Introduction:
The liver is a unique vital organ located in the right upper quadrant of the abdomen, and it performs more than five hundred endocrine and exocrine functions. The liver is a natural detoxifier that metabolizes drugs and maintains bodily nutrients and balance. The liver acts as a connected series between the portal system and the lungs. Diseased conditions of the liver can affect the systemic circulation of the body. Diseases like hepatomegaly (enlarged liver), cirrhosis (scarring of the liver), and acute hepatitis can increase portal hypertension, resulting in many complications.
What Is Porto-Pulmonary Hypertension?
Pulmonary arterial hypertension (PAH), aggravated by portal hypertension, with or without severe hepatic illness, is known as porto-pulmonary hypertension (POPH). According to the current categorization of pulmonary hypertension, it falls within group 1. It has significant clinical implications while only affecting between two and three percent of those with portal hypertension. According to one study, the incidence of POPH in patients receiving a liver transplant (LT) is 8.5 percent, which is thought to be higher. This condition poses difficulties for patients with liver disease and elevated pulmonary artery pressure that makes transplantation of the liver more dangerous. So, transplantation is contraindicated in this condition.
What Causes Porto-Pulmonary Hypertension?
The pathogenesis of this condition involves endothelial and smooth muscle proliferation, whose cause is unknown. Theories such as genetic predisposition and thromboembolic disease from portosystemic shunts are believed to increase blood flow through the pulmonary system with liver disease.
The main cause of porto-pulmonary hypertension is cirrhosis (scarring of the liver, which leads to liver failure), hepatitis (mainly hepatitis B and C), nonalcoholic steatohepatitis (fat buildup in the liver, which causes inflammation and damage), and chronic alcohol abuse. Other causes that lead to severe liver disease are also responsible for conditions like autoimmune liver disease, parasitic infections, and rare disorders of the liver. Most of the affected individuals do not develop any severe symptoms until they develop jaundice, abdominal swelling, and leg swelling. These chronic liver conditions remain silent until they advance.
What Are the Signs and Symptoms of Porto-Pulmonary Hypertension?
The individual with portopulmonary syndrome usually does not exhibit any symptoms. If they show some, they are:
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Fatigue.
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Generalized weakness (malaise).
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Lightheadedness.
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Orthopnea (shortness of breath in sleeping position).
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Oppressive chest discomfort (squeezing chest pain).
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Tachycardia (shortness of breath), especially while sitting or standing.
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Syncope (fainting or passing out).
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Hemoptysis (bright red blood along with sputum).
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Spider angioma (broken blood vessels under the skin).
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Cirrhosis (an end-stage liver disease that causes scarring).
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Jaundice (yellowish discoloration of the skin, mucous membrane, and eye whites).
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Hepatomegaly (liver swelling).
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Gynecomastia (enlargement of breast glands in men).
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Palmar erythema (conditions which turn hands red).
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Cyanosis (bluish tinge over the skin and lips).
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Clubbing the fingers, the tips of the fingers spread and become rounder than normal.
How Is the Diagnosis Made for Porto-Pulmonary Hypertension?
Diagnostic evaluation is done to rule out potential causes of dyspnea, like other forms of pulmonary hypertension.
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Electrocardiography - General cardiopulmonary screening tests that reveal right atrial and ventricular enlargement, right ventricular strain pattern, and right axis deviation.
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Chest Radiographs - Dilation of pulmonary arteries, as well as enlargement of right-sided chambers, are seen.
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PFT (Pulmonary Function Tests) - Non-invasive tests to check how the lungs are working.
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Lung Scan - A perfusion lung scan is done.
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Arterial Blood Gas - Arterial blood gas values are checked.
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Transthoracic Echocardiogram - As with other kinds of pulmonary arterial hypertension, transthoracic echocardiography (TTE) is the most effective screening test for POPH. Using a TTE, every individual with portal hypertension should be checked for POPH.
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Computed Tomography - To determine whether severe lung disease is present and to create a baseline from which the disease may be tracked over time, a chest CT scan needs to be performed.
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Laboratory Investigations - Serological screening tests for HIV (human immunodeficiency virus), hepatitis, and connective tissue diseases should be part of the laboratory investigation.
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Right Heart Catheterization - Right heart catheterization should be used to provide a definitive diagnosis following the initial TTE screening. Before a liver transplant, right heart catheterization is essential for the detection of POPH since statistics indicate that patients with POPH have a higher chance of dying after a liver transplant. To categorize POPH severity and choose the best course of treatment depending on the disease's severity, the right cardiac catheterization is further crucial.
What Is the Treatment for Porto-Pulmonary Hypertension?
In mild conditions, porto-pulmonary hypertension requires no treatment.
For moderate to severe cases, liver transplantation is done to cure the condition. In some cases, the state disappears within a month of a liver transplant, whereas, in others, it worsens after the transplant over time. The evolution of disease postoperatively is highly unpredictable. Thus, pulmonary vasodilators are recommended with the aim of lowering porto-arterial pressure and minimizing the risk of graft failure.
Some of the vasodilators used are as follows:
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Nitric oxide (NO) is a very effective pulmonary vasodilator when used in inhaled form. Its concentration cannot be titrated without an endotracheal tube. Thus, its administration is restricted to the ICU and operating room in cases of portopulmonary worsening and acute right ventricular failure.
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Epoprostenol (Prostacyclin), a vasodilator used parenterally, also has platelet-inhibiting and antiproliferative effects. The main side effect of this is thrombocytopenia.
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IIoprast (inhaled Prostacyclin), a pulmonary vasodilator, improves exercise tolerance.
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Bosentan (endothelin receptor antagonist).
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Sildenafil (phosphodiesterase inhibitor).
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Beta-blockers and anticoagulants are not indicated in patients with porto-pulmonary hypertension as they worsen the pulmonary hemodynamics and cardiopulmonary reserve.
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In POPH, calcium channel blockers are not advised because they may aggravate portal hypertension.
What Are the Differential Diagnosis of Porto-Pulmonary Hypertension?
Differential diagnoses of Porto-pulmonary hypertension include conditions like:
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Hepatopulmonary syndrome.
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Pulmonary artery hypertension.
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Obstructive sleep apnea.
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Emphysema (lung condition which causes shortness of breath).
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Chronic obstructive pulmonary disease (COPD).
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Congestive heart failure (a state in which the heart muscle fails to pump blood well).
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Alpha-1 antitrypsin deficiency (an inherited condition affecting the lungs and the heart).
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Mitral stenosis (narrowing of the mitral valve).
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Radiation-induced lung disease.
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Drug toxicity.
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Interstitial lung disease (many combined lung disorders that cause scarring of the tissue of the lungs).
How to Take Care of a Patient With Porto-Pulmonary Hypertension?
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Staying active is one of the best care. Walking and regular exercise will help people breathe better and live a healthier life even if they are experiencing breathing difficulties.
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Consult the healthcare provider regarding the best exercise and the duration of the activity that can be followed because some individuals require oxygen support while exercising.
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Include a healthy diet that involves lots of vegetables, fruits, and whole grains, which will help to improve overall health.
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Take plenty of rest; this condition makes people tired, so take a nap and get a good night's sleep.
Conclusion:
Most of the time, porto-pulmonary hypertension is misdiagnosed as hepatic pulmonary hypertension. Both are rare conditions and have different liver complications. Treating the underlying cause helps in managing the condition faster. One good way to deal with this is to consult online with a cardiologist to keep the condition in control. There is no cure for this condition, but its early diagnosis will make the patient's life easier to live with. Patients with porto-pulmonary hypertension show significantly lower hemoglobin levels, right and left ventricular dilation, and high values of many echocardiographic variables as compared to those with pulmonary hypertension. The prognosis of patients with porto-pulmonary hypertension with liver disease is considered poor.
