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Carcinoid Syndrome And Carcinoid Tumours
Overview
Carcinoid syndrome is a symptom complex observed in potentially malignant slow-growing neuroendocrine tumors that can occur in almost any organ. In 39% of cases, neoplasms that provoke carcinoid syndrome are localized in the small intestine, in 26% - in the appendix, in 15% - in the rectum, in 1-5% - in other parts of the large intestine, in 2-4% - in the stomach. , 2-3% - in the pancreas, 1% - in the liver and 10% - in the bronchi. In 20% of cases, carcinoid tumors of the gastrointestinal tract are combined with other neoplasms of the large intestine.
They are observed at any age, however, the average age of patients with this pathology is 50-60 years. Occasionally develop in childhood and adolescence. Men and women get sick equally often.
Carcinoids grow slowly. In the case of localization in the small intestine, they give metastases in 30-75%, in the large intestine - in 70% of cases. Carcinoids of the appendix metastasize very rarely, in contrast to its other localizations. Most often, carcinoid metastases are described in regional lymph nodes, the peritoneum, various parts of the intestine and the liver.
The tumor is usually located in the submucosal layer of the intestine and grows in the direction of the muscular and serous layers. Its dimensions are small (diameter often ranges from a few millimeters to 3 cm). When dissected, the tumor tissue has a yellow or gray-yellow color, is characterized by a high content of cholesterol and other lipids.
Against the background of carcinoid, thickening and shortening of the cusps of the tricuspid valve and the pulmonary artery valve often occur and, as a result, valve insufficiency, muscle hypertrophy and dilatation of the right ventricle.
The etiology of carcinoid:
Like many other tumors, is unknown. Many symptoms of the disease are caused by the hormonal activity of the tumor. A significant release of serotonin (5-hydroxytryptamine) - a product of the conversion of the amino acid tryptophan, by enterochromaffin tumor cells has been proven. Against the background of carcinoid, the content in the urine of the end product of the conversion of serotonin 5-hydroxyindoleacetic acid is sharply increased and in most cases is 50-500 mg (the norm is 2-10 mg).
The physiological activity of serotonin is manifested when it is in the blood in a free state. Tumor releases of serotonin explain a complex set of body reactions that are observed during carcinoid (serotonin) attacks.
In recent years, it has been proven that the carcinoid produces other biologically active substances (lysylbradykinin and bradykinin, histamine, prostaglandin, polypeptide-p), that is, it is a multihormonal tumor.
Carcinoid syndrome is not seen in all carcinoid tumour patients. This condition generally appears only after metastases in the liver manifest in carcinoids of the small and large intestine. This is because hormones from the gut enter the liver via the portal vein system and are subsequently degraded by liver enzymes. When a tumour spreads to the liver, the products of tumour metabolism begin to reach the general circulation straight through the hepatic veins, without being cleaved in the liver cells.
Symptoms
The most prevalent symptom of carcinoid syndrome is hot flashes. This symptom occurs in 90% of individuals. The top part of the body has a rapid, recurrent, paroxysmal reddening. Hyperemia is typically most noticeable in the face, neck, and neck. Carcinoid syndrome patients report of feeling hot, numb, and burning. A rise in heart rate and a fall in blood pressure accompany hot flashes. Dizziness may occur as a result of a decrease in blood flow to the brain. During an assault, the sclera may become red and lacrimated.
In the initial stages of the development of carcinoid syndrome, hot flashes appear once every few days or weeks. Subsequently, their number gradually increases to 1-2 or even 10-20 times a day. The duration of hot flashes in carcinoid syndrome can range from 1-10 minutes to several hours. Typically, seizures occur on the background of drinking alcohol, spicy, fatty and spicy foods, physical activity, psychological stress, or taking medications that increase serotonin levels. Less often, hot flashes develop spontaneously, for no apparent reason.
Diarrhoea is found in 75% of carcinoid syndrome patients. It happens as a result of enhanced small intestinal motility caused by serotonin. It has a chronic persistent personality. The symptom's intensity might vary substantially. Because malabsorption disrupts all types of metabolism (protein, carbohydrate, fat, water-electrolyte), hypovitaminosis occurs. Drowsiness, muscular weakness, weariness, thirst, dry skin, and weight loss are symptoms of a long-term present carcinoid syndrome. In extreme situations, extensive metabolic abnormalities include edoema, osteomalacia, anaemia, and significant trophic changes in the skin.
Cardiac pathology is found in half of patients suffering from carcinoid syndrome. As a rule, endocardial fibrosis is detected, accompanied by damage to the right half of the heart. Fibrotic changes cause failure of the tricuspid and pulmonary valves and provoke stenosis of the pulmonary trunk. Valve failure and stenosis of the pulmonary artery in carcinoid syndrome can lead to the development of heart failure and stagnation in the systemic circulation, which are manifested by swelling of the lower extremities, ascites , pain in the right hypochondrium due to liver enlargement, swelling and pulsation of the veins of the neck.
In 10% of patients with carcinoid syndrome, bronchospasm is observed . Patients are disturbed by attacks of expiratory dyspnea, accompanied by wheezing and buzzing wheezing. Another fairly common manifestation of carcinoid syndrome is abdominal pain, which may be due to a mechanical obstruction to the movement of intestinal contents due to the growth of the primary tumor or the occurrence of secondary foci in the abdominal cavity.
Complication of the carcinoid syndrome:
A terrible complication of the carcinoid syndrome can be a carcinoid crisis - a condition that occurs during surgical interventions, accompanied by a sharp decrease in blood pressure, increased heart rate, pronounced bronchospasm and an increase in blood glucose levels. The shock that occurs during a carcinoid crisis poses an immediate threat to the patient's life and can be fatal.
Treatment
The main method of treatment is surgery. Depending on the localization and prevalence of the process, radical excision of the primary focus or various palliative operations is possible. In case of carcinoid syndrome caused by tumors of the small intestine, resection of the small intestine is usually performed along with a portion of the mesentery. With damage to the large intestine and neoplasms located in the region of the ileocecal sphincter, a right-sided hemicolectomy is performed.
In case of carcinoid syndrome caused by a neoplasm in the appendix area, an appendectomy is performed. Some oncologists additionally remove nearby lymph nodes. Palliative surgical interventions are indicated at the stage of metastasis, include the removal of large foci (both secondary and primary) to reduce hormone levels and reduce the severity of carcinoid syndrome. Another way to reduce the manifestations of the carcinoid syndrome is embolization or ligation of the hepatic artery.
The indication for chemotherapy in carcinoid syndrome is the presence of metastases. In addition, this method of treatment is used in the postoperative period with heart damage, liver dysfunction and a high level of 5-hydroxyindoleacetic acid in the urine. To avoid the development of a carcinoid crisis, treatment is started with small doses of drugs, gradually increasing the dosage. The effectiveness of chemotherapy in carcinoid syndrome is low. A significant improvement is noted in no more than 30% of patients, the average duration of remission is 4-7 months.
Symptomatic therapy for carcinoid syndrome, serotonin antagonist drugs are prescribed: fluoxetine, sertraline, paroxetine, etc. For tumors that produce a large amount of histamine, diphenhydramine, ranitidine and cimetidine are used. Loperamide is suggested for the treatment of diarrhoea. Furthermore, lanreotide and octreotide, which block the release of physiologically active chemicals in the tumour and can greatly diminish the signs of this disease in more than half of patients, are extensively utilised in carcinoid syndrome.
Tests Required for Diagnosis
The oncologist establishes the diagnosis on the basis of characteristic symptoms, external examination data and objective studies. An elevated level of serotonin is detected in the blood plasma. In the urine, a high content of 5-hydroxyindoleacetic acid is determined. To exclude a false positive result, within 3 days before testing, a patient with suspected carcinoid syndrome is advised to refrain from taking foods containing a large amount of serotonin (walnuts, eggplant, avocados, tomatoes, bananas, etc.) And certain medications.
In doubtful cases, tests with alcohol, catecholamines or calcium gluconate are carried out to stimulate hot flashes. To determine the localization of the tumor and identify metastases, a patient with carcinoid syndrome is sent for ct and mri of internal organs, scintigraphy , radiography , gastroscopy , colonoscopy , bronchoscopy and other studies. If there is sufficient evidence, laparoscopy may be used. Carcinoid syndrome is differentiated from systemic mastocytosis, hot flashes during menopause , and side effects when taking certain medications.
Useful info
The prognosis for carcinoid syndrome is governed by the tumor's prevalence and level of aggressiveness. A full recovery is feasible with the drastic excision of the main focus and the absence of metastases. The prognosis worsens with metastasis. Life expectancy in such situations ranges from 5 to 15 years or more because to the sluggish advancement of carcinoid. Multiple metastases to distant organs, weariness, heart failure, or intestinal blockage are the causes of mortality.
