Encysted pleurisy. Coloured frontal chest X-ray of the lungs of a patient with encysted pleurisy. Pleurisy is the inflammation (right) of the membranes that line the chest cavity and lungs (the pleura). Inflammation causes the lungs to rub against the chest wall, resulting in sharp pain on breathing. Fluid may accumulate in the space between the membranes (pleural effusion), leading to breathing difficulties. Adhesions can arise between the membranes, trapping the effusion. This is symptomatic of encysted pleurisy. Treatment is of the underlying cause, which may be a bacterial or viral infection, cancer or an embolism. Accumulated fluid can be drained surgically.