Rheumatic Fever and Heart Disease
Rheumatic heart disease is a complication rheumatic fever, which is itself a complication of an infectious disease called strep throat. Both strep throat and rheumatic fever can develop in people of any age, but the risk of rheumatic fever as a complication is higher in children aged between five and 15. In addition, rheumatic fever is more likely to develop when strep throat is not treated.
The symptoms of rheumatic fever develop two to three weeks after the onset of strep throat. Symptoms can include fever and swollen joints in addition to sore throat. If the heart is affected by rheumatic fever, symptoms of rheumatic heart disease might develop during this time. This is not always the case, however, and heart-related symptoms might only develop much later.
The overall risk of rheumatic fever is low in Western countries where antibiotics are readily available to treat strep throat, but the incidence of rheumatic fever and rheumatic heart disease remains high in developing countries. If strep throat progresses to rheumatic fever, up to 39% of children will develop rheumatic heart disease (Chin).
Why does Rheumatic Fever cause Cardiac Symptoms?
Untreated strep infection that progresses to rheumatic fever can cause serious and permanent heart damage. The Group A Streptococcus organism that causes strep throat is capable of causing large-scale heart inflammation which can cause initial heart damage, and also lead to the formation of scar tissue on the heart.
Acute rheumatic fever with heart involvement can potentially affect the entire heart, causing different types of inflammation. The different structures of the heart that can be affected are:
- Pericardium, the membranous lining that surrounds the heart. (This inflammation is called pericarditis.)
- Endocardium, the interior lining of the chambers and valves (endocarditis).
- Myocardium, the heart muscle itself (myocarditis).
The most likely part of the heart to be affected by inflammation is the endocardium; therefore it is the valves of the heart that are most at risk of damage.
Symptoms of Rheumatic Heart Disease
During the initial episode of rheumatic fever, the only sign of heart involvement in many cases is occasional shortness of breath. In cases of severe rheumatic fever, heart-related symptoms might include chest pain, chest swelling, and heart palpitations.
After the rheumatic fever has passed, symptoms of rheumatic heart disease might develop at any time, if the heart has been damaged by the fever.
If the aortic or mitral valves of the heart have been damaged, the main symptom that might develop is shortness of breath that worsens during and after exercise or other strenuous activities. This symptom develops due to oxygen deficiency as a result of impaired valve function. Often, the impaired valve function is only noticeable during exercise, because strenuous activities increase the body’s oxygen requirements.
A doctor who examines someone with rheumatic heart disease can use a stethoscope to detect abnormal movement of blood in the heart, also known as a heart murmur. This symptom develops because damage to the heart valves can cause blood to circulate in the heart in an abnormal fashion. Sometimes, the exit of blood from the heart can be impaired, potentially leading to congestive heart failure.
American Heart Association: Rheumatic Heart Disease/Rheumatic Fever
Seattle Children’s Hospital Research Foundation: Rheumatic Heart Disease
Thomas K Chin, MD, for eMedicine: Rheumatic Heart Disease
University of California San Francisco Benioff Children’s Hospital: Rheumatic Heart Disease