We’ve all been there — skimming past neuroendocrine tumors in a textbook five minutes before ward rounds, hoping no one asks about serotonin metabolism. 😅 But once you see your first classic carcinoid syndrome patient — flushed, wheezy, and dropping BP like a bad WiFi signal — you’ll never forget it.
Let’s make sure you don’t forget it either.
But before we dive into anything, let’s understand the basics:
🧬 What is Carcinoid Syndrome?
Carcinoid syndrome is the result of bioactive peptide secretion (like serotonin, kallikrein, and histamine) by a carcinoid tumor — typically a neuroendocrine tumor of the GI tract that has metastasized to the liver (bypassing first-pass metabolism 🔁).
Patient walks into your clinic with:
- A history of flushing
- Episodic diarrhea
- Mild wheeze
- And a suspiciously right-sided murmur
BOOM! This is Carcinoid Syndrome without any question!
To remember all this, you don’t need Dr. House — you just need a good mnemonic!! 😀
Carcinoid Syndrome Mnemonic: “CARCinoid”
| Letter | Clinical Feature |
|---|---|
| C | Cutaneous flushing 🌡️ (episodic, often after meals/alcohol) |
| A | Asthmatic wheezing 😮💨 (bronchospasm due to serotonin & bradykinin) |
| R | Right-sided valvular heart lesions ❤️ (think tricuspid regurgitation & pulmonary stenosis — because serotonin gets filtered out by lungs before reaching the left heart) |
| C | Cramping & Diarrhea 🚽 (due to increased GI motility and serotonin excess) |
🏥 Real Talk from the Wards at Sheikh Khalifa Bin Zayed Hospital, Quetta
Had a 54-year-old gentleman who’d been treated for “asthma” for 6 years (spoiler alert: it wasn’t asthma). What finally tipped us off was his persistent diarrhea and new murmur. Echo? Tricuspid regurg. 24-hour urinary 5-HIAA? Through the roof.
Lesson? Think carcinoid when the symptoms don’t add up — especially when they’re oddly specific and unusually dramatic.
🧪 Bonus Exam Tip
- Urinary 5-HIAA is your best diagnostic friend (metabolite of serotonin).
- Octreotide scan helps localize the tumor.
- Treatment? Somatostatin analogs like octreotide/lanreotide to control symptoms, and surgical resection when feasible.
Happy learning, folks! 🙂
📚 Written by:
Dr. Aurangzaib Qambrani
MBBS, PLAB, MRCP-UK
General Medicine, Gastroenterology & Cardiac Care Unit
Sheikh Khalifa Bin Zayed Hospital, Quetta
