Uroabdomen (Urine leaking in abdominal cavity) in Cats
Dr. Anne Marie Manning
The normal urinary tract is composed of two kidneys, two ureters, a urinary bladder and a urethra. As blood flows through the kidneys, waste products are removed and pass through thin tubes called ureters into the bladder. The urinary bladder is a reservoir for these waste products. Blunt trauma such as automobile injury, a kick to the abdomen, or a fall
When the bladder is sufficiently full, there is an urge to urinate and the urine is voluntarily released from the bladder, through the urethra and out the body. Any damage of the urinary tract can lead to leakage of urine outside of the urinary tract, resulting in urine accumulation within the abdomen. This is referred to as uroabdomen or uroperitoneum.
A uroabdomen is a life threatening condition. Accumulation of urine in the abdomen creates serious disturbances in electrolytes such as potassium, which has adverse effects on the heart. Waste products that normally are cleared by the kidneys and eliminated in the urine are retained within the abdomen causing serious elevations in kidney values. Additionally, irritation and inflammation of the lining of the abdomen (peritonitis) results. If a urinary tract infection was present at the time of urine leakage, then septic peritonitis may result.
Uroabdomen can result from various causes, but the most common is related to trauma. Damage to the kidney, ureter, bladder, or urethra may cause urine to leak into the abdomen. Some common forms of trauma that can result in a disruption of the urinary tract include:
Penetrating abdominal trauma with knives, bullets, arrows, needles, scalpels, bite wounds or fractured bone fragments from pelvic trauma
Various diseases can also lead to disruption of the urinary tract and subsequent uroabdomen. Some of these include:
An attempt at palpation or expression of the bladder by the veterinarian may cause the bladder to rupture. This generally occurs only when the bladder wall is compromised or weakened by an underlying problem
Rupture or laceration of the bladder during cystocentesis, placement of a urinary catheter, placement of a peritoneal dialysis catheter or during surgical procedures.
Cancer of the bladder
Unsupervised outdoor animals are at an increased risk for traumatic injuries due to automobiles, malicious individuals or animal attacks. This results in an increased risk of developing uroabdomen.
Cats with Feline Lower Urinary Tract Disease (FLUTD) are at an increased risk as these cats often require bladder palpation and cystocentesis for diagnostic purposes or passage of a urinary catheter for therapeutic purposes.
What to Watch For
External signs of injury such as bruising, broken bones, or changes in behavior that may indicate the pet has been traumatized
Lack of urination or production of very little urine within a 24 hour period following a traumatic event
Distension of the abdomen as urine accumulates
Lethargy, depression, loss of appetite, vomiting, abdominal pain
Increased respiratory rate due to pain
As with any illness, a medical history is taken and a thorough physical examination is performed. Your veterinarian will likely ask how long the pet has been ill, if there is any possibility of trauma, and about your pet's urination habits. The physical examination will concentrate on the abdomen and rear areas of the pet. Normal urination does not mean the pet does not have a ruptured bladder. Small bladder tears can cause leakage of urine into the abdomen but the bladder can still fill and urine can be voided.
Various tests may be necessary to determine if there is fluid in the abdomen, what type of fluid is present and the cause of the fluid accumulation.
A complete blood count (CBC) can help determine the white blood cell, red blood cell and platelet counts. In a uroabdomen, these results may be normal.
A biochemistry profile will evaluate the function of the liver and kidneys and can detect abnormalities in the electrolytes.
Urinalysis is performed if urine is obtained from the bladder.
Abdominocentesis is one of the most important tests performed in diagnosing uroabdomen. A needle is inserted into the abdominal cavity and any fluid present is collected an analyzed. To determine if the fluid is urine, the creatinine level of the fluid is compared to the creatinine level of the blood. Creatinine is a by-product of waste production in the kidneys. Typically excreted in the urine, the level of creatinine will be higher in urine than in the blood. If the creatinine of the fluid is higher than the creatinine of the blood, the fluid is urine.
Blood gas tests are used to determine the acid base status of the pet.
Radiographs +/- contrast radiography are important in determining where a leak has occurred within the urinary tract.
Abdominal ultrasound is sometimes helpful in determining if there is an abnormality within the urinary tract.
Bacterial culture and sensitivity may be needed to determine if there is a bacterial component to the uroabdomen.
Uroabdomen is a serious illness. Aggressive treatment is necessary to prevent continued illness and potential death. Hospitalization with intravenous fluids is the first step in treatment. Antibiotics are often administered to fight any infection. Uroabdomen and the cause of the uroabdomen can be painful, so pain medications are typically administered to help ease the discomfort.
The majority of uroabdomen cases require surgical repair. The animal is anesthetized and the lower abdomen is surgically opened. The urine is suctioned from the abdomen and the tear in the urinary tract is identified. The most common source of urine in the abdomen is from a tear in the bladder. If present, the rupture site of the bladder is sutured.
Tears in the ureters can also be sutured, but this procedure may require the experience and equipment of a veterinary surgeon. If the kidney is badly damaged, surgical removal may be performed.
After surgical repair of the rupture site, the abdomen is flushed and cleaned with sterile saline. All traces of urine should be removed. The urinary tract is then tested to make sure there are no more leaks. The abdominal incision is then closed with sutures or staples.
A urinary catheter is often placed during surgery and left in place for 2-3 days after surgery to keep the urinary bladder and urinary tract empty. This allows the urinary tract to heal.
For some causes of uroabdomen, such as a very small tear in the urinary bladder or a tear of the urethra, medical therapy may be effective. A urinary catheter is placed and left in for 5 to 7 days. The hope is that without the continual irritation of urine, the small tear will have a chance to heal. After 5 to 7 days, the urinary catheter is removed and the pet is allowed to urinate on his own. The pet is closely monitored for poor response and may need surgical repair in the future.
Home Care and Prevention
There is no home care for uroabdomen. Any animal that sustains a blunt trauma or is unable to urinate should be examined by a veterinarian. After treatment, the pet must be closely monitored for normal urination, blood in the urine, straining or painfulness. Vomiting and lack of appetite should prompt a visit to the veterinarian. Some pets may be sent home with a temporary urinary catheter in place. The catheter must be monitored for normal urine flow and the pet must be prevented from attempting to remove the catheter.
The best way to prevent uroabdomen is to reduce the risk of blunt trauma by keeping your cats indoors. Illness that causes uroabdomen usually cannot be prevented.