Febrile Child. Mark Bromley PGY 2 Adam Oster FRCPC. Agenda. 1. Pathophysiology (briefly). 2. Young Infants (1 – 3 months). 3. Neonates (Birth – 1 month). 4. 3 months – 3 years. What is Fever?. An elevation of body temperature?
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Febrile Child Mark Bromley PGY 2 Adam Oster FRCPC
Agenda 1. Pathophysiology (briefly) 2. Young Infants (1 – 3 months) 3. Neonates (Birth – 1 month) 4. 3 months – 3 years
What is Fever? • An elevation of body temperature? • Fever is an ↑ temperature as part of a specific biological response, mediated and controlled by the CNS • Not heat stress • Not heat illness
NORMAL BODY TEMPERATURE • Varies over the course of the day (circadian rhythm) • Normal daily temperature variation is 0.5 ºC • ↑ after an illness • Is controlled by the thermoregulatory center located in the anterior hypothalamus
(Pyrogens)Infectious agents / Toxins / Mediators of inflammation • Cellular sources: monocytes, neutrophils, lymphocytes • Many others, when stimulated Infectious • Most exogenous pyrogenic substances are from • Bacterial • Fungal • Viruses • Induce pyrogenic cytokines by infecting cells Non-Infectious • Inflammation • Trauma • Antigen-antibody complexes
Temperature Regulation Heat Gain Clothing Behaviour Liver Muscle HYPOTHALIMUS Lungs Skin Heat Loss
Case • 2 month ♂ • Previously well • No meds • Vaccines are up to date • HPI • 2 day history of fever • This AM he is more irritable & ↓PO intake • Rhinorrhea and non-productive cough • Baby looks good …but you think you should probably check vitals How would you like to check temp?
What is a fever • Wunderlich • 1 million measurements in 25,000 patients • Determined the upper limit of normal • Infants • Rectal temp >38oC
What is a Fever • Rectum: Gold Standard • > 38oC to > 38.2oC ….depending on the study and local custom • Not influenced by ambient temperature and its use is not limited by age • It is frightening for small children and may be psychologically harmful for older children. • Discomfort and is painful for patients with peri-rectal infxn / irritation • Varies depending how deeply the thermometer is inserted into the rectum, local blood flow, and the presence of stool and diarrhoea • May lag behind a rapidly changing core temp ?poor blood flow to the rectum • In the presence of shock, perfusion of the bowel, including the rectum, may be markedly impaired, and RT will lag significantly behind changing core temp
What is a Fever • TACTILE • Oldest and still the most widely used method of evaluating body temp • Inaccurate, mainly because of the lowering of skin temp during the early phase of fever • Operator dependent • Medical staff 42% accurate • Mothers 80% accurate • Axilla • Safe, easily accessible, and reasonably comfortable • requires supervision in case displacement occurs • takes longer than rectal or sublingual measurement (5min mercury 40–80s electronic) • inaccurate • Fever » vasoconstriction » skin temperature cooling as the core temperature rises • Sweating and evaporation cause the AT to be lower than the core body temperature • Rectal temperature and AT differed by up to 3°C and AT was occasionally very low
What is a Fever • Oral • generally 0.6 ºC lower than rectal temp b/c of mouth breathing • Tympanic • 60% of total heat loss from the body occurs via radiation in the form of infrared heat rays • ↑ during fever • As the tympanic membrane receives its blood supply from the carotid artery, its temperature may reflect that of blood flowing into the hypothalamus • A suitable detector without a probe contact can measure the infrared rays emitted by the tympanic membrane • Benefits: • Fast and easy to use • No risk of cross infection • Not influenced by environmental temp • Deficits: • Inaccurate in children < 3 years
Subjects: Children < 2y presenting to an acute care site • Each child had 6 temps taken • Temporal: 3 by nursing + 2 by parents • Rectal: 1 by nursing • Results: • Good correlation • Conclusions: • Variability too high for infants < 3months • Max temp of 3 taken may be a useful screening measure
Design: Cross-sectional agreement emergency department study • Subjects: 327 children <24 months of age • Methods: Temp measured rectally & Temporally by a single nurse • Outcome Measures: • Temp cut-off to detect rectal fever ≥38.0°C and ≥ 38.3°C • Sensitivities of >=90% and >=95% was determined
Results: • The mean difference between the rectal minus TAPM was -0.19°C ± 0.66°C • The sensitivities of TAPM temperature of ≥37.7°C to detect rectal fever • ≥ 38.0°C / 90% (95% confidence interval: 0.83; 0.94) • ≥ 38.3°C / 97% (95% confidence interval: 0.92; 0.99) • Conclusions: • The TAPM thermometer cannot replace the rectal • TAPM temperature of <37.7°C can be safely used as a screen to exclude rectal fever ≥ 38.3°C in infants 3 to 24 months
What do we do at the ACH? • Under 3 months rectal • Temporal for the rest
Case Continued • Vitals: 125 25 80/46 37.8oC • What do you want to do? • Are you worried? • Is this kid hiding bacteria? • Does Mom’s tactile fever count?
N=292 infants • Age < 2 months with a Hx of fever who were admitted for possible sepsis • Among the 19 infants with serious bacterial infection, all exhibited abnormal clinical and/or laboratory features on evaluation that were suggestive of underlying serious infection
Case • 2 month male • Sniffles and loosening stools x 2days • ↓feeding • PMHx: previously well • Birth history • SVD at term • Maternal GBS status negative • No maternal history of STI • Unremarkable nursery course
What is your approach? • Is this a low risk kind of baby? …high risk kind of baby
HISTORY • Associated symptoms (resp, GI) • Behaviors (feeding, irritability, activity) • Sick contacts (siblings, babysitters, day care) • Previous illness, or antibiotics • Birth history • maternal fever, • maternal group B streptococcus status (prophylaxis) • maternal history of STI (HSV, gonorrhea & chlamydia) • PROM • the infant's nursery course
Relying solely on clinical exam results in missed SBIs in this age group • Lab testing is required
We are looking for the high risk children …ideally a rule with • Great sensitivity • Good specificity • Excellent for those of us with limited clinical experience
Boston (Low Risk) Criteria Fever ≥ 38.0 oC • ≥ 37 weeks gestation • Infant was previously well • Infant was well appearing • (no soft tissue / ear / bone infections) HISTORY 29-89 days old LAB • WBC ≤ 20/uL • Urinalysis < 10 WBC/hpf (No Bacteria) • CSF ≤ 10 WBC/mm3 • Stool < 5 WBC/hpf • CXR – Normal When Obtained
Boston Criteria • Low Risk • Ceftriaxone 50mg/kg • Discharged with follow-up • Results: • 27 patients (5.4%) had a SBI • 9 (1.8%) had bacteremia • 8 (1.6%) had urinary tract infections w/o bacteremia • 10 (2.0%) had bacterial gastroenteritis w/o bacteremia • 476 (94.6%) did not • Conclusions: • Of the 27 infants with SBIs Clinical screening criteria did not enable discrimination between infants with and without SBI • All infants with SBI received an appropriate course of ABx and were well at follow-up • One infant had osteomyelitis diagnosed 1 week after entry into the study, received an appropriate course of IV ABx, and recovered fully Outpatient treatment of febrile infants 28 to 89 days of age with intramuscular administration of ceftriaxone Pages 22-27 Marc N. Baskin, Edward J. O'Rourke and Gary R. Fleisher
hilidelphia (Low Risk) Criteria Fever ≥ 38.2 oC • ≥ 37 weeks gestation • Infant was previously well • Infant was well appearing • (no soft tissue / ear / bone infections) HISTORY 29-56 days old LAB • WBC ≤ 15/uL (band:neutrophil ≤ 0.2) • Urinalysis < 10 WBC/hpf (No Bacteria) • CSF ≤ 8 WBC/mm3 • CXR – Normal • Stool < 5 WBC/hpf & no blood When Obtained
hilidelphia Criteria • Low Risk • Discharged with follow-up • Results: • N=422 • 43 patients (10%) had a SBI – all were “High Risk” • Low Risk: 101 – no SBIs • Conclusions: • Of the 27 infants with SBIs Clinical screening criteria did not enable discrimination between infants with and without SBI • All infants with SBI received an appropriate course of ABx and were well at follow-up • One infant had osteomyelitis diagnosed 1 week after entry into the study, received an appropriate course of IV ABx, and recovered fully Byington CL, Rittichier KK, Bassett KE, et al. Serious bacterial infections in febrile infants younger than 90 days of age: the importance of ampicillin-resistant pathogens. Pediatrics 2003;111(5 Pt 1):964–8.
Rochester (Low Risk) Criteria Fever ≥ 38.0 oC • ≥ 37 weeks gestation • Infant was previously well • Infant was well appearing • (no soft tissue / ear / bone infections) < 60 days old HISTORY LAB • WBC 5–15/uL • Urinalysis < 10 WBC/hpf (No Bacteria) • Stool < 5 WBC/hpf • CXR When Obtained
High Risk: Hospitalized + Emperic Abx • Low Risk: Sent Home • (reasonable follow-up)
Neonatal fever: utility of the Rochester criteria in determining low risk for serious bacterial infections • Design: retrospective study • Population: 134 patients younger than 29 days …fever without a source evaluated in the ED • Results: • Employing the Rochester criteria to the fully cultured neonates who could be risk-stratified, the sensitivity 86.4% • specificity 46.4% • positive predictive value 26.8% • negative predictive value 93.8% Neonatal fever: utility of the Rochester criteria in determining low risk for serious bacterial infections. Ferrera PC; Bartfield JM; Snyder HS Am J Emerg Med 1997 May;15(3):299-302.
Low Risk High Risk Term Well Appearance No Focus of Infxn WBC < 15 Urinalysis<10/hpf CXR – no infiltrate Stool – no blood few WBCs Age < 28d* Look Toxic Fail Criteria When Obtained *Ferrera PC et al Neonatal fever: utility of the Rochester criteria in determining low risk for serious bacterial infections. Am J Emerg Med. 1997;15:299-302 *Kadish et al. Applying outpatient protocols in febrile infants 1-28 days of age: can the threshold be lowered? Clin Pediatr. 2000;39:81-88 *Baker MD, Bell LM. Unpredictability of serious bacterial illness in febrile infants from birth to 1 month of age. Arch Pediatr Adolesc Med. 1999;153:508-511
High risk management? • Full septic work up • Hospital admission • Empiric antibiotics • CSF clear : 24h ceftriaxone • CSF pleocytosis: 48h Amp/Ceftriaxone …consider Vancomycin • Urine positive: Amp/Gent (cultures)
Low risk management A) Blood/urine/CSF cultures Ceftriaxone IM single dose Re-evaluation in 24h B) Urine culture No abx therapy Careful observation
Lumbar Puncture • Boston/Phily Criteria require it • Rochester does not • Bacterial meningitis is rare (4.1/1000) • PE and peripheral WBC are unreliable ∴ strongly consider LP • ?Antibiotics
Management of febrile (38ºC) healthy infant 28-90 days without source
Case • 20 day male PMHx • SVD at term • GBS negative Mom • Apgars 9/9 • Discharged at 24 hours HPI • Mother took a temp at 38.2oC • He has been feeding well with good weight gain • Not irritable or lethargic
In the ED 38.3oC 140 80/45 24 • Looks well / active / bright • Normal tone • Are you worried? • What would you like to do?
Issues in the 0-30 day old • Immature immune system • Improves steadily in the first three months of life • The immunologic task switches at birth from this coexistent state (graft preservation) to protection from invading pathogens • Neonates are more susceptible to SBI than older infants
Issues in the 0-30 day old • Exposure to pathogens in the birth canal • Do not exhibit classic signs of sepsis • May deteriorate quickly • May not be able to mount a fever • ++ with prems
Etiology Vertical Transmission Family Hospital workers • Viral (most common)* • HSV • Varicella • Enterovirus • Influenza • Adenovirus • RSV • Bacterial* ~12% • Maternal Flora • GBS • Gram negative organisms ( E Coli) • Listeria • Strep Pneumo • H. Influenza ↑ Prevalence with Age *Baskin, MN. The prevalence of serious bacterial infections by age in febrile infants during the first 3 months of life. Pediatr Ann 1993; 22:462. *Baker, MD, Bell, LM. Unpredictability of serious bacterial illness in febrile infants from birth to 1 month of age. Arch Pediatr Adolesc Med 1999;153:508.
Sources of (SBI) Infection Infants ages 29 to 56 days who presented to an ED with rectal temperatures ≥38.2ºC Baker, MD, Bell, LM, Avner, JR. Outpatient management without antibiotics of fever in selected infants. N Engl J Med 1993; 329:1437.
The young febrile infant may demonstrate few, if any, interpretable clues to the underlying illness
Infants between 1 and 28 days old with a fever should be presumed to have a serious bacterial infection (Level A)
Case • 8 day ♀ • Presents with fevers, irritability and poor feeding • PMHx: • SVD at term • No Maternal Risk Factors • PE: No obvious source • CBC: WBC 8.6 …The nurse asks “do we really need to do the LP? What are the chances of meningitis with a normal WBC?”
[Ann Emerg Med. 2003;41:206-214] • Methods: logistic regression modeling and receiver operating characteristic curve analysis of peripheral blood WBC count and cerebrospinal fluid WBC count • Subjects: 3-89 day-old infants undergoing a sepsis evaluation • Results: 22 of 5,353 infants had bacterial meningitis • For diagnosing acute bacterial meningitis, the peripheral blood WBC count was poorly discriminating and significantly inferior to the cerebrospinal fluid WBC count • When relying on single and interval-based high-risk thresholds of peripheral blood WBC counts alone, the majority of infants with acute bacterial meningitis would have been missed. • Conclusion: Decisions to perform or withhold lumbar puncture should not be based on prevailing interpretations of the total peripheral blood WBC counts to maximize detection of bacterial meningitis in young infants