Before jumping on to the topic that is clinical features of pulmonary hypertension let us know that what is pulmonary hypertension and how it is caused
Right ventricle pumps blood into the pulmonary arteries coming from the body . The pressure of blood in the pulmonary arteries is significantly lower than the pressure in the systemic circulation. But when pressure in the pulmonary circulation becomes elevated, it is referred to as pulmonary hypertension or pulmonary artery hypertension PAH
This usually results from constriction, or stiffening, of the pulmonary arteries that supply blood to the lungs. As a result, it becomes more difficult for the heart to pump blood forward to the lungs. This stress on the heart leads to enlargement of the right ventricle from which eventually fluid can build up in the liver and other tissues, mainly in peripheries.
The main cause of pulmonary hypertension is vasoconstriction of blood vessels of lungs .Over time these blood vessels become more stiffer and thicker by fibrosis, this further increases the blood pressure, as a result of increased blood flow to heart , hypertrophy of right ventricle may be caused , a condition termed as cor pulmonale pulmonary heart disease this effects the efficiency of heart to pump blood at regular rate ,although it may lead to heart failure . Lesser amount of blood circulates in the lungs and this lesser amount of oxygenated blood is received by left side of heart which may lead to severe hypoxia during any physical activity.
While pulmonary venous hypertension and hypoxic pulmonary hypertension differ from pulmonary arterial hypertension in a way that in the former, left heart fails to pump blood effectively leading to pooling of blood in the lungs which causes pulmonary edema and pleural effusion while in later low levels of oxygen trigger a negative response and cause pulmonary arteries to constrict leading to same pathophysiology as in pulmonary hypertension.
Although pulmonary hypertension is considered to be rare disease as per year out of 1million 2-3 individuals are infected. Well the ratio of its incidence is higher in adult females as compared to adult males. The incidence is even higher in patients with pulmonary embolism. In patients with COPD 1.1% individuals develop pulmonary hypertension.
Pulmonary hypertension is classified into two main categories.
1 primary pulmonary hypertension idiopathic
2 secondary pulmonary hypertension due to an under lying disease.
The secondary is more common than primary one.
Another classification is based on the underlying causes, such as:
• drug-induced pulmonary hypertension,
• pulmonary hypertension associated with collagen vascular disease, HIV, and schistosomiasis a parasitic infection, and
• pulmonary hypertension of unknown cause idiopathic pulmonary hypertension
• Pulmonary hypertension due to left ventricular failure
• Pulmonary hypertension due to lung disease and or hypoxia including:
b Sleep apnea
c Pulmonary fibrosis or
d Living at high altitudes
Pulmonary hypertension caused due to clotting disorders e.g. pulmonary emboli , pulmonary thrombosis, known as Chronic Thromboembolic Pulmonary Hypertension;
• Pulmonary hypertension due to miscellaneous causes including diseases such as:
metabolic disorders glycogen storage disease
Primary pulmonary hypertension has no identifiable causes it is also referred to as idiopathic pulmonary hypertension. While this is more common in young people and in females than males.
Genetic causes of primary pulmonary hypertension have been discovered now. It‘s known that it is caused by mutations in a gene called BMPR2. BMPR2 that encodes a receptor that is present on the surface of cells
As pulmonary hypertension is referred to as increase in blood pressure mainly affecting the pulmonary arteries and veins, respectively. This elevated blood pressure in the lungs vasculature leads to shortness of breath, dizziness, tiredness and fainting although these effects can be exuberated by exertion and the patient may suffer from decreased exercise tolerance or ultimately heart failure Persons suffering from pulmonary hypertension are vulnerable to such symptoms upon exercise.
Usually symptoms of pulmonary hypertension develop gradually and in this way the patient might feel a need to visit the physician for general symptoms for many years.
Well relatively common symptoms of pulmonary hypertension that have been observed in patients include fatigue, syncope fainting, dyspnea shortness of breath , basically it reflects difficulty in taking deep breaths , peripheral edema swelling around feet and ankles angina pectoris chest pain may also be relatively observed that radiates to both arms and back of shoulder while very rarely hematopysis blood in sputum is seen .
Among the above common symptoms dyspnea is usually felt when the patient lays down flat or is asleep , referred to as a condition known as orthopnea or paroxysmal nocturnal dyspnea that is opposite to platypnea , this results when fluid has accumulated in the lungs and difficulty in breathing occurs when the person lays down or sleeps. In order to measure severity of orthopnea it is taken in account that how many pillows you use to prop the body to enable breathing.
To determine the actual cause of pulmonary hypertension proper diagnosis is necessary. A detailed family history is too established to know whether the cause is familial heredity or not. While for a pharmacist it is also necessary to develop a history of drugs which were being used by the patient in the past or are currently being used by the patient. Although drugs such as cocaine, methamphetamine and alcohol can lead to cirrhosis and tobacco can lead to emphysema so these effects caused by the use of such drugs are considered significant.
Although a series of tests are required to distinguish pulmonary arterial hypertension from its relative, pulmonary venous hypertension, hypoxia and underling thromboembolic disorders.
Initially when a patient approaches a physician, physical examination is performed to check for typical signs of pulmonary hypertension. The major physical parameters involve altered heart sounds that include widely split S2 second heart sound with a loud P2 pulmonic valve closure sound pulmonic valve is a semilunar valve that lies at the conjunction of pulmonary artery with right ventricle. Semilunar valves are the valves present in arteries leaving the heart. Other parameters of physical examination are sternal heaves, possible S3 or third heart sound. Other sounds may include an elevated jugular venous pressure due to which the jugular vein markedly appear swollen on the neck, this an alarming sign of hypertension , pulmonary regurgitation which is basically the backflow of blood from pulmonary artery via pulmonic valve in the right ventricle during diastole , peripheral edema accumulation of fluid in the peripheries especially the ankle and feet this usually results as the blood coming from the vena cava into the heart has not been actively transported to the lungs this delayed action results in accumulation of fluid in peripheries, due this same reason ascites can occur that is accumulation of fluid in the peritoneal cavity of abdomen .
Another important way of diagnosis is the hepatojuglar reflex its an alternative way of determining juglar venous pressure JVP. For this purpose the physician firmly presses the right upper quadrant of abdomen for 10-60 sec with a pressure of 20-35 mmHg while observing juglar vein in the neck. Negative abdomino-juglar reflex is observed with a lack of swelling in the jugular vein, while a positive result is seen with a rise in juglar venous pressure and an increase of 4cm may be observed.
Clubbing is also a vital sign of pulmonary hypertensive patients, other common names of clubbing are also used such as Drumstick fingers, Hippocratic fingers or Watch glass nails, this condition is demonstrated as swelling of fingers.
Further procedures have also been helpful to confirm presence of pulmonary hypertension and to exclude diagnosis of other possible diseases these procedures usually include pulmonary function test: blood tests are done to exclude infectious diseases such as HIV or autoimmune diseases, liver disease; ECGelectrocardiography is also done. Arterial blood gas is also an effective procedure to determine gas exchange levels in blood related to lung function, this test basically gives detail of partial pressures of carbon dioxide and oxygen in blood. Along with it X-ray of lung is done followed by CT scan if interstitial lung disease is suspected, a ventricular –perfusion or V/Q scan test is also carried out to exclude thromboembolic state.
Biopsy is not suggested until it is known that pulmonary hypertension is due to interstitial lung disease. Some physicians suggest a 6 min. walk test for their patients in initial diagnose of these of the disease, for the purpose the patient the patient is asked to walk for a specified time that is 6 min. in order to check that the patient can walk properly or not for this much time with shortness of breath, by this the physician can better correlate survival of patient.
Blood BNPBrain Natriuretic Peptide level is also checked , this peptide is produced by ventricles at the phase of excessive stretching of heart muscle cells cardiomyocytes to decrease systemic vascular resistance and central venous pressure, at the same time increase natriuresis ; on the other hand it is an potent indicator of pulmonary hypertension.
Treatment is based on the diagnosis that whether it is arterial, venous, hypoxic, thromboembolic or miscellaneous. Lifestyle changes are recommended along with medicaments while oxygen therapy is used in emergency conditions. The goals of treatment for pulmonary hypertension is to treat the underlying cause, to reduce symptoms improve quality of life and the development of blood clots also to increase the supply of blood and oxygen to the heart, while reducing the workload.
Treatments strategies involve medications, oxygen, and lung transplant.
Following are the medications for pulmonary hypertension:
anticoagulants e.g. Aspirin, heparin, warfare are helpful in resolving clots and further prevention of clots in thromboembolic disease.
calcium channel blockers ,relax blood vessels and increase the blood supply and oxygen to the heart, while reducing the workload;
continuous intravenous infusion of epoprostenol prostacyclin (derived from PGI2 is currently considered most effective therapy it widens the lung arteries by acting as vasodilator and prevents blood clot by inhibiting platelet activation.
(treprostinilanother prostacyclin has more or less the same effects the former
(bosentan, a dual ETA and ETB endothelin receptor antagonist new drug for treatment that also widens the lung arteries and decreases blood pressure by blocking to the endothelin receptors and producing anticoagulant effect.
nitric oxide inhalers, are also helpful in widening pulmonary arteries .
(Viagra sildenafil it causes the pulmonary arteries to widen
diuretics which help to reduce edema and improve the heart's performance.