Transcript Fever in Family Practice Don Spencer, MD October 6, 2000
Fever in Family Practice
Don Spencer, MD
October 6, 2000
UNC Department of Family Medicine
Topics: Fever in Family Practice
Measurement
Measurement: Tympanic
Impairment of IR sensor from water vapor
Measurement: Tympanic
Chicago marathon
Measurement: Axillary, 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 Fever
38 C degrees (100.4 F)
Rectal
Unbundled
No antipyretics
Diurnal variation 1deg.C (Kruse)
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Highest later afternoon, early evening
FUO
FUO: Causes (Arnow)
FUO: Causes Over Time
FUO: Evaluation
Febrile Child
Febrile Child: Toxicity
lethargy
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poor eye contact, interaction with people/environment
signs of poor perfusion
marked hypoventilation or hyperventilation
cyanosis
Toxic and <90 days old
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17% probability of having a serious bacterial infection including an 11% probability of bacteremia and a 4% probability of meningitis
Age categories
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<1 months
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2-3 months
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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
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quality of crying
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reaction to parent stimulation
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state variation
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color
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state of hydration
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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
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<=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
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65%-75% frequency
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4%-7% invasion rate H influenzae type b (1980’s data)
– –
10%-20% 7%-20% N meningitidis
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5%-15%
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25%-35% Salmonella species
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5%-15%
–
?
Febrile Child: OB
Risk of occult bacteremia for a given temperature
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>39.4
°
3%
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>40.0
°
6%
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>40.5
°
13%
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>41.1
°
26%
Contrasted with no change in risk for SBI
Febrile Child: OB
Risk of occult bacteremia for a given wbc
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5,000
100% sensitivity, 3% PPV
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10,000
92%, 5%
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15,000
65%, 8%
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20,000
38%, 13%
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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:
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Not well rested
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Not having other children
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Thought about a blood test
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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 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
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Phenobarbital reduces 25sz/100pts/yr to 5
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Valproic Acid reduces 35% to 4% of pts
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Carbamazepine/Phenytoin ineffective
Intermittent therapy
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Antipyretic ineffective
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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
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www.aap.org/policy/ac9830.htm
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Few recognizable signs or symptoms other than fever
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5% of children 2m-2yr without source of fever evident after H&P have UTI
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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
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
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Redirection of blood flow to deep vascular beds from skin
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autonomic components (decreased sweating) endocrine components (decreased secretion of vasopressin, cortisol and corticotropin)
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behavioral components (shivering, seeking a warmer environment)
Pathophysiology
Pathophysiology: Fever
improves the efficiency of
benefits
macrophages in killing invading bacteria
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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
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cytokines: interleukin-1beta, interleukin 6, tumor necrosis factor alpha, and interferons beta and gamma
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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
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Adverse effects of fever
Brain damage, dehydration
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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
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Drops 80 mg/0.8cc
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Syrup 160 mg/5cc
Ibuprofen 5-10 mg/kg > 6 mos
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Drops 100 mg/2.5cc
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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
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Make full set of prepared materials and references available to peers
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Follow up on learning issues and distribute knowledge gained
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