Which of the following is a potential complication of untreated GABHS infection?

Rheumatic fever is a potential complication of untreated Group A beta-hemolytic streptococcus (GABHS) infection, particularly following streptococcal pharyngitis (strep throat). If GABHS infection is not adequately treated, the body can mount an autoimmune response to the bacteria, which can result in inflammation affecting multiple systems, most notably the heart, joints, skin, and nervous system.

The development of rheumatic fever typically occurs two to three weeks after the initial throat infection. In some cases, it can lead to serious long-term complications, such as rheumatic heart disease, which can damage heart valves and lead to serious cardiovascular issues later in life.

While chronic sinusitis is a concern in the context of recurrent GABHS infections, it is not a direct complication of the initial untreated strep throat. Similarly, although endocarditis can occur, it is less common and typically associated with other underlying conditions rather than with GABHS. Interstitial pneumonia is also not a typical direct complication of GABHS infections, as it generally relates more to viral infections or other pathogens rather than untreated streptococcal infections.