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a heat casualty, but does not prevent it - caution is always needed. The member's need for drinking water
will increase with corresponding increases in activity and heat exposure. Acclimated members will sweat
earlier and more profusely but with lower salt loss. Heat injuries range in severity from heat cramps to
heat exhaustion to heat stroke. While the mechanism of heat cramps is not understood, there is convincing
evidence to suggest it is the result of sodium depletion or over-hydration. Heat exhaustion and heat stroke
probably represent a continuum of disease, varying in intensity and severity of tissue damage. Both are
characterized by water and sodium loss.
Heat-Related Illnesses: Heat Cramps
LTC Richard Kramp, MC, USARisk Factors: More likely to occur in sodium depleted or over-hydrated soldiers after strenuous physical
activity in a hot, humid environment. Troops that are not fully acclimatized are at increased risk.
Subjective: Symptoms
Painful, tonic contractions of skeletal muscles frequently preceded by palpable or visible fasciculation.
Focused History: Which muscles are involved? (usually all or part of large skeletal muscles) What does the
pain feel like? (usually severe) Do you have frequent leg cramps at night? (suggest vascular problems, not
heat cramps) What makes the symptoms worse? (Manipulation of the muscle may precipitate cramping)
Objective: Signs
Inspection/ Palpation: Muscle cramping with possible fasciculations, rapid resolution after oral or IV salt
solution.
Assessment:
Differential Diagnosis - tetany due to alkalosis (hyperventilation, severe gastroenteritis, cholera) or
hypocalcemia; strychnine poisoning; black widow spider envenomation or abdominal colic. These are usually
easily to eliminate with a short history.
Plan:
Treatment
Primary: Re-hydrate with 0.1% salt solution po (salt tablets are not recommended) or normal saline solution
IV if more rapid treatment needed. If a sports drink is used, dilute it 50/50 with water.
Patient Education
General: Patients with heat cramps usually have sodium deficits or over-hydration. Eating the entire MRE
and adding salt to tray pack meals should replenish salt stores over several days.
Activity: Allow 2 to 3 days to replenish salt and water deficits before resuming work in the heat.
Diet: Increase salt application to food and water intake.
Prevention and Hygiene: Consume adequate quantities of salt and water as part of the normal diet.
No improvement/Deterioration: If recovery is not rapid (within 1-2 hours with oral fluids, within 15-30
minutes with normal saline), return for reevaluation.
Follow-up Actions
Consultation Criteria: If recover is not rapid (within 1-2 hours with oral fluids, within 15-30 minutes with
normal saline).
NOTE: An attempt should be made to determine a reason for the episode so that appropriate advice can be
given to the command and the operator.