What are the diagnostic criteria for Polycystic Kidney Disease (PKD)?

From the Guidelines

Polycystic kidney disease (PKD) is diagnosed through a combination of imaging tests, genetic testing, and family history evaluation, with ultrasound being the primary diagnostic tool, and genetic testing confirming the diagnosis by identifying mutations in genes like PKD1, PKD2, or PKHD1 1.

Diagnosis Criteria

The diagnosis criteria for autosomal dominant PKD vary by age, with younger patients (under 30) needing fewer cysts for diagnosis than older patients.

• For people with a positive family history of ADPKD aged 16–40 years, the cutoff of >10 cysts on magnetic resonance imaging (MRI) has been used to diagnose ADPKD, and the cutoff of <5 cysts has been used to exclude ADPKD 1.
• In a family with a known pathogenic variant, targeted screening for the specific variant is usually sufficient to diagnose or exclude ADPKD 1.

Imaging Tests

Imaging tests such as ultrasound, CT scans, or MRI may be used to detect multiple cysts in both kidneys.

• Ultrasound is the primary diagnostic tool, which can detect multiple cysts in both kidneys 1.
• CT scans or MRI may provide more detailed images when needed, with MRI being more accurate in measuring height-adjusted total kidney volume 1.

Genetic Testing

Genetic testing can confirm the diagnosis by identifying mutations in genes like PKD1, PKD2, or PKHD1, with PKD1 and PKD2 mutations causing autosomal dominant PKD (the most common form) and PKHD1 mutations causing autosomal recessive PKD 1.

Management and Treatment

Early diagnosis is important as treatments like tolvaptan can slow disease progression in appropriate patients.

• Hypertension management, pain control, and treatment of complications like urinary tract infections are essential components of care 1.
• Regular monitoring of kidney function and cyst growth helps guide treatment decisions and timing for potential kidney transplantation if end-stage renal disease develops 1.

From the Research

Diagnosis of Polycystic Kidney Disease

• The diagnosis of autosomal dominant polycystic kidney disease (ADPKD) relies on imaging criteria in the setting of a positive familial history 2.
• Ultrasound examination (US) of the kidneys is the most important imaging diagnostic method, and is highly sensitive and specific in patients over 30 years of age 3.
• The Ravine criteria are applied in US, and modifications with other imaging techniques such as computed tomography (CT) and magnetic resonance (MR) are used 3.
• Genetic testing can identify a causative mutation in over 90% of cases, and can provide differential diagnoses and identify factors underlying disease variability 2, 4.

Role of Genetic Testing

• Genetic testing is currently seldom indicated for ADPKD diagnosis, but can be useful in certain clinical situations where imaging cannot provide a definitive diagnosis 4, 5.
• Next-generation sequencing (NGS) can provide a high-throughput, accurate, and comprehensive screen of multiple cystic disease and modifier genes at a reduced cost 4.
• Genetic diagnosis can benefit families and improve clinical management of patients, and may be enhanced with emerging therapeutic options 6.

Imaging and Disease Progression

• The most sensitive parameter in evaluating disease progression is total renal volume, which is currently used in clinical studies but has not been fully proven for monitoring individual patients 3.
• The rate of glomerular filtration rate (GFR) decline is usually constant, and monitoring GFR is important in individuals who have developed renal insufficiency 3.
• Other tests, including markers of kidney injury and vascular flow parameters, are used mainly in clinical studies 3.