An inguinal hernia occurs when internal abdominal tissue, such as fat or a loop of intestine, pushes through a weak spot in the muscle wall of the groin. Urinary retention is the inability to completely empty the bladder, ranging from difficulty starting a stream to a complete inability to void. An inguinal hernia can cause retention because the physical presence of the herniated tissue interferes with the normal function of the urinary tract. This complication is a serious medical event that requires prompt medical attention to prevent damage to the bladder and kidneys.
Anatomy of an Inguinal Hernia
The inguinal canal is a narrow passageway in the lower abdominal wall, running obliquely through the groin region. In males, this canal contains the spermatic cord, and in females, it holds the round ligament of the uterus. An inguinal hernia forms when abdominal contents protrude into this canal, creating a visible or palpable bulge in the groin.
The lower portion of the urinary bladder sits in close proximity to the inner opening of the inguinal canal. The bladder is a flexible organ, making it vulnerable to displacement or compression from a nearby hernia. Even without displacement, the herniated tissue is positioned directly next to the structures responsible for urine flow, setting the stage for mechanical interference with urination.
How Hernia Pressure Causes Retention
Retention results from mechanical obstruction of the urinary outflow tract. The most common mechanism involves the hernia sac, which contains the protruding abdominal tissue, pressing directly upon the bladder neck or the urethra. This external pressure acts like a clamp, narrowing the channel through which urine must pass to exit the body.
The second mechanism involves a sliding hernia, where a portion of the bladder wall is dragged into the hernia sac as the abdominal contents push through the defect. This partial herniation physically distorts the lower urinary tract.
When the bladder wall is pulled into the canal, it can cause the urethra or bladder neck to kink or become acutely angled. This kinking creates a severe obstruction that prevents the flow of urine. This mechanical interference results in difficulty initiating urination and an inability to fully empty the bladder.
Identifying the Signs of Acute Retention
Acute urinary retention is the sudden, painful inability to urinate, requiring immediate medical attention. Patients experience severe lower abdominal pain due to the rapid overstretching of the bladder wall. This pain is accompanied by a strong, persistent urge to urinate.
Diagnosis begins with a physical examination where a doctor observes a firm, distended, and tender mass in the lower abdomen, indicating a greatly enlarged bladder. They will also confirm the presence of the inguinal hernia, which often appears as a noticeable bulge in the groin.
Imaging studies, such as an ultrasound, are used to confirm the diagnosis and determine the extent of the problem. Ultrasound visualizes the urinary tract and confirms a large post-void residual volume in the bladder. The imaging can also show the hernia sac’s relationship to the bladder, indicating direct compression or displacement. Identifying these signs quickly is important, as prolonged retention can lead to kidney damage and other serious complications.
Medical Intervention and Resolution
The immediate priority for acute urinary retention is bladder decompression to relieve pressure. This involves inserting a catheter into the urethra to drain the accumulated urine, providing immediate relief from the pain and pressure. This initial step stabilizes the patient and protects the upper urinary tract from sustained back-pressure.
While catheterization addresses the immediate crisis, the definitive solution requires surgical repair of the underlying inguinal hernia. The procedure, known as a herniorrhaphy or hernioplasty, aims to return the herniated tissue, including any portion of the bladder, back to the abdominal cavity. This action removes the source of mechanical compression or traction on the urinary tract.
Surgeons may employ an open approach, involving a single incision in the groin, or a laparoscopic technique. The goal is to repair the defect in the abdominal wall, often using a synthetic mesh to reinforce the weakened area. Successfully resolving the hernia permanently eliminates the risk of retention caused by physical displacement.