severe muscle cramps, and SHOCK. Severe dehydra-
tion requires urgent treatment from a hospital
emergency department or trauma center.
COMMON CAUSES OF DEHYDRATION
acuteGASTROENTERITIS DIABETES
excessive diuretic use excessive laxative use
heavy sweating inadequate drinking
persistent DIARRHEA persistent VOMITING
strenuous exercise sustained FEVER
See alsoHEAT EXHAUSTION; HEAT STROKE.heat exhaustion Overheating of the body in
conditions of extreme heat or heavy physical
activity. Symptoms of heat exhaustion come on
suddenly and may include blanched SKIN, heavy
sweating, NAUSEA, and lightheadedness. Get the
person into a cool environment, such as a shaded
area or an air-conditioned location, as quickly as
possible. Loosen clothing, offer cool water or cool
sports drinks (nothing iced), and spray or moisten
the skin with cool water. When these measures
are effective, the person improves dramatically
and does not need further medical care.
Though heat exhaustion is mild and nearly
always improves with appropriate interventions
such as these, untreated heat exhaustion may
progress toHEAT STROKE, a potentially life-threaten-
ing disturbance of body temperature. Call 911 to
summon emergency medical aid if the person’s
temperature is higher than 102ºF or the person
has seizures.
See also DEHYDRATION; FEVER; SPORTS DRINKS AND
FOODS.
heat stroke A life-threatening emergency in
which the body is unable to lower body tempera-
ture. Heat stroke most commonly develops when
there is a combination of intense physical activity
and high environmental temperature. Though
most people who develop heat stroke first experi-
ence HEAT EXHAUSTION, symptoms of heat stroke
may appear suddenly. Such symptoms include
- hot, flushed SKIN
- absence of sweating
- HEADACHE
- rapid HEART RATE(tachycardia)
- HALLUCINATION
- disorientation, agitation, or loss of CONSCIOUS-
NESS - seizures
Body temperature is usually above 102ºF.
Urgent treatment is necessary to avert permanent
BRAINand other neurologic damage. Call 911 to
summon emergency medical aid, then get the per-
son into an air-conditioned location, if possible, and
remove outer layers of clothing. Spray a mist of
water or apply cool, wet washcloths to the skin. If
possible, place ice packs or extremely cold objects
under the armpits and at the groin; at these loca-
tions large volumes of BLOODcirculate near the
skin’s surface. Position the person lying on his or
her back with feet and legs elevated about 12
inches (SHOCKposition). Emergency medical per-
sonnel may have cooling blankets and will begin
intravenous fluids, then transport the person to a
hospital or trauma center for further care.
See also DEHYDRATION; FEVER.hypothermia The sustained loss of body heat
resulting in low body temperature. Hypothermia
occurs with extended exposure to cold external
temperatures. Cool, wet conditions may also result
in hypothermia. The key symptom of mild
hypothermia, in which body temperature is no
lower than 95ºF, is intense shivering. Attempt to
warm the person getting him or her into a warm
location, removing wet clothing and wrapping in
warm blankets, and offering warm fluids to drink.
When body temperature drops below 95ºF in
moderate hypothermia, the body loses the ability
to shiver and the rate of heat loss increases. HEART
RATEslows, BLOOD PRESSUREdrops, and METABOLISM
slows. The person is often confused or agitated,
may paradoxically feel warm, and feels increas-
ingly sleepy. Emergency response includes warm-
ing efforts as well as calling 911 to summon
emergency aid personnel. Moderate hypothermia
often requires further medical care to stabilize
body temperature.
The lower body temperature drops, the less
likely recovery becomes. Body temperature below
90ºF, severe hypothermia, is very precarious.Heat and Cold Injuries 375