Pulmonary emboli were once thought to cause transudative effusions, but have been recently shown to be exudative. The mechanism for the exudative pleural effusion in pulmonary thromboembolism is probably related to increased permeability of the capillaries in the lung, which results from the release of cytokines or inflammatory mediators (e.g. vascular endothelial growth factor) from the platelet-rich blood clots. The excessive interstitial lung fluid traverses the visceral pleura and accumulates in the pleural space.Conditions associated with transudative pleural effusions include:
Congestive heart failure
Liver cirrhosis
Severe hypoalbuminemia
Nephrotic syndrome
Acute atelectasis
Myxedema
Peritoneal dialysis
Meigss syndrome
Obstructive uropathy
End-stage kidney disease

Exudative
When a pleural effusion has been determined to be exudative, additional evaluation is needed to determine its cause, and amylase, glucose, pH and cell counts should be measured. Red blood cell counts are elevated in cases of bloody effusions (for example after heart surgery or hemothorax from incomplete evacuation of blood). Amylase levels are elevated in cases of esophageal rupture, pancreatic pleural effusion, or cancer. Glucose is decreased with cancer, bacterial infections, or rheumatoid pleuritis. pH is low in empyema (<7.2) and maybe low in cancer. If cancer is suspected, the pleural fluid is sent for cytology. If cytology is negative, and cancer is still suspected, either a thoracoscopy, or needle biopsy of the pleura may be performed. Gram staining and culture should also be done. If tuberculosis is possible, examination for Mycobacterium tuberculosis (either a Ziehl–Neelsen or Kinyoun stain, and mycobacterial cultures) should be done.
Differential
It may not be possible to tell the difference between beta blocker toxicity and calcium channel blocker overdose based on signs and symptoms. Management
The medical management of CCB toxicity may be difficult. It may not improve with the usual treatments used for a low blood pressure and a slow heart rate. In those who have no symptoms or signs six hours following taking an immediate release formulation and 24 hours after taking an extended release formulation need no further medical treatment. Detoxification
Activated charcoal is recommended if it can be given within an hour or two of taking the calcium channel blockers. In those who have taken an extended release formulation of a CCB but are otherwise doing fine, whole bowel irrigation with polyethylene glycol may be useful. Causing vomiting by the use of medications such as ipecac is not recommended. Insulin
High doses of intravenous insulin with glucose may be useful and are a first line treatment in overdoses. As this treatment may cause a drop in blood sugar and blood potassium levels, these should be monitored closely. Other
Intravenous calcium gluconate or calcium chloride is considered a specific antidotes. Slow heart rate can be treated with atropine and sympathomimetics. Low blood pressure is treated with vasopressors such as adrenaline.There is tentative clinical evidence and good theoretical evidence of the benefit of lipid emulsion in severe overdoses of CCBs. Methylene blue may also be used for those with low blood pressure that does not respond to other treatments.