Hyperthermia and Heat Illness
Presented by:
Eric Johnson, MD
Emergency
Medicine
of
Idaho,
Boise
ejohnson@emidaho.com
Epidemiology:
During 1979-1997, the most recent years for which data are
available, an annual average of 381 deaths in the US were attributable to
"excessive heat exposure" (see end for definition).
1995 was a disastrous year for heat-related fatalities with 1021
heat related deaths. July heat wave in Chicago and Milwaukee was
unprecedented.
-
89% occurred in permanent homes
-
57% male/ 43% female
-
67% age 60-89
1999 Chicago heat wave data:
·
80 died
·
53% < 65 years
·
Psych illness common.
·
Most protective factor = working air conditioner.
2003 France Heat wave
Definitions:
·
Hyperthermia is a rise a body temperature above the hypothalamic set
point when heat dissipating mechanisms are impaired or overwhelmed
by external or internal heat
·
Heat Illness: used to describe all adverse effects on the body of a
raised core temperature
·
Heat rash:[miliaria rubra or prickly heat] rash caused by plugged sweat
glands, retention of sweat and secondary inflammatory reaction
·
Heat edema: self limited swelling of the feet and hands usually seen
early with heat exposure
·
Heat cramps: muscular cramps associated with exercise
(usually post exercise) and secondary to relative hyponatremia.
·
Heat syncope
: fainting ascribed to the dilatation of peripheral
blood vessels resulting from raised environmental temperature.
·
Heat exhaustion
: Is the result of water/salt depletion in the face of
heat stress. Precursor of heat stroke.
·
Heat stroke
: complex clinical disorder characterized by:
a) Core temperature rises above 40 [104-106*F]
b Central nervous system changes/abnormalities.
c) Proposed:
"form of hyperthermia associated with a
systemic inflammatory response leading to a syndrome of multi-
organ dysfunction in which encephalopathy predominates".
AP: Europe Heat Wave Killed Some
19,000
The Guardian (UK) 9-26-2003 | Pamela Sampson
