Introduction
Lung diseases affect lung function. Lung diseases can affect airways, tissues, circulation, or a combination. Lung circulation diseases cause clotting, scarring, or inflammation and affect the circulation of the lungs' blood vessels. This results in poor oxygen uptake and causes shortness of breath. This also disrupts heart function.
What Are Lung Circulation Diseases?
The pulmonary arteries and veins are the blood vessels involved in lung (pulmonary) circulation. The body's deoxygenated (oxygen-poor) blood enters the heart's right atrium and is pumped into the right ventricle through the tricuspid valve. Blood from the right ventricle is pumped into the pulmonary artery through the valve. The deoxygenated blood is carried to the lungs by the pulmonary artery. The carbon dioxide is released, oxygen enters during respiration, and the deoxygenated blood is converted into oxygenated blood in the lungs.
The oxygenated blood from the lungs is carried to the heart's left atrium through the pulmonary veins. This oxygenated blood then enters the left ventricle through the mitral valve. The oxygenated blood from the left ventricle then enters the aorta through the aortic valve, is distributed to the body, and the cycle continues. Many conditions like pulmonary hypertension, pulmonary embolism, cardiac shunt, pulmonary shunt, and vascular resistance affect this pulmonary circulation.
What Is Pulmonary Hypertension?
Pulmonary hypertension is when the blood pressure in the pulmonary arteries is increased. The mean arterial pressure is greater than 25 mmHg at rest or greater than 30 mmHg during exercise. Pulmonary arterial hypertension causes the narrowing of the arteries within the lungs. This increases the workload for the heart to pump blood through the narrow arteries to the lungs. The narrowed blood vessels become thicker, and fibrosis occurs over time. This vasoconstriction further increases blood pressure and impairs blood flow.
Pulmonary hypertension increases the workload for the right side of the heart, and the right ventricular muscles do not get enough oxygen due to increased contractility, resulting in right heart failure. Less blood flow to the lungs decreases the blood flow to the left side of the heart. This increases the workload for the left side of the heart to supply oxygenated blood to the body, resulting in left heart failure gradually. Pulmonary venous hypertension is due to left heart failure. Elevated pressure in the left ventricle increases the pressure in the pulmonary veins.
Signs and Symptoms:
The signs and symptoms include:
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Shortness of breath.
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Fatigue.
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Chest pain.
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Increased heartbeat.
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Right-side abdominal pain.
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Poor appetite.
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Swollen legs and ankles.
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Cyanosis (bluish discoloration of the skin).
Treatment:
Pulmonary hypertension cannot be cured, but the treatment slows down the progression of the disease.
Treatment options include:
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Medications are given to treat the symptoms and complications. Vasodilators are given to open the narrowed blood vessels and to improve blood flow. Calcium channel blockers are prescribed to relax the muscles in the walls of the blood vessels. Blood thinners are given to prevent clot formation in the blood vessels. Diuretics are given to remove excess fluid from the body and to reduce the workload on the heart.
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Oxygen therapy is advised to improve the oxygen levels in the blood.
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Surgical procedures like atrial septostomy are done to relieve the pressure on the right side of the heart. Lung or heart-lung transplants are performed in severe cases.
What Is Pulmonary Embolism?
A blood clot (thrombus) from any region of the body, usually the legs, travels to the lungs and blocks the arteries. This blood clot that travels is called emboli, and the process of blocking the arteries is embolism. This blocks the blood flow to the lungs, reduces oxygen levels, and increases pressure in the pulmonary arteries. This can result in heart or lung failure and death if not treated.
Signs and Symptoms:
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Shortness of breath.
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Sharp chest pain.
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Cough with blood or blood-streaked sputum.
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Rapid heartbeat.
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Excessive sweating.
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Dizziness.
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Leg pain and swelling.
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Cyanosis.
Treatment of Pulmonary Embolism:
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Anticoagulants (blood thinners) are the mainstay treatment for pulmonary embolism. This decreases the ability to form clots and prevents the formation of blood clots. Drugs like Warfarin, Heparin, Low molecular weight Heparin, and Fondaparinux are given.
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Compression stockings are given to compress the legs to prevent blood pooling.
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Surgery is done to remove the embolus if other treatments are not effective.
What Is Cardiac Shunt?
A cardiac shunt refers to a deviation in the heart's blood flow pattern. It can be right-left shunt, left-right, bidirectional, systemic-pulmonary, or pulmonary-systemic. A left-to-right shunt occurs when the blood from the left side of the heart enters the right side through a hole in the septum that divides the right and the left heart or through the hole in the walls of arteries leaving the heart. It can be congenital or acquired.
Signs and Symptoms:
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Shortness of breath.
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Fatigue.
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Clubbed fingers.
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Coughing up blood.
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Poor weight gain.
Treatment:
Small shunts do not require treatment. Larger shunts are treated surgically, and the blood flow is redirected.
What Is Pulmonary Shunt?
In a pulmonary shunt, the deoxygenated blood from the right side of the heart enters the left side without undergoing oxygenation in the pulmonary capillaries. This occurs when the alveoli in the lungs are filled with fluid. This reduces the oxygen in the blood and causes hypoxemia.
Treatment:
Treatment varies from person to person. Mild shunts are treated with exercise and positive end-expiratory pressure. Larger shunts require oxygen therapy and mechanical ventilation.
What Is Vascular Resistance?
The resistance offered by the pulmonary circulation to push the blood through the circulatory system to create flow is called pulmonary vascular resistance. Hypoxic vasoconstriction caused due to pulmonary edema, pulmonary emboli, and cardiovascular diseases increase pulmonary vascular resistance. Pulmonary vascular resistance is the main cause of pulmonary hypertension.
Treatment:
Medications like Prostacyclin, inhaled or intravenous, and Prostaglandin E1 are given to treat pulmonary vascular resistance.
Conclusion:
Pulmonary circulation diseases affect the lungs blood vessels and reduce the oxygen level in the blood. The complications are serious and inevitable. Consulting the doctor on experiencing any symptoms is essential to prevent the progression of the disease and further complications. Pulmonary circulation diseases cannot be completely cured, but proper treatment prevents progression and complications.
