Neuroendocrine cells inhabit the gastrointestinal system and airways of the lungs in large numbers, producing hormones that regulate the function of nearby tissues. A carcinoid is a rare, slow-growing tumor that arises from neuroendocrine cells. While most carcinoid tumors do not cause symptoms, the American Cancer Society estimates that approximately 10 percent of people affected develop a constellation of symptoms known as carcinoid syndrome. Substances secreted by the tumor mediate the symptoms of carcinoid syndrome.
Flushing
The National Cancer Institute reports that flushing presents as a hallmark symptom of carcinoid syndrome. Bright facial flushing typically predominates, although other areas of the body may also exhibit flushing. With long-standing carcinoid syndrome, the skin of the face may begin to thicken. "The Merck Manual for Healthcare Professional" explains that facial flushing occurs due to the effects of tumor-produced histamine and bradykinin. These substances cause relaxation and opening of the blood vessels leading to reddening of the skin.
Intermittent Abdominal Pain and Diarrhea
Intermittent, cramping abdominal pain and diarrhea may occur with carcinoid syndrome, notes the University of Maryland Medical Center. Nerves of the autonomic or involuntary nervous system typically control the activity of the intestines. Tumor production of the hormone serotonin overrides normal autonomic controls causing increased intestinal muscle contractions. Colicky abdominal pain and diarrhea result. Dehydration may develop with severe diarrhea.
Wheezing
Information provided by MayoClinic.com notes that wheezing and accompanying shortness of breath may occur intermittently with carcinoid syndrome. Serotonin and histamine production by the carcinoid tumor may cause constriction of the airways, producing episodes that may mimic asthma attacks.
Low Blood Pressure
Drs. Sean Stitham and James Mason note in a Medline Plus entry that low blood pressure may occur with carcinoid syndrome. Histamine, bradykinin and serotonin can affect the muscle cells within the walls of blood vessels, precipitating relaxation and dilation. A fall in blood pressure typically results.
Rapid Heart Rate
Excess circulating serotonin from the tumor may cause episodes of increased heart rate, as pointed out on MayoClinic.com. This and other symptoms of carcinoid tumor may be precipitated by certain foods, red wine or strenuous physical activity.
Swelling of the Feet and Ankles
Edema or swelling of the feet and ankles may occur with carcinoid syndrome, notes the National Cancer Institute. Long-standing carcinoid syndrome may damage the heart valves and compromise overall heart function. In a review article published in the journal "Heart," Drs. David Fox and Rajdeep Khattar state that approximately 50 percent of people with carcinoid syndrome have heart valve damage. The presence of swelling in the lower extremities may indicate significant heart valve damage and early heart failure.
References
- American Cancer Society: What is a Gastrointestinal Carcinoid Tumor?
- American Cancer Society: What is a Lung Carcinoid Tumor?
- National Cancer Institute: General Information About Gastrointestinal Carcinoid Tumors
- Merck Manual for Healthcare Professionals: Carcinoid Syndrome
- Merck Manual for Healthcare Professionals: Carcinoid Tumors
