CRACKCast E167 – Pediatric Fever

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This episode of CRACKCast covers Rosen’s Chapter 166 (9th Ed.), pediatric fever. You will have an excellent approach to this common presentation after listening to this episode.

Shownotes: PDF Here

Rosen’s In Perspective

  • When it comes to dealing with pediatric fever, we usually break down kids into four age ranges:
    • 0-28 days
    • 1-3 months
    • 3-36 months
    • > 3 yr
  • These divisions reflect vaccination milestones and age specific pathogens

Let’s review some A&P:

  • Fever is defined as any elevation in body temperature equal to or above 100.4°F (38.0°C).
    • Rectal temp is the MUST method of measurement in infants 0 – 3 months old. **
      • Caveats:
        • rectal route should not be used in patients who are potentially immunocompromised (eg, children with fever who are receiving cytotoxic chemotherapy) because of the risk of mucosal damage leading to bacteremia.
      • What’s clinically significant?
        • rectal temperature of 100.4°F (38.0°C) is considered to be a clinically significant fever in an infant younger than 3 months, whereas a toddler with a temperature of 103.1°F (39.5°C) and an upper respiratory infection may not need any evaluation beyond a thorough history and physical examination.
  • Where do the SBI’s come from?
    • Presence of pathogenic bacteria in a previously sterile site and includes urinary tract infection (UTI), bacteremia, meningitis, osteomyelitis, bacterial gastroenteritis, bacterial pneumonia, cellulitis, and septic arthritis.

[1] List 10 non-infectious causes of fever in children

Break this down into categories:

  • Infectious – viral/bacterial/fungal
  • NON-infectious:
    • Drugs –
      • Overdoses that uncouple oxidative phosphorylation
        • Salicylates
        • Iron
      • Sympathomimetics / MDMA
      • MH
      • NMS
      • Serotonin syndrome
    • Metabolic
      • Leukemia
      • Lymphoma
      • Neuroblastoma
      • Wilms tumor
      • Juvenile RA
      • **kawasaki’s disease**
      • Vasculitides
      • hyperthyroidism
    • Environmental
      • **bundling**
      • Hot environment
    • Structural
      • Central stroke/brain tumour

CNS hemorrhages usually cause hyperpyrexia (>41.5 c)

[2] List 3 bacterial pathogens responsible for infections in the following age groups: 0-28d, 1-3m, 3-36m, and >3y

    1. 0-28 days
      1. GBS, Listeria, E. Coli
    2. 1-3 months
      1. H.flu; pneumococcus, meningococcus, e coli
    3. 3-36 months
      1. Same as above, less Hflu.
    4. > 3 yr
      1. Same as above, but add in Group A Strep. 

See Table 166.1 for a more comprehensive list.

 

[3] List 5 tests to perform on CSF

  • cell counts & manual differential diagnosis,
  • Gram staining,
  • Culture,
  • measurement of CSF protein and glucose concentrations.
  • HSV PCR testing

[4] Describe the empiric management of fever in the neonate (0-28 days)

 Management: 

  • ampicillin (100 mg/kg/24 hours divided every 6 hours)
    • First dose: 50-100 mg/kg dose
  • plus either:
    • gentamicin (5 mg/kg/24 hours divided every 8 to 12 hours)
    • or
    • cefotaxime (150 mg/kg/24 hours divided every 8 hours).
      • First dose: 100 mg/kg dose
    • Empirical acyclovir should be added if risk factors for HSV disease exist (60 mg/kg/24 hours divided every 8 hours).
      • First dose: Body weight >2 kg: IV: 20 mg/kg/dose every 8 hours

 

Indications for coverage for HSV:

  • Maternal hx of genital herpes
  • Ill appearing**
  • Fever + seizure
  • Cutaneous vesicles
  • Transaminitis or coagulopathy

[5] Why is ceftriaxone not recommended for the neonate?

Bilirubin displacement!!

Ceftriaxone should be avoided in infants younger than 28 days old because of a theoretic risk of inducing acute bilirubin encephalopathy as ceftriaxone causes bilirubin to be displaced from its protein binding sites.

[6] Describe one of: Rochester vs. Philadelphia criteria.

Table 166.2: Summary of Major Strategies for the Management of Febrile Infants Younger Than 3 Months Old

Philadelphia Rochester
Age 29 to 60 days old <60 days old
Temperature >100.8° F (38.2° C) >100.4° F (38.0° C)
Examination Well, no focus Well, no focus
Laboratory values (define low risk) WBCs >15,000/mm3 WBCs 5000 to 15,000/mm3
Band/neutrophil ratio <0.2 Absolute band count <1500
UA <10 WBCs/hpf (negative Gram stain) UA <10 WBCs/hpf
CSF <8 WBCs/hpf (negative Gram stain) Stool <5 WBCs/hpf (if obtained)
Chest radiograph normal, stool negative (if obtained)
High risk Admission + IV antibiotics Admission + IV antibiotics
Low risk Home, no antibiotics Home, no antibiotics
Performance Sensitivity 98% (92% to 100%) Sensitivity 92% (83% to 97%)
Specificity 42% (38% to 46%) Specificity 50% (47% to 53%)
PPV 14% (11% to 17%) PPV 12% (10% to 16%)
NPV 99.7% (98% to 100%) NPV 98.9% (97% to 100%)

Nowadays the approach to the febrile infant is more nuanced. Check out this Uptodate topic: Here

[7] Define simple and complex febrile seizure. What are indications for LP? 

Simple =

  • < 15 min in duration!
  • Single seizure in 24 hrs
  • Nonfocal, generalized tonic-clonic seizure

Complex =

  • >15 mins
  • Focal seizure
  • > 1 seizure in 24 hrs
  • Occurring < 6 months or >5 yrs of age 

Indications for LP:

AAP suggests that a lumbar puncture be performed in:

  1.  any child with signs of meningeal irritation after the first febrile seizure and
  2. be considered in symptomatic children who are incompletely immunized
  3. or have received prior antibiotic therapy.

[8] What is the likelihood of a) recurrent febrile seizure after 1 st presentation; and b) risk of epilepsy after first febrile seizure?

Recurrent febrile seizure after 1st presentation:

Parents should be warned that recurrence is common and is inversely related to age of first febrile seizure and height of the fever. Overall 33% of children who have a febrile seizure will have another one, and that 75% of these will occur within a year.

If the child is younger than 1 year old, the recurrence is 50%, and children presenting with temperatures of 101.3°F (38.5°C) has a 35% chance of recurrence versus 13% at 104°F (40°C). (seems counter-intuitive!)

Risk of epilepsy after first febrile seizure:

The risk of epilepsy in the general population is thought to be 0.5% to 1%, whereas the risk in a patient who has had a febrile seizure is 1% to 2%.

[9] List 6 causes of Fever and Petechiae

  1. Meningococcemia
  2. Pneumococcemia (pneumococcal bacteremia)
  3. Toxic shock syndrome
  4. Necrotizing fasciitis
  5. RMSF
  6. Bacterial endocarditis
  7. DIC
  8. Miliary tuberculosis
  9. Vasculitis – lupus
  10. ITP
  11. HSP
  12. Leukemia
  13. HIV

[10] Describe the criteria for the diagnosis of Toxic Shock Syndrome

Box 166.1 (9th Ed.): Centers for Disease Control and Prevention Case Definition for Toxic Shock Syndrome

  • Fever: Temperature >102° F (38.9° C)
  • Hypotension: Systolic blood pressure 90 mm Hg for adults or less than fifth percentile by age for children <16 years old; orthostatic drop in diastolic blood pressure by 15 mm Hg
  • Orthostatic syncope or dizziness
  • Diffuse erythroderma
  • Desquamation: 1 to 2 weeks after onset of illness, particularly involving palms and soles
  • Multisystem involvement (three or more of the following organ systems):
    • Gastrointestinal: Vomiting or diarrhea at onset of illness
    • Muscular: Severe myalgia or creatine kinase elevation more than two times the normal upper limit
    • Mucous membranes: Vaginal, oropharyngeal, or conjunctival hyperemia
    • Renal: Blood urea nitrogen or serum creatinine more than two times the normal upper limit, or pyuria (>5 WBCs/high-power field)
    • Hepatic: Bilirubin or transaminases more than two times the normal upper limit
    • Hematologic: Platelets <100,000/L
    • CNS: Disorientation or alterations in consciousness without focal neurologic signs in the absence of fever and hypotension
  • Negative results on the following tests, if obtained:
    • Blood, throat, or CSF cultures for another pathogen (blood cultures may be positive for Staphylococcus aureus)
    • Serologic tests for Rocky Mountain spotted fever, leptospirosis, or measles

Criteria for a probable case include a patient with temperature >102° F (38.9° C), hypotension, diffuse erythroderma, desquamation (unless the patient dies before desquamation can occur), and involvement of at least three organ systems. A probable case is a patient who is missing one of the characteristics of the confirmed case definition.

[11] Which sickle cell patients require prophylaxis and why? Which antibiotic?

Febrile children with sickle cell disease are at particular risk for overwhelming infection. In fact, infection is the most common cause of sickle cell–related death, occurring in up to 40% of patients with sickle cell disease who die. (they have functional asplenia due to frequent splenic infarctions). 

They are at risk for infection with encapsulated organisms, including S. pneumoniae and H. influenzae.

Because of this risk of bacterial disease, it is recommended that all children with sickle cell disease be completely immunized.

That’s why any young (<5 yrs old) febrile child should receive prophylactic antibiotics. If they are older and have a history of severe pneumococcal infections or splenectomy – they should still receive antibiotic prophylaxis.

The dose of penicillin is 125 mg orally twice daily until 3 years old (at about 14 kg) and 250 mg orally twice daily after 3 years old.

[12] List the Duke criteria for infectious endocarditis.

 See Box 166.2 (9th Ed.)

Mnemonic: Bacterial Endocarditis FIVE PM

Major Criteria

B : Blood culture +ve

  1. Typical micro-organisms in 2 separate cultures or
  2. Persistently +ve blood cultures drawn 12 hours apart or
  3. Single +ve blood culture for Coxiella burnetii

E : Endocardial involvement

  1. +ve echocardiogram (vegetation, abscess or valve dehiscence) or
  2. New valvular regurgitation

Minor criteria

  1. Fever > 38 oC
  2. Immunologic phenomena (glomerulonephritis, Osler’s nodes, Roth’s spots, Rheumatoid factor)
  3. Vascular phenomena (major arterial emboli, septic pulmonary infarcts, mycotic aneurysm, intracranial hemorrhage, conjunctival hemorrhage, Janeway lesions)
  4. Echocardiographic findings (suggestive but not definitive)
  5. Predisposing (heart condition or IV drug user)
  6. Microbiologic evidence (Positive blood culture but not meeting major criteria)

Definitive Diagnosis requires 2 Major  or 3 Minor + 1 Major or  5 Minor

Source: http://tube.medchrome.com/2012/03/how-to-remember-dukes-criteria-for.html

Wisecracks

[1] Provide a differential diagnosis for fever (review question)  

  • Infectious – viral/bacterial/fungal
  • NON-infectious:
    • Drugs –
      • Overdoses that uncouple oxidative phosphorylation
        • Salicylates
        • Iron
      • Sympathomimetics / MDMA
      • MH
      • NMS
      • Serotonin syndrome
    • I x
    • Metabolic
      • Leukemia
      • Lymphoma
      • Neuroblastoma
      • Wilms tumor
      • Juvenile RA
      • **kawasaki’s disease**
      • Vasculitides
      • hyperthyroidism
    • Environmental
      • **over bundling/overdressing the neonate**
      • Hot environment
    • Structural
      • Central stroke/brain tumour

CNS hemorrhages usually cause hyperpyrexia (>41.5 c)

[2] Which patients are excluded from the Rochester Criteria?

These are higher risk features that either require a FSW or high risk management.

  • Insufficient data on hx or physical or labs
    • Of note some red flag historical features that sometimes may be overlooked: these patients are not low risk; they would be defined as high risk if any of these are present.
      • < 37 weeks gestation
      • Received perinatal abx
      • Treated for unexplained hyperbilirubinemia
      • Received any antimicrobial agents
      • Previously hospitalized
      • Chronic or underlying illness
      • Hospitalized longer than mother
    • Unwell appearing

[3] What are the low-risk Rochester Criteria, and how are these children managed?

 

Low risk:

Age </= 60 days
Temp ■     ≥38.0°C
Hx: ■     Term infant

■     No perinatal antibiotics

■     No underlying disease

■     Not hospitalized longer than the mother

Physical exam: ■     Well appearing

■     No sign of focal infection (middle ear, soft tissue, bone/joint)

Lab parameters: ■     CSF: NA (no lumbar puncture is indicated)

■     WBC >5000 and <15,000/mm3

■     ABC <1500

■     UA ≤10 WBCs/hpf

■     Stool: ≤5 WBCs/hpf smear (if indicated)

Mangement:

  • Home/outpatient
  • No antibiotics
  • Follow-up required

 

[4] Which age groups should always have a urinalysis when presenting with fever without source?

KEY point:

[5] Which children should have a CXR to r/o pneumonia in the setting of fever without source?

  • Very high WBC (> 25,000)
  • Hypoxemia
  • Respiratory distress
  • Tachypnea
  • Focal lung findings on auscultation
  • High fever > 39 C and an elevated ANC

[6] What is the risk of SBI in children less than 3 months with an apparent viral syndrome?  

This has been studied (by Levine) in children < 60 days old:

  • Those with temp > 38 and 22% positive for RSV:
    • overall, children with documented RSV had a lower incidence of concomitant SBI than did those without RSV (12.5% vs. 7%), there was no significant difference in rates of SBI in children younger than 28 days old (14.2% in RSV-negative neonates vs. 10.1% in RSV-positive infants). Most of the bacterial infections were UTIs.
  • In older children > 3 months with viral syndromes:
    • In over 1300 patients with temperature above 102.2°F (39.0°C) who had a recognizable viral syndrome, the risk of bacteremia was 0.2%.

In another study

  • A large multicenter trial of febrile infants less 60 days old revealed a decreased risk (2.5% vs. 11.7%) if the infant was influenza positive.

Reference: Levine DA, Platt SL, Dayan PS, et al: Risk of serious bacterial infection in young febrile infants with respiratory syncytial virus infections. Pediatrics 113(6):1728–1734, 2004.

This post was copyedited and uploaded by Owen Scheirer.

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Chris Lipp
Chris Lipp is one of the founding Fathers for CrackCast. He currently divides his time as an EM Physician in Calgary (SHC/FMC) and in Sports Medicine (Innovative Sport Medicine Calgary). His interests are in paediatrics, endurance sports, exercise as medicine, and wilderness medical education. When he isn’t outdoors with his family, he's brewing a coffee or dreaming up an adventure…..
Adam Thomas

Adam Thomas

CRACKCast Co-founder and newly minted FRCPC emergency physician from the University of British Columbia. Currently spending his days between a fellowship in critical care and making sure his toddler survives past age 5.
Adam Thomas
- 18 hours ago