Fever of unknown Fever of unknown originorigin

Dr Rafat MosalliDr Rafat Mosalli

Different body sitesDifferent body sites

• RectalRectal standardstandard• OralOral 0.5-0.60.5-0.6 lowerlower• AxillaryAxillary 0.8-1.00.8-1.0 lowerlower• Tympanic 0.5-0.6Tympanic 0.5-0.6 lowerlower

Documented:Documented:• In the absence of antipyreticsIn the absence of antipyretics• In ED or office or by hx from reliable In ED or office or by hx from reliable

parents/adultsparents/adults

Fever Without SourceFever Without Source

• ““An acute febrile illness in which An acute febrile illness in which the etiology of the fever is not the etiology of the fever is not apparent after a careful history apparent after a careful history and physical examination.”and physical examination.”

Baraff et al, Pediatrics Baraff et al, Pediatrics 1993; 92:1-121993; 92:1-12

Fever of Unknown Fever of Unknown OriginOrigin

1. 1. Fever of 38Fever of 38C or greater which C or greater which has has continued for a 2 to 3 weeks continued for a 2 to 3 weeks

2. 2. Absence of localizing clinical Absence of localizing clinical signssigns

3. 3. Negative simple investigationsNegative simple investigations

Occult bacteremiaOccult bacteremia

• “…“…a positive blood culture in the a positive blood culture in the setting of well appearance and setting of well appearance and without focus (e.g. no pneumonia)without focus (e.g. no pneumonia)

• Fleisher et al, J Pediatrics 1994Fleisher et al, J Pediatrics 1994

Serious Bacterial Serious Bacterial InfectionInfection

• “…“…Include meningitis, sepsis, bone Include meningitis, sepsis, bone and joint infections, urinary tract and joint infections, urinary tract infections, pneumonia and enteritis”infections, pneumonia and enteritis”

Baraff et al, Pediatrics 1993; 92:1-Baraff et al, Pediatrics 1993; 92:1-1212

Frequency of febrile Frequency of febrile illnessillness

• 35% of unscheduled ambulatory 35% of unscheduled ambulatory care visitscare visits

• 65% of kids see doc before age 2y65% of kids see doc before age 2y• Majority (75%) for T < 39 Majority (75%) for T < 39 C C • 13% T > 39.513% T > 39.5

EpidemiologyEpidemiology

• Incidence of bacteremia in febrile Incidence of bacteremia in febrile infants in post-Hib erainfants in post-Hib era

• 2-3% 2-3% if < 2 months, T > 38if < 2 months, T > 38CC

• < 2% if 3-36 months, T >39< 2% if 3-36 months, T >39CC

Occult bacteremia Occult bacteremia organismsorganisms

• Streptococcus pneumoniaStreptococcus pneumonia > 85% > 85%

• Neisseria meningitidisNeisseria meningitidis 3-5% 3-5%

• Others:Others:• S. aureusS. aureus• S. pyogenesS. pyogenes (GAS) (GAS)• SalmonellaSalmonella species species• Haemophilus influenzaeHaemophilus influenzae type B type B

(now (now rarerare – previously 10%) – previously 10%)

Outcomes of occult bacteremia Outcomes of occult bacteremia without antibioticswithout antibiotics

• Persistent feverPersistent fever 56%56%• Persistent bacteremiaPersistent bacteremia 21%21%• MeningitisMeningitis 9%9%

• S. pneumoniaS. pneumonia 6% 6%• H. InfluenzaeH. Influenzae 26% (now rare) 26% (now rare)

Should fever be Should fever be treatedtreated??

• ProsPros• Decrease discomfortDecrease discomfort• Calm the familyCalm the family• Extreme (>41Extreme (>41C) may cause C) may cause

permanent brain damage permanent brain damage rare,rare,rarerare,rare,rare

• Decrease risk of febrile convulsions in Decrease risk of febrile convulsions in prone kids??prone kids??

Should fever be Should fever be treatedtreated??

• ConsCons• Adverse effect of antipyretic may Adverse effect of antipyretic may

outweigh benefitsoutweigh benefits• May obscure diagnostic/prognostic May obscure diagnostic/prognostic

signssigns• Fever usually short-lived and benignFever usually short-lived and benign• Fever is normal and adaptive Fever is normal and adaptive

physiologic responsephysiologic response

What is the eventual What is the eventual etiology of fever in etiology of fever in children with FUOchildren with FUO??

How should a child with How should a child with FUO be evaluatedFUO be evaluated??

• FUO is more likely to be an unusual FUO is more likely to be an unusual presentation of a common disorder presentation of a common disorder than a common presentation of a than a common presentation of a rare disorder. rare disorder.

• detailed history and thorough detailed history and thorough physical examinationphysical examination

• avoid indiscriminately ordering a avoid indiscriminately ordering a large battery of tests. large battery of tests.

CausesCauses

Evaluation optionsEvaluation options

[ ] CBC[ ] CBC[ ] blood culture[ ] blood culture[ ] urinalysis [ ] urinalysis [ ] urine culture[ ] urine culture[ ] CXR[ ] CXR[ ] LP[ ] LP[ ] Nothing[ ] Nothing

Management optionsManagement options

[ ] Admit[ ] Admit[ ]Treat empirically, or[ ]Treat empirically, or

[ ]Observe, no treatment[ ]Observe, no treatment

[ ] Send home, follow-up within 24 [ ] Send home, follow-up within 24 hourshours

[ ]Treat empirically, or[ ]Treat empirically, or

[ ]No treatment[ ]No treatment

Treatment optionsTreatment options

[ ] Oral [ ] Oral

[ ]Amoxicillin[ ]Amoxicillin[ ]Amoxicillin/clavulanate[ ]Amoxicillin/clavulanate[ ]Other[ ]Other

[ ] Intravenous[ ] Intravenous

[ ]Ceftriaxone[ ]Ceftriaxone[ ]Other[ ]Other

Fever Without SourceFever Without SourceAge 3 – 36 MonthsAge 3 – 36 Months

• Risk of occult bacteremia Risk of occult bacteremia

• 3-11%, mean 3-11%, mean 4.3%4.3% for T>39 for T>39CC

• Risk greater withRisk greater with• Higher temperaturesHigher temperatures• WBC > 15,000 (WBC > 15,000 (13%13% vs vs 2.6%2.6%))

• Risk of pneumococcal meningitis (w/o Risk of pneumococcal meningitis (w/o abx tx) abx tx) 0.21% (1:500)0.21% (1:500)

FWS – age 3-36 months:FWS – age 3-36 months:Consensus RecommendationsConsensus Recommendations

• CHILD APPEARS TCHILD APPEARS TOXIC:OXIC:

• ADMIT to hospitalADMIT to hospital• Sepsis w/uSepsis w/u• Parenteral abxParenteral abx

FWS – age 3-36 months:FWS – age 3-36 months:Consensus RecommendationsConsensus Recommendations

• CHILD NON-TOXIC, T < 39CHILD NON-TOXIC, T < 39CC

• No diagnostic tests or antibioticsNo diagnostic tests or antibiotics• Acetaminophen 15 mg/kg prn for Acetaminophen 15 mg/kg prn for

feverfever• Return if fever persists > 48 hours or Return if fever persists > 48 hours or

clinical condition deterioratesclinical condition deteriorates

Heptavalent conjugate Heptavalent conjugate pneumococcal vaccinepneumococcal vaccine

• very efficaciousvery efficacious• Likely to make most of the foregoing Likely to make most of the foregoing

pneumococcal in 3-36 month group pneumococcal in 3-36 month group obsoleteobsolete

• Finally become routine by MCHFinally become routine by MCH

Given at 2,4,6 month and 12-15mGiven at 2,4,6 month and 12-15m