Common complications

15 May 2023

Catheter-associated urinary tract infection (CAUTI)

The natural process of protecting the urinary tract against bacteria (urethral immune defense, regular emptying of bladder) is compromised during catheterization. It is common that microbes adhere, colonize and form biofilm on the catheter inner and/or outer surface.

After 1-2 weeks of catheter treatment it is estimated that almost everyone has bacteria in the urine which subsequently may lead to infections.

The risk for invasion of bacteria and subsequent infections increases with every day of catheterization and the source of microorganisms may either be:

  • Endogenous – often microbial strains from near surroundings (e.g. meatal, rectal or vaginal)
  • Exogenous – often microbial strains from contaminated hands of health care personnel during catheter insertion or manipulation or from one patient to another

Other risk factors for CAUTI include female gender, reduced general condition, diabetes mellitus, suppressed immune system and keeping the drainage bag above the level of the bladder.

Common symptoms of CAUTI include:

  • Fever
  • Chills
  • Urgency
  • Pelvic pain
  • Bladder and/or urethral pain
  • Nausea
  • Loss of appetite

Prevention of CAUTI

The most important factor in the prevention of CAUTI is to limit the length of time a patient has a catheter. Correct handling and the correct choice of catheter material for long term use are also crucial factors.

  1. Avoid unnecessary catheterization
  2. Consider infection protection catheters such as BIP Foley Catheter
  3. Remember basal hygiene routines, not to carry microbes between patients
  4. Use aseptic techniques where catheter sterility is kept intact during insertion
  5. Use closed drainage systems or catheter valves, to avoid manipulation of the urine
  6. Consider alternative treatments, such as suprapubic or intermittent catheterization

Treatment of CAUTI

CAUTI can be caused by either a single microbial strain or a mixed culture. The symptoms can vary, which affects the need and choice of treatment.

Start with collecting urine for a urinary analysis (not dipstick). If possible, wait for the results before starting the antibiotic treatment. Change catheter after about 24 hours as biofilm on the catheter cannot be treated with antibiotics.


Urinary tract infections that are not treated can spread to the kidney, causing more pain and illness and it may develop into urosepsis. This is particularly common in people who have limited or no sensation below the waist or who are unable to speak for themselves. Sepsis can develop as the body´s overreaction to an infection and is often deadly. Sepsis kills and disables millions of people every year worldwide and requires early diagnosis and rapid treatment for survival.

Bactiguard is the proud sponsor of World Sepsis Day, arranged annually by the Global Sepsis Alliance to raise awareness about the condition and reduce mortality caused by sepsis.

Urethral trauma

Trauma of the urethra can occur during the catheterization procedure and by the pressure of the catheter on the urethral mucosa during treatment.


Especially sensitive parts in the male urethra are the meatus and the curvatures. A urethral stricture is a scar tightening the urethral lumen that might be caused by a traumatic catheterization and also by the constant pressure of an indwelling catheter. Catheter induced meatal erosion is sparsely described in the literature but common nevertheless. It is a meatal cleavage caused by the downward pressure of an indwelling catheter, i.e. an iatrogenic hypospadias.


How to prevent it Be careful when catheterizing, use the smallest possible catheter. Decrease the downward pressure of the catheter on the meatal part through e.g. tight underwear with penis upwards.


Estrogen contributes to the moisture and elasticity of the mucosa. After menopause estrogen decreases and the urethral mucosa become more sensitive and irritated, causing discomfort and an increased risk for increased bacterial invasion.


How to prevent it Consider local estrogen treatment to women with catheter treatment after menopause.


Hematuria means that there are red blood cells in the urine (erythrocyte concentration >5 x 109/L). If the urine is visibly colored by blood, the symptom is described as macroscopic or gross hematuria, unlike microscopic hematuria where the bleeding is not visible.

What to do? The care for patients with macroscopic hematuria or gross hematuria includes cleaning the bladder from blood and clots. Intermittent manual irrigation or continuous irrigation is recommended when necessary.


40-50% of patients with long-term indwelling catheter treatment may be affected by encrustation which causes recurrent catheter blockage, catheter bypassing or urinary tract infections. Catheter encrustation is caused by some types of bacteria, most commonly Proteus mirabilis, which is one of the intestinal bacteria. The encrustation is the result of a chain reaction after inserting an indwelling catheter. Main components are biofilm, bacteria producing urease and increased pH. As the urine becomes alkaline (pH>7), crystallization is induced.

What to do? A regular intake of fluid may prolong the time to encrustation. Perform a bladder washout or change the catheter when encrustation causes catheter blockage. BIP Foley catheters and silicone catheters have been proven to reduce adhesion of bacteria causing encrustation.

Catheter blockage

Catheter blockage can be caused by encrustation, blood clots, tissue fragments or biofilm. Blockage can also be caused by pressure on a kinked catheter or urinary bag tube. Obstipation can cause problems with the catheter outlet function.

What to do? Check the catheter and the tube of the urinary bag. Consider bladder washout with sterile saline; otherwise change the catheter if blocked. A regular intake of fluid may prolong the time for new blockage to occur. Assess bowel function.


Several things can affect the odour of the urine, such as food and fluid intake, medication or bacterial colonization. The odour may not be harmful but disturibing for the patient.

What to do? Try to adjust the food or fluid intake and check if any medication may be the source of the problem. Bactiguard coated catheters has been shown to be beneficial for some patients.

Inability to remove the catheter

It is rare that the catheter cannot be removed, but it may happen that either the balloon doesn’t deflate or the device itself is stuck to the patient’s tissue.

The catheter is stuck to the tissue – what to do?

  1. Help the patient to relax his/her pelvic floor muscle
  2. Inject sodium chloride solution or lubricant gel next to the catheter
  3. Gently try to withdraw the catheter, sometimes for a couple of minutes. Do not use force.

Inability to deflate the balloon – what to do?

  1. Remove the syringe and try a different one
  2. Gently instill another 1-2 ml sterile water in case of blockage and check the valve
  3. Use a needle and syringe to aspirate the inflation arm
  4. Do not attempt to burst the balloon by overinflating it. If a balloon should burst, cystoscopy may be required to remove balloon fragments

Alternatively: Cut the catheter, while securing it not to be drawn back into the urethra. Ultrasound guided transabdominal balloon puncture may be required.

Catheter bypassing (leakage) and urgency

Urine bypassing the catheter often occurs in combination with urgency. Leakage and urgency can depend on a variety of causes.

Size of the catheter

Why? A too large catheter puts pressure on the urethral mucosa, which can cause irritation.

What to do? Try a smaller size, but not smaller than 12 Fr in adults.

Fluid intake

Why? Too little fluid causes concentrated and dark urine that can cause irritation of the bladder.

What to do? Assess the fluid intake and try to encourage the patient to adjust drinking to give the urine a normal yellow color.

Urinary tract infection

Why? Bacteria infiltrate and irritate the mucosa in the bladder and the urethra.

What to do? On the suspicion of a urinary tract infection causing leakage and urgency, a urine culture should be taken before treatment with antibiotics.

Catheter blockage

Why? See “Catheter blockage” specific heading.

What to do? Check the flow, rinse the bladder with sterile saline and change the catheter if needed/if not unblocked.

The catheter balloon

Why? A large balloon might put a pressure on the trigonum and a small balloon glide into the bladder neck, both causing irritation.

What to do? Check the balloon size. Primary, follow the manufacturer’s recommendation.


Why? Filled bowels can cause irritation through pressure on the bladder, the urethra and the catheter.

What to do? Assess the bowel function and address constipation.

Mucosal atrophy in women after menopause

Why? The urethral mucosa in women is provided with estrogen. After menopause the hormone decreases and the urethral mucosa becomes more sensitive to the catheter.

What to do? Consider local treatment with estrogen.

Overactive bladder

Why? All of the above and neurogenic disorders might cause contractions of the muscles in the bladder wall.

What to do? Assess the different causes and address them. If there is a neurogenic disorder, drug treatment might be considered.


Source: All material has been written and reviewed by Märta Lauritzen, registered nurse and urotherapist and Helena Thulin, registered nurse and PhD, Karolinska University Hospital, Stockholm.