Study

1. Hyperthermia
Heat stroke/Sun stroke

2. • Elevated body temperature due to
failed thermoregulation
• Occurs when a body produces or absorbs
more heat than it dissipates

3. Thermoregulation
Achieved by combined action of
• Peripheral Thermoreceptors
(Skin, Abd. Viscera, M. mem:, Spinal cord, Great veins)
• Central Thermodetectors
(Pre-optic area of ant. hypothalamus)

4. Thermoregulation
Consists of neural and hormonal components
• Decreased body temp. causes
Increase in the secretion of adrenaline,
thyroxin, thyrotropic hormone
• Increased body temp. causes
decrease in the secretion of adrenaline,
thyroxin, thyrotropic hormone

5. Heat production in the body
• intracellular oxidative & other processes
• Liver and heart
• Muscles (80%)
• From exterior by radiation, conduction
and convection

6. Heat loss from the body
• Conduction, convection and evaporation
• Lungs
• Feces
• urine

7. Etiology of Heat stroke
• High environmental temp. and humidity
• Prolonged and severe muscular exertion
• Limited supply of drinking water
• Anhydrosis or hypohydrosis
• Ill ventilated rooms
• Over crowding
• Less capability of heat tolerance
• Dehydration
• Neurogenic hyperthermia occurs due to the poisoning
with strychnine, mycotoxins and iodide

8. Pathogenesis
Heat stroke
Damage to the CNS
Tachycardia
Dyspnea
Convulsion
Coma
Resp. failure
Death

9. Clinical signs
• High elevation of body temp. (106-110oF)
• Tachycardia, dyspnea, decreased pulse rate
• Open mouth breathing
• Protrusion of tongue
• Frothy discharge from mouth and nostrils
• Anhydrosis
• Stumbling, animal trying to lie down
• Polydipsia, animal seeks cool places
• Collapse, convulsions, coma and death

10. Treatment/management
• Well ventilated shady rooms
• Cold application (ice cold water,
ice blocks, ice cold rectal enema)
• Adequate drinking water
• Fluid therapy
• Corticosteroids (prevent cerebral
edema)
• Supportive therapy

11. Hypothermia
• Decrease of body temperature due to the
excessive loss of heat or insufficient
production. This condition is not common in
tempered areas of the world. It is particularly
seen in cold, wet, and windy weather.

12. Etiology
• Exposure to excessively cold air temperature (winter
season)
• Decreased muscular activity in new born and old animals
e.g. parturient paresis, acute ruminal impaction
• Reduction in metabolic activities such as hypoglycemia,
hypocalcaemia, acidosis, and electrolytes (potassium)
imbalance
• Peripheral vasodilatation as in shock
• Anesthesia
• Damage to thermo-regulatory center
• Profuse diarrhea particularly in winter

13. Clinical signs
• Sub-normal body temperature, cold skin and
extremities
• Decrease in respiratory and pulse rate
• Shallow breathing, depression, lethargy
• In terminal stages, low cardiac output
(bradycardia) leading to hypoxia, coma and
death

14. Treatment
• Attempt should be made to rise the body
temperature by providing blanket or
gas/electrical heater, keep the animal in
preheated rooms.
• Administer pre-warmed dextrose solution
• Corticosteroids may be used to prevent shock
• Rectal enemata with Luke-warm water may help
in rising core body temperature
• Supportive therapy with B complex may help in
enhance the metabolic activity