Urinary tract infections (UTIs): Causes, symptoms, risk factors, and treatment

Are you experiencing pain or burning sensations when urinating, having unusual pelvic or flank pain, or other urinary problems? You might need to see a doctor because you might have a urinary tract infection (UTI) that is causing your symptoms.

Image showing internal organs of the body

Key takeaways

  • Urinary tract infections (UTIs) are infections that occur in the urinary system and are usually caused by bacteria.
  • UTIs are typically treatable but can cause some complications if left untreated or poorly treated.
  • People who suspect they have a urinary tract infection should consider consulting a healthcare provider. Their healthcare providers may order tests like urinalysis and a full blood count (FBC) for a proper diagnosis and recommend treatments, depending on the microorganism that caused the infection.

Urinary tract infections (UTIs) are common infections of the urinary system. The urinary system is responsible for removing waste products from the body in the form of urine and consists of the kidneys, ureters, bladder, and urethra. The kidneys are two bean-shaped organs located at the back, at the angle between the last ribs and the spine, responsible for urine production. The ureters are two tubes through which the urine passes to the bladder for temporary storage before it is sent out of the body through the urethra. 

The urinary system also helps in maintaining pH and electrolyte balance and producing hormones that help in regulating blood pressure and producing blood cells, among others. Ideally, this tract is free of bacteria, and its one-way flow helps keep the tract free from microorganisms. Nevertheless, microorganisms (particularly bacteria) can find their way into the tract. When this happens, urinary tract infection (UTI) sets in.

Urinary tract infections can affect anybody, regardless of age and gender. However, it's mostly seen in women, babies, and elderly people. About 60% of women and 12% of men develop UTIs once in their lifetimes, accounting for about 8 million visits to various health facilities. This shows that women are more prone to UTIs than men. 

This article will discuss everything about urinary tract infections, their causes, symptoms, risk factors, and treatment.

What is a urinary tract infection?

Urinary tract infections are infections that occur in the urinary system. They happen when bacteria, often from the anus or genitals, enter the urethra and infect the urinary tract. UTI can affect any part of the tract but is more commonly seen to affect the bladder than other parts of the tract. 

Owing to the fact that the length of the female urethra is short and is closer to the vagina and anus, bacteria easily enter the urinary tract. This makes women more prone to UTIs than males.

Types of urinary tract infections and their symptoms

The types of infection and symptoms depend on the part of the urinary tract affected. The different types of UTIs and their symptoms include:


Urethritis is an infection of the urethra, the tube that transmits urine from the bladder to the outside of the body. Aside from UTIs, urethritis can also be caused by sexually transmitted infections (STIs)

Some symptoms of urethritis are:


This is the most common type of UTI. Cystitis is an infection of the bladder caused primarily by bacteria. However, it can be noninfectious. 

Symptoms of cystitis may include:

  • Having a strong, persistent urge to urinate (urinary urgency)
  • Feeling of pain or burning sensation when urinating
  • Blood in the urine
  • Cloudy or foul-smelling urine
  • Pelvic pain 
  • A feeling of full bladder after urinating


Pyelonephritis is an infection of the kidney caused by an ascending infection from the bladder or urethra. It is a less common type of UTI but it can be a serious issue. 

Some of its symptoms are:

  • Fever
  • Chills
  • Nausea and vomiting
  • Pain in the flank (side of the abdomen) or lower back
  • Passing bloody or cloudy urine

Causes of UTI

UTIs are caused by microorganisms, usually bacteria. Large numbers of microorganisms live in the area around the vagina and rectum, as well as on the skin. These microorganisms may find their way into the urethra and may travel into the bladder or kidneys. This causes inflammation and irritation in the lining of the tract, leading to infection.

Escherichia coli (E. coli) is the major bacterium causing UTIs. It causes about 80% to 85% of both lower and upper urinary tract infections. Other causative bacteria may include Staphylococcus saprophyticus, Enterococcus faecalis, Proteus mirabilis, and Klebsiella pneumonia.

Additionally, fungi, mostly the candida species, and viruses, especially the herpes simplex virus, can cause infection of the urethra and can ascend the urinary tract to infect other urinary organs.

Risk factors of UTI

Some factors make some people more prone to having UTIs than others. They include:

  • Menopause: Reduced estrogen in menopausal women causes thinning of the lining of the genitourinary tract, putting them at risk of getting UTIs. Also, changes in the vaginal flora (bacteria that are normally present in the vagina) can increase the risk.
  • People with diabetes and a weakened immune system: A compromised immune system weakens the ability of the body to fight even simple, uncomplicated infections, leading to recurrent infections in people with conditions like this. Additionally, in people with diabetes, the high glucose (sugar) in their urine can create an environment for bacterial growth. This increases their risk of having UTIs.
  • Pregnancy: In pregnancy, the ureters dilate and kink, causing stasis of urine, which can be a breeding environment for microorganisms.
  • Prostatitis: In prostatitis, the prostate gland is enlarged. This can obstruct the flow of urine, thereby creating an environment for bacterial growth.
  • Kidney stones: Stones (calculi) in the kidney or along the tract can cause reduced flow of urine or obstruction along the tract, leading to the growth of bacteria.
  • Use of urethral catheter: catheterization, which is the use of tubes to allow urine to pass out of the bladder, may increase the risk of developing UTIs. People with neurological problems who are mostly on catheters are more prone to this.
  • Use of certain birth control methods: using birth control methods that contain spermicides can cause changes in the bacterial flora, creating room for disease-causing bacteria to grow.

Other risk factors for UTI may include:

  • Previous cases of UTI
  • Poor sexual hygiene
  • Poor personal hygiene
  • Age (children and older people are more likely to get UTIs)

Complications of UTI

UTIs are treatable. However, when left untreated or poorly treated, it can cause complications. Some complications of UTI include:

  • Sepsis: This is a serious medical condition where a person's body has a severe response to an infection.
  • Congenital problems in babies, e.g., hypospadias, spina bifida, congenital cataract, and small intestine atresia/stenosis, and pregnancy complications, e.g., preterm delivery, low birth weight, intrauterine growth retardation, and preeclampsia, when UTI occurs in pregnancy. 
  • Repeated urinary tract infections
  • Kidney damage
  • Narrowed urethra in men as a result of repeated infections

How to know if you have a UTI

Some symptoms that can point towards having UTIs include:

  • Frequent urination
  • Pain or burning sensation when urinating
  • Urinary urgency
  • Flank or lower abdominal pain
  • Feeling of full bladder after urination

If you're experiencing any of the above symptoms, it's best to consult a healthcare provider for a proper examination and treatment.

Diagnosis and treatment for UTI

Diagnosis of UTI is based on a medical history, physical examination, and laboratory findings.

Your doctor will ask you some questions about the symptoms you've been having. The above-mentioned symptoms might prompt the doctor to suspect you have a UTI. A laboratory investigation will confirm this finding. Some of the laboratory  investigations for UTI include:

  • Urinalysis: Urine analysis is a diagnostic test done to examine a urine sample for various components like cells, bacteria, substances, and other indicators of illness.
  • Urine microscopy, culture, and sensitivity (M/C/S): This is done to check the type of microorganism causing the infection and the likely drug the organism is sensitive to.
  • Full blood count (FBC):  FBC is a common blood test that provides information about the blood cells, e.g., red blood cells, white blood cells, and platelets. This test helps detect conditions like anemia, infections, blood disorders, and certain cancers. 

In cases of complicated or recurrent UTIs, your doctor might send you for a radiological investigation to see if there are structural problems putting you at risk of the infection. These investigations include:

  • Ultrasonography
  • Computed tomography scan (CT scan)
  • Magnetic resonance imaging (MRI)

Furthermore, treatment of UTIs depends on the causative organism. In cases of bacterial infections, antibiotics are used as the first line of treatment. Some of the antibiotics used in the treatment of UTIs include nitrofurantoin, cephalosporin antibiotics (e.g., ceftriaxone), trimethoprim/sulfamethoxazole, or quinolones antibiotics (e.g., ciprofloxacin). Doctors also sometimes prescribe pain relievers to help alleviate the pain felt during urination. 

In addition to the use of drugs, it's important to drink plenty of water and urinate frequently to help flush the organisms out of the body.

Can UTI go away on its own without treatment?

"Simple, uncomplicated UTIs in people with strong immune systems and with no background risk factors for recurrent infections are most likely to go on their own without any treatment," said Dr. Abolore Adewale, a consultant nephrologist at the Federal Teaching Hospital, Lokoja, Kogi State, Nigeria, "however, in most instances, antibiotics may be prescribed for a few days to help combat the infections."

How fast do antibiotics cure UTIs?

"In simple, uncomplicated UTIs, antibiotics are prescribed for about 5-7 days, while in complicated UTIs and for people with background risk factors for recurrent UTIs, they are given for about two weeks," said Dr. Adewale. 

He added that prescribed medications usually work to resolve the infection within the first week of treatment, but patients are advised to ensure they finish their antibiotic regimen to prevent antimicrobial resistance. 

Tips for preventing UTI

Here are some tips that can help reduce one's risk of having UTIs:

  • Drink enough water.
  • Practice good personal hygiene.
  • Urinate frequently and avoid holding back the urge to urinate.
  • Avoid using irritating feminine products in the vulva area.
  • Treat vaginal infections, e.g., thrush.
  • Wipe the vulva from front to back.
  • Keep the genitals dry. Avoid wearing underwear that will keep the genitals moist and create an environment for bacterial growth.
  • Practice good sexual hygiene, e.g., wash hands before and after sex, take a bath after sexual activity, and urinate after sex.

When to seek medical care

You need to see your doctor if you experience the above-mentioned symptoms suggestive of urinary tract infections. Additionally, if you've been placed on drugs for the treatment of UTIs and your symptoms persist or get worse, be sure to complain to your healthcare provider for a proper evaluation of your condition.

Here are some questions you can ask your doctor about your condition:

  • What caused my UTI?
  • Do I have predisposing factors for UTIs?
  • Am I at risk of having complications?
  • What is the prognosis for my condition?
  • Are there some home remedies that I can use for my treatment?

You can also ask any other questions of concern to you, and your healthcare provider will explain everything you need to know.