Definition
- Fever: ≥ 38 oC measured rectally (oral are 0.6 oC lower than rectal and axillary are 0.6 oC lower than oral
- Fever of unknown origin: daily rectal temperature >38.3oC lasting >2weeks (cause not determined through history, physical, diagnostics)
- Heatstroke: temperature >42oC with anhydrosis and coma (80% mortality)
Pathophysiology
- Raised hypothalamic set point (infection, collagen vascular disease, malignancy) –> antipyretics are helpful
- Excess heat production (salicylate overdose, hyperthyroid, environmental heat, malignant hyperthermia)
- Defective heat loss (ectodermal dysplasia, heat stroke, anticholinergic overdose)
Differential Diagnosis
- Infection:
- Viral vs bacterial
- 0-3months: UTI is most common bacterial infection (E. coli, enterococcus)
- Bacteriemia, meningitis (N meningitides if petechiae)
- HSV (neurologic findings)
- Appendix, AOM (S. pneumo, H influenzae), gastroenteritis, strep pharyngitis, bronchiolitis, pneumonia (S. pneumo, Mycoplasma pneumo, H. flu, GBS, RESV, Influenza, Parainfluenza, Adenovirus, Coxsackie)
- Cardiac abnormality – think endocarditis
- Inflammatory
- Kawasaki (5 days of high fever, truncal/polymorphous rash, bilateral nonpurulent conjunctivitis, changes in oral mucosa specifically lips and tongue, desquamation, cervical lymphadenopathy)
- Inflammatory bowel disease
- Juvenile rheumatoid arthritis
- Drugs/Toxins
- Neoplasm
- Acute lymphocytic leukemia (ALL)
- Lymphoma
Fevers that kill…
0-2 months |
2-36 months |
36+ months |
Meningitis |
Meningococcemia |
Meningococcemia |
Bacteremia/Sepsis |
Meningitis |
Appendicitis |
HSV |
Bacteremia/Sepsis |
Meningitis |
Meningoencephalitis |
Bacterial tracheitis |
Tuberculosis |
|
Appendicitis |
Acute Lymphocytic Leukemia |
|
Tuberculosis |
|
|
Kawasaki’s |
|
History
- Clarify: onset, duration, how measured, height
- Up until the age of 5 the rectal route is gold standard. Oral may be used in toddlers but thermometer should be held under tongue for ~4 minutes. The TM route is becoming more favourable. Axillary method should not be used.
- General symptoms: playful, listless, malaise, lethargy
- Systems: CNS, Resp, GI, GU, MSK, Derm
- Obstetrics: GBS status, premature rupture of membranes (PROM), premature
- Season:
- Winter – influenza, RSV
- Spring/Autumn – parainfluenza
- Summer – enterovirus
- Immunizations: encapsulated (S. pneumo, N. meningitides, HiB)
- Travel
- Animal exposure
Physical exam
- ABCs, vitals
- Assess hydration status
- Full physical (including CNS)
Rochester Criteria
- According to eMedicine:
- Rate of bacteremia
- Febrile infants younger than 2 months: 2-3%
- First month of life: 7-8%
- Infants aged 3-24 months: 3.5-4%
- Nontoxic infants aged 0-60 days (SBI): 4-16%.
- Rate of bacteremia
- Useful for identifying febrile infants (<90days of age) who are at a low risk of having a serious bacterial infection
- Infants must be previously healthy and have no history of antibiotics
- No evidence of ear, soft tissue or skeletal infection
- WBC between 5000 and 15000/mm3
- Bands <1500/mm3
- U/A with <10WBC/hpf
- If diarrhea, stool < 25WBC/hpf
Investigations
- Full septic workup:
- CBC+D
- Blood culture
- Urinalysis
- Urine culture
- Lumber puncture (LP) (especially < 2months but for exam say if less than 1 yr ALWAYS)
- +/- Chest x-ray
- Swabs (NP, throat, rectal)
- ESR
- Stool for C+S and O+P
Full septic workup for kiddies under 1 yr with lethargy and non specific symptoms (including LP)
Management
- Treatment…
- If at increased risk from complications
- If increased metabolic demands because at risk for decompensation
- If uncomfortable
- Tylenol 10-15mg/kg q4-6h
- Ibuprofen 5-10mg/kg q6-8h
- No ASA (Reye’s syndrome – post URTI/Varicella – vomiting, CNS changes, liver enlargement)
- Antibiotics (empiric antibiotics if suspected meningitis – continue until culture results back!)
- Up to 3 months
- Listeria, E. coli, GBS, pneumococcus, meningococcus, H. flu
- Amp/Gent in month 1 (synergistic)
- Amp + Cefotaxime/Ceftriaxone (good BBB penetration) in month 2-3
- Listeria, E. coli, GBS, pneumococcus, meningococcus, H. flu
- 3 months to 3 years
- May have occult bacteremia
- Teething can cause low grade fever
- Full septic workup minus LP (unless risks)
- Up to 3 months