Radiation Pericarditis

How radiation affects the pericardium

Radiation damages small blood vessels and causes inflammation and later fibrosis (scarring) in the tissues in its path. The pericardium is especially sensitive. The risk depends on:

• the total radiation dose to the heart
• the volume of heart and pericardium in the field
• treatment techniques (older techniques exposed much more of the heart)
• combined chemotherapy, especially anthracyclines
• younger age at treatment

Other radiation-related heart problems, sometimes occurring together, include coronary artery disease, valve disease, heart muscle damage (cardiomyopathy) and rhythm problems.

Types

Acute radiation pericarditis

Develops during or within weeks of treatment, often associated with tumors next to the heart. Causes chest pain and fever, and usually settles.

Delayed pericarditis and pericardial effusion

Occurs months to years after treatment. Fluid builds up around the heart (pericardial effusion). Small effusions may cause no symptoms; large or rapidly accumulating effusions can compress the heart (cardiac tamponade).

Constrictive pericarditis

The pericardium becomes thick, stiff and scarred, sometimes calcified, preventing the heart from filling properly. It develops slowly, often 10 or more years after radiation, and causes signs of right-sided heart failure. See constrictive pericarditis.

Symptoms

• sharp, stabbing chest pain, worse lying flat or breathing deeply, eased by sitting up and leaning forward
• fever (acute form)
• shortness of breath, particularly on exertion or lying flat
• fatigue and reduced exercise tolerance
• swelling of the legs, ankles and abdomen (fluid buildup)
• swollen neck veins
• palpitations

Constrictive pericarditis can be mistaken for liver disease or heart failure from other causes.

Diagnosis

1. History of chest radiotherapy, including dose and dates if available.
2. Examination: a pericardial rub, signs of fluid, raised neck veins.
3. ECG: may show typical pericarditis changes or low voltage with effusion.
4. Echocardiogram: detects effusion, tamponade and signs of constriction.
5. Cardiac MRI or CT: shows thickening, inflammation and calcification of the pericardium.
6. Cardiac catheterization: measures pressures inside the heart to confirm constriction and distinguish it from restrictive cardiomyopathy, which can also follow radiation.
7. Blood tests: inflammatory markers, troponin, and tests to exclude infection or cancer recurrence.
8. Fluid analysis if effusion is drained, to rule out cancer in the pericardium.

Treatment

Acute pericarditis

• Anti-inflammatory medicines such as NSAIDs and colchicine, prescribed and monitored by a doctor.
• Short courses of steroids in selected cases.
• Rest from strenuous exercise until symptoms settle.

Pericardial effusion

• Monitoring for small effusions without symptoms.
• Pericardiocentesis: draining fluid with a needle for large effusions or tamponade.
• Pericardial window: a surgical opening to drain recurring effusions.

Constrictive pericarditis

• Diuretics to reduce swelling and breathlessness.
• Pericardiectomy: surgical removal of the scarred pericardium. It is a major operation, and outcomes after radiation-related constriction are less favorable than for other causes, partly because of associated damage to heart muscle, valves and arteries.

Long-term follow-up

Anyone who had substantial chest radiation, particularly as a child or young adult for Hodgkin lymphoma, should have long-term cardiac surveillance. Cardio-oncology guidance recommends periodic assessment with echocardiography and screening for coronary disease, starting several years after treatment, along with control of blood pressure, cholesterol, diabetes and smoking.

Prevention

Modern radiotherapy uses CT planning, lower doses, smaller fields, breath-holding techniques (for left-sided breast cancer), proton therapy in some cases, and cardiac shielding to keep heart exposure as low as possible.

Frequently asked questions

What is radiation pericarditis?

It is inflammation of the sac around the heart caused by radiation therapy to the chest. It can appear during treatment or many years later, and may cause fluid around the heart or scarring that restricts the heart's filling.

How long after radiation can pericarditis occur?

Acute pericarditis can occur during or within weeks of treatment. Delayed pericarditis and effusions usually appear months to a few years later, and constrictive pericarditis can develop 10 to 20 years or more after radiotherapy.

What are the symptoms of constrictive pericarditis after radiation?

Constrictive pericarditis causes gradually worsening fatigue, breathlessness on exertion, swelling of the legs and abdomen, and swollen neck veins. Symptoms develop slowly and can be mistaken for other heart or liver problems.

Can radiation pericarditis be treated?

Yes. Acute pericarditis is treated with anti-inflammatory medicines. Large effusions can be drained. Constrictive pericarditis may need surgery to remove the scarred pericardium. Long-term heart monitoring is recommended after chest radiotherapy.