Urinothorax (''pl''. urinothoraces) is defined as

urine Urine is a liquid by-product of metabolism in humans and in many other animals. Urine flows from the kidneys through the ureters to the urinary bladder. Urination results in urine being excretion, excreted from the body through the urethra. Cel ...

in the fluid-filled cavity that surrounds the

lung The lungs are the primary organs of the respiratory system in humans and most other animals, including some snails and a small number of fish. In mammals and most other vertebrates, two lungs are located near the backbone on either side of t ...

s. It is usually caused by

obstructive uropathy Obstructive uropathy is a structural or functional hindrance of normal urine flow, sometimes leading to renal dysfunction (obstructive nephropathy). It is a very broad term, and does not imply a location or cause. Presentation Symptoms, less lik ...

. It is mainly diagnosed by analyzing the

pleural fluid The pleural cavity, pleural space, or interpleural space is the potential space between the pleurae of the pleural sac that surrounds each lung. A small amount of serous pleural fluid is maintained in the pleural cavity to enable lubrication be ...

. Treatment involves treating the underlying condition, which typically results in resolution of the urinothorax. It is an extremely rare cause of

pleural effusion A pleural effusion is accumulation of excessive fluid in the pleural space, the potential space that surrounds each lung. Under normal conditions, pleural fluid is secreted by the parietal pleural capillaries at a rate of 0.6 millilitre per kilog ...

Signs and symptoms

The characteristics of people affected by urinothorax are poorly defined. Urological symptoms tend to occur, while the

respiratory symptoms Respiratory diseases, or lung diseases, are pathological conditions affecting the organs and tissues that make gas exchange difficult in air-breathing animals. They include conditions of the respiratory tract including the trachea, bronchi, bron ...

are typically nonexistent or mild.

Difficulty breathing Shortness of breath (SOB), also medically known as dyspnea (in AmE) or dyspnoea (in BrE), is an uncomfortable feeling of not being able to breathe well enough. The American Thoracic Society defines it as "a subjective experience of breathing disc ...

, occurring in moderate to large

s, is the most common respiratory symptom. Other symptoms include

fever Fever, also referred to as pyrexia, is defined as having a body temperature, temperature above the human body temperature, normal range due to an increase in the body's temperature Human body temperature#Fever, set point. There is not a single ...

abdominal pain Abdominal pain, also known as a stomach ache, is a symptom Signs and symptoms are the observed or detectable signs, and experienced symptoms of an illness, injury, or condition. A sign for example may be a higher or lower temperature than ...

chest pain Chest pain is pain or discomfort in the chest, typically the front of the chest. It may be described as sharp, dull, pressure, heaviness or squeezing. Associated symptoms may include pain in the shoulder, arm, upper abdomen, or jaw, along with n ...

, and reduced

urination Urination, also known as micturition, is the release of urine from the urinary bladder through the urethra to the outside of the body. It is the urinary system's form of excretion. It is also known medically as micturition, voiding, uresis, ...

. It typically occurs within hours of the causative condition.

Causes

Urinothorax is usually caused by

. The obstructive uropathy may be at the

urinary bladder The urinary bladder, or simply bladder, is a hollow organ in humans and other vertebrates that stores urine from the kidneys before disposal by urination. In humans the bladder is a distensible organ that sits on the pelvic floor. Urine enters ...

urethra The urethra (from Greek οὐρήθρα – ''ourḗthrā'') is a tube that connects the urinary bladder to the urinary meatus for the removal of urine from the body of both females and males. In human females and other primates, the urethra con ...

l level. Obstructive causes have been caused by prostate disease,

kidney cyst A renal cyst is a fluid collection in or on the kidney. There are several types based on the Bosniak classification. The majority are benign, simple cysts that can be monitored and not intervened upon. However, some are cancerous or are suspicio ...

retroperitoneal fibrosis Retroperitoneal fibrosis or Ormond's disease is a disease featuring the proliferation of fibrous tissue in the retroperitoneum, the compartment of the body containing the kidneys, aorta, renal tract, and various other structures. It may present wi ...

, and supernumerary kidney. Traumatic cases tend to occur on one side, while obstructive cases tend to be bilateral. In cases caused by

urinoma Extravasation of urine refers to the condition where an interruption of the urethra leads to a collection of urine in other cavities, such as the scrotum or the penis in males. It can be associated with a calculus. Mechanism An injury to the ureth ...

, the urinothorax is usually on the same side of it. Rarely, it can be on both sides or on the opposite side of the urinoma. It can also be caused by

renal biopsy Renal biopsy (also kidney biopsy) is a medical procedure in which a small piece of kidney is removed from the body for examination, usually under a microscope. Microscopic examination of the tissue can provide information needed to diagnose, moni ...

kidney transplantation Kidney transplant or renal transplant is the organ transplant of a kidney into a patient with end-stage kidney disease (ESRD). Kidney transplant is typically classified as deceased-donor (formerly known as cadaveric) or living-donor transplantati ...

lithotripsy Lithotripsy is a non-invasive procedure involving the physical destruction of hardened masses like kidney stones, bezoars or gallstones. The term is derived from the Greek words meaning "breaking (or pulverizing) stones" ( litho- + τρίψω rip ...

, failed tube

nephrostomy A nephrostomy is an artificial opening created between the kidney and the skin which allows for the urinary diversion directly from the upper part of the urinary system (renal pelvis). An urostomy is a related procedure performed more distally al ...

, or

cancer Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal b ...

of the urinary tract.

Mechanism

Injury to the

urinary tract The urinary system, also known as the urinary tract or renal system, consists of the kidneys, ureters, bladder, and the urethra. The purpose of the urinary system is to eliminate waste from the body, regulate blood volume and blood pressure, con ...

can result in collections of fluid known as a

. It has the smell of normal

. The urine arrives in the pleural space either retroperitoneally (under the

peritoneum The peritoneum is the serous membrane forming the lining of the abdominal cavity or coelom in amniotes and some invertebrates, such as annelids. It covers most of the intra-abdominal (or coelomic) organs, and is composed of a layer of mesoth ...

), or via the retroperitoneal

lymphatics The lymphatic vessels (or lymph vessels or lymphatics) are thin-walled vessels (tubes), structured like blood vessels, that carry lymph. As part of the lymphatic system, lymph vessels are complementary to the cardiovascular system. Lymph vessel ...

. Urine can reach the pleural space either directly or indirectly. It can reach directly, by going through pores in the

thoracic diaphragm The thoracic diaphragm, or simply the diaphragm ( grc, διάφραγμα, diáphragma, partition), is a sheet of internal Skeletal striated muscle, skeletal muscle in humans and other mammals that extends across the bottom of the thoracic cavit ...

due to a pressure gradient, or by a rupture of a urinoma releasing the contents into the pleural space. It can also reach indirectly, when a urinoma drains into the pleural space via linkage between the lymphatics of the retroperitoneal and pleural regions.

Diagnosis

CT scan showing placement of the nephrostomy tube in a case of urinothorax being treated

Due to the main symptoms typically being urological rather than respiratory, the condition requires exclusion of other conditions and the identification of specific symptoms before diagnosis. Pleural fluid analysis is one way to diagnose the condition. The pleural fluid is most often straw-colored, and it has a distinct smell like

ammonia Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous was ...

. The fluid usually has a nucleated cell count between 50 and 1500 per cm³. The pH of the fluid is usually between 5 and 7. Primary factors for diagnosing urinothorax by pleural fluid include low protein and high

lactate dehydrogenase Lactate dehydrogenase (LDH or LD) is an enzyme found in nearly all living cells. LDH catalyzes the conversion of lactate to pyruvate and back, as it converts NAD+ to NADH and back. A dehydrogenase is an enzyme that transfers a hydride from on ...

content. Low

glucose Glucose is a simple sugar with the molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, using ...

levels and

acid In computer science, ACID ( atomicity, consistency, isolation, durability) is a set of properties of database transactions intended to guarantee data validity despite errors, power failures, and other mishaps. In the context of databases, a sequ ...

ity are also described, but are not reliable ways to diagnose or rule out urinothorax. The most important chemical diagnostic factor of the fluid is that the ratio of

creatinine Creatinine (; ) is a breakdown product of creatine phosphate from muscle and protein metabolism. It is released at a constant rate by the body (depending on muscle mass). Biological relevance Serum creatinine (a blood measurement) is an import ...

to serum is more than 1 and usually more than 10. Abdominal

ultrasonography Ultrasound is sound waves with frequencies higher than the upper audible limit of human hearing. Ultrasound is not different from "normal" (audible) sound in its physical properties, except that humans cannot hear it. This limit varies fr ...

and CT scan can help diagnose the underlying condition of the

genitourinary tract The genitourinary system, or urogenital system, are the organs of the reproductive system and the urinary system. These are grouped together because of their proximity to each other, their common embryological origin and the use of common pathw ...

. If other methods prove inconclusive, an accurate diagnosis can be made by a

technetium-99m Technetium-99m (99mTc) is a metastable nuclear isomer of technetium-99 (itself an isotope of technetium), symbolized as 99mTc, that is used in tens of millions of medical diagnostic procedures annually, making it the most commonly used medical ra ...

kidney scan, which shows albumin labeled with 99Tc that translocates into the pleural space from the genitourinary tract.

Treatment

Treatment mainly consists of treating the underlying disorder of the genitourinary tract. It requires a

multidisciplinary team Interdisciplinarity or interdisciplinary studies involves the combination of multiple academic disciplines into one activity (e.g., a research project). It draws knowledge from several other fields like sociology, anthropology, psychology, ec ...

that includes a

pulmonologist Pulmonology (, , from Latin ''pulmō, -ōnis'' "lung" and the Greek suffix "study of"), pneumology (, built on Greek πνεύμων "lung") or pneumonology () is a medical specialty that deals with diseases involving the respiratory tract.

and

urologist Urology (from Greek οὖρον ''ouron'' "urine" and ''-logia'' "study of"), also known as genitourinary surgery, is the branch of medicine that focuses on surgical and medical diseases of the urinary-tract system and the reproductive organ ...

. A

tube or

Foley catheter In urology, a Foley catheter (named for Frederic Foley, who produced the original design in 1929) is a flexible tube that a clinician passes through the urethra and into the bladder to drain urine. It is the most common type of indwelling urina ...

can be used to relieve any underlying obstruction. Any injuries are repaired. When the underlying disorder is addressed, the urinothorax rapidly resolves.

Thoracic surgery Cardiothoracic surgery is the field of medicine involved in surgical treatment of organs inside the thoracic cavity — generally treatment of conditions of the heart (heart disease), lungs (lung disease), and other pleural or mediastinal struc ...

is usually not needed, especially if respiratory symptoms are minimal or nonexistent.

Pleurodesis Pleurodesis is a medical procedure in which part of the pleural space is artificially obliterated. It involves the adhesion of the visceral and the costal pleura. The mediastinal pleura is spared. Uses Pleurodesis is performed to prevent recurre ...

is also ineffective. A

chest tube A chest tube (also chest drain, thoracic catheter, tube thoracostomy or intercostal drain) is a surgical drain that is inserted through the chest wall and into the pleural space or the mediastinum in order to remove clinically undesired substanc ...

can be used to drain urine from the pleural cavity.

Prognosis

Urinothoraces typically resolve spontaneously without recurring after the underlying urinary tract disorder is treated.

Epidemiology

Urinothorax remains a rare, possibly under-diagnosed, differential in the case of transudative pleural effusion. There were only 58 reported cases up until January 2006. In the literature, there are under 100 reported cases.

References

External links

* {{Commons category-inline, Urinothorax Diseases of pleura Urinary system