Bladder Infection – Causes and Symptoms of Infectious Cystitis

A bladder infection is known as infectious cystitis – inflammation of the urinary bladder due to an infection. Since bacteria are the most common pathogen responsible for cystitis, it is often termed bacterial cystitis. Certain fungi, viruses and parasites may also cause inflammation of the bladder and these fall into the broad category of non-bacterial cystitis. However, it is important to note that non-bacterial cystitis may also include other non-infectious causes like inflammation due to drugs, chemicals, radiation, autoimmune diseases and other unknown causes.

How do bacteria enter the bladder?

Microorganisms more frequently reach the urinary bladder through the urethra (ascending infection). Less commonly, these pathogens may travel via the blood stream, direct infiltration from other surrounding structures that are not part of the urinary tract, like the vagina in women or rectum or it passes to the bladder through the lymphatic system.

Urine in most parts of the urinary tract is sterile. Most cases of bacterial cystitis are due to bacteria found in the rectum.  When bacteria enter through the distal urethra, it is usually passed out during urination. Coupled with the immune defenses, an infection rarely occurs without other predisposing factors.

Risk Factors for a Bladder Infection

In women, urinary tract infections (often involving the bladder) are common due to a shorter urethra. With men, a bladder infection is less likely to occur because of a longer urethra and bactericidal prostatic fluids unless there is underlying condition like benign prostatic hyperplasia, following kidney or bladder stones or other causes of bladder neck obstruction.

There are other factors that may also be responsible for an ascending infection of the  urinary tract. Some susceptible individuals have certain receptors present on the endothelial lining of the urethra to which certain strains of bacteria can attach to. This prevents it from being ‘washed out’ during urination and facilitates the infectious process. Sexual intercourse often leads to minute tears on the urethra that compromises the integrity of this part of the urinary tract.

Many fungal and viral cases may be seen in immunocompromised patients, as is seen with HIV infection or long standing uncontrolled diabetes mellitus (sugar diabetes), and sexually transmitted infections. Candida and other fungal urinary tract infections may also be a result of long term antibiotic use.

Bladder infections may arise without any of the multitude of predisposing factors being present but this is more likely to occur in acute infectious cystitis. Chronic infectious cases are almost always associated with underlying genitourinary pathology.

Other risk factors include :

• Pregnancy
• Inadequate personal hygiene
• Dehydration
• Diaphragm for birth control

Causes of Bladder Infection

There are a number of microorganisms that may cause a bladder infection. Some of the  organisms include :

Bacteria

• Escherichia coli
• Proteus mirabilis
• Streptococcus fecalis
• Staphylococcus saprophyticus
• Klebsiella spp
• Chlamydia trachomatis
• Mycobacterium tuberculosis

Virus

• Herpes simplex (HSV-1 and HSV-2)
• Adenoviruses

Fungus

• Candida albicans
• Cryptococcal spp

Parasites

• Schistosoma haematobium

Symptoms of Bladder Infection

The three cardinal symptoms (triad) of bladder inflammation, including infectious cystitis, include :

• Frequent urination, often waking at night to urinate (nocturia)
• Burning sensation or pain upon urination (dysuria)
• Pelvic pain

Other signs and symptoms of a bladder infection may vary in severity and may be absent at times. This includes :

• Blood in urine (hematuria)
• Cloudy urine
• Strong smelling urine
• Abdominal, flank and/or back pain
• Fever with/without chills
• Nausea or vomiting

Patients may also report pain during intercourse (dyspareunia) which could also be a symptom of underlying genitourinary pathology.

Article reviewed by Dr. Greg. Last updated on January 26, 2011