Virtsatieinfektion

Virtsatieinfektion (urinary tract infection) is an infection of the urinary system, most often caused by bacteria that ascend from the urethra to the bladder. The majority involve the lower urinary tract, causing cystitis or urethritis, but infections can also reach the kidneys, leading to pyelonephritis. Escherichia coli is the most common causative organism; other bacteria include Klebsiella, Proteus, and Staphylococcus saprophyticus. UTIs are more common in women than men due to anatomical differences and hormonal factors, and risk increases with age, diabetes, urinary retention, catheter use, and pregnancy.

Symptoms commonly include painful urination (dysuria), a frequent urge to urinate, suprapubic discomfort, and cloudy or foul-smelling urine. Blood in the urine may occur. Fever and flank pain suggest upper tract involvement. In older adults, infections may present with nonspecific symptoms such as confusion or weakness.

Diagnosis relies on clinical history and urinalysis, which may show leukocyte esterase and nitrites. A urine culture can confirm the infecting organism and guide treatment in complicated cases, persistent symptoms, or recurrent infections.

Treatment typically involves antibiotics. Uncomplicated cystitis in nonpregnant adults is usually treated with a short course (3–7 days) of agents such as nitrofurantoin, trimethoprim-sulfamethoxazole, or fosfomycin. Pyelonephritis or severe illness may require longer therapy and sometimes initial intravenous antibiotics. Pregnancy requires careful selection of antibiotics and clinical supervision. Recurrent infections may warrant preventive strategies, including hydration, urinating after intercourse, and, in selected cases, prophylactic antibiotics.

Prognosis is generally favorable with appropriate treatment, though untimely or recurrent infections can lead to complications such as kidney involvement or sepsis.