25%): vesicoureteral reflux (VUR) in 16 (21%), ureteropelvic junction obstruction in 2 (3%), and renal duplex kidney in 1 (1%). Sixty-one infants (80% of total) had normal contralateral urinary tract on the 2 successive neonatal renal ultrasound scans. Among them, 4 of 61 (7%) infants presented with low-grade VUR on VCUG that had resolved spontaneously before 2 years of age. The sensitivity, specificity, positive predictive value, and negative predictive value of two successive ultrasound scans in the neonatal period to predict contralateral urological anomalies on VCUG were 75%, 95%, 80%, and 93%, respectively. CONCLUSIONS: In infants with antenatally diagnosed MCDK, two successive normal neonatal renal ultrasound scans will rule out clinically significant contralateral anomalies, thereby rendering the need for a neonatal VCUG unnecessary.

Predictive factors of ultrasonographic involution of prenatally detected multicystic dysplastic kidney.

OBJECTIVE: To evaluate possible predictive factors of involution on ultrasonography (US) or disappearance of a prenatally detected multicystic dysplastic kidney (MCDK). PATIENTS AND METHODS: Forty-five children with unilateral MCDK detected by prenatal ultrasonography between 1989 and 2002 were analysed. All patients except one had (99m)Tc isotopic scintigraphy to confirm the absence of renal function in the MCDK. All children were managed conservatively with follow-up visits every 6 months, with US 6-monthly during the first 2 years of life and yearly thereafter. Survival was analysed using the Kaplan-Meier method to evaluate the involution of the MCDK, with differences between subgroups assessed using the two-sided log-rank test. Cox's regression model was applied for the multivariate analysis. RESULTS: The mean (range) follow-up was 50 (12-167) months; in all, 279 ultrasonograms were taken, the mean (range) number per patient being 6 (3-10). US showed partial involution of the MCDK in 30 (67%) cases and complete involution in nine (20%). The absolute MCDK length remained almost unchanged in six children (13%). Univariate analysis showed that four variables were possibly associated with complete involution of the MCDK (gender, impalpable kidney, renal length at admission using two thresholds, 62 and 78 mm). After adjusting by Cox's model only a renal length at diagnosis of <62 mm remained associated with complete involution (relative risk 8, 95% confidence interval 0.98-68; P = 0.05). CONCLUSION: These results suggest that only a renal length of <62 mm on initial US was predictive of complete involution of the MCDK during the follow-up.

Natural history of multicystic kidney conservatively managed: a prospective study.

We report the long-term clinical results of conservative management of children with unilateral multicystic dysplastic kidneys (MCDK). Between 1989 and 2002, 43 children with MCDK detected by prenatal ultrasonography were prospectively followed. At birth, ultrasonography confirmed the prenatal findings in all cases. Patients underwent a radioisotope scan and micturating cystogram in order to confirm the diagnosis and to exclude other uropathies. Follow-up ultrasound (US) examinations were performed at 6-month intervals during the first 2 years of life and yearly thereafter. The mean follow-up time was 42 months (range 12-156 months). Two children developed hypertension during follow-up. In total 257 US scans were performed. The mean number of US scans per patient was 6 (range 3-10). US scans demonstrated partial involution of the MCDK in 30 (70%) cases and complete involution in 8 (19%). The absolute MCDK length remained almost unchanged in 5 children (11%). The estimated median time of complete involution of the MCDK was 122 months [95% confidence interval (CI)=86-158 months]. A total of 33 (76.7%) contralateral kidneys underwent compensatory hypertrophy, reaching a renal length above the 95th percentile during follow-up. The estimated median time for the occurrence of compensatory hypertrophy was 30 months (95% CI=15-45 months). In conclusion, the natural history of MCDK is usually benign but patients must have long-term follow-up with US scans and blood pressure measurements.

Spontaneous improvement of hypertension in multicystic dysplastic kidney: a case report.

We report a case of transitory hypertension associated with unilateral multicystic dysplastic kidney (MCDK). A newborn girl with MCDK, detected by prenatal ultrasonography, was conservatively treated and has been followed for 18 months at the Pediatric Nephrourology Unit (HC-Belo Horizonte, Brazil). Arterial hypertension was observed at about 4 months of age and was associated with high levels of plasma renin activity and circulating angiotensin, and also with changes in renal Doppler ultrasonography. For these reasons, a nephrectomy was initially proposed. However, a spontaneous improvement of blood pressure levels was noticed at about 10 months of age. Serial Doppler ultrasonography showed involution of the affected renal volume and decreased arterial flow. The anatomical improvement was observed simultaneously with normalization of the peripheral renin and angiotensin values. The literature is reviewed regarding the relationship between hypertension and MCDK.