What is Carcinoid ?

Carcinoid is a cancer, usually occurs in the digestive tract, which can produce a large number of neuropeptides and amines. Both these substances have effects that mimic hormones. When carcinoid spreads to the liver, there will be redness, bluish skin, abdominal cramps, diarrhea, heart damage and other symptoms of a carcinoid syndrome.

Carcinoid tumors produce a large number of neuropeptides and amines (substances that mimic hormones) such as bradykinin, serotonin, histamine and prostaglandins. Under normal circumstances, these substances to control internal body functions. If the number is excessive, can cause symptoms of carcinoid syndrome.


CAUSE
Carcinoid tumors are usually derived from hormone-forming cells that line the small intestine (enteroendokrin cells) or other cells of the gastrointestinal tract, pancreas, testes, ovaries, or lungs. The cause of the formation of carcinoid tumors is unknown.

Other cancers (eg wheat cell carcinoma of the lung and medullary carcinoma of the thyroid gland) also produce substances that cause carcinoid syndrome. If carcinoid tumors formed in the digestive tract, then the substances that mimic hormones are released into the bloodstream and flows directly into the liver. In their hearts are destroyed by enzymes.

Tumors that had spread to the liver releasing hormone-like substances into the stream without first processed in the liver. Therefore if you have not spread to the liver, carcinoid tumors originating from the digestive tract usually causes no symptoms. If it has spread to the liver, then the substance is flowing throughout the body, causing symptoms of carcinoid syndrome are varied, depending on the substance released.

Carcinoid tumors in the lungs and ovaries also cause symptoms because the substances they produce bypass the liver and is spread widely through the bloodstream.


SYMPTOMS
Less than 10% of patients who had carcinoid syndrome. Most people have symptoms that mimic colorectal cancer, particularly abdominal pain and changes in bowel habits as a result of obstruction.

The initial symptoms are most commonly found from carcinoid syndrome is a reddish skin that cause discomfort, especially in the head and neck. Redness is thought to be caused by excessive histamine and bradykinin, which causes widening of blood vessels. Redness is often triggered by emotions, eating, or drinking alcohol or hot liquids.

Skin color can change dramatically, from pale to red and then become bluish (cyanosis). Excessive serotonin triggers contraction of the muscles around the intestines, causing diarrhea, cramping, and abnormal absorption of food. Abnormalities of food absorption (malabsorption) cause malnutrition (nutritional disorder) and causes a foul-smelling fatty stools.

carcinoid syndrome damage can cause heart and lungs. Abnormal fibers formed in the heart (fibrosis endokardial), which caused heart valve damage and disruption of the heart's pumping ability. Serotonin in the blood stream are destroyed when it passes through the lungs (before reaching the left heart), because it's almost all cardiac abnormalities occur on the right side.

Some people experience asmatik wheezing (wheezing breath sounds); other patients experience loss of sexual desire and become impotent.


Diagnosis
Diagnosis based on results of a CT scan, MRI, endoscopy, and chemical examination of the urine.

If the thought of a carcinoid tumor, then the urine examination to determine levels of acid 5-hydroxy indole acetic acid (5-HIAA), which is one of the serotonin metabolite. Three days before the examination, the patient should not eat foods that are rich in serotonin (eg, pineapple, tomatoes, plums, avocados, bananas, eggplant and walnuts) and not taking certain medications (guaifenesin, metokarbamol, and phenothiazines).

A CT scan or MRI performed to determine the spread of tumors to the liver. Sometimes need to do further tests and exploratory surgery to determine the location of the tumor and its spread.

Diagnostic arteriography and radionuclide skening the latest techniques to find carcinoid tumors and spread. Recent findings indicate that most carcinoid have receptors for the hormone somatostatin. Because it is radioactive somatostatin could be injected into the blood and use of nuclear skening can be known of carcinoid and its spread. Approximately 90% of cases can be detected using this technique.


TREATMENT
If the tumor is limited in certain areas (eg, lung, appendix, small intestine, or rectum), surgical removal may cure this disease. If the tumor has spread to the liver, surgical removal can not cure the disease, merely relieve symptoms.

Radiation therapy and chemotherapy are ineffective in treating carcinoid tumors. However, combinations of certain chemotherapy drugs (streptozosin with fluorouracil and sometimes doxorubicin) may relieve symptoms. Okreotid can also relieve symptoms, tamoxifen, interferon alpha and eflornitin can suppress tumor growth. To control the redness, given phenothiazines, cimetidine and fentolamin. For carcinoid tumors in the lungs that episodes of severe flushing is sometimes given prednisone.

Diarrhea can be controlled with codeine, tincture of opium, diphenoxylate, siproheptadin or metisergid. To treat high blood pressure can be given various anti-hypertensive drugs (eg methyldopa and fenoksibenzamin).