A urinary tract infection (UTI) is a common condition where bacteria invade and multiply within the urinary system, which includes the kidneys, ureters, bladder, and urethra. Millions of people experience UTIs each year, with women being particularly susceptible due to their shorter urethras. Whether these infections can cause back pain depends significantly on the infection’s location within the urinary tract.
Understanding Urinary Tract Infections
A urinary tract infection occurs when germs, most often bacteria from the digestive tract like E. coli, enter the opening of the urethra and begin to multiply. UTIs are categorized into two main types: lower UTIs and upper UTIs. Lower UTIs affect the urethra (urethritis) or the bladder (cystitis). These infections cause localized discomfort related to urination.
Upper UTIs are more serious, involving the ureters and kidneys, a condition referred to as pyelonephritis. While lower UTIs primarily cause discomfort during urination, upper UTIs often present with more widespread symptoms. Only upper UTIs, specifically kidney infections, are commonly associated with back pain.
How UTIs Can Cause Back Pain
Back pain from a UTI indicates the infection has progressed to the kidneys, leading to pyelonephritis. The kidneys are situated in the back, between the lower ribs and the hips. When bacteria infect these organs, the resulting inflammation and swelling can irritate the kidney tissues and the surrounding renal capsule.
This irritation activates pain receptors, which send signals through the spinal nerves to the brain, causing pain in the flank, side, or lower back region. The swelling and pressure on the kidneys can also lead to muscle spasms and stiffness in the surrounding areas. The back pain associated with a kidney infection is often described as a dull, constant ache, though it can also be sharp or intense, and may occur on one or both sides. This pain can sometimes radiate upwards to the upper back or to the abdomen and groin.
Accompanying Symptoms of a UTI
When a UTI has advanced to affect the kidneys, it presents with a range of symptoms beyond back pain. Individuals may experience an increased need to urinate, often accompanied by a burning sensation during urination. The urine might appear cloudy, have a strong odor, or contain visible blood.
Systemic symptoms, indicating a more widespread infection, can also develop. These include fever, chills, nausea, and vomiting. Some individuals might also feel tired or weak. These additional symptoms help differentiate a kidney infection from other causes of back pain.
When to Seek Medical Attention
It is important to seek medical care promptly if a UTI is suspected, especially if back pain is present. Untreated UTIs, particularly those that have spread to the kidneys, can lead to serious complications such as kidney damage, kidney failure, or sepsis, a life-threatening condition where bacteria enter the bloodstream.
Immediate medical attention is advised if back pain is accompanied by a high fever (above 101°F or 38.3°C), persistent nausea, or vomiting. Other red flag symptoms include severe back or flank pain, blood in the urine, or changes in mental state, such as confusion, particularly in older adults. While mild UTIs may be treated with oral antibiotics, severe kidney infections often require intravenous antibiotics and sometimes hospitalization to prevent further complications.