Pulmonary hypertension is a rare, progressive disease that can cause permanent lung damage and failure of the right ventricle of the heart. It is defined as high blood pressure in the pulmonary artery or lung vasculature, and is not directly related to the blood pressure measured by a cuff on the arm. When arteries that supply the lungs constrict and their walls thicken, blood pressure builds up, backs up, and eventually cannot carry as much blood or pick up as much oxygen. This leads to dizziness, shortness of breath, coughing, and fainting among other symptoms that are exacerbated by exertion.
Pulmonary hypertension can be one of five types: arterial, venous, thromboembolic, hypoxic, and miscellaneous. The conventional classification of pulmonary hypertension as primary (of unknown cause) and secondary (due to another medical condition) types has generally been abandoned and should no longer be used.
The most common form of pulmonary hypertension is pulmonary venous hypertension, which develops as a result of a reduction of blood flow downstream of the pulmonary vein, usually due to left-sided heart disease. A symptom that is often experienced by those with pulmonary venous hypertension, and rarely by those with the arterial type is difficulty breathing while lying down (orthopnea or paroxysmal nocturnal dyspnea).
Pulmonary arterial hypertension (PAH) can be idiopathic (of unknown cause), familial (when a family history exists), associated with significant venous or capillary involvement, Persistent Pulmonary Hypertension of the Newborn (PPHN), which has been linked to the antidepressant Zoloft, or Associated Pulmonary Arterial Hypertension (APAH), which is linked to a number of conditions, including those caused by drug use or exposure to certain toxins.
Drugs that have been associated with the onset of pulmonary hypertension include:
- Fenfluramine (Pondimin)
- Other amphetamines
- Chemotherapeutic drugs
To diagnose the disease, the physician may perform a physical examination to look for a loud P2 or pulmonic valve closure sound, parasternal heave, pedal enema, jugular venous distension, hepatojugular reflux, ascites, clubbing, and tricuspid insufficiency among other indicators. To establish the cause, a thorough medical history is conducted and a family history is reviewed to determine if the condition is familial. Cocaine or methamphetamine use is considered significant, as well as alcohol consumption leading to cirrhosis and smoking leading to emphysema.
Treatment is determined by the type (or cause). Usually in cases of pulmonary venous hypertension, the goal is to optimize the function of the left ventricle with diuretics, ACE inhibitors, beta blockers, etc., or by repairing or replacing the mitral or aortic valve. PAH is typically treated with lifestyle changes, diuretics, digoxin, oral anticoagulants, and oxygen therapy.
Other forms of treatment may include lung transplant or drugs such as:
- Calcium channel blockers
- Epoprostenol IV (prostacyclin, treprostinil)
- Nitric oxide inhalation
- Viagra (sildenafil)