Classification systems

Guide to classifying UTIs:

There are five widely used classification systems according to; site, severity, episode, symptoms, and complicating factors.

For acute treatment, site and severity are most important.

Classification according to:

  • Lower urinary tract infection (cystitis) is an inflammatory condition of the urinary bladder mucosa with general signs and symptoms including infection, dysuria, frequency, urgency, malodorous urine, enuresis, hematuria, and suprapubic pain.
  • Upper urinary tract infection (pyelonephritis) is a diffuse pyogenic infection of the renal pelvis and parenchyma. The onset of pyelonephritis is generally abrupt. Clinical signs and symptoms include fever (> 38°C), chills, costovertebral angle or flank pain, and tenderness.
  • In a lower urinary tract infection, children may have only mild pyrexia; are able to take fluids and oral medication; are only slightly or not dehydrated; and have a good expected level of compliance.
  • When a low level of compliance is expected, such children should be managed as those with severe UTI. In severe UTI, infection is related to the presence of fever of > 39°C, the feeling of being ill, persistent vomiting, and moderate or severe dehydration. Most severe UTIs are upper urinary tract infections.

Classification according to episode:

  • First
  • Persistent
  • Recurrent
  • Breakthrough
  • Classification according to symptoms:
    - Typical symptoms
    - Atypical symptoms
  • In neonates and infants, the most common symptoms are fever, vomiting, lethargy and/or irritability.
  • Infants and children may have non-specific signs such as poor appetite, failure to thrive, lethargy, irritability, vomiting or diarrhea.
  • Toilet trained children may report cystitis symptoms along with fever/flank pain.
  • Uncomplicated UTI
    Infection occurs in a patient with a morphologically and functionally normal upper and lower urinary tract, normal renal function and competent immune system.
  • Complicated UTI
    That occurs in children with known mechanical or functional pathology of the urinary tract.
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