American Board of Internal Medicine (ABIM) Certification Practice Exam

Which nephrotic syndrome is characterized by focal and segmental damage?

1. Minimal Change Disease

2. Focal Segmental Glomerulosclerosis

3. Membranous Nephropathy

4. Amyloidosis

The correct answer is: Focal Segmental Glomerulosclerosis

Focal Segmental Glomerulosclerosis (FSGS) is the correct choice because it is specifically characterized by the presence of focal (affecting some glomeruli but not all) and segmental (affecting only parts of the glomeruli) damage to the kidney's filtering units. This pattern of injury is critical for diagnosis and is unique to FSGS among the listed conditions. In contrast, Minimal Change Disease is characterized by a lack of significant findings on light microscopy and primarily presents with diffuse podocyte injury rather than focal and segmental damage. Membranous Nephropathy involves a thickening of the glomerular capillary wall due to immune complex deposition, which does not fit the focal and segmental criteria. Amyloidosis involves deposits of amyloid protein in the kidney tissue, producing altered kidney structure and function, but again does not describe the focal segmental nature that FSGS does. Understanding the specific morphology and patterns of damage in kidney diseases is critical for effective diagnosis and management, and FSGS stands out due to its unique presentation involving both focal and segmental aspects.