Why Urinary Tract Infections Occur

25 November, 2020
You can know why urinary tract infections occur by analyzing the conditions that predispose them. Every age and circumstance has its own risk factors. In this article, we’ll delve deeper into this.

To understand why urinary tract infections (UTIs) occur, it’s important to first define what this type of infection is. In the same way, it’s essential to understand what the predisposing factors are. A urinary tract infection is an infection that occurs in any part of the urinary system. This mainly includes the urethra, bladder, ureters, and kidneys.

It’s a quite common infection. In this regard, it’s estimated that up to 50% of women have suffered from it at least once. This represents a lot of consultations regarding urinary symptoms, particularly in health services that serve a lot of female patients.

For you to be able to understand why urinary tract infections occur, first we must clarify that their origin is bacterial. These microorganisms ascend from the urethra and install themselves in one of the urinary organs, causing symptoms when they colonize.

The symptoms of urinary tract infections according to location

Before we delve right into why urinary tract infections occur, we’ll talk about their symptoms first. We know that, according to its location within the urinary system, the symptoms they cause vary.

When the infection is in the kidneys, it’s called pyelonephritis. This clinical picture is the most dangerous, as it manifests with high fever, vomiting, and back pain. On the other hand, cystitis is an infection of the bladder. This is the most common form. Its main symptoms are burning urination and repetitive urination. Some patients may even suffer from lower abdomen pain.

Finally, there’s urethritis, which is the urinary tract infection that colonizes the urethra. It mainly manifests with a urethral discharge that’s confused with sexually transmitted diseases. This makes it essential to clarify the diagnosis with complementary methods.

A digital representation of the bladder.

Keep reading: 5 Drinks to Fight UTI, Urinary Tract Infections

Why UTIs occur: risk factors

It’s important to list the risk factors of this condition. These are situations or characteristics that, if present, make this infection more likely. It doesn’t mean that having one of these risk factors is an indispensable condition for a urinary tract infection. However, they may favor its appearance.

The risk is increased by:

  • Being a woman. Women are more prone to urinary tract infections. Their shorter urethra facilitates the rise of bacteria from the outside.
  • Sexual activity. At the stage of active sexuality, women may suffer from sex-induced cystitis. This is a quite common clinical picture that has a characteristic time of onset.
  • Menopause. When a woman stops menstruating, her estrogen levels drop. As she has less estrogen, her mucosa dries out, including the mucosa of the urinary tract. That dryness favors the rise of bacteria.
  • Urinary obstructions. If the urinary system is blocked by any cause, the bacteria can breed there. Here, we can mention kidney stones, prostatic hypertrophy in men, and the use of catheters for medical reasons due to more serious pathology.

Causes of urinary tract infections by location

As we mentioned above, a urinary infection may affect the upper or lower part of the urinary system. According to the location, certain causes will also be more common than others.

  • The main cause of pyelonephritis is the rise of bacteria from the bladder. The clinical picture usually begins as cystitis (bladder infection) that doesn’t resolve properly.
  • Most cystitis cases are caused by Escherichia coli. Although other bacteria can also cause cystitis, they’re isolated cases that aren’t common. When a person has cystitis symptoms, the doctor quickly suspects that the culprit is Escherichia coli.
  • On the other hand, an infection of the urethra has another range of causes. Escherichia coli isn’t the only star bacteria of urethritis. The proximity of the urethra and vagina in women makes microorganisms, such as chlamydia and mycoplasma, other causes of this infection.
A woman urinating.

Keep discovering in this article: Pain When Urinating: Causes and Symptoms

UTIs often occur differently depending on your age

Finally, you can also analyze why urinary tract infections occur depending on the sufferer’s age. At different ages, some causes are more likely and others cease to be:

  • In young women, cystitis often comes with the practice of sex.
  • During menopause, women who have stopped menstruating have urinary tract infections due to lower estrogen levels.
  • Next, men over 40 have an increased risk of prostatic hypertrophy. An enlarged prostate obstructs urine flow, favoring infections.
  • Finally, in the elderly, the risk factor is hospitalization. This is because hospitalizations are often accompanied by urinary catheter placement.
  • Andreu, Antonia, et al. “Diagnóstico microbiológico de las infecciones del tracto urinario.” Enfermedades Infecciosas y Microbiología Clínica 29.1 (2011): 52-57.
  • Jiménez, J. F., E. Broseta, and M. Gobernado. “Infección urinaria.” Actas Urol Esp 26.7 (2002): 563-573.
  • Durán, Ana María Guzmán, and Andrés Valdivieso Dávila. “Infección urinaria: diagnóstico y tratamiento.” ARS MEDICA Revista de Ciencias Médicas 26.3 (2018).