Pulmonary infarction is the death of lung tissue (necrosis) that occurs when its blood supply is cut off. This condition is not a primary disease but a serious complication arising from another health problem. A pulmonary infarction represents a significant disruption to the lung’s function and requires prompt medical attention.
Causes of Pulmonary Infarction
The most frequent cause of a pulmonary infarction is a pulmonary embolism (PE), when an object, usually a blood clot, lodges in one of the lung’s arteries. These clots most often originate as a deep vein thrombosis (DVT) in the legs or pelvis. When a piece of this clot breaks free, it becomes an embolus, traveling through the heart and into the pulmonary circulation where it can block blood flow.
Not every pulmonary embolism results in an infarction because the lungs have a dual blood supply from the pulmonary and bronchial arteries. This redundancy means that if a pulmonary artery is blocked, the bronchial circulation can often keep the tissue alive. Infarction is more likely when a smaller artery is obstructed or in individuals with pre-existing conditions like heart failure or chronic lung disease, which may have already compromised their circulation.
Several factors increase the risk of developing blood clots. Prolonged immobility, such as during long-distance travel or recovery from surgery, can cause blood to clot in the veins. Other risk factors include certain types of cancer, smoking, obesity, pregnancy, and the use of estrogen-containing medications. Some individuals may also have inherited genetic disorders that make their blood more prone to clotting.
Symptoms and Diagnostic Process
A primary symptom is sharp, stabbing chest pain that intensifies with deep breathing or coughing, known as pleuritic chest pain. This pain occurs because the infarction may extend to the outer surface of the lung, irritating the sensitive lining between the lungs and the rib cage.
Another common symptom is dyspnea, or shortness of breath. Coughing is also prevalent and may be accompanied by hemoptysis, the coughing up of blood. In some cases, a low-grade fever and a rapid heart rate may develop as the body responds to the tissue injury.
Diagnosing a pulmonary infarction involves a clinical evaluation and specialized testing. The most definitive imaging test is a computed tomography pulmonary angiography (CTPA) scan. This procedure involves injecting a contrast dye and using a CT scanner to create images that can reveal blockages in the pulmonary arteries and identify infarcted tissue. A D-dimer blood test may also be used; it measures a substance released when blood clots break down, though it is less specific.
Medical Treatment Strategies
Treatment for pulmonary infarction is focused on managing the underlying pulmonary embolism to prevent the clot from growing and new clots from forming. The primary therapy is the use of anticoagulant medications, known as blood thinners. Drugs such as heparin and oral anticoagulants like warfarin or newer direct oral anticoagulants (DOACs) are prescribed. These medications do not dissolve the existing clot but are effective at preventing further complications.
For patients with a massive pulmonary embolism that causes severe symptoms, more aggressive treatments may be necessary. Thrombolytic therapy, which involves administering “clot-busting” drugs like alteplase, can rapidly dissolve the blockage. These medications carry a higher risk of bleeding and are reserved for life-threatening situations. In other cases, a procedure may be performed to physically remove the clot, either through a catheter-directed therapy or a surgical embolectomy.
Supportive care is also provided to manage symptoms. Patients often receive supplemental oxygen to alleviate shortness of breath and ensure the body’s tissues are adequately oxygenated. Pain medication is also administered to control the pleuritic chest pain.
Recovery and Long-Term Outlook
The recovery period involves the body’s natural healing processes. The damaged lung tissue does not regenerate; instead, over weeks to months, it is replaced by scar tissue. This scar tissue is permanent but in most cases of smaller infarctions, it does not cause long-term breathing problems.
The prognosis for individuals is positive, provided the underlying pulmonary embolism is diagnosed and treated quickly. Long-term management is focused on mitigating the risk of recurrence. This involves continuing anticoagulant therapy for at least three to six months, and sometimes indefinitely, depending on the individual’s specific risk factors.
Patients are also counseled on managing modifiable risk factors. This may include lifestyle changes such as smoking cessation, weight management, and staying active to prevent venous stasis. For some, pulmonary rehabilitation programs involving structured exercise and breathing techniques can help improve lung function. Regular follow-up with a healthcare provider is necessary to monitor the effects of treatment and adjust the plan as needed.