Pulmonary veno occlusive disease (PVOD) is a rare complex clinical disease responsible for pulmonary hypertension in the arteries of lungs. This condition in past was referred by various names such as pulmonary venous sclerosis, venous pulmonary hypertension etc. The condition primarily affects the venous system of the lungs.
The exact cause of pulmonary veno occlusive disease is not known but several factors have been implicated such as infection, genetics, blood cancer, chemotherapy etc. The clinical profile of PVOD includes progressive breathlessness on exertion or on lying down, lethargy, dizziness, chronic cough. As the condition gets worse there may be coughing of blood, blue discoloration of skin, pain in chest, frequent fainting episodes.
There is no known treatment yet found for cure of pulmonary veno occlusive disease. However, certain medicines such as vasodilators and steroids are used to reduce the severity of symptoms. The prognosis of PVOD is very poor. Patient may not survive more than 2 years after its detection.
What Causes Pulmonary Veno Occlusive Disease?
Pulmonary veno occlusive disease is characterized by blockage in veins and venules of the lung. In the beginning occlusion may be caused due to swelling of the tissues of vein which later on turns into thick sclerotic fibrous tissue. The exact etiology of pulmonary veno occlusive disease is not known, but most probable causes suspected by medical fraternity are as follows:
- Infection: Viral infection such as cytomegalovirus, Epstein-Barr virus, measles, may cause insult to the internal lining of the pulmonary veins leading to cascade of pathological changes and finally obstruction in the vein. In some cases toxoplasma infection is blamed to be the cause. HIV infection is also suspected to cause PVOD.
- Genetics: Pulmonary veno occlusive disease is seen in siblings thus the risk component of genetic involvement is suspected. The condition may occur in infants as well as children in their teens.
- Toxins: PVOD is reported in many patients after the use of chemotherapeutic medicines. Besides chemotherapy, exposure to environmental chemicals is also linked to cause pulmonary veno occlusive disease. Soda ash, silica, and various other chemicals have been implicated.
- Autoimmune diseases such as lupus, Raynaud disease, scleroderma, rheumatic arthritis are found to be associated with pulmonary veno occlusive disease in few cases.
- PVOD is also known to result in patients suffering from blood cancer such as leukemia and lymphoma.
Symptoms Of Pulmonary Veno Occlusive Disease
Pulmonary veno occlusive disease can occur in an infant as well as adults; it can develop at any age. Males have slight preponderance for this condition. Following are the symptoms and signs of PVOD:
- Breathlessness on exertion. Most patients present with progressive breathlessness on exertion.
- Tiredness and fatigue.
- Bluish discoloration of skin and tongue.
- Chest pain, coughing of blood, fainting spell on exertion occur when pulmonary hypertension is severe. Coughing of blood is not massive or life threatening.
- Difficulty in breathing on lying down. This may be due to collection of fluid in the pleural space of lungs.
- The heart has to work harder for pumping of blood into the lungs due to pulmonary hypertension. As a result the heart muscles fatigue and enlarge eventually leading to congestive heart failure.
Treatment Of Pulmonary Veno Occlusive Disease
X-ray chest, CT scan of chest, echocardiogram, lung function test and blood oximetry test will help to diagnose pulmonary veno occlusive disease.
Currently there is no known treatment to cure pulmonary veno occlusive disease. However, certain medicines such as vasodilators and steroids are used to reduce the severity of symptoms. Steroids are used especially in patients having associated autoimmune diseases and interstitial lung diseases.
Patient is provided with artificial oxygen for a long time due to difficulty in breathing. Lastly lung transplant is found to be the only therapy that can improve and prolong the life of patient.