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| Pulmonary hypertension can be ''primary'' (occurring without an obvious cause) or ''secondary'' (a result of other disease processes.) | 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 ]. It |
'''Primary pulmonary hypertension''' (PPH) is considered a ]. It has been linked to mutations in the ''BMPR2'' gene, which encodes a ] for bone morphogenic proteins (Deng ''et al'', ]), as well as the ''5-HT(2B)'' gene, which codes for a ] receptor (Blanpain ''et al'', ]). However, it is not understood what roles these genes play in PPH. | ||
| 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 ] attributable to the abnormal thickening of the vessel wall and narrowing of the ] of ]s in the lungs. Recently, characteristic proteins of ] 8 (also known for causing ]) were identified in vascular lesions of PPH patients (Cool ''et al'', 2003). | |||
| ⚫ | ''Secondary pulmonary hypertension'' (SPH) is often due to ] (COPD). Other factors that have been linked to secondary pulmonary hypertension are: | ||
| ⚫ | '''Secondary pulmonary hypertension''' (SPH) is often due to ] (COPD). Other factors that have been linked to secondary pulmonary hypertension are: | ||
| * ] featuring left-right shunting | * ] featuring left-right shunting | ||
| ** ] is reversal of the shunt due to pulmonary hypertension | ** ] is reversal of the shunt due to pulmonary hypertension | ||
Revision as of 02:49, 30 May 2004
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.
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.
Clinical improvement is often measured in a "six-minute walking test", i.e. the distance a patient can walk in six minutes.
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. Although pulmonary artery pressure can be estimated on the basis of echocardiography, pressure sampling with a Swan-Ganz catheter provides the most definite measurement.
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. It has been linked to mutations in the BMPR2 gene, which encodes a receptor for bone morphogenic proteins (Deng et al, 2000), as well as the 5-HT(2B) gene, which codes for a serotonin receptor (Blanpain et al, 2003). However, it is not understood what roles these genes play in PPH.
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, characteristic proteins of human herpesvirus 8 (also known for causing Kaposi sarcoma) were identified in vascular lesions of PPH patients (Cool et al, 2003).
Secondary pulmonary hypertension (SPH) is often due to chronic obstructive pulmonary disease (COPD). Other factors that have been linked to secondary pulmonary hypertension are:
- congenital heart disease featuring left-right shunting
- Eisenmenger's syndrome is reversal of the shunt due to pulmonary hypertension
- pulmonary embolism
- pulmonary fibrosis
- systemic sclerosis
- portal hypertension (the "hepatopulmonary syndrome")
- sarcoidosis
- asthma
- AIDS
- sickle-cell anemia (Gladwin et al, 2004)
- hypothyroidism (Curnock et al, 1999)
- obesity
- use of appetite suppressants (e.g. Fen-phen, see Abenhaim et al, 1996)
A common consequence of 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. Oedema and fluid retention follow.
Epidemiology
Women are almost twice as likely to present with PPH than men.
Treatment
Treatment is determined by the condition underlying the cause of the hypertension. For instance, long term oxygen therapy has been proven to be useful in patients with chronic obstructive pulmonary disease, and when the pulmonary hypertension is due to chronic thromboembolism, pulmonary endarterectomy can be performed.
In PPH, lifestyle changes, digoxin, diuretic, oral anticoagulants, oxygen therapy and vasodilators are the mainstays of treatment. Synthetic prostacyclin (an eicosanoid) per continuous infusion is tried occasionally in some types of pulmonary hypertension.
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).
References
- Abenhaim L, Moride Y, Brenot F et al. Appetite-Suppressant Drugs and the Risk of Primary Pulmonary Hypertension. N Engl J Med 1996;335:609-16. Abstract.
- Cool CD, Rai PR, Yeager ME, Hernandez-Saavedra D, Serls AE, Bull TM, Geraci MW, Brown KK, Routes JM, Tuder RM, Voelkel NF. Expression of Human Herpesvirus 8 in Primary Pulmonary Hypertension. N Engl J Med 2003;349:1113-22.
- Curnock AL, Dweik RA, Higgins BH, Saadi HF, Arroliga AC. High prevalence of hypothyroidism in patients with primary pulmonary hypertension. Am J Med Sci. 1999;318:289-292.
- Deng Z, Morse JH, Slager SL, et al. Familial primary pulmonary hypertension (gene PPH1) is caused by mutations in the bone morphogenetic protein receptor-II gene. Am J Hum Genet 2000;67:737-44.
- Gladwin MT, Sachdev V, Jison ML, Shizukuda Y, Plehn JF, Minter K, Brown B, Coles WA, Nichols JS, Ernst I, Hunter LA, Blackwelder WC, Schechter AN, Rodgers GP, Castro O, Ognibene FP. Pulmonary Hypertension as a Risk Factor for Death in Patients with Sickle Cell Disease. N Engl J Med 2004;350:886-95.