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Revision as of 09:05, 28 May 2004 by Jfdwolff (talk | contribs) (Changed structure, added some stuff)(diff) ← Previous revision | Latest revision (diff) | Newer revision → (diff)In medicine, pulmonary hypertension is an increase in arterial blood pressure in the pulmonary artery or lung vasculature. Dependant on the cause, it can be a severe disease with a markedly decreased exercise tolerance and right-sided heart failure.
Signs and symptoms
A history usually reveals gradual onset of shortness of breath, fatigue, angina pectoris, syncope (fainting) and peripheral edema.
Women are almost twice as likely to present with PPH than men. Obesity and the use of appetite suppressants (e.g. Fen-phen) are among the risk factors.
In order to establish the cause, the physician will generally conduct a thorough medical history and physical examination. A detailed family history is taken to determine whether the disease might be familial.
Diagnosis
Diagnostic tests generally involve blood tests, electrocardiography, arterial blood gas measurements, X-rays of the chest (generally followed by high-resolution CT scanning). A biopsy of lung tissue, angiography with endoluminal biopsy of the pulmonary artery, or biopsy of any associated skin lesions, is often attempted to obtain tissue for histopathological investigation.
Causes and mechanism
Normal pulmonary arterial pressure in a person living at sea level has a mean value of 12-16mmHg. Definite pulmonary hypertension is present when mean pressures exceed 30-20mmHg.
Pulmonary hypertension can be primary (occurring without an obvious cause) or secondary (a result of other disease processes.)
- Primary pulmonary hypertension (PPH) is considered a genetic disorder. Patients usually have no symptoms until they reach their late twenties or early thirties. PPH is very rare but often fatal. It is characterized by elevated pulmonary vascular resistance attributable to the abnormal thickening of the vessel wall and narrowing of the lumen of arterioles in the lungs. Recently, human herpesvirus 8 (also known for causing Kaposi sarcoma) was linked to PPH
- A very common cause of secondary pulmonary hypertension (SPH) is chronic obstructive pulmonary disease (COPD). Many other disease processes such as pulmonary embolism, pulmonary fibrosis, sarcoidosis and asthma are also known to result in SPH. Sickle-cell anemia, hypothyroidism
A common association with chronic pulmonary hypertension is cor pulmonale (right sided heart failure) believed to be caused by the increased load on the right ventricle and atrium of the heart. A chest radiograph (x-ray) will often reveal an enlarged right atrium and ventricle, and prominent pulmonary arteries. An ECG will often demonstrate right ventricular hypertrophy or strain.
Treatment
Treatment is determined by the condition underlying the cause of the hypertension. For instance, long term oxygen therapy can be useful in patients with obstructive lung disease. In PPH, lifestyle changes, digoxin, diuretic, oral anticoagulants, oxygen therapy and vasodilators are the mainstays of treatment.
When the pulmonary hypertension is due to chronic thromboembolism, pulmonary endarterectomy can be performed.
Prognosis
Several studies have reported a mean survival of 2-3 years from time of diagnosis with the cause of death usually being right ventricular failure (cor pulmonale).
External links
- The Merck Manual of Diagnosis and Therapy: Cor Pulmonale
- The Pulmonary Hypertension Association
- Facts About Primary Pulmonary Hypertension from the National Heart, Lung, and Blood Institute (NHLBI)
- Appetite-Suppressant Drugs and the Risk of Primary Pulmonary Hypertension, in NEJM, by Abenhaim, L. et al., 1996.