A urinary tract infection (UTI) occurs when bacteria, most often from the digestive tract, enter and multiply within any part of the urinary system, which includes the kidneys, ureters, bladder, and urethra. These infections are a common health concern, affecting millions of individuals annually, with women being particularly susceptible. While typically treatable with antibiotics, neglecting a UTI can lead to a cascade of worsening symptoms and significant health complications.
Initial Progression in the Bladder
When a urinary tract infection begins, it commonly affects the bladder, a condition known as cystitis. Initially, symptoms might include frequent urination, a persistent urge to urinate even with an empty bladder, and a burning sensation during urination, medically termed dysuria. Lower abdominal discomfort or pressure can also be present.
As the infection remains untreated, these localized symptoms often intensify. The discomfort in the lower abdomen can evolve into persistent pelvic pain, and the urine may become cloudy, develop a foul odor, or even show visible signs of blood, a condition known as hematuria. At this stage, bacterial proliferation can begin to irritate and potentially damage the bladder lining, leading to increased inflammation.
Spread to the Kidneys
If a bladder infection is not effectively treated, the bacteria can ascend the ureters, which are the tubes connecting the bladder to the kidneys, leading to a more severe infection of the kidneys known as pyelonephritis. Pyelonephritis is considered a medical emergency requiring prompt treatment.
Symptoms of pyelonephritis are more pronounced and systemic than those of a bladder infection. Individuals may develop a high fever, often reaching 102°F (39°C) or higher, accompanied by chills, nausea, and vomiting. A hallmark symptom is severe pain in the flank, which is the area in the back or side just below the ribs, usually indicating the affected kidney. An untreated kidney infection can result in acute kidney injury and may cause scarring of the kidney tissue, which can impair kidney function over time.
Severe Systemic Complications
The most dangerous outcome of an untreated kidney infection occurs when bacteria spread beyond the kidneys and enter the bloodstream, leading to a life-threatening condition called urosepsis or sepsis. Sepsis is the body’s overwhelming and potentially fatal response to an infection, where the immune system’s reaction begins to damage its own tissues and organs. Symptoms of sepsis can be widespread and may include confusion or disorientation, rapid heart rate, and a high respiratory rate, typically over 22 breaths per minute.
As sepsis progresses, blood pressure can drop significantly, a condition known as septic shock, which prevents adequate blood flow to organs. This can lead to multi-organ failure, affecting systems such as the kidneys, lungs, and liver, potentially resulting in kidney failure or respiratory failure. Severe or recurrent episodes of pyelonephritis can lead to long-term consequences, including chronic kidney disease and permanent kidney damage due to persistent scarring of the renal tissue.
Specific Considerations
Untreated UTIs pose heightened risks for certain groups. Pregnant individuals face an increased risk of complications such as premature labor and low birth weight. Physiological changes during pregnancy contribute to a higher susceptibility to UTIs.
In men, UTIs are less common but can signal underlying issues like prostate enlargement, and they are more prone to complicated infections, potentially involving the prostate gland, or prostatitis. Children with untreated UTIs have a higher risk of kidney scarring, leading to long-term kidney problems and high blood pressure later in life.
Elderly individuals may present with atypical symptoms such as confusion, weakness, or falls, rather than the classic urinary discomfort, making diagnosis challenging. Their weakened immune systems also put them at a higher risk for severe complications like sepsis. Individuals with compromised immune systems or underlying conditions, such as diabetes or kidney stones, face a greater likelihood of developing severe or recurrent infections.