Urinary Tract Infections

Essentials

Differential diagnosis

Asymptomatic bacteriuria Antibiotics for Asymptomatic Bacteriuria, Antibiotics Vs. No Treatment for Asymptomatic Bacteriuria in Pregnancy

• Only in pregnant women should asymptomatic bacteriuria be screened for and treated Antibiotics Vs. No Treatment for Asymptomatic Bacteriuria in Pregnancy.
• Advancing age, diseases and declining functional capacity increase the prevalence of asymptomatic bacteriuria; see Table T6.

Cystitis in female patient Antibiotic Duration for Lower Urinary Tract Infections in Elderly Women, Duration of Antibacterial Treatment for Uncomplicated Urinary Tract Infection in Women, Antimicrobial Agents for Treating Uncomplicated Urinary Tract Infection in Women

• It is not necessary to collect a urine specimenin occasional acute cystitis of a woman aged 18 to 65 years if the clinical picture is unambiguous.
  • Rapid tests (chemical screening of urine, particle count in urine) can be used to confirm the diagnosis in clinically unclear cases.
• Narrow-spectrum antimicrobial drugs (trimethoprim, nitrofurantoin, pivmecillinam) are the primary choice. Duration of treatment is 3 days Duration of Antibacterial Treatment for Uncomplicated Urinary Tract Infection in Women (see table T1).
• If the patient's urine flow is abnormal due to functional or structural defects or if the patient has renal failure, longer antimicrobial courses (5-7 days) may be necessary.

• Gram-negative ESBL bacteria produce extended spectrum beta-lactamases and are thus resistant to penicillins and cephalosporins.

Acute pyelonephritis Oral Treatment for Symptomatic Severe Urinary Tract Infections in Non-Elderly, Treatment Duration of Febrile Urinary Tract Infection

• Fever and flank or back pain, as well as CRP concentration > 40 mg/l, suggest a renal level infection. Urinary symptoms may be absent.
• A patient with pyelonephritis who is in good general condition can be treated at home with oral medication Oral Treatment for Symptomatic Severe Urinary Tract Infections in Non-Elderly. Treatment duration with fluoroquinolones is 5-7 days in women and 10-14 days in men Treatment Duration of Febrile Urinary Tract Infection, and 7-14 days with other antimicrobial agents (table T2).
• Because of fluoroquinolone-resistant pathogens, checking the urine culture results is especially important in those patients with pyelonephritis whose treatment was started with empirical fluoroquinolone therapy.

UTI in a male patient

• UTIs in men require further urological investigations.
• Prostatic hyperplasia Benign Prostatic Hyperplasia predisposes the patient to infections.
  • The prostate should be palpated and the amount of residual urine determined Determining the Volume of Residual Urine by Ultrasonography. If indicated, plasma PSA and creatinine should also be determined.
• For treatment, see Table T8
• In a febrile UTI, treatment duration is 10-14 days (table T2).
  • UTI in men is often associated with prostatitis or epididymitis.
  • Palpation of the prostate and the scrotal organs is indicated.
  • Effective concentrations will not be achieved in the prostate with nitrofurantoin or pivmecillinam.
  • A urologist should be consulted after a febrile infection.
• Acute prostatitis Acute Bacterial Prostatitis is a rare infection with severe symptoms; almost all cases are sequelae of a recent prostate biopsy.
• Chronic bacterial prostatitis Chronic Prostatitis should be suspected if the UTI recurs after treatment (same causative bacteria).
• If bacterial culture remains negative, the condition in question may be chronic pelvic pain syndrome Syndroma Pelvis Spastica.

UTI during pregnancy Treatments for Symptomatic Urinary Tract Infections during Pregnancy, Safety of Nitrofurantoin during Pregnancy, Antibiotics Vs. No Treatment for Asymptomatic Bacteriuria in Pregnancy, Duration of Antibiotic Treatment in Asymptomatic Bacteriuria in Pregnancy

• The eradication of infection must be confirmed by culture.
• Asymptomatic bacteriuria should be treated and monitored as cystitis since it may predispose the patient to pyelonephritis and premature delivery Antibiotics Vs. No Treatment for Asymptomatic Bacteriuria in Pregnancy.
• The recommended treatment duration in cystitis and asymptomatic bacteriuria is 3-7 days Duration of Antibiotic Treatment in Asymptomatic Bacteriuria in Pregnancy; see table T3
• Treatment for pyelonephritis during pregnancy should be initiated at a hospital.
  • Cefuroxime1.5 g 3 times daily i.v.
  • Ceftriaxone is also effective when administered intramuscularly and it can be chosen as the initial drug, if dosage once per 24 h or intramuscular administration are of benefit.
  • Further treatment with oral first generation cephalosporins, e.g. cephalexin 500 mg 4 times daily for 10 days
• Nitrofurantoin prophylaxis may be considered in recurrent UTIs during pregnancy.

UTI among residents in long-term care facilities

• Asymptomatic bacteriuria is common among these patients, and urine cultures should be taken and empirical treatment started only after other possible diseases and infections that may be affecting the patient's general condition have been excluded and if, based on clinical signs and symptoms, a decision has been made to treat the UTI with antibiotics.
• Due to the multiplicity and variety of the causative agents and their changing sensitivity to antimicrobials, a urine specimen for culture should always be obtained when UTI in an institutionalized patient is treated with antimicrobials.
• The antimicrobial drug should be chosen individually according to the epidemiological situation in the institution and the patient's clinical condition; the aim should be to use antimicrobials with the narrowest possible spectrum.

Recurrent UTI

• The same strain: recurrence within 2 weeks after treatment (relapse)
• A new strain, or recurrence more than 2 weeks after treatment (reinfection)
• In recurrent cystitis, prophylactic antimicrobial medication is used only if non-pharmacological treatment and, in postmenopausal women, topical oestrogen has/have been found ineffective. Antibiotics for Preventing Recurrent Urinary Tract Infection (Uti) in Non-Pregnant Women. An alternative to continuous medication is advance prescription of courses of therapy to be taken in case of recurrence.
  • With increased antimicrobial resistance, prophylactic antimicrobial treatment of UTI is not very effective
  • It may have significant adverse effects; particularly in elderly patients taking ACE inhibitors, angiotensin receptor blockers or spironolactone, there is a risk of hyperkalaemia Trimethoprim or Trimethoprim-Sulfamethoxazole and Risk of Hyperkalaemia Among Patients Taking Renin-Angiotensin System Blockers or even sudden death Trimethoprim or Trimethoprim-Sulfamethoxazole and Risk of Hyperkalaemia Among Patients Taking Renin-Angiotensin System Blockers.
  • The effect ends when the prophylactic medication is discontinued.
  • Increased antimicrobial resistance is another disadvantage.
  • The efficacy of prophylactic medication has not been studied in elderly patients with multiple diseases.
• Checklist for patients with at least three UTIs within one year: see Table T9.

• Checklist before starting prophylactic antimicrobial treatment:
  • Are there any contraindications?
  • Will a postcoital dose be sufficient?
    • In women who have recurrent UTIs that are clearly associated with sexual intercourse, single-dose postcoital antimicrobial prophylaxis is effective T5 Antibiotic Prophylaxis after Predisposing Events (Including Postcoital Prophylaxis) for Prevention of Recurrent Cystitis.
• Can a course of antimicrobial medication be prescribed for the particular patient to have at home in case need arises?
  • Patients should be reminded to contact health care if symptoms do not subside in 2 days.
• Are there any factors supporting the use of prophylactic antimicrobial medication?
  • Immunosuppression, renal level infections, patient severely frustrated with the situation
• Antimicrobial treatment for the prevention of recurrent cystitis
  • Alternatives: 50-75 mg nitrofurantoin or 100 mg trimethoprim in the evening
    • Nitrofurantoin should not be chosen if eGFR is < 50 ml/min/1.73 m² .
  • Methenamine hippurate (1 g twice daily) is more effective than placebo but less effective than antibiotics in the prevention of UTIs Methenamine Hippurate for Preventing Urinary Tract Infections.
  • In renal failure, beta-lactam antibiotics (e.g. cephalexin 250 mg once daily) can be used for prophylaxis.

Further investigations

• Imaging studies or urological investigations of the urinary tract are not necessary in women who have recurrent episodes of cystitis or a single episode of pyelonephritis.
• Consultation with a urologist is recommended in a febrile UTI of a male patient.
• Investigations are warranted if
  • an acute pyelonephritis recurs or there is no response to appropriate treatment within a few days
  • there are signs of an obstruction to the urine flow or other clearly complicating factors.
• Abdominal pains in conjunction with pyelonephritis or an atypical causative agent (e.g. proteus or candida) are indications for ruling out renal infection stones.
• The first-line additional investigation is renal ultrasonography.