Karen L. Krok; Andrés Cárdenas

Disclosures

Semin Respir Crit Care Med. 2012;33(1):3-10. 

In This Article

Diagnosis

The diagnosis is based on the presence of cirrhosis with portal hypertension and the exclusion of cardiopulmonary disease. The majority of effusions can be seen on a frontal chest x-ray, although sometimes a lateral chest x-ray is needed as well.

A thoracentesis should be performed to exclude a primary cardiopulmonary process. In a study of 60 cirrhotic patients admitted to the hospital with pleural effusions,[21] 70% (42 patients) were found to have an uncomplicated hepatic hydrothorax (without infection, blood or pus). Of the other 18 patients, nine had spontaneous bacterial empyema, two had pleural tuberculosis, two had adenocarcinoma, two had parapneumonic effusion, and three were undiagnosed exudates. When the effusion was right sided, 80% were an uncomplicated hepatic hydrothorax; but when the effusion was left-sided only 35% were an uncomplicated hepatic hydrothorax. Hence the presence of a left-sided pleural effusion in a cirrhotic patient should not be assumed to be an uncomplicated hepatic hydrothorax. Pleural fluid analysis is mandatory.

Diagnostic tests to be ordered on the pleural fluid include cell count, Gram stain and culture in blood culture bottles, and serum and fluid protein, albumin, and lactate dehydrogenase (LDH).[6,17] The composition of hepatic hydrothorax is transudative in nature and therefore similar to the ascitic fluid; it will also have a serum to pleural fluid albumin gradient greater than 1.1 as is found in ascites secondary to portal hypertension. Other tests from the pleural fluid that would be appropriate depending on the clinical circumstances include triglycerides, pH, adenosine deaminase and polymerase chain reaction (PCR) for mycobacteria, amylase, and cytology to exclude chylothorax, empyema, tuberculosis, pancreatitis, and malignancy, respectively. These additional tests should be considered when the fluid is an exudate or when the pleural effusion is left sided.

The characteristics and the interpretation of pleural fluid in hepatic hydrothorax are described in Table 1. In uncomplicated hepatic hydrothorax the polymorphonuclear cell count is less than 500 cells/mm3, and the total protein concentration is less than 2.5 g/dL.[17,29] LDH levels are also low consistent with a transudate. Total protein and albumin may be slightly higher in hepatic hydrothorax compared with levels in the ascitic fluid.[11,30] Diuresis can also increase the total protein levels in the fluid that is sampled. When uncertainty exists regarding the etiology of the pleural effusion, the finding of an elevated serum soluble Fas ligand may help distinguish a hepatic hydrothorax from one resulting from heart failure in patients with viral hepatitis.[31]

In addition to pleural fluid analysis, other tests may also be important and informative. Pertinent laboratory tests such as a basic metabolic panel, hepatic panel, prothrombin time, and brain natriuretic peptide (BNP) should be obtained in the proper clinical setting. In addition, a computed tomographic (CT) scan of the chest will exclude mediastinal, pulmonary, or pleural lesions or malignancies. Echocardiography should be performed to evaluate cardiac function.

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