Following infection by group-A streptococcus bacteria (such as strep throat), a number of different inflammatory syndromes can occur in the body.
These include rheumatic diseases such as acute rheumatic fever (ARF) and poststreptococcal reactive arthritis, as well as other diseases such as poststreptococcal glomerulonephritis and PANDAS (pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections).
These poststreptococcal or “post-strep” diseases can affect people of all ages, but are most common in children and teenagers. They usually occur at least one week after strep infection, though it may not be apparent that the patient was previously infected.
The symptoms associated with poststreptococcal inflammatory diseases are not caused by the strep bacteria itself, but rather by the immune system’s response to the prior infection.
Acute rheumatic fever (ARF) affects the joints, skin, heart, blood vessels and brain. In addition to fever, it can cause several other symptoms, such as arthritis (joint inflammation), rashes, subcutaneous nodules (bumps under the skin), chorea (involuntary movements of the extremities) and heart disease. Symptoms typically begin two to three weeks after a strep infection. The characteristic arthritis of ARF is migratory (meaning it moves from joint to joint), and it may be very painful. Heart inflammation (carditis) develops in up to half of all patients with ARF, and this may be asymptomatic at first. Children with carditis may become very sick with signs of heart failure either early in the disease course, or many years later.
Post-strep reactive arthritis causes joint pain and swelling, but unlike in acute rheumatic fever, the arthritis is not migratory but localized, and this usually starts less than 10 days after a strep infection. Children with post-strep reactive arthritis are at a much lower risk of developing carditis, though they should still be monitored carefully for this complication. Rashes, nodules, and chorea do not occur in post-strep reactive arthritis.
If acute rheumatic fever or another strep-related disease is suspected, your child’s doctor will perform a throat culture and/or send blood work to look for evidence of a prior strep infection. Particularly in rheumatic fever, the throat culture may be negative. This does not rule out the diagnosis, however. Blood work may also be useful to look for general signs of inflammation or to rule out other causes of the symptoms. EKG and echocardiogram, as well as full evaluation by a cardiologist, are important tests that can rule out or confirm heart involvement.
Patients with acute rheumatic fever or another poststreptococcal disease are treated with antibiotics (usually penicillin) to make sure the infection is eradicated. After the initial course of antibiotics, prophylactic antibiotics are given to prevent any subsequent strep infection and associated inflammation. Patients with post-strep reactive arthritis typically receive antibiotics for one year. Those with rheumatic fever with no heart involvement are usually treated until age 21, while patients with carditis are recommended to take prophylaxis well into adulthood (and possibly for life).
NSAIDs are typically used for the joint pain and swelling associated with ARF and post-strep reactive arthritis. Patients with carditis are typically treated with aspirin, and may sometimes require steroids. Other medications may be required if other organs are affected.
In patients with both acute rheumatic fever and post-strep reactive arthritis, the joint inflammation resolves on its own. Carditis may lead to chronic heart disease and ultimately heart failure, particularly if unrecognized and untreated. Patients with a history of poststreptococcal inflammatory disease, particularly those with carditis, are at high risk of developing repeat episodes of carditis with subsequent strep infections. Antibiotic prophylaxis as above can prevent future strep infections and repeated damage to the heart.