B. Constrictive pericarditis is a cause of ascites.
Serum-ascites albumin gradient or SAAG of 1.1 g/dL or greater with an ascitic fluid total protein level of 2.5 g/dL (25 g/L) or greater indicates a cardiac cause of ascites.
Constrictive pericarditis is the most likely cause in this case. The patient has history of previous cardiac surgery, which is a risk factor for constrictive pericarditis. The ascitic fluid analysis should always include measurements of both albumin and total protein, complete cell count with percent neutrophils, and bacterial cultures if infection is suspected. The serum-ascites albumin gradient (SAAG) is calculated by subtracting the ascitic fluid albumin level from the serum albumin level. SAAG of 1.1 g/dL or greater with an ascitic fluid total protein level of 2.5 g/dL (25 g/L) or greater points toward a cardiac cause of ascites. This patient's lab results meet both of these criteria, making a cardiac cause for his ascites likely. Over 90% of patients with constrictive pericarditis have jugular venous distention and clear lungs on examination. Other less common findings include Kussmaul sign (rise in jugular pressure on inspiration), paradoxical pulse, and a pericardial knock on cardiac auscultation.
Patients with cirrhosis, portal hypertension, and resultant ascites will also have a SAAG greater than 1.1 g/dL, but the ascitic fluid total protein level will be less than 2.5 g/dL. Therefore, causes of cirrhosis such as alcoholic and nonalcoholic are less likely in this patient's ascites.
Tuberculous peritonitis is very uncommon and is associated with a SAAG less than 1.1 g/dL with an ascitic fluid total protein level greater than 3 g/dL. Additionally lymphocytic predominance in the cell count with differential is found with Tuberculous peritonitis. Although the high ascitic fluid total protein level is above 3 g/dL and the SAAG is greater than 1.1 g/dL, there is no predominance of lymphocytes on the ascitic fluid cell count. This excludes tb peritonitis as a likely diagnosis.
Reference
Gordon FD. Ascites. Clin Liver Dis. 2012 May;16(2):285-99. PMID: 22541699
