ENVIRONMENTAL EMERGENCIES■ Antivenom(see Table 13.5)
■ For all eastern coral snake bites (even if asymptomatic!)
■ Otherwise, if any systemic symptoms
■ No antivenom available for Arizona coral snake (less toxic)
■ A horse-serum antivenom—administer test dose and watch for allergic
reactions
■ All coral snake bites require admission for observation.
A 2-year-old boy is brought to your ED after being found unconscious in
his car seat. His mother left him in the locked car while shopping. His
field dextrose stick is 96. His rectal temperature on arrival is 105°F. What
is the preferred mechanism to rapidly lower this child’s core temperature while
still allowing for monitoring of vital signs?
This child has sustained heat stroke. Rapid lower of his core body temperature
is essential for a good neurologic outcome. Many cooling techniques are available,
but using evaporative technique where a mist of 40°C water is sprayed on the
patient’s skin, while air is fanned over the body (using standing fans), allows for
access to the patient and limits shivering (which generates heat).H EAT-R E L ATE D I LLN E SSHeat-related illness is a continuum of disease extending from minor heat ill-
ness to heat exhaustion and heat stroke.
MECHANISMS OFHEATLOSS/GAIN
■ Conduction:Direct physical contact with another surface →heat loss or
gain (eg, ice packs, heating pad).
■ Convection:Heat transfer via circulating air or water molecules (eg, wind
chill)
■ Radiation:Heat transfer by electromagnetic waves. (eg, heat from the sun,
poor insulation in cold environment)
■ Evaporation:Heat transfer as water is vaporized (eg, sweating)
PATHOPHYSIOLOGY
■ Theanterior hypothalamusis the body’s thermostat and regulates body
temperature.
■ ↑Core body temperature →peripheral vasodilation (to dissipate heat via
convection),→perspiration and respiration (for evaporative heat loss).
■ Acclimatization to hot environment = earlier and greater sweating, dilute
sweat.
Risk factors for heat illness can be divided into three groups (see Table 13.6):
■ Increased heat production
■ Decreased heat loss
■ Impaired ability to move to a cool environment
Malignant hyperthermia deserves special mention. It is due to a genetic insta-
bility of skeletal muscle that allows for excessive calcium release in the muscle
cell when exposed to certain anesthetic agents (including succinylcholine) →
muscle rigidity and profound hyperthermia.
What is the difference between
hyperthermia and fever?
Hyperthermia = hypothalamus
overwhelmed by heat
production.
Fever = ↑hypothalamic set
point from circulating
cytokines.