What Is Urinary Tract Infection?
A urinary tract infection is an infection of the urinary tract, which includes the kidneys, bladder, and urethra. Urinary tract infections are usually caused by infections by fecal bacteria.
Symptoms of urinary tract infections include pain with urination (dysuria), cloudy urine (pyuria), feeling the urge to urinate, needing to urinate more frequently, blood in the urine (hematuria), inability to control the bladder or pain in the lower abdomen. Infections of the upper urinary tract may cause fever and chills, nausea and vomiting, and flank pain.
Treatment includes antibiotic medications, pain medications, and intravenous fluids.
You should go to your primary care physician, an urgent care, or a walk-in clinic to be treated. UTIs must be treated with antibiotics as soon as possible to prevent the infection from getting worse and/or spreading.
How common is Urinary Tract Infection?
Urinary Tract Infection is also known as
- Bladder infection
- Kidney infection
Urinary Tract Infection Symptoms
Urinary tract infections are diagnosed by clinical evaluation and laboratory testing of urine, with urine culture indicated in some cases. The symptoms of a urinary tract infection generally differ based on whether the infection is in the lower urinary tract (cystitis) or the upper urinary tract (pyelonephritis). Symptoms of cystitis include:
- Pain with urination: The pain usually comes on suddenly and lasts for less than a week, although in some cases may last longer.
- Needing to urinate more frequently or feeling the urge to urinate: This may occur because the infection and inflammation irritate the urinary tract.
- Blood in the urine (hematuria): In some cases, there is a small amount of blood that can only be seen under a microscope. In other cases, there may be enough blood that the urine turns red.
- Inability to control the bladder (urinary incontinence): Some people with urinary tract infections, particularly older individuals, may develop an inability to control the bladder. They may also experience urination at night while they are sleeping.
- Pain in the lower abdomen above the pubic area: This area may be tender if pushed upon. This occurs in approximately 10 to 20 percent of women with acute uncomplicated cystitis .
- Confusion: Among older people, urinary tract infections may cause confusion or a change in mental status. In some cases, this may be the only symptom in older individuals.
People with pyelonephritis may have the symptoms listed above. In addition, they may also experience:
- Pain in the flank area: Some people with pyelonephritis may experience pain in the flank area, which is where the kidneys are located. The area may be painful if pushed on.
- Fever and/or chills: In some cases, the chills may be severe enough that the individual is visibly shaking. In severe cases, the individual may become very ill-appearing, especially if the infection spreads to the bloodstream.
- Nausea and vomiting: Some people with pyelonephritis may develop nausea and vomiting.
Urinary Tract Infection Causes
Most urinary tract infections are caused by bacteria, although some cases may be caused by fungi. The urinary tract can be divided into an upper part and a lower part. The upper part consists of two kidneys, which produce urine, as well as ureters that lead from each kidney to the bladder. The lower part consists of the bladder, which stores urine, as well as the urethra, which passes urine.
An infection of the upper urinary tract is known as pyelonephritis. An infection of the lower urinary tract is known as cystitis. Generally, pyelonephritis causes more severe symptoms than cystitis. Urinary tract infections can also be classified as uncomplicated or complicated, which refers to cases in individuals with abnormal urinary tracts or additional risk factors such as a weakened immune system or pregnancy .
Specific causes and risk factors for developing a urinary tract infection include infections by fecal bacteria, sexual intercourse, having an underlying urinary tract problem, having a urinary catheter, having a weakened immune system, and having an infection in the blood.
Infection of the urinary tract by fecal bacteria
The primary cause of urinary tract infections is an infection of the urinary tract by fecal bacteria. Because the anal area is located close to the urethra (which passes urine), fecal bacteria can colonize the urinary tract and possibly ascend up to the urinary tract to the bladder or kidneys, causing an infection. Because the urethra in women is located closer to the anal area than the urethra in men, women are much more likely to get urinary tract infections. The most common bacteria that causes urinary tract infections is Escherichia coli or E. coli, which causes approximately 75 to 95 percent of cases of uncomplicated cystitis and pyelonephritis .
Having sexual intercourse
Having sexual intercourse increases the risk of developing a urinary tract infection because it exposes the urinary tract to bacteria. The risk of developing a urinary tract infection is increased among individuals with a new sex partner within the past year. Among men, having anal intercourse, in particular, increases the risk of developing a urinary tract infection.
Having an underlying problem with the urinary tract
Underlying problems of the urinary tract may include conditions such as having kidney stones, strictures (a narrowing in the urinary tract that can occur after surgery), or stents (which can be placed in the urinary tract to keep a passage open).
Having a urinary catheter
The risk is greatest with having an indwelling urinary catheter, since leaving it in place for many days increases the risk of infection. Having a bladder catheter placed in a way that is not sterile also increases the risk of developing a urinary tract infection.
Having a weakened immune system
Having a weakened immune system increases the risk of developing many infections, including urinary tract infections. This can occur in people with certain medical conditions such as HIV or diabetes, as well as in people receiving medications that weaken the immune system such as chemotherapy.
Having an infection in the blood
In some cases, having an infection in the blood can lead to the development of a urinary tract infection. In particular, bacteria in the blood can spread to the kidneys, causing pyelonephritis .
Treatment Options and Prevention
Urinary tract infections are primarily treated with antibiotic medications. People with cystitis and non-severe pyelonephritis are usually treated as an outpatient with oral medications. People with severe pyelonephritis may be treated in the hospital with intravenous medications. Specific treatments include the following.
People with urinary tract infections are typically treated with antibiotic medications to treat the infection. The specific antibiotic used will vary depending on the severity of infection, the organism causing the infection, and other factors.
- Oral antibiotics: Examples of oral antibiotics that may be used include nitrofurantoin (Macrobid), trimethoprim-sulfamethoxazole (Bactrim), amoxicillin-clavulanate (Augmentin), ciprofloxacin (Cipro), or levofloxacin (Levaquin), among others.
- IV antibiotics: People with pyelonephritis may receive intravenous antibiotic medications such as ceftriaxone (Rocephin), cefepime (Maxipime), vancomycin, among others.
In most cases, pain associated with urinary tract infections will get better with antibiotic treatment. However, some people may benefit from taking short-term medications to relieve the pain. In particular, phenazopyridine is a pain medication available over-the-counter that can help relieve urinary pain .
In cases of severe pyelonephritis, you may need to receive intravenous fluids to maintain your hydration until the infection is improved and you are able to maintain hydration on your own through oral liquids.
For people with recurrent urinary tract infections
People with recurrent urinary tract infections (three or more urinary tract infections in the past 12 months, or two or more urinary tract infections in the past six months) can reduce their risk of developing a recurrent urinary tract infection by approximately 95 percent by taking an antibiotic medication regularly as prophylaxis . Examples of antibiotics that may be recommended as prophylaxis include nitrofurantoin (Macrobid), trimethoprim-sulfamethoxazole (Bactrim), cephalexin (Keflex), and fosfomycin (Monurol).
When to Seek Further Consultation
If you develop any symptoms of a urinary tract infection such as pain with urination, urinary frequency or urgency, blood in the urine, or abdominal or flank pain, you should see your physician. Your physician can perform an evaluation to determine if you have a urinary tract infection, and the offer the appropriate treatment.
Questions Your Doctor May Ask to Diagnose
To diagnose this condition, your doctor would likely ask about the following symptoms and risk factors.
- Have you experienced any nausea?
- Do you have a rash?
- Any fever today or during the last week?
- How would you describe the nature of your abdominal pain?
- Is your abdominal pain getting better or worse?
The above questions are also covered by our A.I. Health Assistant.
- Colgan R, Williams M. Diagnosis and treatment of acute uncomplicated cystitis. Am Fam Physician. 2011 Oct 1;84(7):771-6. AAFP Link
- Czaja CA, Scholes D, Hooton TM, Stamm WE. Population-based epidemiologic analysis of acute pyelonephritis. Clin Infect Dis. 2007;45(3):273-280. NCBI Link
- What is kidney (renal) infection - pyelonephritis? Urology Care Foundation. Urology Care Foundation
- Wang A, Nizran P, Malone MA, Riley T. Urinary tract infections. Prim Care. 2013;40(3):687-706. NCBI Link
- Hooton TM. Recurrent urinary tract infection in women. Int J Antimicrob Agents. 2001;17(4):259-268. NCBI Link