Hepatic hydrothorax
Hepatic hydrothorax is a rare form of pleural effusion that occurs in people with liver cirrhosis. It is defined as an effusion of over 500 mL in people with liver cirrhosis that is not caused by heart, lung, or pleural disease. It is found in 5-10% of people with liver cirrhosis and 2-3% of people with pleural effusions. It is much more common on the right side, with 85% of cases occurring on the right, 13% on the left, and 2% on both. Although it is most common in people with severe ascites, people with mild or no ascites have had the condition. Symptoms are not specific and mostly involve the respiratory system. The condition is diagnosed based on the existence of liver cirrhosis and fluid build-up in the abdomen (ascites) and analysis of the fluid. The fluid has a low protein content. Mainly, the condition is treated by medical management, such as diet adjustment and usage of diuretics. In cases that do not respond, known as refractory cases, the condition is treated with a transjugular intrahepatic portosystemic shunt (TIPS). The only curative treatment is a liver transplant. Prognosis is usually poor. Symptoms Hepatic hydrothorax has no specific symptoms as it generally occurs with ascites and other manifestations of increased pressure in the portal vein caused by liver disease. Pleural fluid causes symptoms far more easily than ascitic fluid, due to the lower volume of the pleural cavity as compared to the abdominal cavity. The main symptoms are usually related to the symptoms of liver cirrhosis and ascites. Less often, it may be the only manifestation of chronic liver disease. The symptoms depend on many factors, such as the effusion's volume, rate of accumulation, and the co-existence of cardiopulmonary disease. The disease may cause no symptoms and be incidentally detected by medical scans, or it may cause large pleural effusions that result in respiratory symptoms like cough, shortness of breath, low blood oxygen, and respiratory failure. Most people have progressive difficulty breathing and reduced tolerance for exercise. Rarely, there may be acute cases that accumulate fluid rapidly and result in circulatory collapse. In some cases, the main symptoms of people with cirrhosis are respiratory and related to the effusion. Mechanism The disease has no known precise, defined mechanism, but several have been proposed. They are similar to the mechanisms behind ascites in cases of portal hypertension. The most medically accepted mechanism is that low albumin levels in blood reduce osmotic pressure and increase pressure in the azygos vein, causing it to leak plasma into the pleural cavity. The most accepted theory is that fluid originating from ascites travels through defects in the diaphragm into the pleural cavity. These defects exist in the normal population. The defects are usually less than 1 cm and are more common of the right side. The tendency towards the right side could be due to the left side being more muscular and the right side being more tendinous due to the proximity to the liver.