True of Rheumatic fever is:
**Core Concept**
Rheumatic fever is a complication of streptococcal pharyngitis, characterized by autoimmune destruction of heart valves, joints, skin, and brain. It occurs due to molecular mimicry between streptococcal antigens and host cardiac tissue.
**Why the Correct Answer is Right**
The correct answer is related to the pathogenesis of rheumatic fever. The autoimmune response in rheumatic fever is triggered by cross-reactivity between antibodies against group A beta-hemolytic streptococcus (GABHS) and host cardiac antigens. This cross-reactivity is due to the molecular similarity between streptococcal antigens and cardiac tissue. The immune system, in an attempt to clear the streptococcal infection, also targets the heart valves, leading to inflammation and scarring.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because rheumatic fever is not directly caused by a viral infection. While viral infections can trigger autoimmune responses, the primary trigger for rheumatic fever is a bacterial infection.
**Option B:** This option is incorrect because rheumatic fever is not primarily characterized by an acute inflammatory response. While inflammation is a component of the disease, it is the autoimmune destruction of cardiac tissue that is the hallmark of rheumatic fever.
**Option C:** This option is incorrect because rheumatic fever is not primarily caused by a genetic predisposition. While genetic factors may influence the susceptibility to rheumatic fever, the primary trigger is an environmental factor (the streptococcal infection).
**Clinical Pearl / High-Yield Fact**
One key aspect of rheumatic fever is the association between the Jones criteria and the diagnosis. The Jones criteria are a set of clinical and laboratory criteria that help diagnose rheumatic fever. The major criteria include carditis, arthritis, chorea, erythema marginatum, and subcutaneous nodules. The minor criteria include fever, arthralgia, elevated erythrocyte sedimentation rate, and leukocytosis.
**Correct Answer:** C.