The early symptoms of mesothelioma are generally non-specific, and may lead to a delay in diagnosis. Sometimes resembling viral pneumonia, pleural mesothelioma patients may present with shortness of breath, chest pain and/or persistent cough; some patients show no symptoms at all. A chest x-ray may show a build-up of fluid or pleural effusion (discussed below). The right lung is affected 60% of the time, with involvement of both lungs being seen in approximately 5% of patients at the time of diagnosis. Less common symptoms of pleural mesothelioma include fever, night sweats and weight loss. Symptoms of peritoneal mesothelioma may include pain or swelling in the abdomen due to a build-up of fluid, nausea, weight loss, bowel obstruction, anemia or swelling of the feet.