Carcinoid Syndrome: Causes, Symptoms, and Treatment Options

If you or someone you care about has been diagnosed with carcinoid syndrome, it’s natural to have questions and concerns. This condition is caused by certain rare tumours called carcinoid tumours that release hormones into your bloodstream, leading to symptoms like flushing, diarrhoea, and wheezing. While it can sound overwhelming, many people manage it well with the right treatment and support. 

In this guide, you’ll learn what causes carcinoid syndrome, what symptoms to look out for, and which treatment options may help improve comfort and quality of life.

What is Carcinoid Syndrome?

Carcinoid syndrome happens when a type of tumour known as a carcinoid tumour produces and releases certain chemicals into your bloodstream. These tumours usually grow slowly and are part of a group called neuroendocrine tumours (NETs), which often begin in the digestive tract or lungs. 

When these tumours spread, especially to the liver, the chemicals they release can no longer be filtered properly by your body. This leads to a set of symptoms commonly referred to as carcinoid syndrome. Though it may sound complex, it is manageable with early care.

Is Carcinoid Syndrome Common?

No, carcinoid syndrome is not very common, and most people with a carcinoid tumour never develop this condition. In fact, only a small number of these tumours release enough hormone-like substances to cause symptoms. Carcinoid syndrome typically occurs in people who have carcinoid tumours that are advanced. It is more likely to appear in people with advanced or metastatic neuroendocrine tumours, particularly when the tumour has spread to the liver. 

Although rare, awareness is growing, and better tests have made diagnosis easier today than in the past. If caught early, the condition can often be treated effectively and comfortably with medical support and care.

Carcinoid Syndrome Symptoms

When your body is affected by carcinoid syndrome, you may notice some symptoms that are unusual or ongoing. These symptoms are linked to the chemicals released by the tumour. If you notice any of these signs, it’s important to speak with your doctor.

• Flushing of the face and neck: A sudden redness or warmth, often triggered by stress, eating, or alcohol. These episodes can last a few seconds to several minutes.
• Chronic diarrhoea: Frequent, watery bowel movements that can lead to dehydration, tiredness, or weight loss if left unmanaged.
• Wheezing or shortness of breath: You may feel like your chest is tight or notice a whistling sound when you breathe. Difficulty breathing and wheezing are common symptoms.
• Fast heartbeat or palpitations: Feeling like your heart is racing, even when you are at rest.
• Swelling in the legs or ankles: This may occur due to the impact on your heart or circulation.
• Fatigue: Feeling unusually tired, even after resting.

Carcinoid Syndrome Causes

Carcinoid syndrome is caused by substances released by a carcinoid tumour, usually when the tumour has grown large or spread to other organs such as the liver. These chemicals, including serotonin, are normally broken down by the liver before they affect your body. When they bypass the liver or overwhelm its ability to break them down, symptoms begin to appear.

• Neuroendocrine tumours in the digestive system: Tumours in the small intestine, appendix, or colon are common sources. These tumours can secrete serotonin and other substances into your bloodstream.
• Tumours in the lungs: These are less common but can cause symptoms earlier since they release chemicals directly into the bloodstream.
• Hormone production: The tumours release serotonin and other hormones, which affect your digestive system, lungs, and blood vessels.
• Liver metastases: When tumours spread to the liver, the liver’s filtering function becomes less effective, allowing chemicals to circulate freely.
• Tumour size and location: Larger tumours or those near blood vessels are more likely to cause symptoms.

Risk Factors For Carcinoid Syndrome

While anyone can develop a carcinoid tumour, certain risk factors may make you more likely to develop carcinoid syndrome, especially if the tumour begins producing hormones.

• Having a neuroendocrine tumour: This is the main risk factor, especially if the tumour is located in your gastrointestinal tract or lungs.
• Tumour spread to the liver: Tumours that have metastasised to the liver have a higher chance of causing carcinoid symptoms, as the liver cannot filter the chemicals effectively.
• Type of tumour: Well-differentiated tumours that grow slowly but spread over time are more likely to lead to symptoms.
• Age: This condition is more often diagnosed in people aged 50 and above.
• Genetic conditions: Certain inherited syndromes, such as multiple endocrine neoplasia type 1 (MEN1) and neurofibromatosis type 1 (NF1), may increase your risk of developing neuroendocrine tumours.
• Delayed diagnosis: If the tumour has been present for a long time without being detected, it may eventually cause symptoms.

Being aware of these risks can help you monitor your health and catch signs early.

Complications of Carcinoid Syndrome

Carcinoid syndrome can lead to some complications if not treated, especially when the chemical imbalances in your body affect your organs over time. Understanding these helps you stay informed and ready to act if symptoms change.

• Carcinoid heart disease: This occurs when chemicals affect the heart valves, especially on the right side, leading to shortness of breath, tiredness, and swelling.
• Carcinoid crisis: A rare but serious event where symptoms suddenly worsen during stress or surgery. It may include a sharp drop in blood pressure and breathing issues.
• Nutrient deficiencies: Excess serotonin production can reduce your body’s levels of tryptophan, leading to a niacin (vitamin B3) deficiency and symptoms like fatigue or skin issues. This is known as pellagra.
• Liver problems: Tumours in the liver can cause blockages or interfere with liver function, leading to jaundice or other symptoms.
• Emotional effects: Dealing with ongoing symptoms can lead to feelings of anxiety or depression. Support and understanding are important parts of care.

Early and ongoing treatment can help you avoid or manage these issues.

How is Carcinoid Syndrome Diagnosed?

Diagnosing carcinoid syndrome often starts with recognising the symptoms and confirming the presence of a carcinoid tumour. Doctors use several tests to understand what’s happening in your body and how best to treat it.

• Urine test (5-HIAA): Measures a substance made when your body breaks down serotonin. Elevated levels may suggest hormone-producing tumour.
• Blood tests: These check for markers such as chromogranin A, which can indicate a neuroendocrine tumour.
• Imaging scans: CT, MRI, or PET scans help find where the tumour is located and if it has spread.
• Endoscopy or colonoscopy: These tests help doctors look directly into the stomach or intestines to find and possibly biopsy tumours.
• Physical examination and history: Your doctor will ask about symptoms like flushing, diarrhoea, or wheezing, and check for signs such as swelling or jaundice.
• Echocardiogram: If heart involvement is suspected, a scan of your heart may be done to check for valve problems.

Prevention

At this time, there’s no guaranteed way to prevent carcinoid syndrome, as it is linked to the growth and spread of a carcinoid tumour, as it is linked to the growth and spread of a carcinoid tumour, since it is linked to the growth and spread of a carcinoid tumour. However, you can take steps to protect your health and improve early detection.

• Know your symptoms: Recognising carcinoid symptoms like flushing or diarrhoea early can lead to faster diagnosis and better outcomes.
• Follow up on unusual digestive symptoms: If you have ongoing stomach or bowel issues, it’s worth discussing them with your doctor.
• Stay up to date with check-ups: If you have a neuroendocrine tumour, regular scans and tests can help track changes and prevent complications.
• Avoid known triggers: For people already diagnosed, avoiding foods or situations that trigger flushing or diarrhoea can improve comfort.
• Talk about your family history: If there’s a history of neuroendocrine tumours, let your doctor know.
• Healthy habits: Eating a balanced diet, not smoking, and reducing alcohol may help your overall health and reduce risks.

Conclusion

Living with carcinoid syndrome can feel challenging, but with the right care and timely diagnosis, it becomes much easier to manage. Early detection and appropriate treatment can significantly improve quality of life. Paying attention to symptoms and seeking expert support can make a real difference to your quality of life. 

For reliable and advanced testing, Metropolis Healthcare offers trusted diagnostic services, including specialised hormone tests, with the convenience of home sample collection and quick, accurate reports you can depend on.

FAQs

How do you check for carcinoid syndrome?

Doctors use urine, blood tests, and scans to detect hormone levels and locate any carcinoid tumour.

Can you live a long life with carcinoid syndrome?

Yes, with early diagnosis and proper treatment, many people manage symptoms well and live a fulfilling life.

Can carcinoid syndrome go away?

Carcinoid syndrome may improve with treatment, but symptoms often return if the tumour isn't fully removed.

What is the most common site of a carcinoid tumour?

The small intestine, particularly the ileum, is the most common site for a carcinoid tumour to develop.

Do you need chemo for carcinoid syndrome?

Not always. Chemotherapy is used in advanced cases; other treatments are usually preferred for managing symptoms.