Carcinoid Syndrome 1999.4.2

Carcinoid Syndrome 1999.4.2

Carcinoid syndrome refers to a group of rare malignant tumors that grow slowly, most commonly in the digestive system, though they can also occur in the bronchi and lungs. Some carcinoids are asymptomatic, while others can lead to carcinoid syndrome. The most common sites for carcinoid tumors are the appendix, followed by the small intestine, stomach, and bronchi and lungs. The main symptoms of carcinoid syndrome include: ① skin flushing, followed by redness, cyanosis, and pallor—collectively known as the “three-color phenomenon”; ② gastrointestinal symptoms: abdominal distension, diarrhea, and intestinal rumbling, with severe cases showing dehydration and electrolyte imbalance; ③ skin flushing may be accompanied by asthma and difficulty breathing; ④ liver metastasis results in hepatomegaly; ⑤ bone metastasis causes bone pain. Diagnosis: ① urinary histamine measurement: 23–90µg/24h (normal range), with this condition showing a marked increase up to 4.5mg per day; ② serum 5-hydroxytryptamine (5-HT) (normal range 0.1–0.3µg) can rise to 0.3–3µg/mL; ③ flushing provocation test: administer 1µg of adrenaline intravenously, and if the patient exhibits facial flushing within 60–90 seconds, or even experiences hypotension or tachycardia, the test is considered positive.