1. Kid Fevers: Lou Romig MD, FAAP, FACEP Miami Children’s Hospital

2. Fever in Kids: Lou Romig MD, FAAP, FACEP Miami Children’s Hospital

3. Fever Mythology

5. Hot Topics  What is fever?  Facts and fallacies about fever  Febrile seizures  How and why to treat kids with fever

6. What is fever?  Fever is a neurochemical response common to many animals  Controlled in the human hypothalamus and mediated by numerous endogenous and exogenous chemicals

7. What is fever?  Nerves in the hypothalamus maintain a normal “set point” temperature, usually in a range around 37C (98.6F)  Set point varies in a circadian rhythm with lowest at around 4am and highest between 4-8pm

8. What is fever?  Endogenous pyrogens can cause:   body temp  sleepiness   appetite  Increased immune response

9. What about the numbers?

10. What’s “normal”?  Most common definitions are based on a study by Wunderlich in 1868  “Normal” 37C (98.6F)  “Upper limit of normal” 38C (100.4F)  Weaknesses: thermometry used, use of axillary temps

11. What’s “normal”?  Mackowiak and Wasserman 1992:  700 oral temps in 148 healthy young adult subjects  Individual variation precludes the assignment of any single temperature as the normal. Range 35.6(96.0) – 38.2(100.8)

12. What’s “normal”?  There is no substantiation to the belief that the elderly have lower body temps normally  A higher normal range of temp in children has not been documented in the research

13. What’s “fever”?  Mackowiak and Wasserman:  Any oral temp >37.2C (98.9F) in the early morning  Any oral temp >37.8C (100F) at any time

14. Thermometry  Gold standards are rectal for children and oral for older children and adults  Axillary temps are not reliable and may vary as much as 1°C from rectal  There is no reliable conversion factor for axillary vs rectal temps

15. Thermometry  Tympanic thermometry is not accurate and may be technique- dependent  Infrared temporal artery (TA) thermometry is only slightly better than tympanic thermometry  TA temps are consistently lower than rectal temps but there is no reliable conversion factor

16. How hot is “high”?

17. How hot is “high”?  Dubois, 1949  Human upper limit of fever 41 – 42C (105.8-107.6F)  Almost never exceeds 42C unless there’s a failure in thermoregulation

18. How hot is “high”?  McCarty and Dolan, 1976  40C (104F) may be the upper limit of fever in infants <12 weeks old  Remember that young infants can have infections with normal or lowered body temps

19. Fever Mythology

20. Fever can cause damage…

21. Why the concern? Seizures and complications Brain damage because of the infection causing the fever (meningitis or encephalitis)

22. Fact or fiction?  No human studies published  Animal studies suggest that a body temp of >42C (107.6F) in humans may trigger enough adverse effects on a cellular level to cause death

23. Fact or fiction?  Animal studies:  T> 105 may cause respiratory alkalosis and occasional electrolyte imbalances  T > 105.8 may cause cellular swelling and damage in the brain, kidneys and liver

24. An infection is more dangerous if it gives a high fever or if the fever doesn’t come down with treatment…

25. Hi temp = “bad” infection? No studies have conclusively proven any correlation between height of temperature and outcome of an infection or disease outcome.

26. Hi temp = “bad” infection? Several studies suggest that children with temperatures greater than 41°C (105.8°F) have a greater chance of having a serious bacterial illness.

27. Hi temp = “bad” infection? Several studies suggest that fever of ≥ 40°C (104 °F) signals increased risk of serious bacterial illness for infants from birth to three months of age.

28. Poor response to tx = bad?  Failure of antipyretics to control fever has not been proven to correspond with severity of illness.  Improved general appearance after antipyretics may indicate a less severe illness.

29. Cover up if you have chills!

30. What’s cookin’ with chills?  Chills are evidence of the hypothalamus causing the body to generate heat to reach the altered set- point.  Covering up will only keep in the heat.

31. Don’t give milk to babies with fever! Oh, Puhleeez!

33. “Doin’ the fever flop”

34. Characteristics of F.S.  Incidence of 2-5% in US  6 mo – 3 yrs, median 18-22 mo  Boys more often than girls  Often occurs with the first fever of an illness

35. Characteristics of F.S.  85% of all F.S. last for <15 min and don’t recur within 24 hrs  50% have temp between 39- 40C  25% have temp > 40C

36. Characteristics of F.S.  1/3 will have recurrence of F.S.  The younger the age at 1 st F.S., the higher the incidence of recurrence  El-Radhi, 1998  Presenting temp <39 for 1 st F.S. have 2.5x risk for recurrence within the same illness and 3x risk for recurrence with other illnesses

37. Characteristics of F.S.  Simple F.S. are generalized tonic-clonic with brief post- ictal period  Complex or atypical F.S. can be focal, atonic, or prolonged

38. It’s in the genes Multiple studies have shown several genetic loci that code for susceptibility to febrile seizures

39. Fever + Sz  Febrile Seizure  Meningitis/Sepsis  Seizure disorder  Medication/Poison-induced “Febrile seizure” is NOT an EMS diagnosis

40. Febrile Seizures: Fact or Fiction

41. F.S. are caused by the rate of rise of temp  Berg, 1993 – failed to prove the rate of rise theory  Bottom line – we don’t know what causes F.S.!

42. F.S. cause brain damage  No studies have demonstrated that febrile seizures without complicating hypoxia cause brain damage  One study suggests that recurrent F.S. may result in decreased IQ

43. F.S. can cause “epilepsy”  Risk factors for afebrile sz:  Complex 1 st F.S.  Abnormal neuro state before 1 st F.S.  Afebrile sz history in parents or siblings  If >2 risk factors, 10% chance of developing “epilepsy”

44. Treating the fever can prevent F.S.  Canfield, 1980; Knudson, 1991; van Stuijvenberg, 1998  Antipyretics are not protective  Rectal/oral diazepam at time of fever is protective  Daily oral phenobarbital is protective but has undesirable side effects

45. Treating the fever can prevent F.S. There is no evidence that bringing the fever down by any means will stop or prevent a febrile seizure.

46. The Bottom Line for F.S.  They’re more scary than dangerous  Most resolve without anticonvulsant treatment  Antipyretic treatment does not prevent or treat F.S.  Not all seizures with fever are febrile seizures

48. Antipyretics  There is no evidence to support one antipyretic over another when considering effectiveness  No delivery route (po/pr) is more effective than another

49. Antipyretics  Several studies have shown that many parents:  Don’t even attempt to treat fever before seeking medical evaluation  Don’t give correct antipyretic doses

50. Antipyretics  Acetaminophen (APAP) 10-15 mg/kg po/pr q4h  There is no difference in effectiveness based on po or pr routes  There is no increased effectiveness when pr dose of APAP is increased to 45mg/kg  Ibuprofen 10mg/kg po q6-8h

51. APAP vs Ibuprofen  There is no significant benefit to using either antipyretic preferentially  There is no benefit in alternating the two meds but there is a significantly increased chance of dosing error and possible overdose

52. Cooling methods  Never use ice, cold water or alcohol  Use tepid water or cool compresses over head and pulse points

53. Beware of chills if using external cooling

54. Should we even treat fever?  Animal studies suggest that the fever mechanism is a positive adaptive response  Triggers host immune responses  May stabilize cell membranes

55. (Why) should we treat fever?

56. Reasons to treat fever  Increased metabolic stress and oxygen demand:  Patients with poor cardiac reserve  Patients with poor pulmonary reserve  Lowering the “seizure threshold”

57. Reasons to treat fever  Patient comfort  Parent comfort

58. Should EMS providers be treating fever?

59. Pro’s  Providing an additional service to our customers  Comfort measure

60. Con’s  Treat and release?  Documentation of fever  Dosing of meds  Reinforcement of fears

61. Summary  Fever is not the clearly defined concept many believe it to be.  Both the lay public and the medical community need more education about fever.  “Fever Phobia” is unfounded.  Fever treatment by EMS personnel is controversial.