Carcinoid syndrome

 ICD9           = 259.2|
 ICDO           = M8240/3-8245 |
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 OMIM           = |
 MedlinePlus    = 000347 |
 eMedicineSubj  = med |
 eMedicineTopic = 271 |
 DiseasesDB     = 2040 |

}} Carcinoid syndrome refers to the array of symptomsthat occur secondary to carcinoidtumors. Carcinoid tumors are discrete, yellow, well-circumscribed tumors that can occur anywhere along the gastrointestinal tract(GI). They most commonly affect the appendix, ileum, and rectum. These tumors are unique in that they are endocrinein nature. They secrete hormonesinto the blood stream, which then travel to end organsand act upon them via appropriate receptors. Although quite rare, 15 cases/1,000,000 population, carcinoid tumors account for 75% of GI endocrine tumors.

Pathophysiology

Carcinoid tumors secrete vasoactive substances such as serotonin, histamine, catecholamines, and prostaglandins. These hormones acts upon many tissues of the body including the central nervous system, blood vesselsof the intestinal tract, and platelets, ultimately altering blood flow. Prior to metastasis, the liveris capable of metabolizingmost of the hormones elaborated by such tumors, rendering patients asymptomatic. Only about 5% of patients with carcinoid tumors ever develop symptoms of the carcinoid syndrome which includes, flushing, diarrhea, hypotension, edema, asthma-like bronchoconstrictionattacks, and valvular heart disease. The onset of these symptoms suggests that the tumor has metastasized to the liver, allowing serotonin and its various by-products to reach systemic circulation.

Diagnosis

With a certain degree of clinical suspicion, diagnosisis made by measuring the 24 hour urinelevels of 5-HIAA (5-hydroxyindoleacetic acid), a breakdown product of serotonin. Patients with carcinoid syndrome usually excrete >25 mg of 5-HIAA per day.

Treatment

For symptomatic relief of carcinoid sydrome:

• Octreotide (somatostatin analogue- neutralizes serotonin and decreases urinary 5-HIAA)
• Methysergide maleate (antiserotonin agent but not used because of serious side effect of retroperitoneal fibrosis)
• Cyproheptadine (antihistamine)

Alternative treatment for qualifying candidates:

• Surgicalresection of tumor and chemotherapy(5-FU and doxorubicin)

Prognosis

Prognosisvaries from individual to individual. It ranges from a 95% 5 year survival for localized disease to a 20% 5 year survival for those with liver metastases. However, median survival for patients with carcinoid sydrome is 2.5 years from the first episode of flushing.

Synonyms

Thorson-Bioerck syndrome, argentaffinomasyndrome, Cassidy-Scholte sydrome, flush syndrome

References

1. "Endocrine Tumors of the GI Tract and Pancreas." Harrison's Manual of Medicine. Eugene Braunwald. 15th edition. New York: McGraw-Hill, 2002. 298-299.
2. "Malignant Carcinoid Syndrome." Current Medical Diagnosis & Treatment. Lawrence M. Tierney, Jr. 43rd edition. New York: Lange Medical Books/McGraw-Hill, 2004. 1625.
3. "Carcinoid Syndrome." Griffith's 5 Minute Clinical Consult. Mark Dambro. Mobile Version 6.0.139. Lippincott, Williams and Wilkins, 2003.

See also

• Kulchitsky cells

External links

• Merck

This article is licensed under the GNU Free Documentation License.
It uses material from the http://en.wikipedia.org/wiki/Carcinoid+syndrome Wikipedia article Carcinoid syndrome.