Definition
Autosomal recessive polycystic kidney disease (ARPKD) is a rare, severe polycystic kidney disorder of infancy and childhood, caused by mutations in PKHD1 (chromosome 6, encoding fibrocystin).
Presentation
- Often detected antenatally on ultrasound: bilaterally enlarged, echogenic kidneys with oligohydramnios
- Severe cases show the Potter sequence — pulmonary hypoplasia, limb and facial deformities from oligohydramnios; respiratory failure is a leading early cause of death
- Survivors develop hypertension and progressive chronic kidney disease
- Congenital hepatic fibrosis is characteristic, leading to portal hypertension (varices, splenomegaly)
Investigations
- Ultrasound: bilaterally enlarged kidneys with a diffuse, microcystic appearance
- Genetic testing for PKHD1; assess liver involvement (hepatic fibrosis, portal hypertension)
Management
- Supportive: respiratory support in the neonate, blood pressure control, management of CKD and eventual renal replacement therapy
- Manage hepatic complications (portal hypertension)
- Genetic counselling — recessive inheritance means a 1-in-4 recurrence risk
MRCP-specific traps
- ARPKD pairs renal cystic disease with congenital hepatic fibrosis — do not confuse it with the hepatic cysts of ADPKD.
- Think ARPKD in a neonate with huge kidneys and oligohydramnios; think ADPKD in an adult with hypertension and a family history.
Summary
ARPKD is a recessive PKHD1 disorder presenting antenatally or in infancy with enlarged kidneys, oligohydramnios/Potter sequence and congenital hepatic fibrosis with portal hypertension. Management is supportive, treating hypertension, CKD and hepatic complications.
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