Bowel obstruction refers to a blockage in the intestines that prevents food, fluids and gas from moving through the digestive tract. This can lead to a dangerous backup of stool, gas and fluid in the intestines. Urinary retention refers to an inability to completely empty the bladder. Urinary retention causes urine to remain in the bladder after urination. There are several potential causes of urinary retention, including bowel obstruction in some cases.
Bowel obstructions have the potential to place pressure on the urinary tract, which can make it difficult for the bladder to fully empty. In other cases, bowel obstructions may contribute to urinary retention indirectly due to dehydration or electrolyte imbalances. However, the link between bowel obstructions and urinary retention depends on the location and severity of the obstruction. Mild obstructions in the lower intestines are less likely to affect urinary function compared to high-grade obstructions in the colon or small intestine.
Causes of Bowel Obstruction
Bowel obstructions have several potential underlying causes:
– Hernias – Portions of the intestines push through weak spots in the abdominal wall and become trapped. This twists and squeezes the intestines.
– Adhesions – Scarring from past abdominal or pelvic surgery can cause narrowing of the intestines. Food and waste get stuck at these scar tissue sites.
– Volvulus – A section of the intestines twist around itself, causing a closed off loop. This commonly occurs in the sigmoid colon.
– Intussusception – The intestines telescope in on themselves, like a collapsible cup. This typically affects infants and children.
– Colon cancer – Tumors in the colon can protrude into the intestinal pathway and block it off.
– Diverticulitis – Inflammation or infection of small pouches called diverticula on the colon.
– Foreign body obstruction – Children sometimes swallow small objects like coins, buttons or toy parts that become lodged in the intestines.
– Paralytic ileus – The intestines temporarily stop moving due to infection, medication side effects, electrolyte imbalances or other disorders.
The small intestine is the most common site of obstruction, followed by the colon. The severity of symptoms depends on the location and degree of blockage. Partial obstructions allow some food and stool movement, while complete obstructions result in a total backup.
Signs and Symptoms
The most common signs and symptoms of intestinal obstruction include:
– Cramping abdominal pain that comes and goes
– Inability to pass gas or have a bowel movement
– Swelling of the abdomen
– Vomiting, especially vomiting up stool in severe cases
– Constipation
– Diarrhea, especially later in the course of the obstruction
– Inability to tolerate food or fluids without vomiting
– Fever in some cases
As the obstruction worsens, the abdominal pain becomes more constant. The abdomen often becomes increasingly distended and firm to the touch. Vomiting becomes more frequent and feculent. Incomplete, or partial bowel obstructions have milder symptoms that may come and go.
Diagnosis
If bowel obstruction is suspected, the doctor will take a full history and perform a physical exam. Key aspects of the history include asking about past surgeries, history of cancer, recent changes in bowel habits, diet changes and use of medications that can cause constipation.
During the abdominal exam, the doctor assesses for distension, tenderness, masses and hernias. Blood tests may show signs of dehydration or electrolyte imbalances.
Imaging tests are necessary to confirm the diagnosis and determine the location:
– Abdominal x-ray – Can detect blocked intestines filled with air and stool. around 80-90% accurate.
– CT scan – Provides detailed images of the intestines, location of obstruction and surrounding anatomy. Over 90% accurate.
– MRI – Used as an alternative to CT without radiation exposure. Not used as commonly.
– Contrast studies – Barium or water-soluble contrast dye is swallowed or given by enema to outline the intestines.
Other tests may include colonoscopy or endoscopy to view the lining of the colon if needed to rule out lesions.
Causes of Urinary Retention
Urinary retention refers to the inability to fully empty the bladder. Urine gets trapped, leading to bladder distension. There are several possible underlying causes:
– Benign prostatic hyperplasia (BPH) – Enlargement of the prostate gland compresses the urethra in older males. Most common cause in men.
– Prostate cancer – Tumor growth in the prostate obstructs urinary flow.
– Urethral strictures – Scarring causes narrowing of the urethra. Can result from trauma, infections, inflammation or prior surgeries.
– Bladder stones – Crystals forming in the bladder block the urethral opening. More common in men.
– Urinary tract infections – Swelling from infection obstruct urinary flow.
– Neurogenic bladder – Nerve signals between the bladder and brain are disrupted, often by spinal cord injuries. Causes inability to sense when the bladder is full.
– Medications – Some drugs like anticholinergics, antihistamines, decongestants, antidepressants and antipsychotics affect bladder function.
– Diabetes mellitus – Nerve damage and bladder dysfunction can develop over time.
Link Between Bowel Obstruction and Urinary Retention
Bowel obstructions can potentially contribute to urinary retention through the following mechanisms:
– **Direct compression** – Intestinal obstructions in the descending colon or rectosigmoid region can physically compress the bladder. This prevents full emptying. More likely with high-grade obstructions.
– **Bladder distension** – The swollen, backed-up intestines push against the full bladder. This increases pressure and makes it harder for the bladder to empty.
– **Neural effects** – The nerve plexus controlling bladder function can become impaired due to the local inflammatory effects of a bowel obstruction.
– **Dehydration** – Vomiting, reduced fluid intake and shifts in fluids can lead to dehydration. Concentrated, decreased urine volume is harder to void.
– **Electrolyte imbalances** – Imbalances like hyperkalemia impair bladder contraction.
– **Side effects of treatment** – Some medications like narcotics that are used to treat obstructions can interfere with normal bladder function.
However, several factors influence whether a bowel obstruction actually triggers urinary retention:
– **Grade of obstruction** – Complete obstructions are more likely to impact voiding than partial obstructions.
– **Location** – Lower intestinal obstructions below the rectosigmoid colon are less likely to affect the bladder.
– **Duration** – Longer standing obstructions increase the risk of secondary effects like dehydration.
– **Individual susceptibility** – Those with prostate enlargement or other urinary issues are more prone.
So in summary, bowel obstructions can directly compress the bladder and make it harder to void. But obstruction alone does not always cause retention – other risk factors and susceptibilities also contribute. Mild, partial or distal obstructions may not impair urination.
Diagnosing Urinary Retention
If a patient with bowel obstruction develops trouble urinating, doctors will investigate for urinary retention. Signs and symptoms include:
– Difficulty initiating urination
– Prolonged time to fully void
– Dribbling after urination ends
– Sensation of “incomplete emptying”
– Decreased urine volume
– Overflow incontinence in severe cases
Doctors can confirm urinary retention and check post-void residual urine with:
– Physical exam – Distended bladder may be felt on abdominal palpation
– Bladder ultrasound – Measures urine left after voiding
– Straight catheterization – Catheter drains post-void urine to measure residual volume
– Uroflowmetry – Checks speed and completeness of urinary flow
Normal post-void residual is under 50 mL. Higher amounts suggest incomplete emptying. Retention is likely if over 200 mL of urine remains.
Treating Bowel Obstructions with Urinary Retention
The main priority is dealing with the underlying bowel obstruction, while managing the urinary retention simultaneously. Treatment approaches include:
– **Fluid resuscitation** – IV fluids help correct dehydration and electrolyte disturbances. This may improve urinary function.
– **Bladder drainage** – Placing a Foley catheter or performing intermittent straight catheterization helps empty the bladder.
– **Medications** – Alleviating nausea, vomiting and pain improves hydration and urination. Antispasmodics relax gut muscles.
– **Surgery** – Severe obstructions or those that fail to resolve with conservative treatment require operative repair. This removes the obstruction.
– **Bowel rest** – Stopping oral intake allows the intestines to rest while fluid and nutrition are given intravenously.
– **Monitoring** – Ongoing monitoring of fluid status, kidney function, electrolytes and urinary output.
– **Addressing underlying causes** – Treating contributory factors like BPH or prostate cancer may improve bladder dysfunction long-term.
The urinary retention will often resolve once the bowel obstruction has been relieved and normal intestinal function returns. But some individuals require ongoing bladder management if dysfunction persists.
Preventing Bowel Obstruction and Urinary Retention
Certain measures may help reduce the risk of developing a bowel obstruction that could potentially impair urinary flow:
– Drink plenty of fluids and maintain well-hydrated
– Eat high fiber foods to prevent constipation
– Treat chronic constipation with laxatives if needed
– Maintain physical activity and mobility
– Manage medical conditions like diabetes, prostate disorders and neurological diseases
– Use medications as prescribed; report severe constipation
– Prevent post-surgical adhesions with minimally invasive techniques or anti-adhesion agents
– Have routine cancer screening based on age and risk factors
Seeking prompt medical attention for signs of intestinal obstruction can help prevent complications like urinary retention. Those with risk factors may need monitoring for urinary impairments if an obstruction occurs.
Conclusion
Bowel obstructions can potentially contribute to urinary retention through effects like direct bladder compression, dehydration and neural impairment. However, the risk depends on the severity and location of the obstruction, as well as individual susceptibilities. Mild, partial or distal obstructions may not affect urination. Management focuses on urgently resolving the obstruction while monitoring for retention. Preventive measures like hydration, fiber intake, physical activity and proper medication use can help avoid problematic constipation, bowel obstructions and subsequent urinary dysfunction. But prompt medical attention is key if an obstruction does arise.