What is Carcinoid Syndrome? Symptoms, Causes, & Treatment

Carcinoid syndrome is a collection of symptoms that can develop when certain slow-growing tumors called carcinoid tumors release hormones into your bloodstream. These tumors typically start in your digestive system or lungs and produce substances that your body normally makes in much smaller amounts.

While the name might sound alarming, carcinoid tumors are often slow-growing and manageable with proper treatment. Many people live full, active lives with this condition when it's properly diagnosed and cared for by their medical team.

What are the symptoms of carcinoid syndrome?

The most recognizable symptom is facial flushing that comes and goes unexpectedly. Your face, neck, and sometimes chest may turn red and feel warm, lasting anywhere from a few minutes to several hours.

The symptoms you might experience stem from the excess hormones these tumors release. Here are the most common signs your body might show:

• Sudden facial flushing or redness that feels warm to the touch
• Watery diarrhea that may occur several times daily
• Wheezing or difficulty breathing, especially during flushing episodes
• Fast or irregular heartbeat during symptom flares
• Abdominal cramping or bloating
• Nausea that may come with flushing episodes

Some people also experience less common symptoms that develop over time. These might include skin changes on your face or hands, joint pain, or swelling in your legs.

What makes this condition unique is that symptoms often come in episodes rather than being constant. You might feel perfectly fine between flares, which can make the condition challenging to recognize initially.

What causes carcinoid syndrome?

Carcinoid syndrome develops when carcinoid tumors produce too much of certain hormones, particularly serotonin. These tumors are a type of neuroendocrine tumor that grows slowly and can appear in various parts of your body.

The syndrome typically occurs when tumors have spread to your liver or when the primary tumor is located outside your digestive tract. This happens because your liver normally filters and breaks down excess hormones, but when tumors bypass this filtering system, hormones flood your bloodstream.

Several factors determine whether carcinoid tumors will cause syndrome symptoms:

• Location of the primary tumor (lung or certain digestive areas are more likely)
• Size and number of tumors present
• Whether tumors have spread to your liver
• How much hormone the tumors are actively producing
• Your body's ability to process these excess hormones

Most carcinoid tumors in your small intestine don't cause syndrome unless they spread to the liver. However, tumors in your lungs or ovaries can cause symptoms even without spreading because they release hormones directly into your general circulation.

When to see a doctor for carcinoid syndrome?

You should contact your healthcare provider if you experience recurring facial flushing combined with diarrhea, especially if these episodes happen regularly over several weeks. While many conditions can cause these symptoms individually, the combination warrants medical evaluation.

Seek prompt medical attention if you develop severe symptoms during an episode. These include significant difficulty breathing, chest pain, severe abdominal pain, or dizziness that doesn't improve when the flushing subsides.

It's also important to see your doctor if you notice that certain foods, stress, or activities consistently trigger your symptoms. Keeping track of what brings on your episodes can help your healthcare team make an accurate diagnosis and develop an effective treatment plan.

What are the risk factors for carcinoid syndrome?

Having existing carcinoid tumors is the primary risk factor for developing this syndrome. However, not everyone with carcinoid tumors will develop the syndrome.

Your likelihood of developing carcinoid syndrome increases with these factors:

• Age over 50, when carcinoid tumors are more commonly diagnosed
• Having carcinoid tumors that have spread to your liver
• Primary tumors located in your lungs, stomach, or ovaries
• Multiple carcinoid tumors present in your body
• Family history of neuroendocrine tumors or multiple endocrine neoplasia syndromes
• Certain genetic conditions that increase tumor risk

Gender also plays a role, with women being slightly more likely to develop carcinoid tumors overall. However, when it comes to carcinoid syndrome specifically, the risk is more closely tied to tumor location and spread than to demographic factors.

Having said that, many people with risk factors never develop carcinoid syndrome, and some people without obvious risk factors do. This is why paying attention to symptoms and getting proper medical evaluation is more important than worrying about risk factors alone.

What are the possible complications of carcinoid syndrome?

While carcinoid syndrome is often manageable, untreated cases can lead to complications that affect your heart and overall health. The good news is that proper treatment significantly reduces the risk of these problems.

The most serious complication is carcinoid heart disease, which affects the heart valves. The excess hormones can cause thickening and scarring of certain heart valves, particularly on the right side of your heart. This develops gradually and might not cause symptoms initially.

Other complications that can develop over time include:

• Carcinoid crisis, a rare but serious reaction with severe flushing and blood pressure changes
• Nutritional deficiencies from chronic diarrhea and poor nutrient absorption
• Bowel obstruction if tumors grow large enough to block intestinal passages
• Pellagra, a condition caused by niacin deficiency from altered metabolism
• Fibrosis or scarring in abdominal tissues around tumors

Carcinoid crisis is particularly concerning because it can occur during medical procedures, severe stress, or sometimes without warning. During a crisis, you might experience severe flushing, dangerous blood pressure swings, and heart rhythm problems.

The encouraging news is that regular monitoring and appropriate treatment can prevent most of these complications. Your healthcare team will watch for early signs and adjust your treatment plan accordingly.

How is carcinoid syndrome diagnosed?

Diagnosing carcinoid syndrome involves measuring hormone levels in your urine and blood, along with imaging studies to locate any tumors. Your doctor will likely start with a 24-hour urine test to check for elevated levels of 5-HIAA, a breakdown product of serotonin.

Blood tests can measure serotonin levels directly and check for other hormones these tumors might produce. Your doctor might also test for chromogranin A, a protein that many neuroendocrine tumors release.

Imaging studies help locate the primary tumor and determine if it has spread. These typically include:

• CT scans of your chest, abdomen, and pelvis to look for tumors
• Octreotide scans, which use a radioactive tracer that binds to carcinoid tumors
• MRI scans for detailed images of specific areas
• Echocardiogram to check your heart valves for damage
• Endoscopy procedures if digestive tract tumors are suspected

Sometimes diagnosis takes time because symptoms can be subtle or mistaken for other conditions. Your doctor might ask you to keep a symptom diary, noting when flushing or diarrhea occurs and what might have triggered it.

If initial tests suggest carcinoid syndrome, your doctor may recommend avoiding certain foods and medications that can trigger symptoms while completing the diagnostic workup.

What is the treatment for carcinoid syndrome?

Treatment focuses on controlling your symptoms and managing the underlying tumors. The approach your healthcare team chooses depends on your specific situation, including where your tumors are located and how active they are.

Medication is often the first line of treatment for controlling symptoms. Somatostatin analogs like octreotide or lanreotide can significantly reduce flushing and diarrhea by blocking hormone release from tumors.

Your treatment plan might include several approaches:

• Monthly injections of somatostatin analogs to control hormone production
• Anti-diarrheal medications for symptom relief between injections
• Niacin supplements to prevent pellagra
• Heart medications if carcinoid heart disease is present
• Targeted therapy drugs for progressive tumors
• Liver-directed treatments if tumors have spread there

Surgical removal of tumors may be recommended when possible, especially if you have a single primary tumor that can be completely removed. However, surgery isn't always feasible, particularly if tumors have spread extensively.

For tumors in your liver, specialized procedures like hepatic artery embolization can reduce tumor blood supply and hormone production. These treatments can provide significant symptom relief even when complete tumor removal isn't possible.

How to manage carcinoid syndrome at home?

Managing your symptoms at home involves identifying and avoiding triggers while supporting your overall health. Many people find that certain foods, stress, or activities can bring on flushing episodes.

Dietary changes can make a significant difference in how you feel day to day. Avoiding foods high in tyramine, histamine, or that are known triggers can reduce symptom frequency and severity.

Consider making these lifestyle adjustments:

• Avoid alcohol, spicy foods, and aged cheeses that commonly trigger symptoms
• Eat smaller, more frequent meals to ease digestive symptoms
• Stay hydrated, especially during diarrhea episodes
• Practice stress-reduction techniques like gentle exercise or meditation
• Keep a symptom diary to identify your personal triggers
• Take medications exactly as prescribed, even when feeling well

During flushing episodes, find a cool, comfortable place to rest until symptoms subside. Loose, breathable clothing can help you feel more comfortable during these times.

It's helpful to educate family members about your condition so they can provide support during symptom flares. Having a plan for managing severe episodes, including when to seek emergency care, gives both you and your loved ones peace of mind.

How should you prepare for your doctor appointment?

Preparing for your appointment helps ensure you get the most from your time with your healthcare provider. Bringing detailed information about your symptoms will help your doctor understand your condition better.

Start by writing down all your symptoms, including when they occur and how long they last. Note any patterns you've noticed, such as foods, activities, or situations that seem to trigger episodes.

Bring this information to your appointment:

• A detailed symptom diary covering at least two weeks
• List of all medications, supplements, and vitamins you take
• Your medical history, including any previous cancer diagnoses
• Family history of tumors or endocrine disorders
• Questions you want to ask about treatment options
• Information about how symptoms affect your daily activities

Consider bringing a trusted family member or friend to your appointment. They can help you remember important information and provide emotional support during discussions about diagnosis and treatment options.

Don't hesitate to ask questions about anything you don't understand. Your healthcare team wants to help you feel informed and confident about your care plan.

What's the key takeaway about carcinoid syndrome?

Carcinoid syndrome is a manageable condition that responds well to appropriate treatment. While receiving this diagnosis can feel overwhelming, many people with carcinoid syndrome live full, active lives with proper medical care and lifestyle adjustments.

The most important thing to remember is that early diagnosis and treatment make a significant difference in your quality of life and long-term outlook. Working closely with your healthcare team to find the right combination of medications and lifestyle changes can effectively control your symptoms.

Stay connected with your medical team and don't hesitate to reach out if you notice changes in your symptoms or have concerns about your treatment. With ongoing care and attention, you can successfully manage this condition while maintaining your overall health and well-being.