Fever in Family PracticeFever in Family Practice

Don Spencer, MD October 6, 2000 UNC Department of Family Medicine

Topics:Topics:Fever in Family PracticeFever in Family Practice

Febrile Child

Temperature Measurement

Fever Syndromes

Pathophysiology

Geriatric Fevers

FUO

Treatment

Tympanic AxillaryDefinition

OBSBI AAP

Toxicity Parental Anxiety

Overall

Febrile Sz PFAPAUTIPneumonia

MeasurementMeasurement

Tympanic thermometer

Definition of fever

Axillary thermometer

Measurement: TympanicMeasurement: Tympanic

Impairment of IR sensor from water vapor

Measurement: TympanicMeasurement: Tympanic

Chicago marathon

Measurement: Axillary, Measurement: Axillary, Forehead (Shann)Forehead (Shann)

120 patients Paired differences and SD’s, not correlation

coefficients “The axillary temperature can be measured safely

at any age, and the axillary temperature plus 1 degree C is a good guide to the rectal temperature in patients older than 1 month. Forehead strip thermometers are easy to use, but they do not estimate the rectal temperature as accurately as the axillary temperature does”

Measurement: Definition of Measurement: Definition of FeverFever

38 C degrees (100.4 F) Rectal Unbundled No antipyretics Diurnal variation 1deg.C (Kruse)

– Highest later afternoon, early evening

FUOFUO

FUO: Causes (Arnow)FUO: Causes (Arnow)

FUO: Causes Over TimeFUO: Causes Over Time

FUO: EvaluationFUO: Evaluation

Febrile ChildFebrile Child

Serious Bacterial Infection

Occult Bacteremia

Parental Anxiety

AAP Guidelines

Overall Approach

Toxicity

Febrile Child: ToxicityFebrile Child: Toxicity lethargy

– poor eye contact, interaction with people/environment

signs of poor perfusion marked hypoventilation or hyperventilation cyanosis Toxic and <90 days old

– 17% probability of having a serious bacterial infection including an 11% probability of bacteremia and a 4% probability of meningitis

Febrile Child: SBIFebrile Child: SBI Age categories

– <1 months– 2-3 months– 3-36 months

meningitis septicemia bone and joint infection urinary tract infection pneumonia bacterial gastroenteritis

Febrile Child: SBI CriteriaFebrile Child: SBI Criteria Yale Acute Illness Observation Scale

– quality of crying– reaction to parent stimulation– state variation– color– state of hydration– response (talk, smile) to social overtures

specificity of 88% and a sensitivity of 77% (<24mos)

Febrile Child: SBI CriteriaFebrile Child: SBI Criteria Rochester Criteria T>=38, Age <= 60 days 99.5% NPV for bacteremia

– appear well– were previously healthy– have no focal infection– have WBC count 5000-15 000/mm3– band form count<=1500/mm3)– <=10 WBC per high power field on microscopic examination of

spun urine sediment– <=5 WBC per high power field on microscopic examination of a

stool smear (if diarrhea).

Febrile Child: SBI CriteriaFebrile Child: SBI Criteria Febrile infants <=60 days of age who meet the Rochester

criteria may be managed by observation without antimicrobial therapy or alternatively may receive intramuscular ceftriaxone as a single dose. Blood and urine specimens for bacterial culture should be obtained on all infants, and, if antimicrobial therapy is chosen, a lumbar puncture should be performed and cerebrospinal fluid cultured for bacterial pathogens prior to the administration of the antimicrobial agent. These management options may be exercised in either the inpatient or outpatient setting. Infants who are managed as outpatients require close observation by competent caregivers at home and availability of a responsible physician for follow-up. Infants who meet the Rochester criteria but who cannot be adequately observed at home should be hospitalized though not necessarily treated.

Febrile Child: Occult Febrile Child: Occult BacteremiaBacteremia

1970’s (Cont Ped 6/97, Jeffrey R. Avner, MD) S pneumoniae

– 65%-75% frequency– 4%-7% invasion rate

H influenzae type b (1980’s data)– 10%-20%– 7%-20%

N meningitidis– 5%-15%

– 25%-35% Salmonella species

– 5%-15%– ?

Febrile Child: OBFebrile Child: OB Risk of occult bacteremia for a given

temperature– >39.4°

3%

– >40.0° 6%

– >40.5° 13%

– >41.1° 26%

Contrasted with no change in risk for SBI

Febrile Child: OBFebrile Child: OB Risk of occult bacteremia for a given wbc

– 5,000 100% sensitivity, 3% PPV

– 10,000 92%, 5%

– 15,000 65%, 8%

– 20,000 38%, 13%

– 25,000 23%, 19%

Febrile Child: OB (Avner)Febrile Child: OB (Avner) “We know that fewer than 3% of these children have

bacteremia, and that the vast majority of these bacteremias are caused by pneumococcus. More than 94% of cases of pneumococcal bacteremia resolve spontaneously and do not progress to meningitis, even without antibiotics.”

“The widespread use of Hib immunization has made OB caused by Hib a rare event.”

“Based on comparison to actual incidence figures, meningitis is probably less likely to develop than published rates of OB and serious sequelae would suggest.”

“No data demonstrate that any antibiotic, including ceftriaxone, prevents the sequelae associated with OB.”

Febrile Child: AAP GuidelineFebrile Child: AAP Guideline

Over 300 articles reviewed for 1993 guideline What is the lowest temperature that defines a fever? At what age must a non-toxic-appearing infant with

what degree of fever, if any, be hospitalized? What are the appropriate criteria, including

laboratory results, necessary to define a "low-risk" febrile infant less than 90 days old who need not be hospitalized for possible sepsis?

When should outpatient antibiotics be considered for the management of these low-risk febrile infants?

Febrile Child: AAP GuidelineFebrile Child: AAP Guideline

Which antibiotic should be used? What is a reasonable plan for the evaluation of a

child 3 to 36 months of age with fever without source?

When should the diagnostic tests of complete blood cell differential count, blood culture, urinalysis, urine culture, and chest radiograph be performed?

When should antibiotics be considered in the outpatient management of children 3 to 36 months of age with fever without source?

Which antibiotic should be used?

Febrile Child: AAP Guideline <3mosFebrile Child: AAP Guideline <3mos

Febrile Child: AAP Guideline 3-36 mosFebrile Child: AAP Guideline 3-36 mos

Febrile Child: Parental Febrile Child: Parental AnxietyAnxiety

Increased anxiety found when parents:– Not well rested– Not having other children– Thought about a blood test– Worried about trusting the physician

Febrile Child: Overall Approach Febrile Child: Overall Approach (Prober)(Prober)

The younger the child, the more uncertainty Toxic child demands uncertainty Non toxic child causes controversy Careful followup important Act on test results or don’t order them Document observations and reasons for actions

Fever syndromesFever syndromes

Febrile Seizures

PFAPA

UTI

Pneumonia

Febrile Child: Febrile SeizuresFebrile Child: Febrile Seizures SFS: <15min, generalized,once/24h 6 months to 5 years Chance of recurrence: 50% <1yr, 30%>1yr SFS: no risk of structural damage or

cognitive decline SFS: epilepsy risk by age 7 only slightly

greater www.aap.org/policy/ac9859.htm

Febrile Child: Febrile SeizuresFebrile Child: Febrile Seizures

Contiuous anticonvulsant rx– Phenobarbital reduces 25sz/100pts/yr to 5– Valproic Acid reduces 35% to 4% of pts– Carbamazepine/Phenytoin ineffective

Intermittent therapy– Antipyretic ineffective– Diazepam 44% reduction in febrile sz

Febrile Child: PFAPAFebrile Child: PFAPA

Periodic Fever Aphthous stomatitis Pharyngitis Adenitis Lasts 3-6 d, recurs every 3-8 wks Infectious Vs. immunologic etiology

Febrile Child: PneumoniaFebrile Child: Pneumonia

361 febrile infants 3 months or less “The 95% confidence interval based

on all 361 infants implies that the probability of a normal chest roentgenogram in an infant with no clinical evidence of pulmonary disease is 98.98% or greater.”

Fever syndromes: UTIFever syndromes: UTI UTI in children

– www.aap.org/policy/ac9830.htm– Few recognizable signs or symptoms other

than fever– 5% of children 2m-2yr without source of fever

evident after H&P have UTI– Evaluation of 1st UTI in children <2 yrs with

sonogram and possibly VCUG or RNC (radionuclide cystography)

The rate of VUR in children <1 with UTI is >50%

Fever Syndromes: UTI Fever Syndromes: UTI AlgorithmAlgorithm

Pediatrics 4/99;103:843-852

PathophysiologyPathophysiology

Fever Response

Fever Benefits

Mediators

Pathophysiology: Fever Pathophysiology: Fever ResponseResponse “Fever is a complex, coordinated autonomic,

neuroendocrine, and behavioral response that is adaptive and is used by nearly all vertebrates as part of the acute-phase reaction to immune challenge.”

Up regulation of thermostatic set point in hypothalamus– Redirection of blood flow to deep vascular beds from

skin– autonomic components (decreased sweating)– endocrine components (decreased secretion of

vasopressin, cortisol and corticotropin)– behavioral components (shivering, seeking a warmer

environment)

PathophysiologyPathophysiology

Pathophysiology: Fever Pathophysiology: Fever benefitsbenefits improves the efficiency of macrophages in

killing invading bacteria– Cytokines are immune potentiating

impairs the replication of many microorganisms

anorexia minimizes the availability of glucose for bacterial growth, promoting proteolysis and lipolysis

somnolence reduces the demand by muscles for energy substrate

Pathophysiology: MediatorsPathophysiology: Mediators Endogenous pyrogens

– cytokines: interleukin-1beta, interleukin-6, tumor necrosis factor alpha, and interferons beta and gamma

– lipid mediators of inflammation: prostaglandin E

liver produces acute-phase reactants, some bind divalent cations necessary for the proliferation of many microorganisms

PathophysiologyPathophysiology

TreatmentTreatment

Should it be treated at all? (Kruse) For

– Adverse effects of fever Brain damage, dehydration

– Febrile seizures

– Discomforts

Against– Obscuring signs

– Medication adverse effects

– Protective effects of fever

Treatment: AntipyreticsTreatment: Antipyretics

5 cc = 5 ml = 1 teaspoon Acetaminophen 15 mg/kg/dose

– Drops 80 mg/0.8cc– Syrup 160 mg/5cc

Ibuprofen 5-10 mg/kg > 6 mos– Drops 100 mg/2.5cc– Syrup 100 mg/5cc

Alternating?

Treatment: Treatment: NonpharmacologicNonpharmacologic

Unbundle Increase fluid intake Sponge bath interleukin-2 administered intravenously

– “We conclude that active cooling should be avoided in unsedated patients with moderate fever, because it does not reduce core temperature but does increase metabolic rate, activate the autonomic nervous system, and provoke thermal discomfort” Lenhardt

Geriatric FeversGeriatric Fevers

Geriatric Fevers (Chassagne)Geriatric Fevers (Chassagne)

Table II. Sensitivity and Specificity of Parameters in the Bacteremic Elderly

Geriatric FeversGeriatric Fevers

Table IV. Bacteremic Elderly (Group 1) and Bacteremic Young (Group 3)

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