Congestive Heart Failure (CHF): This is often the most common cause of bilateral pleural effusions due to the increased pressure in the pulmonary veins leading to fluid leakage into the pleural space.

Nephrotic Syndrome: Significant protein loss in the urine can lead to hypoalbuminemia, reducing oncotic pressure and causing fluid to accumulate in the pleural space.
Pulmonary Embolism: While more commonly associated with unilateral effusions, bilateral pleural effusions can occur, especially if there are multiple emboli.
Cirrhosis with Hepatic Hydrothorax: Fluid can accumulate in the pleural space due to the increased pressure in the hepatic veins and the movement of fluid from the peritoneal cavity to the pleural space.
Lymphoma: Both Hodgkin's and non-Hodgkin's lymphoma can cause bilateral pleural effusions due to direct involvement of the pleura or secondary to lymphatic obstruction.

Malignant Pleural Effusion: Various cancers (e.g., lung, breast, ovarian) can metastasize to the pleura, causing effusions. Missing this diagnosis could significantly impact treatment and prognosis.
Tuberculosis (TB): Especially in endemic areas, TB can cause pleural effusions. It's crucial to consider TB due to its public health implications and the need for specific treatment.
Pulmonary Arterial Hypertension: This condition can lead to right heart failure, resulting in bilateral pleural effusions. Early diagnosis is critical for managing this condition.

Lymphangioleiomyomatosis (LAM): A rare lung disease that primarily affects women, leading to the growth of abnormal smooth muscle-like cells in the lungs, which can cause pleural effusions.
Yellow Nail Syndrome: Characterized by yellow discoloration of the nails, lymphedema, and pleural effusions, this syndrome is very rare and often diagnosed after excluding other causes.
Uremic Pleurisy: In patients with end-stage renal disease, uremic pleurisy can cause pleural effusions. This diagnosis is considered when other causes are ruled out in the context of severe renal impairment.