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Hereditary polycystic kidney diseases in children: changing sonographic patterns through childhood
Fred E Avni1, Gretel Guissard, Michelle Hall
1Department of Paediatric Imaging, Children University Hospital Queen Fabiola ULB, Brussels, Belgium. f.e.avni@huderf.be
Insights
Autosomal recessive polycystic kidney disease (ARPKD) shows evolving ultrasound patterns, with diffuse hyperechoic foci correlating with renal failure. Autosomal dominant polycystic kidney disease (ADPKD) has stable features, with large cysts indicating diagnosis.
Area of Science:
- Pediatric Nephrology
- Medical Imaging
- Genetics
Background:
- Autosomal recessive polycystic kidney disease (ARPKD) and autosomal dominant polycystic kidney disease (ADPKD) are genetic kidney disorders.
- Ultrasound (US) is crucial for diagnosing and monitoring these conditions in children.
- Understanding US changes over time is vital for predicting disease progression and outcomes.
Purpose of the Study:
- To track ultrasound (US) changes in children with ARPKD and ADPKD.
- To determine if US findings correlate with the onset of renal failure.
- To differentiate between ARPKD and ADPKD based on US characteristics.
Main Methods:
- Retrospective review of US features in 29 pediatric patients (16 ARPKD, 13 ADPK) with at least two examinations.
- Analysis of kidney size, echogenicity, corticomedullary differentiation (CMD), and cyst presence/size.
- Statistical correlation (Pearson exact chi-square test) between US changes and renal failure onset (GFR < 50 ml/min/1.73 m²).
Main Results:
- ARPKD: Kidneys often enlarged and hyperechoic, with evolving CMD. Diffuse hyperechoic foci developed in 14 patients, strongly correlating with renal failure (P=0.0125).
- ADPKD: Kidney and cyst sizes generally remained stable. Large cysts (>3 cm) were common. No renal failure observed in this cohort.
- In older children, US findings of ARPKD and ADPKD can become similar.
Conclusions:
- ARPKD exhibits diverse and evolving US patterns, with hyperechoic foci predicting renal failure.
- Large cysts are characteristic of ADPKD, which shows fewer US changes over time.
- US monitoring aids in differentiating ARPKD and ADPKD and assessing renal failure risk.
Objective:
To determine which US changes occur with time in children affected by autosomal recessive (ARPKD) and autosomal dominant polycystic kidney disease (ADPKD) and whether any of these changes correlate with the onset of renal failure.
Materials And Methods:
We reviewed the US features of 29 patients (16 ARPKD, 13 ADPK) imaged by at least two US examinations. We analysed the size and echogenicity of the kidneys, corticomedullary differentiation (CMD), the presence, location and size of cysts and any other anomaly that developed with time. In order to determine whether a relationship could be found between any of the US changes and the onset of the renal failure (based on a glomerular filtration rate < 50 ml/min per 1.73 m2), a Pearson exact chi-square test was calculated.
Results:
For ARPKD, renal size was above 4 standard deviations (SD) in 10 of 16 patients, but it remained stable during evolution (10/16). The kidneys appeared hyperechoic (16/16), without CMD in the majority (11/16) of patients. Changes in the appearance of CMD over time were observed in five patients. Small cysts (< 1 cm) were present at the time of diagnosis in seven patients, larger cysts (> 1 cm) in three. A diffuse microcystic pattern was observed in three patients. Diffuse hyperechoic foci developed in 14 patients--13 of whom had developed renal failure at the time of the examination or rapidly thereafter (statistical correlation P=0.0125). For ADPKD, renal size was between 0-2 SD in 7 of 13 patients and above 2 SD in the other 6. Renal echogenicity was normal in five, difficult to assess in five and the kidneys appeared hyperechoic without CMD in three patients. Cysts larger than 1 cm were present in 8 of 12 patients (> 3 cm in 5). In four patients, the cysts measured less than 1 cm. In the last child, the diagnosis had been made antenatally and the first cysts appeared at the age of 6 months. The size of the kidneys (13/13) and of the cysts (11/13) remained stable. No renal failure occurred.
Conclusions:
ARPKD may manifest with various US patterns and there may be evolution in the appearances over time. Our study confirms a significant relationship between the development of diffuse hyperechoic foci and the onset of renal failure. In older children, ARPKD and ADPKD may closely resemble each other. Large (> 3 cm) cysts are the US hallmark for the diagnosis of ADPKD; furthermore, fewer US changes occur with time during childhood in ADPKD.