Urinoma: Symptoms, Types, Causes and Treatment

Urinoma is a medical condition characterized by the abnormal collection of urine outside the urinary tract. While it may sound straightforward, its implications can be serious if not promptly recognized and treated. Understanding the symptoms, types, causes, and treatment of urinoma is vital for both clinicians and patients, especially as it may mimic other abdominal or flank pathologies. This comprehensive article delves into the key aspects of urinoma, drawing on the latest research and case studies to provide a clear, evidence-based overview.

Symptoms of Urinoma

Recognizing the symptoms of urinoma can be challenging, as they often overlap with other urinary tract or abdominal conditions. However, early identification is crucial to avoid complications such as infection, abscess formation, or loss of kidney function.

Symptom	Characteristics	Common Presentation	Source
Pain	Sudden, severe, colicky	Flank, abdominal, lumbar regions	1 2 3 6 9
Fever	With or without infection	May indicate abscess or sepsis	3 4 6 9
Hematuria	Microscopic or gross	Blood in urine	1 4 11
Constitutional Symptoms	Malaise, nausea, vomiting	Systemic signs of infection or inflammation	2 6 9

Table 1: Key Symptoms

Pain: The Cardinal Symptom

• The most common and striking symptom of urinoma is pain, typically localized to the flank, abdomen, or lower back, depending on the site of urine leakage.
• Pain may be sudden and colicky, especially if associated with underlying obstruction or trauma 1 2 3 6 9.

Fever and Signs of Infection

• Fever is another frequent symptom, especially when the urinoma becomes infected or develops into an abscess.
• Systemic signs such as tachycardia, leukocytosis, and even sepsis can occur if left untreated 3 4 6 9.

Hematuria and Urinary Symptoms

• Blood in the urine (hematuria) may be present, particularly in cases involving trauma, stones, or spontaneous rupture during pregnancy 1 4 11.
• Some patients report urinary retention or changes in urinary output 6.

Constitutional and Systemic Symptoms

• Nausea, vomiting, and general malaise are not uncommon, especially in larger urinomas or when there is an associated infection 2 6 9.
• In chronic cases, symptoms may be more subtle or develop gradually.

Types of Urinoma

Not all urinomas are created equal. Their classification is based on location, etiology, and in some cases, the underlying pathology or patient population.

Type	Location/Context	Typical Patient/Scenario	Source
Perirenal	Around kidney	Stones, trauma, obstruction	1 4 5 6 7
Subcapsular	Beneath kidney capsule	Trauma, forniceal rupture	1
Retroperitoneal	Behind peritoneum	Obstruction, trauma, abscess	2 3 9
Urinary Ascites	Free fluid (abdomen)	Pediatric, congenital, valves	3 7
Urinothorax	Into pleural cavity	Rare, pediatric, valves	7

Table 2: Urinoma Types

Perirenal and Subcapsular Urinomas

• Perirenal urinomas are most common, forming around the kidney due to leakage from trauma, obstruction (stones), or surgical injury 1 4 5 6 7.
• Subcapsular urinomas are less common, occurring beneath the kidney's capsule, typically after blunt trauma or forniceal rupture 1.

Retroperitoneal and Urinary Ascites

• Retroperitoneal urinomas are found in the space behind the peritoneal lining, often in cases of trauma, ureteral injury, or as a complication of abscess formation 2 3 9.
• Urinary ascites refers to free urine accumulation within the abdominal cavity, sometimes seen in children with congenital urinary tract anomalies like posterior urethral valves 3 7.

Urinothorax

• Urinothorax is an exceptionally rare type, where urine leaks into the pleural cavity, more often reported in pediatric populations with severe congenital urinary obstruction 7.

Causes of Urinoma

Understanding the causes of urinoma is critical for effective management. The underlying etiology often guides both the urgency and type of intervention required.

Cause	Description	Typical Scenario	Source
Trauma	Blunt, penetrating, or iatrogenic injury	Accidents, surgeries, procedures	1 3 6
Obstruction	Stones, strictures, tumors, posterior urethral valves	Kidney stones, congenital defects	1 4 6 7
Infection/Inflammation	Pyeloureteritis, interstitial nephritis	Spontaneous cases, NSAIDs, infection	2 5
Iatrogenic	Post-surgical or procedural injury	Ureteral surgery, stent placement	3 9
Pregnancy/Postpartum	Forniceal rupture due to increased pressure	Late pregnancy, postpartum	11

Table 3: Causes of Urinoma

Trauma: The Most Common Cause in Adults

• Trauma, whether blunt (e.g., car accidents), penetrating (e.g., stab wounds), or iatrogenic (surgical injury), is the leading cause of urinoma formation in adults 1 3 6.
• Disruption of the renal collecting system or ureter allows urine to leak into surrounding tissues, forming a urinoma.

Obstructive Uropathy

• Acute obstruction, such as from ureteral stones, strictures, tumors, or congenital anomalies, is another significant cause 1 4 6 7.
• Even small distal ureteral stones can precipitate urinoma formation, particularly if they cause forniceal rupture 4.
• In children, congenital conditions like posterior urethral valves are a notable cause 7.

Infection and Inflammation

• In rare cases, severe urinary tract infections (e.g., pyeloureteritis) or inflammatory conditions (such as NSAID-induced interstitial nephritis) can weaken the urinary tract wall, leading to spontaneous urinoma 2 5.
• These cases may occur without the typical triggers of trauma or obstruction.

Iatrogenic and Post-Procedural Causes

• Medical procedures involving the urinary tract, such as ureteral surgery, stent placement, or even difficult catheterizations, can inadvertently injure the ureter or kidney, resulting in urine leakage 3 9.

Pregnancy and Postpartum

• Increased pressure on the urinary tract during pregnancy, particularly in the third trimester or postpartum period, can cause spontaneous renal fornix rupture and subsequent urinoma formation 11.

Treatment of Urinoma

The management of urinoma depends on its size, cause, location, and the presence of complications such as infection or renal impairment. Early intervention is crucial to prevent serious outcomes, including abscess formation and loss of renal function.

Treatment	Approach/Indication	Outcome/Consideration	Source
Conservative	Small, asymptomatic, non-infected	Often reabsorbed, monitor closely	7 9 11
Urinary Diversion	Stents, nephrostomy tubes	Relieves obstruction, promotes healing	8 9 10 11
Percutaneous Drainage	Large, symptomatic, infected	Fluid removal, infection control	2 8 9 10
Surgical Repair	Persistent leak, complex injuries	For severe/iatrogenic cases	3 8
Antibiotics	Infection or abscess present	Guided by fluid culture	2 9

Table 4: Urinoma Treatments

Conservative Management

• Small, asymptomatic, or non-infected urinomas can often be managed conservatively, especially in pediatric cases or after relief of obstruction 7 9 11.
• Close monitoring with imaging and renal function tests is essential to ensure resolution.

Urinary Diversion

• Placement of ureteral stents or percutaneous nephrostomy tubes is the mainstay for managing larger urinomas, those associated with obstruction, or spontaneous ruptures (such as in pregnancy) 8 9 10 11.
• These devices divert urine away from the leak site, allowing healing and reducing further extravasation.

Percutaneous Drainage

• For large, symptomatic, or infected urinomas, image-guided percutaneous drainage is highly effective 2 8 9 10.
• This approach not only relieves symptoms but also prevents progression to abscess or sepsis.

Surgical Repair

• In cases of persistent leakage, complex injuries, or failure of minimally invasive approaches, surgical repair may be necessary 3 8.
• This is more common in iatrogenic injuries or when there is significant tissue damage.

Antibiotic Therapy and Supportive Care

• When infection or abscess is present, broad-spectrum antibiotics are initiated and later tailored to culture results from drained fluid 2 9.
• Monitoring of renal function and correction of electrolyte disturbances are critical components of supportive care 9.

Conclusion

Urinoma is a rare but potentially serious complication of urinary tract injury or obstruction. Prompt diagnosis and targeted management are essential to prevent lasting harm. By understanding its symptoms, types, causes, and treatment, clinicians—and patients—can work together for optimal outcomes.

Key Points:

• Symptoms: Flank or abdominal pain, fever, hematuria, and systemic illness are typical; early recognition is vital 1 2 3 4 6 9 11.
• Types: Classified by location (perirenal, subcapsular, retroperitoneal, urinary ascites, urinothorax) and context (trauma, obstruction, infection) 1 2 3 4 5 6 7.
• Causes: Most commonly due to trauma and obstruction (stones, congenital anomalies); can also occur from infection, iatrogenic injury, or during pregnancy 1 2 3 4 5 6 7 9 11.
• Treatment: Ranges from conservative management for small, uncomplicated cases to drainage procedures, urinary diversion, surgery, and antibiotics for complicated or infected urinomas 2 3 7 8 9 10 11.

Early intervention and individualized care remain the cornerstones of successful urinoma management.