Environmental heat diagnoses: Difference between revisions

Revision as of 02:14, 9 February 2021

Background

Heat related illnesses includes a wide range diagnoses from benign heat rash to heat stroke.

Types of heat dissipation

Conduction: heat exchange between two surfaces in contact (placing ice pack in axilla)
Convection: heat exchange between a surface and a fluid (fanning)
Radiation: transfer of heat between body and environment through electromagnetic waves (reliant on temperature gradient)

Heat Illness Etiology

All types are due to inadequate thermoregulation

Classic Heat Illness
- Occurs without physical exertion
Exertional
- Preceded by physical activity

Clinical Features

Heat Illness Types

Heat cramps
- Muscles cramps due to electrolyte depletion
Heat syncope
- Prolonged standing +vasodilation + volume loss → decreased central venous return → decreased CO→ decreased cerebral perfusion pressure
Heat exhaustion (temperature usually < 40°C)
- headache, n/v, weakness, vertigo, no CNS dysfunction
- Water depletion: inadequate fluid replacement to match fluid loss (sweat)
- Salt depletion: large volume of fluid loss is replaced with water (with inadequate salt)
Heat stroke (temperature usually > 40°C)
- Similar to heat exhaustion plus CNS dysfunction (seizure, AMS), transaminitis, DIC, rhabdomyolysis

Differential Diagnosis

See also hyperthermia

Environmental heat diagnoses

Evaluation

Clinical diagnosis
Evaluate for alternate etiologies of hyperthermia if no clear exposure

Management

Heat cramps
- Mild: oral electrolyte solution
- Severe: IV NSS
Heat syncope
- Supine position
Heat exhaustion
- Mild: oral fluid replacement
- Severe: IV fluid replacement and replete electrolytes as needed
Heat stroke
- ABCs
- Rapid cooling
- IVF, replete electrolytes
- Benzos: for seizures and shivering

Disposition

Heat stroke requires admission
Other conditions can be discharged after improvement with treatment

References

Authors:

@@ Line 1: / Line 1: @@
-==Heat Edema==
+==Background==
-#Self-limited, mild edema of feet, ankles, and hands
+*Heat related illnesses includes a wide range diagnoses from benign [[heat rash]] to [[heat stroke]].
-#Appears w/in first few days of exposure to a hot environment
+===Types of heat dissipation===
-##Commonly seen in travelers just arriving from a colder climate
+*Conduction: heat exchange between two surfaces in contact (placing ice pack in axilla)
-#Resolves spontaneously in days to weeks
+*Convection: heat exchange between a surface and a fluid (fanning)
-#Treatment
+*Radiation: transfer of heat between body and environment through electromagnetic waves (reliant on temperature gradient)
-##Elevation of legs
-##Use of support hose
-##Diuretics are contraindicated
-==Miliaria (Heat Rash)==
+===Heat Illness Etiology===
-#Pruritic, maculopapular, erythematous rash over normally clothed areas of body
+''All types are due to inadequate thermoregulation''
-##See [[Media:Miliaria.jpg]]
+#Classic Heat Illness
-#Pathophysiology
+#*Occurs without physical exertion
-##Acute inflammation of sweat ducts caused by blockage of pores by macerated skin
+#Exertional
-###Ducts become dilated under pressure and ultimately rupture
+#*Preceded by physical activity
-####This produces superficial vesicles in malpighian layer of skin on a red base
-#####May progress to miliaria profunda (white papules) if duct ruptures a second time
-#Treatment
-##Antihistamines
-##Dicloxacillin or erythromycin if appears superinfected
-==Heat Cramps==
+==Clinical Features==
-#Painful, involuntary, spasmodic contractions of skeletal muscles
+===Heat Illness Types===
-##Usually affects calves, thighs and shoulders
+#[[Heat cramps]]
-#Occurs to pts who are sweating profusely and replace fluid losses with water
+#*Muscles cramps due to electrolyte depletion
-##May occur during exercise or during a rest period several hrs later
+#[[Heat syncope]]
-#Treatment
+#*Prolonged standing +vasodilation + volume loss → decreased central venous return → decreased CO→ decreased cerebral perfusion pressure
-##Self-limited
+#[[Heat exhaustion]] (temperature usually < 40°C)
-##Pain is difficult to tx; often does not respond to opiates alone
+#*headache, n/v, weakness, vertigo, no CNS dysfunction
-##Gatorade or NS IV
+#*Water depletion: inadequate fluid replacement to match fluid loss (sweat)
+#*Salt depletion: large volume of fluid loss is replaced with water (with inadequate salt)
+#[[Heat stroke]] (temperature usually > 40°C)
+#*Similar to heat exhaustion plus CNS dysfunction (seizure, AMS), transaminitis, DIC, rhabdomyolysis
-==Heat Tetany==
+==Differential Diagnosis==
-#Hyperventilation > respiratory alk > extremity/circumoral paresthesia, carpopedal spasm
+''See also [[hyperthermia]]''
-#Differentiate from heat cramps based on little pain, no cramping in muscle compartments
+{{Template:Heat Emergencies}}
-#Treatment
-##Remove from heat, decrease resp rate
-==Heat Syncope==
+==Evaluation==
-#Variant of postural hypotension
+*Clinical diagnosis
-##Results from combination of volume depletion and peripheral vasodilatation
+*Evaluate for alternate etiologies of [[hyperthermia]] if no clear exposure
-##Occurs in nonacclimatized during early stages of heat exposure (esp elderly)
-#Management
-##Diagnosis of exclusion
-##Remove pt from heat source, give PO or IV rehydration
-##Hospitalization usually is not necessary
-==Source==
+==Management==
-Tintinalli
+#[[Heat cramps]]
+#*Mild: oral electrolyte solution
+#*Severe: IV NSS
+#[[Heat syncope]]
+#*Supine position
+#[[Heat exhaustion]]
+#*Mild: oral fluid replacement
+#*Severe: IV fluid replacement and replete electrolytes as needed
+#[[Heat stroke]]
+#*ABCs
+#*Rapid cooling
+#*IVF, replete electrolytes
+#*Benzos: for seizures and shivering
+==Disposition==
+*[[Heat stroke]] requires admission
+*Other conditions can be discharged after improvement with treatment
-[[Category:Environ]]
+==See Also==
+*[[Hyperthermia]]
+*[[Celsius Fahrenheit Temperature Conversion]]
+==References==
+<references/>
+[[Category:Environmental]]