Approach to fever without a source in completely immunized* children 6 to 36 months of age

UTI: urinary tract infection; CVA: costovertebral angle; LE: leukocyte esterase; WBC: white blood cell; HPF: high-power field.

* Complete immunization means that the child has received the primary series of 3 immunizations with conjugate vaccines against Streptococcus pneumoniae (PCV7 or PCV13) and at least 2 or 3 doses, depending upon vaccine formulation, of Haemophilus influenzae type B (Hib). Some experts consider 2 doses of PCV7 or PCV13 sufficient to prevent invasive S. pneumoniae infection.

¶ Potential sources of fever in children include a focal bacterial illness such as pneumonia, cellulitis, abscess, bacterial arthritis, or osteomyelitis; or a defined viral syndrome such as croup, bronchiolitis, herpetic stomatitis, influenza, COVID-19, or hand, foot, and mouth disease. In addition, patients who meet criteria for Kawasaki disease (ie, 3 or more of the following: fever for >4 days, bilateral bulbar conjunctival injection, oral mucous membrane changes, peripheral extremity changes, polymorphous rash, or cervical lymphadenopathy) or Multisystem Inflammatory Syndrome in Children (fever for 24 hours or longer, laboratory evidence of inflammation, severe illness requiring hospitalization with two or more organ systems involved, recent or current SARS-CoV-2 infection or exposure, and no plausible alternative diagnosis) should be excluded from this algorithm.

Δ Urine culture should be obtained by bladder catheterization or, in toilet-trained children, clean-catch urine.