Urinothorax - Causes, Symptoms, Diagnosis, and Management

Introduction:

Urinothorax is a rare cause of pleural effusion due to peritoneal and retroperitoneal leakage, which causes an accumulation of urine within the pleural cavity. It can occur due to ureteric obstruction or retro-ureteric trauma, including iatrogenic injury from percutaneous or ureteroscopic manipulation and extracorporeal shock wave lithotripsy. It is mostly ipsilateral to the obstructed urinary tract. It has no gender predilection; it can occur in both genders equally.

There is no age predilection as well. There are two possible routes for the urine to accumulate within the pleural cavity: lymphatic drainage due to increased retroperitoneal or intraperitoneal pressure caused by urinoma and direct leakage into the mediastinum by rupture into the pleural cavity. Urinomas classically arise from obstructive uropathy, trauma, or iatrogenic injury to the urogenital system. In addition, there is also a possibility of direct movement of abdominal fluids into the pleural cavity through defects in the diaphragm.

What Are the Causes of Urinothorax?

The etiologies of urinothorax are mentioned below;

Obstructive Urinothorax:

• Prostate disease.

• Bladder carcinoma or metastatic involvement.

• Urethral valves.

• Gravid uterus.

• Supernumerary kidney.

• Retroperitoneal fibrosis.

• Renal cyst.

• Right hydronephrosis with movable obstruction of the left renal vein.

Traumatic Urinothorax:

• Surgical injury.

• Blunt trauma.

• Attempted percutaneous nephrostomy.

• Lithotripsy for renal calculi.

• Renal transplantation.

• Lithotomy.

• Transurethral drainage.

• Ureteroscopy.

• Radiofrequency ablation.

• Acute obstruction secondary to renal calculi with hydronephrosis.

What Are the Signs and Symptoms of Urinothorax?

The signs and symptoms of urinothorax include;

• Pleuritic chest pain.

• Dyspnea or difficulty in breathing.

• Tachypnea or increased respiratory rate.

• Tachycardia or increased heart rate.

• Cyanosis or bluish discoloration of the tongue, nose tip, fingertips, and ear lobules.

• Diminished breath sounds .

• Dullness on percussion.

• Abdominal pain.

• Decreased urine output.

• Fever.

What Are the Diagnostic Tests to Be Carried Out?

The diagnostic tests can be performed are;

• Chest X-ray: It revealed ill-defined patchy opacities in bilateral middle and lower zones.

• Intravenous Pyelography: It showed leakage of contrast from the retroperitoneal space to the pleural cavity.

• Thoracic Computed Tomography (CT) Scan: It can easily detect pleural effusion and underlying urinoma. It can easily confirm a large pleural effusion, mainly to the right hemithorax, and huge mediastinal lymph node masses compatible with the primary disease.

• Abdominal CT Scan: It revealed perihepatic fluid, great masses compatible with the enlarged lymph nodes of the retroperitoneum, which were compressing both the ureters, mainly the right one.

• Contrast Enhanced Computed Tomography (CECT) Of Chest and Abdomen: It revealed moderate right and mild left pleural effusion with underlying atelectasis and a large peritoneal collection in the right posterior pararenal space displacing right kidney anteriorly possibility of post-traumatic urinoma.

• Renal Scintigraphy Using Technetium 99: It is useful to reveal any extravasation of urine from the kidney or ureters to the pleural cavity.

• Ultrasound-Guided Surgical Thoracocentesis: The sample collected is usually straw-colored with a distinctive urine smell. It revealed the pleural fluid to have lactate dehydrogenase (LDH) of 110U/L whereas serum LDH of 412U/L. The pleural fluid LDH to serum LDH ratio is less than 0.6, indicative of transudate as per Light's criteria. The pleural fluid protein content is 2.5 g/dl compared to the serum protein content of 6.2 g/dl. Thus, the fluid collected is suggestive of being transudative with characteristic low pH, low glucose, elevated LDH levels, and low protein content. The most important biochemical marker is the fluid creatinine to serum creatinine ratio, which is always found to be more than one and, in most cases, greater than ten, highly suggestive of urinothorax.

• Abdominal Ultrasound: It revealed dilated right ureteropelvic junction due to compression from extra ureteric tissue and bilateral pleural effusion.

What Is the Management for Urinothorax?

Management of urinothorax depends upon the underlying cause. The correction of the underlying cause usually suffices, resulting in spontaneous resolution of the urinothorax. If the pleural effusion persists, then urine drainage with the help of an intercostal thoracic drainage tube is recommended. First, a needle decompression should be done for patients who are hemodynamically unstable and are showing deteriorating signs and symptoms.

It is performed with the help of a 14-16 gauge and 4.5 cm in length angiocatheter, just superior to the rib of the second intercostal space in the midclavicular line, followed by insertion of the thoracostomy tube, which is inserted at the fifth intercostal space anterior to the mid axillary line. The thoracostomy tube depends upon the patient's height and weight.

Drainage of retroperitoneal collection, right nephrectomy, right ureteral mobilization with drainage of urinoma with marsupialization of fistulas, and repair of the diaphragmatic fistula is done. Postoperatively, the patient is kept on mechanical ventilation and inotropic support. Urinothorax resolves spontaneously without recurring after the underlying urinary tract disorder is treated. Hence, the prognosis of the disease is excellent.

What Are the Differential Diagnosis for Urinothorax?

The differential diagnosis includes;

• Pleural effusion.

• Hemothorax.

• Chylothorax.

• Pulmonary consolidation.

Conclusion:

Pleural effusion due to urinary tract obstruction can result in urinothorax. A wide variety of obstructive urinary tract lesions or trauma, such as prostatic hypertrophy, renal cysts, urethral valves, prostatic carcinoma, renal calculi, and renal transplantation, can cause urinothorax. It is usually ipsilateral to the obstructive urinary lesion and has no gender predilection. A combination of early intervention with appropriate diagnostic tests helps diagnose and treat the same.

However, the characteristic biochemical marker is the high pleural fluid creatinine to serum creatinine ratio that provides the confirmatory diagnosis of urinothorax. Also, the ultrasound-guided surgical thoracocentesis led to high suspicion of urinothorax due to a distinctive urine smell. Correction of underlying conditions usually improves the urinothorax. However, if it persists, a needle decompression should be done for hemodynamically unstable patients, followed by an intercostal thoracic drainage tube placement.