Elevated Troponin and Rheumatic Heart Disease

Today we discussed a case of a woman with chest pain, new atrial fibrillation and an elevated troponin. She likely had rheumatic fever as a child and an echo revealed severe MR with a dilated left atrium. There were some great learning points that came up! Lets discuss.

Troponin is sensitive, not specific! 
When you assess a patient with an elevated troponin do not immediately jump to ACS as the cause! While this will be the most common cause (and certainly one of the more concerning) there are many other etiologies. Always be rigorous in your history and physical exam to decide whether or not ACS is the most likely diagnosis and to rule out others. Some other causes of elevated troponin include:

• Myocardial Infarction
• Post-instrumentation (PCI, cardiac surgery)
• PE
• End stage renal disease
• Pericarditis/Myocarditis
• Aortic Dissection
• Heart Failure
• Sepsis
• Trauma
• Stroke or intracerebral hemorrhage

Check out this great article on the differential diagnosis of elevated troponin: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1860726/

Rheumatic fever is less common in developed countries but we still need to know about it.

Acute rheumatic fever occurs a few weeks after group A strep pharyngitis. However, not everyone who gets group A strep pharyngitis will get rheumatic fever! In fact, in developed countries, only about 3% of patients with untreated group A strep pharyngitis develop rheumatic fever. This number is lower than in developing countries - most likely due to improved hygiene (reduced transmission) and higher rates of antibiotic use for 'strep throat'.

Rheumatic fever is an illness characterized by classic signs and symptoms in a patient who had recent group A strep pharyngitis. 

We are all familiar with the 'Duke Criteria' for endocarditis. Well, rheumatic fever has the Jones Criteria to help you diagnose it:

There is a high probability that your patient has acute rheumatic fever if they had a recent group A strep infection and fulfill 2 major criteria or 1 major + 2 minor critera.

Acute rheumatic fever can lead to rheumatic heart disease.

Those who develop acute rheumatic fever are at high risk of having cardiac involvement and developing cardiac complications. Lasting complications of rheumatic heart disease are due to heart valve destruction and include CHF, stroke, endocarditis and death. How does pharyngitis cause heart disease you ask? Well it's not perfectly understood but you can explain it using buzzwords like 'molecular mimicry' (antibodies against strep will attack native cells/tissue, like myocytes). You'll have to check out another source if you want to learn more about that...

So the key is to prevent acute rheumatic fever by promptly diagnosing and treating group A strep pharyngitis in the first place!

Mitral regurgitation is the most common valve pathology of rheumatic heart disease. These patients will frequently develop chronic mitral regurgitation. According to the ACC/AHA guidelines (which I have summarized here), you should consider surgery for severe mitral regurgitation when any of the following indications are met:

• Acute, symptomatic severe MR
• Chronic MR which is symptomatic 
• Chronic MR with LV dysfunction
• Chronic MR for patients undergoing other cardiac surgery 
• Atrial fibrillation
• Pulmonary hypertension
• Mitral valve prolapse and ventricular arrhythmias

Thanks Team 1 for a great case!

Check out the following resources for more info:

1. Seckeler MD, Hoke TR. The worldwide epidemiology of acute rheumatic fever and rheumatic heart disease. Clinical Epidemiology. 2011;3:67-84. doi:10.2147/CLEP.S12977.
2. Korff S, Katus HA, Giannitsis E. Differential diagnosis of elevated troponins.Heart. 2006;92(7):987-993. doi:10.1136/hrt.2005.071282.
3. Bonow RO, Carabello B, de Leon AC, Jr., et al. ACC/AHA guidelines for the management of patients with valvular heart disease: A report of the American College of Cardiology/American Heart Association Task Force on practice guidelines (Committee on management of patients with valvular heart disease)12. J Am Coll Cardiol. 1998;32(5):1486-1582. doi:10.1016/S0735-1097(98)00454-9.