Are there official recommendations for treating pleural effusion?

Depends: The treatment is to the underlying ethiology. Mechanically, if the lung parenchyme is functional, the compression atelectasis by hydraulic compression of the lung will diminish the functional residual capacity of the lungs proportional to the volume of fluid. If the fluid remains for a long time, the lung may get trapped thus requiring decortication if no malignancy present.

Drainage: Pleural effusions that cause symptoms can be drained either with needle aspiration (thoracentesis), with catheter drainage (pgitail), or with tube drainage (chest tube) ... Recurrent pleural effusions can be treated with indwelling pleurx catheter, especially if the lung is trapped and will not re-expand as in malignant effusion, or with thoracoscopic pleurodesis.