Carcinoid crisis and pseudoanaphylactic reactions: Carcinoid crisis is when all of the symptoms of carcinoid syndrome come at the same time. Carcinoid crisis is the most serious and life-threatening complication of carcinoid syndrome, and is generally found in people who already have carcinoid syndrome.The crisis may occur suddenly, or it can be associated with stress, chemotherapy, or anesthesia. It is characterized by abrupt flushing of face and sometimes upper body, usually severe falls in blood pressure and even bronchospasm with wheezing can (infrequently) occur. The attack may look like an anaphylactic attack. Diarrhea is an important part of carcinoid syndrome but is not usually simultaneous with the carcinoid crisis. It more commonly occurs as part of the anaphylactic reaction of an allergic or pseudoallergic reaction. Standard allergy tests are not usually positive in such cases. 24-hour urine histamine, blood histamine and blood tryptase tests, particularly if obtained at time of attack or just afterwards will establish diagnosis. Of allergic or pseudo allergic so called idiopathic anaphylactic attacks and mast cell disease.Epinephrine will provoke – not help carcinoid attacks. Urine 5HIAA is helpful when positive but if depended on as the sole chemical test for carcinoid syndrome will miss 50% of cases! Better also to measure blood serotonin, tryptophan and chromogranin A. Other blood markers associated with rare cases of severe attacks of flushing, diarrhea and fall in blood pressure are VIP, calcitonin and gastrin. They too should be measured. If any or all of the above are positive, further elaborate tests and treatment will be needed with details depending on which test(s) are positive. A carcinoid crisis may be prevented and successfully treated with octreotide, a therapy that can increase low blood pressure and control the production of hormones.
