Nephrolithiasis is defined as what condition?

Nephrolithiasis refers specifically to the condition characterized by the presence of kidney stones. These stones form in the kidneys from substances that crystallize in the urine, and their presence can lead to various complications, including obstructions and severe pain. The formation of kidney stones can occur due to several factors, such as dehydration, dietary choices, and certain metabolic disorders.

The other options do not accurately describe nephrolithiasis. Painful urination is associated with various urinary tract issues but is not limited to the presence of kidney stones. Difficulty in swallowing pertains to a separate condition related to the esophagus and is not related to nephrolithiasis. Inflammation of the renal pelvis, known as pyelonephritis, is also a distinct condition and does not define nephrolithiasis. Thus, the correct answer encompasses the specific definition of the condition, highlighting the presence of kidney stones.