Fever in Family Practice Don Spencer, MD October 6, 2000

“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 Fever



38 C degrees (100.4 F)



Rectal



Unbundled



No antipyretics



Diurnal variation 1deg.C (Kruse)

–

Highest later afternoon, early evening

FUO

FUO: Causes (Arnow)

FUO: Causes Over Time

FUO: Evaluation

Febrile Child

Occult Bacteremia

Serious Bacterial Infection

AAP Guidelines

Overall Approach

Toxicity

Parental Anxiety

Febrile 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



Age categories

–

<1 months

–

2-3 months

–

3-36 months

Febrile Child: SBI



meningitis



septicemia



bone and joint infection



urinary tract infection



pneumonia



bacterial gastroenteritis

Febrile 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 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 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 Bacteremia

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: OB



Risk of occult bacteremia for a given temperature

–

>39.4



–

>40.0



–

>40.5



13%

–

>41.1



26%



Contrasted with no change in risk for SBI

Febrile 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)

   

“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 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 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 <3mos

Febrile Child: AAP Guideline 3-36 mos

Febrile Child: Parental Anxiety



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 (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 syndromes

Febrile Seizures

PFAPA

UTI

Pneumonia

Febrile 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 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: PFAPA



Periodic Fever



Aphthous stomatitis



Pharyngitis



Adenitis



Lasts 3-6 d, recurs every 3-8 wks



Infectious Vs. immunologic etiology

Febrile 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: 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 Algorithm

Pediatrics 4/99;103:843-852

Pathophysiology

Fever Response

Fever Benefits

Mediators

 

Pathophysiology: Fever Response

“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)

Pathophysiology

Pathophysiology: Fever



improves the efficiency of

benefits

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: 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

Pathophysiology

Treatment



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: 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: Nonpharmacologic



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 Fevers

Geriatric Fevers (Chassagne)

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

Geriatric Fevers

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

Questions??

PCP: Peer Centered Presentation



Best components of a discussion and a lecture



Broad topic with which audience has prior experience and knowledge



Presenter has no previous expertise compared with peers



Audience of peers directs presentation with questions

PCP



Questions that are not addressed by presenter or peers in audience become learning issues for later study



Presentation time is limited



Presenter does not expect to present all knowledge gained in preparation for presentation

PCP



Commitments of presenter after presentation

–

Make full set of prepared materials and references available to peers

–

Follow up on learning issues and distribute knowledge gained



FPC Intranet Clinicians’ Page

Fever in Family Practice Don Spencer, MD October 6, 2000

Transcript Fever in Family Practice Don Spencer, MD October 6, 2000