American Board of Internal Medicine (ABIM) Certification Practice Exam

What defines the severity of kidney cyst burden in relation to diagnosis of ADPKD in individuals over 60 years of age?

1. Two cysts in each kidney

2. Three cysts in each kidney

3. Four cysts in each kidney

4. Five cysts in each kidney

The correct answer is: Four cysts in each kidney

The severity of kidney cyst burden in the context of diagnosing Autosomal Dominant Polycystic Kidney Disease (ADPKD) in individuals over 60 years of age is defined by the presence of four cysts in each kidney. This threshold is significant because ADPKD, which is characterized by fluid-filled cysts forming in the kidneys, typically manifests with an increasing number of cysts as individuals age. In older adults, particularly those over the age of 60, the presence of four or more cysts indicates a higher likelihood that the individual is affected by ADPKD. This number provides enough evidence of the disease's progression and correlates with the potential for renal complications and the need for monitoring and management of kidney function. The criteria used for the diagnosis take into account the age-related natural history of the disease and the understanding that the cyst burden generally increases with time, making the identification of four cysts in each kidney a relevant criterion for diagnosing ADPKD in this age group. Therefore, four cysts is an important benchmark in clinical practice for confirming the diagnosis of ADPKD among older adults.