Carcinoid tumors are slow-growing tumors usually found in the intestine or an airway of the lung. They are abnormal growths of nerve and hormone-producing tissues and can be cancerous. These tumors produce chemicals such as serotonin that are released into the blood, causing carcinoid syndrome. This syndrome produces a cluster of symptoms that can include heart disease.
Symptoms of Valve Disease
The chemicals released into the blood by carcinoid tumors cause damage to predominantly two of the four valves of the heart. The tricuspid valve is on the right side of the heart, and tricuspid regurtitation occurs when the tricuspid valve leaks blood back through the heart toward the veins when the heart contracts. Symptoms of isolated tricuspid regurgitation tend to be vague, such as fatigue. However, pulmonary stenosis may also occur, causing further symptoms. In pulmonary stenosis, the valve leading from the lungs back to the heart is constricted. It can cause shortness of breath, chest pain and decreased tolerance for activity.
Symptoms of Heart Failure
The chemicals released by a carcinoid tumor can damage the inner lining of the heart, called the endocardium. They can make it fibrotic, meaning an inflexible layer of connective tissue, or scarring, builds up in the inner walls of the heart. This can lead to the heart pumping inefficiently, causing heart failure. Symptoms of heart failure include shortness of breath, particularly when lying flat, exercise intolerance, fatigue, swelling in the extremities, dizziness and confusion.
Extra-Cardiac Disease
There are additional symptoms clustered together with the carcinoid syndrome that help to set it apart from other causes of heart disease. These symptoms include diarrhea, flushing or reddening of the skin, nausea, vomiting and constriction of the airways.
References
- "Robbins & Cotran Pathologic Basis of Disease"; Vinay Kumar et al; 8th Ed 2009
- "Harrison's Principles of Internal Medicine"; Anthony Fauci et al; 17th Ed 2008
