Pulmonary Infarction

intensive care
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A pulmonary infarction is the death of a portion of lung tissue caused by an an interruption of its blood supply, most commonly due to blockage in the blood vessels supplying the lung tissue.

Symptoms of Pulmonary Infarction

Symptoms of a pulmonary infarction can be quite variable. Typically a pulmonary infarction is accompanied by hemoptysis (coughing up of blood), fever, dyspnea (shortness of breath), and/or pleurisy-like pain (chest pain in the area of the infarction when drawing a breath).

In some cases, however, a pulmonary infarction will produce next to no symptoms. In fact, an old pulmonary infarction is sometimes diagnosed as an incidental finding when a nodule or mass is seen on a routine chest x-ray.

Causes of Pulmonary Infarction

By far, the most common cause of pulmonary infarction is pulmonary embolism (a blood clot that travels to the lung). However, several other medical conditions can produce a pulmonary infarction, including cancer, autoimmune diseases such as lupus, various infections, sickle cell disease, infiltrative lung diseases such as amyloidosis, or embolization of air or other materials from an intravenous catheter.

Whatever the cause, pulmonary infarction is relatively rare, because lung tissue has three potential sources for oxygen: the pulmonary artery, the bronchial artery (arteries that supply the bronchial tree), and the alveoli themselves (the air sacs within the lungs).

This means that pulmonary infarctions are most commonly seen in people who have significant underlying lung disease, such as chronic obstructive pulmonary disease.

Treatment of Pulmonary Infarction

The treatment of pulmonary infarction includes supportive care, and the management of the underlying condition.

Supportive care includes maintaining adequate blood oxygenation by administering oxygen, and controlling pain to make breathing more comfortable. If adequate blood oxygen cannot be maintained by delivering oxygen by nasal cannula or face mask, the patient may need to be intubated and placed on a ventilator.

Other treatment depends on the suspected underlying cause. Aggressive treatment must be instituted for sickle cell crisis or infection, if those causes seem likely. Treatment should be stepped up (if possible) for any autoimmune disease that has caused the problem, and treatment options need to be reassessed if cancer is the cause.

However, in the large majority of cases pulmonary infarction is caused by a pulmonary embolus. In these cases the treatment includes, in addition to supportive care, the institution of anticoagulant medication, usually with intravenous heparin, followed in a few days by an oral anticoagulant.

However, in cases where the pulmonary embolus is massive and appears to be producing a large pulmonary infarction, or especially if blood flow to the lungs is so compromised that the cardiac output is dropping, it may be necessary to administer fibrinolytic (“clot busting”) drugs to attempt to dissolve the clot that is obstructing blood flow.

The extra risk involved in using such drugs, in these circumstances, is outweighed by the acute risk of death if the clot remains where it is.

And if the situation is dire enough, it may even be necessary to attempt a surgical procedure to remove the obstructing clot.

Sources:

Parambil JG, Savic CD, Tazelaar HD, et al. Causes and presenting features of pulmonary infarctions in 43 cases identified by surgical lung biopsy. Chest 2005 Apr;127(4):1178-83.

Kucher N, Goldhaber SZ. Management of massive pulmonary embolism. Circulation 2005; 112:e28.

Kabrhel C, Jaff MR, Channick RN, et al. A multidisciplinary pulmonary embolism response team. Chest 2013; 144:1738.

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