Cystitis is a common condition that causes inflammation of the bladder. It leads to symptoms like pain and burning during urination, frequent and urgent need to urinate, and lower abdominal discomfort. Understanding the leading cause of cystitis can help guide prevention and treatment approaches.
What is Cystitis?
Cystitis refers to inflammation of the bladder, typically due to an infection. It is a common condition, particularly among women, that leads to irritating urinary symptoms. The medical term for cystitis is cystourethritis or bladder infection.
The bladder is a hollow, muscular organ that stores urine produced by the kidneys. It expands like a balloon as it fills with urine. Cystitis causes the bladder lining to become inflamed, irritated, and swollen. This leads to a burning feeling and pain when trying to urinate.
There are a few different types of cystitis:
- Acute cystitis – a sudden short-term bladder infection, usually caused by E. coli bacteria.
- Recurrent cystitis – repeated bouts of acute cystitis.
- Interstitial cystitis – a chronic bladder condition leading to long-term pelvic pain and frequent urination. It is not caused by infection.
- Radiation cystitis – bladder inflammation after pelvic radiation therapy treatments.
- Drug-induced cystitis – bladder irritation from certain medications, like chemotherapy.
Acute cystitis from a bacterial infection is the most common cause of bladder inflammation. Women tend to get cystitis more often than men due to their shorter urethras.
What Causes Cystitis?
The leading cause of acute and recurrent cystitis is a urinary tract infection. Bacteria are typically introduced to the bladder through the urethra and multiply, infecting the bladder wall lining.
The most common causative bacteria is Escherichia coli (E. coli), accounting for up to 90% of acute bladder infections. Certain strains of E coli have features that help them adhere to and invade the bladder lining.
Other bacteria that can sometimes cause cystitis include:
- Klebsiella
- Proteus
- Enterobacter
- Pseudomonas
- Staphylococcus
- Streptococcus
Less commonly, bladder inflammation may be caused by a fungus, virus, or chemical irritation. Interstitial cystitis also leads to similar urinary symptoms as cystitis, but it is not caused by an infection. Instead, it involves a defect in the bladder lining itself.
Risk Factors
Certain factors can increase susceptibility to developing cystitis.
Female Anatomy
Females have a much greater risk due to their shorter urethra, which allows bacteria quick access to the bladder. The urethra’s proximity to the rectum also increases chances of getting coliform bacteria like E. coli into the urinary tract.
Sexual Activity
Sexual intercourse can introduce bacteria into the urinary tract, so increased frequency of intercourse raises cystitis risk. Using spermicides and diaphragms has also been associated with recurrent bladder infections.
Menopause
After menopause, decreased estrogen levels lead to changes in vaginal flora and the urinary tract that can predispose women to cystitis.
Urinary Tract Abnormalities
Any urinary tract structural or functional issues that block urine flow and cause incomplete bladder emptying increase risk of infection. Examples include kidney stones, enlarged prostate, and neurogenic bladder.
Catheters
Indwelling catheters, like those used during hospitalization or for conditions like incontinence, drastically increase chances of introducing bacteria into the urinary tract.
Personal Hygiene
Wiping from back to front after using the toilet can expose the urethra to bacteria from the rectum. Douching can also upset the normal vaginal flora balance.
Genetics
There seems to be some genetic predisposition to recurrent cystitis. Some women have inherent differences in immune response or vaginal environment that make them more prone to getting UTIs.
Diabetes
Women with diabetes have higher glucose levels in their urine, which allows bacteria to grow more rapidly.
Weakened Immune System
Any condition that impairs the body’s normal immune response allows bacteria to more easily colonize the bladder, like HIV, chemotherapy, or immunosuppressant medication use.
Diagnosing Cystitis
Cystitis may be suspected based on symptoms of burning with urination, pelvic discomfort, and increased urinary frequency and urgency. It can be confirmed via urinalysis and urine culture.
Urinalysis
This dipstick test of a urine sample detects levels of white blood cells and bacteria. High levels indicate inflammation and infection. Microscopic urine examination may also show increased white blood cells.
Urine Culture
This test pinpoints the specific bacteria causing the infection and identifies which antibiotic it is susceptible to. Urine is incubated to allow any bacteria present to multiply. A culture is considered positive if over 100,000 colony-forming units of a typical UTI bacteria are found per milliliter.
Other Tests
Your doctor may order additional tests like a CT scan or cystoscopy (bladder scope exam) if an anatomical abnormality is suspected. Bloodwork can also check for conditions like diabetes that may be contributing to recurrent cystitis.
Number One Cause of Cystitis
The number one cause of cystitis is an acute bladder infection, most often caused by the bacteria Escherichia coli. It accounts for up to 90% of sudden onset (acute) cases of cystitis.
E. coli Bacteria
Escherichia coli normally lives in the digestive tract without causing issues. However, certain strains have virulence factors that allow them to infect the urinary tract. E. coli is the most common cause of urinary tract infections, including cystitis.
Virulence factors possessed by uropathogenic E. coli include:
- Pili – tiny hair-like projections that help E. coli adhere to the bladder wall.
- Toxins – damages cells in the bladder lining.
- Polysaccharide coating – helps the bacteria evade the immune response.
After entering the urethra, E. coli travels up to the bladder, where it attaches to cells and causes inflammation and injury to the bladder lining. This triggers the painful symptoms of cystitis.
Recurrence
Even after treatment with antibiotics, E. coli cystitis recurs frequently. Recurrent cystitis is defined as 2 or more episodes within 6 months, or 3 or more episodes within 1 year. About 25-30% of women who get an initial UTI will experience recurrences.
Recurrence is thought to be due to E. coli embedding in the bladder cells, forming reservoirs unaffected by antibiotics. Stress, sexual intercourse, or other factors can reactivate the infection. The same strain of E. coli generally causes repeated episodes in susceptible individuals.
Other Common Causes
While E. coli accounts for the large majority of cystitis cases, other bacteria can sometimes overgrow and infect the bladder, including:
Staphylococcus saprophyticus
Staph saprophyticus is the second most common cause of UTIs, responsible for 5-15% of infections. It tends to affect younger women and sexually active women.
Klebsiella
Klebsiella species cause up to 5% of UTIs. Klebsiella is among the most concerning causes of cystitis due to its resistance to multiple antibiotics.
Proteus
Proteus mirabilis is found in 1-2% of UTIs. It forms stones and crystalline biofilms in the bladder that can block urine flow.
Prevention
To help avoid recurrent episodes of E. coli cystitis, some key prevention approaches include:
- Urinate after sexual intercourse to flush away bacteria.
- Wipe front to back after using the toilet.
- Drink plenty of fluids, especially water.
- Avoid potentially irritating feminine products.
- Take showers instead of baths.
- Urinate as soon as you feel the urge.
- Consider taking preventive antibiotics after sexual intercourse if UTIs are frequent.
- Maintain good hygiene of the genital area.
Treatment
Most cases of acute cystitis can be successfully treated with a course of oral antibiotic medication. Some options include:
- Trimethoprim/sulfamethoxazole – considered first-line treatment
- Fluoroquinolones like ciprofloxacin or levofloxacin
- Nitrofurantoin – cannot be used for upper UTIs though
- Fosfomycin
The choice of antibiotic depends on local resistance patterns and patient factors. Usually a 3-7 day course is prescribed. Symptoms should start improving within a few days.
For recurrent UTIs, extended-release antibiotics taken daily or post-coital antibiotics may be prescribed. Other options include vaginal estrogen therapy in postmenopausal women and bladder instillations. Probiotics may help prevent recurrences.
When to See a Doctor
You should seek medical care if you experience the following:
- Fever or flank pain – may indicate kidney infection
- Vomiting – may suggest upper UTI
- Bloody urine
- Failure to respond to over-the-counter UTI medications
- More than 2 UTIs in 6 months or 3 per year – recurrent infections need evaluation
Seeking prompt medical treatment is important if a kidney infection is suspected, as this can lead to serious complications if left untreated. Recurrent UTIs also warrant further investigation and specialized care.
Conclusion
In summary, the number one cause of cystitis is Escherichia coli, accounting for up to 90% of acute bladder infections. Certain E. coli strains possess virulence factors that facilitate colonization and invasion of the normally sterile urinary tract. Recurrent cystitis is also frequently due to repeat E. coli UTIs.
Other less common causes of cystitis include Staphylococcus saprophyticus, Klebsiella, and Proteus species. However, E. coli remains the predominant causative bacteria in both sporadic and recurrent cases.
Cystitis treatment targets the underlying bacterial infection, usually with oral antibiotics. Preventing repeat infections through protective measures and behavioral modifications is also important. Seeking prompt medical care for severe or recurrent cystitis is advised.