Acute rheumatic fever and rheumatic heart disease: Clinical sciences

Acute rheumatic fever, or ARF for short, is a systemic inflammatory condition that develops after an infection with Group A Streptococcus, or GAS for short. Acute rheumatic fever, which is thought to be an immune-mediated condition, affects the joints, skin, nervous system, and heart. Moreover, if not recognized and treated on time, it can cause damage and scarring of the heart valves and structures. This condition is also known as rheumatic heart disease or RHD.

Now, if a pediatric patient is presenting with a chief concern suggesting ARF or RHD, first perform an ABCDE assessment to determine if they are unstable or stable. If unstable, stabilize their airway, breathing, and circulation. Next, obtain IV access, consider starting IV fluids, and begin continuous vital sign monitoring, including blood pressure, heart rate, and pulse oximetry. Finally, start broad-spectrum intravenous antibiotics, and, if needed, don’t forget to provide supplemental oxygen.

Okay, now let’s go back to the ABCDE assessment and take a look at stable patients. Start by obtaining a focused history and physical exam. First, let’s discuss patients with ARF. Your patient will likely report a history of fever and joint pain, as well as a recent history of infection characterized by a sore throat, with or without tonsillar exudates. On the other hand, physical exam findings typically include joint tenderness, with or without effusion; a serpiginous rash; painless nodules on the shin; and even abnormal, uncontrolled movements. In some patients, you might detect a heart murmur as well!

These history and exam findings should make you suspect a recent GAS infection. Your next step is to obtain a rapid strep antigen test or a throat culture. Additionally, you should check strep antibodies, including antistreptolysin O; or anti-DNase B antibodies. Finally, don’t forget to check the patient’s inflammatory markers, like ESR and CRP; and obtain an ECG and echocardiogram.

Now, here’s a clinical pearl to keep in mind! Strep antibody assays, like ASO and anti-DNase B, are often used to confirm the presence of a recent GAS infection, especially when a rapid antigen test or throat culture is negative. However, these assays can be challenging to interpret, since antibodies linger in the body for months. So, you should not make decisions based on a single titer measurement! Instead, follow the trend in your patient’s titers, because increasing titers are highly suggestive of recent GAS infection!

Now, when it comes to labs, you may find that the rapid strep antigen test or throat culture is positive, or that your patient has detectable antibodies to strep. In addition, the ESR and CRP are usually elevated. Finally, the ECG might reveal a prolonged PR interval, while the echo may show valvulitis or pericarditis. At this point, you should suspect acute rheumatic fever.

Once you suspect acute rheumatic fever, your next step is to assess for the JONES criteria, which consists of several major and minor criteria. Major criteria include Joint involvement, more specifically migratory polyarthritis; Carditis, usually involving the left-sided heart valves, especially the mitral valve, or pericarditis; Nodules, which are subcutaneous and painless; Erythema marginatum; and finally, Sydenham chorea, which is a disorder associated with an involuntary, nonpurposeful movement. Moreover, you can use the JONES mnemonic to remember the major criteria of acute rheumatic fever.

On the other hand, the minor criteria include clinical features, such as fever and arthralgia; lab criteria, like elevated ESR or CRP; and ECG findings, such as a prolonged PR interval. The JONES criteria are met when a patient fulfills at least 2 major criteria, OR 1 major criterion plus 2 minor criteria. There is one exception to this; that is, the presence of Sydenham chorea alone is enough to diagnose ARF. Now, if JONES criteria are not met, you should consider an alternative diagnosis. On the other hand, if JONES criteria are met, you can diagnose ARF.

Now that you’ve diagnosed ARF, let’s move on to treatment. This starts with antibiotics and anti-inflammatory medications. Penicillins are the mainstay of antibiotic treatment, either in the form of oral amoxicillin; or oral or intramuscular penicillin. On the other hand, the first-line treatment of symptomatic arthritis or carditis includes NSAIDs. If carditis does not respond to NSAIDs, or if they are contraindicated, you can consider aspirin or systemic corticosteroids.