Urinothorax is a rare finding that can occur if there is leakage of urine from the urinary tract.
Risk factors:
(1) trauma
(2) surgery or other intervention on the urinary tract (lithotripsy, etc)
(3) rupture in the urinary tract (stone, diverticulum, etc)
Urinary ascites may be present.
The gross appearance and odor may be clues to the diagnosis.
Pleural fluid analysis is important in making the diagnosis:
(1) the ratio of pleural fluid creatinine to serum creatinine is greater than 1 (up to 20)
(2) low pH
(3) low glucose
(4) very high LDH
(5) high UN (usually > 100 mg/dL)
(6) high potassium
