Carcinoid syndrome is brought about by a rare cancerous tumor referred to as the carcinoid tumor. This tumor produces some chemicals into the bloodstream and affects the lungs, ovaries and the gastrointestinal tract. Typically people don't experience the symptoms until they are at an advanced stage. It should however be noted that just a small percentage of carcinoid tumors usually secrete chemicals that cause the carcinoid syndrome. Usually the liver efficiently degrades the secreted chemicals before they travel into the body to cause the symptoms. Advanced tumors can spread to the liver itself thus secreting chemicals which are not effectively degraded before reaching the bloodstream. It is noted that many people who experience the carcinoid syndrome usually have an advanced tumor which has spread up to the liver. There are however some carcinoid tumors which are not advanced yet they cause the carcinoid syndrome. A good example is the lung carcinoid tumors which secrete chemicals very far in the upstream. There are various sign and symptoms of this syndrome which are mainly categorized according to the chemicals produced by the carcinoid tumor in the blood stream. One of the symptoms is skin flushing whereby the upper chest and face changes to red from pink especially when one takes food or drinks alcohol. Another symptom is diarrhea whereby the patients experience a high frequency of eatery stools which are usually accompanied by some painful abdominal cramps. Another symptom is the facial skin lesions where by the upper lip and the nose usually has purplish areas in the spider-like veins. The other symptom is difficult breathing or asthma-like symptoms which include the shortness of breathe wheezing which is mainly accompanied by skin flushing (Mayo clinic stuff, 2010).Anesthetic Management
The three main origin areas for carcinoid tumors are lungs, stomach or bronchi for foregut carcinoid; tumors, appendix, small intestine for proximal large bowel for midgut carcinoid tumors and rectum or distal colon for hindgut carcinoid tumors. It's imperative to note that the most prevalent site for carcinoid tumors is the appendix followed by rectum, lungs, ileum stomach and bronchi. The considerations made during anesthetic management of carcinoid syndrome include mediator disease prevention. Studies have shown that tumors release numerous hormones and mediators like bradykinins, tachykininns, adrenocorticotropichormone, prostaglandin, substance P, vasoactive intestinal peptide, neurotensin, dopamine among others. The main anesthetic aim is to avoid the triggering factors and grounding for preoperative carcinoid crisis management. Previous studies have failed to provide conclusive results on how effective prophylactic treatment with kentanserin, cyproheptadinne and aprotinin is effective. In this regard, they have advocated for histamine blockers and octreotide pre-treatment only. Octreotide propels pharmacologic actions which are similar to somastatin which is a natural hormone. It inhibits growth hormone, insulin and glucagon. It also suppresses the response of luteinizing hormone to gonadotropin in hormone relieve and inhibits serotonin, vasoactive peptide, gastrin, sectretin, pancreatic polypeptide and motilin release. It also decreases the blood flow of splanchnic. Aesthetic management also uses histamine blockers incases where gastric carcinoid tumor is being treated. This is because histamine release is more predominant in gastric carcinoid tumors. It's also advisable to administer octreotide 3 weeks before surgery is conducted. However, different carcinoid syndrome tumors require different styles of aesthetic management. The success of aesthetic management is founded on good communication between the anesthetist, endocrinologist and the surgeon. This encompasses apt exploration and treatment of carcinoid peptides effects and preventing their release from the responsible tumor. Possibly, one should garner some advice from centers which have managed the individual patient in question before (Vaughan & Brunner, 1997).Pathophysiology
This refers to the functional changes which arise from or are associated with a carcinoid syndrome. Carcinoid tumors usually affect the tip of the appendix. This is because they attack the wall of the appendix thus making its lymphatic involvements nearly universal. For example many patients experience the peritoneal involvement at the same time and very few patients experience distant or regional dissemination. Carcinoid tumors also cause elastic and concentric vascular sclerosis which results into annihilation of the vascular ischemia and Lumina. This is because the fibrosis and elastosis which basically surround the tumor cells nests and the involved tissues and lymph nodes. Carcinoids of the stomach are mainly associated with low production of gastric acid thus causing a condition which is referred to as achlohydria or hypochlohydria. These kinds of tumors never metastasize but at times they produce histamine. Carciniod syndrome also alters metabolism of tryptophan. This is because normally one percent of tryptophan is converted into serotonin but it goes up to above 70% in patients who are suffering from this syndrome. The serotonin is metabolized into HIAA (5-hdroxyindoleacetic acid). This increased production of serotonin results into vasodilatation and also increases the clotting of blood through the stimulation of platelet aggregation. This brings about DIC (disseminated intravascular coagulation). This syndrome also hinders the proper functioning of the bowel because it causes small bowel stenosis accompanied by acute obstruction and even bleeding. The carcinoid disease of the heart usually causes thickening of the heart valves thus disrupting its proper functioning. It also leads to shortness of breath during physical activities, fatigue and can also lead to heart failure. Locationally, most of thecarcinoid tumors are located in the midgut and that's where many symptoms of tumors are located. On the other hand the hindgut has very few carcinoid tumors and therefore very low levels of the chemical or substance is produce d meaning only rare symptoms can be traced in this location(Tebbi, 2009).Preoperative
During this stage of the syndrome management, the most common complain is periodic abdominal pain while the earliest manifestation happens to be coetaneous flushing specifically in the neck and head. The pre-operation preparation of patients mainly requires a correction of deficiencies in circulation of volume and electrolyte levels. There should also be minimized use of histamine releasing agents or even avoid it completely. These agents include morphine, atracurium and thiopental. Fasciculutions also induce the production of carcinoid hormones and it should be prevented through the avoidance of succinylcholine. The preoperative assessment mainly examines the most common clinical signs which include flushing, wheezing, blood pressure or heart rate change and diarrhea (Nagelhou & Plaus, 2009). The preoperative assessment also involves complete blood count, liver function tests, determination of the urine 5-HIAA levels and electrocardiogram. Mainly, the fluid and the electrolyte status are optimized to counteract the effects of histamine both the histamine-2,-1, receptors blockers must be used immensely. The katamine and ephedrine agents should also be minimized. To avoid the catecholamine induced vasoactive mediator release it advisable that there should be aggressive maintenance of normothermia. A somatostatin analog referred to as the octreotide is used in blunting bronchoconstrictive and vasoactive outcomes of carcinoid tumor products. Octreotide inhibits the release of some gastrointestinal hormones and also those from the carciniod tumors. To treat hypertension a-adrenergic agonist such as the phenylephrine infusion are used so as to avoid the hormonal release of B-adrenergic stimulation. Remifentanil infusion should also be used because a standard suppression of intubation response, immediate titratability and a higher capacity of controlling intraoperative hypertension. Also during this stage of the syndrome management, conventional radiology applications to endoscopy can also be of major importance in the diagnosis. Laboratory testing mainly relies on the identification of various biomarkers that are perceived to be the hallmarks of the disease (Sitaraman & Gold finger, n.d)Intra-operative
There are some anesthetic problems which arise from local anesthesia procedures during this stage of management. For example there is excess production of serotonin that causing the hyperkinetic states of tachycardia and hypertension. During this stage of management the preoperative electrolyte abnormalities are expected and treated. The anesthetics which are known to trigger 5-HTrelease like morphine should also be avoided. Bradykinins may or it might not be produced thus causing hypotension which is secondary to both vasodilation, flushing, increased permeability of the capillary and bronchospasm. Hypotension and hypertension are likely to occur due to the release of vasoactive peptides from the tumor and therefore it is mandatory that all patients have what is referred to as the invasive BP monitoring. Catecholamine should be discarded as the first line treatments for hypertension therefore replacing it with other agents such as alpha-adrenergic and vasopressin. Steroids can also be highly applicable for they have shown a very high capability in the management of bronchial symptoms which are associated with bronchoconstriction. H2 antagonism can be used in the prevention of flushing and subsequent hypertension due to its potential in the release of histamine. Somatostatin is also one of the beneficial agents which are mainly used. It can be applied post-operatively for the management of symptoms for it decreases the release of peptides from the tumor. Octreotide which is in form of sandostin sandos SMS201-995 has been used surgery preparation and for treatment of emergency carcinoid crisis.Postoperative
During this kind of management the patient is mainly managed in a high dependency unit (HDU) as further attacks of hypotension and hypertension may occur. A lot of attention is given to fluid balance. Morphine is usually avoided because and the patient's analgesia is controlled with pethidine or fentanyl. There are some anesthetic problems which are associated with this period of the syndrome management for example the induction of anesthesia in the presence of any cardiac tamponade may be very fatal. The elimination of the vasoconstrictor compensation can also lead to the collapse of the cardiovascular. For example according to Mason (2001), a 9 year old boy who was about to have a biopsy of the cervical node has died due to holathane induction. Tamponade may also result from venous cannulation. During this period the sudden drainage of a chronic cardiac temponade may result into haemodynamic changes or even the pulmonary oedema. This pulmonary oedema may be propelled by the acute dilation experienced in the in the thinner walled right ventricle and the temporary mismatch which occurs between the output of both ventricles. Another anesthetic problem is that the isolated right arterial compression which occurs following a cardiac surgery may be difficult to diagnose. The management of the syndrome also involves the direct monitoring of central venous and arterial pressures. Another way through which the syndrome can be postoperatively diagnosed is through the minimization of factors which worsen the haemodynamic situations. One of these factors includes the low intravascular volume. This is because the blood volume must be always maintained with the four fluids which are usually given according to the haemodynamic responses. Another factor that worsens the haemodynamic situation is the decreased myocardial contractility which is the reduction of the ventricular filling pressure brought about by some induction agents. Another way in which the syndrome can be managed postoperatively is by ensuring the sudden relief of temponade. This can be achieved through local anesthesia which involves needle pericardiocentesis. ECG and a radiological screening are also done hand in hand with available facilities of emergency theracotomy. The somatostatin infusion used intraoperatively should also be continued in the postoperative period in the situation of the carcinoid patients who have undergone a surgery which didn't involve tumor removal. The careful monitoring of the patients of hemodynamic and oxygenation status should be effectively maintained and also the triggering mechanisms of tumor secretion s must be highly avoided (Pourmand & Abernathy, 2008).Medical Management
Medical management of carcinoid disease entails treatment carcinoid syndrome which is caused by dietary elements, stress, chemotherapy, anesthesia or spontaneous occurrence. The crisis can be life threatening at times and it's characterized by differing degrees of diarrhea, intense flushing, altered mental status, abdominal pain and cardiovascular derangements especially hypotension or hypertension. Various agents have been used to treat this syndrome but the only agent currently known to have a broad effectiveness in treatment and prevention is octreotide (Norton, Barie & Bollinger, 2008). This agent is designed to counter the type-2 somatostatin receptor (SSTR-2) (Norton, Barie & Bollinger, 2008). This receptor is very prevalent in carcinoid tumors. The agent basically reduces peripheral levels of serotonin and reduces gut motility. It also reduces carcinoid crisis risk intraoperatively. When octreotide is used subcutaneously after every 6-12 hours at a starting dose of 150 milligrams, a research trial established that it Improved diarrhea by 50% and flushing by 82% for a period of one year (Norton, Barie & Bollinger, 2008). The side effects of using this agent include steatorrhea and gentle rise in blood glucose levels. However, these side effects are experienced if the agent is used in high doses. The other possible side effects are gall-stone formation which comes with its long term use. There are other somatostatin analogues which are currently undergoing trials. One of them is SOM230 which targets additional receptors of somatostatin. The other treatment for carcinoid syndrome is interferon though it's not widely used because of its side extreme side effects; these include hair loss, fatigue, nausea, pruritis and myalagia. It's mostly used in cases where octreotide has failed to deliver the required results. When used 3-7 days per week at a dosing rate of 1.5-7.0 mU, it was reported to improve diarrhea by 335 and flushing by 65% (Norton, Barie & Bollinger, 2008). However, the responses were transient. It's also used collaboratively with some chemotherapy regiments or hepatic embolization. Other agents are employed to counter carcinoid symptoms. They include antidiarrhea agents like selective bronchodilators, loperamide and diuretics which controls wheezing, diarrhea or heart failure. Recently, seronin receptor antagonists like ketanserin, cyproheptadine, methylsergide, tropisetron and ondansetron have been successful used though with varying degrees of success.
- Mayo Clinic Stuff. (2010). Carcinoid syndrome. Retrieved on 22nd March, 2010, from http://www.mayoclinic.com/health/carcinoid-syndrome/DS00690/DSECTION=symptoms
- Pourmand, P. E., & Abernathy, H. J. (2008). Carcinoid tumors: Perioperative management. MUSC Anesthesia Resident Research Night. Sitaraman, V. S. & Goldfinger, E .S. (n.d). Clinical features of the carcinoid syndrome. Retrieved on 22nd March, 2010, from http://www.uptodate.com/patients/content/topic.do?topicKey=~YYagQHSBXABFQ#H2
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- Tebbi, K. C. (2009). Carcinoid Tumor. Retrieved on 22nd March, 2010, from http://emedicine.medscape.com/article/986050-overview