Which of the following is a major manifestation in the modified Jones' criteria for acute rheumatic fever?

The modified Jones' criteria for diagnosing acute rheumatic fever includes a variety of clinical manifestations, with carditis and arthritis being two of the major criteria. This is significant because acute rheumatic fever is a serious inflammatory condition that follows an infection with Group A Streptococcus and can lead to severe complications, especially involving the heart.

Carditis refers to inflammation of the heart, which can result in symptoms such as chest pain, palpitations, or heart murmurs due to valve damage. Arthritis typically manifests as painful joints, commonly affecting the larger joints like the knees and ankles. The presence of both carditis and arthritis represents a significant overlap of serious issues that can arise from the condition, confirming the diagnosis and allowing for timely management of the patient’s health.

Other manifestations within the modified Jones' criteria include erythema marginatum and neurological symptoms like chorea, but for the purpose of identifying a major manifestation, carditis and arthritis are most critical. Although options like fever and prolonged PR interval do relate to the broader impact of rheumatic fever, they do not comprise the major criteria used for diagnosis in this context.