What laboratory findings indicate rheumatic fever?

Rheumatic fever is a delayed complication that can arise after an infection with group A Streptococcus, typically presenting as post-streptococcal sequelae. One of the key laboratory findings associated with rheumatic fever includes an increased sedimentation rate and elevated levels of C-reactive protein. These markers are indicative of an inflammatory response in the body.

In the context of rheumatic fever, the body responds to the streptococcal infection with systemic inflammation, which is reflected in these laboratory tests. An elevated sedimentation rate indicates that inflammation is present, as it measures how quickly red blood cells settle at the bottom of a test tube; a quicker settling suggests increased levels of inflammatory proteins. Similarly, C-reactive protein is produced by the liver during episodes of inflammation, and its elevated levels signify ongoing inflammatory processes.

This combination of increased sedimentation rate and C-reactive protein is a hallmark of inflammatory conditions following infectious processes, such as rheumatic fever, making it a critical component in the diagnosis and understanding of the pathophysiology associated with this condition.

While elevated white blood cell count, positive throat culture for streptococcus, and decreased hemoglobin levels may all be relevant in understanding infections or anemia, they are