Definition

Pulmonary infarction (PI) occurs when blood flow to a portion of the lung tissue is blocked, causing the tissue to die. PI typically affects only one side of the lung. This is thought to be due to gravity's influence on the pulmonary blood vessels. However, studies have only found that PI is more common in the right lower lung, and the reason for this is unknown. A lung infarction indicates a serious underlying disease that requires further evaluation and treatment.

Causes

A lack of blood flow to lung tissue will result in a reduced supply of oxygen to the lungs. This blood flow delivers the oxygen and nutrients that the tissues require to function. n. If the tissue continues to be deprived of blood flow, tissue death will occur. Dead lung tissue will be replaced by stiff connective tissue.

PI is typically a complication of another disease, with pulmonary embolism being the most common cause. A pulmonary embolism can result in a blockage in pulmonary blood flow. Pulmonary infarction affects 10-15% of people who have pulmonary embolisms. Pulmonary embolism itself is usually caused by a blood clot in a leg vein (deep vein thrombosis) that travels to the pulmonary artery.

In addition to pulmonary embolism, other diseases that can cause pulmonary infarction by forming blockages in the pulmonary blood vessels are:

• Infections
• Malignancy or cancer
• Complications of surgery
• Amyloidosis, a serious condition that makes it difficult for organs and tissues to work properly, due to the build-up of an abnormal protein (amyloid) throughout the body
• Sickle cell anemia, a blockage of blood vessels by sickle-shaped red blood cells, and when it occurs in the pulmonary blood vessels it can cause pulmonary infarction
• Vasculitis or inflammation of blood vessels, inflammation that occurs in the pulmonary blood vessels can cause pulmonary infarction
• Embolism by air or other material that enters the blood vessels through the infusion

Risk Factor

Factors that can increase the risk of a lung infarction are:

• Smoking is associated with an increased incidence of diseases that can lead to pulmonary infarction
• Young adults (peak age is 40 years)
• Individuals with heart disease usually have impaired blood flow, making them more susceptible to forming blood clots
• Cancer
• Injection drug abuse

Meanwhile, risk factors for developing pulmonary embolism include:

• Recent history of surgery and postoperative bed rest
• Heart disease
• Dehydration
• Obesity
• Use of estrogen, usually in birth control pills
• Pregnancy
• Nephrotic syndrome, (when kidneys excrete protein through the urine)
• Autoimmune diseases, such as lupus

Symptoms

Symptoms of pulmonary infarction vary from person to person, depending on the size and location of the infarct. The larger the death of lung tissue, the more severe the symptoms will be. This is also true if the infarct causes damage to the lung lining (pleura). However, most Pulmonary infarctions are caused by a small pulmonary embolism, which results in a small infarct. In this case, symptoms may be mild or even asymptomatic.

In general, the symptoms of pulmonary infarction include:

• A sense of floating
• Fever
• Cough that may be accompanied by blood
• Severe shortness of breath, usually sudden
• Chest pain, usually felt when inhaling
• Continuous burping (rare)
• Weakness

These symptoms are also common in pulmonary embolism, whether or not it resulted in pulmonary infarction. However, symptoms such as coughing up blood or chest pain are a strong indicator that pulmonary infarction has occurred.

Diagnosis

In most cases, pulmonary infarction is discovered accidentally during an examination to look for pulmonary embolism. Doctors will suspect pulmonary infarction in people who have been diagnosed with pulmonary embolism if they have symptoms such as coughing up blood or chest pain, or if a physical examination reveals signs of a large pulmonary emboli. This condition is characterized by rapid breathing, rapid heartbeat, and excessive sweating. An infarction that affects the pleural membranes will also produce a scraping sound. If these signs are not found, PI will most likely go undiagnosed.

Diagnostic tests that can be done to help confirm the diagnosis are:

• Electrocardiogram (ECG)
• D-dimer blood test
• Ventilation/perfusion scan
• Echocardiogram

Meanwhile, typical imaging techniques include chest X-rays and CT scans. A lung X-ray is the first test that detects the presence of a lung infarction, followed by a CT scan to confirm the diagnosis.

Management

A pulmonary infarction can cause shock from blood clots in pulmonary embolisms or collapse of the heart-lung system due to a lack of oxygen. The first step in managing pulmonary infarction is to manage this emergency, which is usually characterized by shortness of breath and a drop in blood pressure. The initial treatment is to support the heart and lungs by providing oxygen and pain relief. If oxygen administration through a nasal tube or facial oxygen mask does not increase blood oxygen levels sufficiently, intubation and ventilator insertion may be required. Once the emergency has been managed successfully, the next step is to treat the conditions that caused the lung infarction.

The first line of treatment for pulmonary infarction caused by a pulmonary embolism is to give blood thinners. The doctor will consider administering blood thinners based on each patient's condition, taking into account the risk of bleeding if blood thinners are given.

If a severe pulmonary embolism causes a large pulmonary infarction or if blood flow to the lungs is severely disrupted to the point where it interferes with the heart, a blood clot removal procedure known as fibrinolytic therapy may be performed. This can be done with a catheter (small flexible tube), medication, or surgery.

Complications

Long-term complications are rarely seen in small-area lung infarctions. Large infarctions, on the other hand, can cause extensive lung tissue death and result in long-term and potentially fatal symptoms.

However, large lung infarctions are uncommon because lung tissue receives oxygen from three sources: pulmonary blood vessels, bronchial blood vessels, and air sacs (alveoli) within the lung. This means that life-threatening lung infarctions are more common in people with serious illnesses like heart failure and chronic obstructive pulmonary disease (COPD).

Prevention

Pulmonary infarction prevention aims to reduce the risk factors associated with it, particularly those associated with pulmonary embolism, which is the most common cause. The prevention methods include:

• Moving soon after surgery or injury, and should be supervised by a doctor
• Wearing stockings to improve leg blood circulation
• Take blood-thinning medications as directed by the doctor, and do not stop or reduce the dose without consulting first
• Stop smoking, as smoking may increase the risk of pulmonary infarction

When to See a Doctor?

Shortness of breath and chest pain are signs that you should seek medical attention. Do not delay seeing a doctor because a lung infarction can spread and be fatal if not treated.

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