Pediatric fever Ddx
Posted by dkwinter

See also:
     Age-appropriate Pediatric Fever Without a Source workup

     Associated localizing symptoms
     Sick contacts
     Day care
     Anything remarkable
     Vital signs
     Neck exam
     CV exam
     Abdominal exam
     Skin exam--rash
          Almost any virus can be accompanied by rash in the pediatric patient, and it is not always necessary to ascertain which virus is causing the illness. If the illness is prolonged or particularly bothersome, antibody titers can be ordered to determine the exact etiology of the illness.
     Physical exam
     CBC, electolytes
     Urine culture
     Blood culture
     LP-CSF analysis, esp if <3mo
     Neonatal sepsis
     Acute otitis media
     Gastroenteritis (viral, bacterial, parasitic)
     Rubeola (Measles)
     Other viral exanthem
     Occult bacteremia
     Food poisoning
     Fifth disease (Parvovirus B19 infection)
     Scarlet fever
     Pneumatic otoscopy--key to look for the decreased TM mobility seen in otitis media
     Tympanometry--useful in infants >6 months of age; confirmed abnormal TM mobility in otitis media
     CBC with differential, blood culture--notably, a WBC >15k/uL is suggestive of occult bacteremia
     Platelets, PT/PTT, D-dimer, fibrin split products, fibrinogen--evidence of DIC is often seen in meningococcemia
     UA and urine culture--UTI may be occult and must be investigated
     LP--CSF analysis--should be performed if there is any concern for meningitis.
          CSF analysis includes cell count and differential, glucose, protein, Gram stain, culture, latex agglutination for common bacterial antigens, and occasionally PCR for specific viruses
     CT-head--used mainly to rule out brain abscess or hemorrhage
     CXR--to dx pneumonia
     Throat culture--to isolate Streptococcus pyogenes (which causes Scarlet fever)
     Parvovirus B19 IgM antibody--the best marker of acute or recent infection in suspected fifth disease
     Skin lesion scrapings--varicella antigens are identifiable by PCR or direct immunofluorescence (DFA) of skin lesions. Also a Tzanck smear may show multinucleated giant cells in varicella infection.
     Varicella antibody titer--may be useful in uncertain cases (look for a fourfold rise in antibody titer following acute infection)
     Bronchoscopy--a diagnostic aid in severe or refractory pneumonia cases
     Serum antibody titers--to identify causative viruses in pediatric infections (not commonly used)
     U/S--renal--to look for anatomic anomalies that predispose to UTI
     Voiding cystourethrogram--to look for vesicourethral reflex in UTI