Final answer:
Tenderness at the costovertebral angles typically indicates kidney inflammation, often associated with conditions like renal colic or pyelonephritis and possibly involving kidney stones.
Step-by-step explanation:
A patient complaining of tenderness along the costovertebral angles is most often indicative of kidney inflammation. This area corresponds to where the kidneys are located and pain in this region is commonly associated with conditions such as renal colic or pyelonephritis. Symptoms may include severe episodic pain in the flank and lower abdomen, nausea, vomiting, and hematuria. Kidney stones may cause obstruction and present with similar symptoms, sometimes requiring medical attention if they are large enough to cause obstruction.