Hyperthermia/Heat stoke/ Heat exhaustion Dr
Description: HyperthermiaHeat stoke Heat exhaustion Dr Mritunjay Kumar Associate Professor Department of Veterinary Medicine VMD, BVC, BASU, Patna Department of Veterinary Medicine Bihar Veterinary College, BASU, Patna Hyperthermia is a state of
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slide1. Hyperthermia/Heat stoke/ Heat exhaustion Dr Mritunjay Kumar
Associate Professor
Department of Veterinary Medicine
VMD, BVC, BASU, Patna Department of Veterinary Medicine
Bihar Veterinary College, BASU, Patna<br>
slide2. Hyperthermia is a state of elevated core temperature that raise rapidly above 400C, secondary to failure of thermoregulation caused by excessive heat production or absorption or deficient heat loss
Etiology
High environmental temperature
Severe muscular exertion (specially in high humidity)
Fatty animal/animals with heavy hair coat
Confined with inadequate ventilation (during transportation)
Dehydration – insufficient tissue fluids to accommodate heat loss by evaporation
Neurogenic hyperthermia- Damage to hypothalamus eg. spontaneous haemorrhage<br>
slide3. Hyperkalaemic periodic paresis in horse
Fescue toxicity (Neotyphodium coenophialum toxin) in ruminants and horses
Administration of tranquilizing drugs to sheep in hot weather
Specific mycotoxins e.g. epidemic hyperthermia by Claviceps purpurea and Acremonium coenophialum
Malignant hyperthermia in the porcine stress syndrome<br>
slide4. Pathogenesis Increased Ambient temperature Increased metabolism and muscular activity Hyperthermia Multi-organ failure Fall in blood pressure Decrease in
Cerebral blood flow
Cardiac blood flow
Gut blood flow
Renal blood flow Increased gut epithelial membrane permeability Brain damage Circulatory failure Digestive failure Renal failure Peripheral vasodilatation Death
(Respiratory failure) Release endotoxin<br>
slide5. Clinical signs
The first observable clinical reaction when temp. exceeds 39.50 C (1030F)- Increased thirst
Most cases temp. exceeds 420 C (1070F) may reach upto 43.50 C (1100F)
Increased heart and respiratory rates with weak pulse of large amplitude
Respiratory rate above 70 beats/min indicates heat stress
Laboured, shallow and irregular respiration
The pulse becomes very rapid and weak
Sweating and salivation- initially followed by marked absence of sweating (anhidrosis)<br>
slide6. The animal seeks cool place
Animal may be restless but soon become dull, stumbles while walking and tends to lie down
Abortion in pregnant animals
Death in most of the species when the core body temp. exceeds the normal value by approximately 5 0 C (80F)
Clinical pathology
Horse- typical hyponatraemic dehydration and azotaemia
Necropsy findings
Vasodilatation
Slow and incomplete blood clotting
Early rigor mortis and putrefaction
No constant or specific histopathological changes<br>
slide7. Treatment
The presence of adequate drinking water together with shade and proper ventilation
Affected animal should be immediately placed in shade and hosed on the midline of the back
Fans should be placed in front of the animal to enhance evaporation and cooling
Cooled water, with or without water
Placement of wet sheets or towels over the head or neck is not recommended as they provide unneeded insulation
Intravenous fluid (0.9% NS) administration
Cold water enema
In very severe cases of hyperthermia, very cold water (2-80 C) should be applied and immediately scraped off<br>
slide8. Prevention and Control
Shade should be in north-south orientation will permit drying
The efficiency of metal shades can be increased by painting metal shade white on the topside and black on the underside
Provide cool clean water and plenty of trough space for drinking
Use shades and intermittent sprinkler system
Enhance airflow by fans
Minimize handling during periods of greater heat stress
Select cattle based on breed and coat characteristics
Use tranquilizing drugs (chlorpromazine) for confinement of animal in high temp. and humidity<br>
slide9. Multiple choice questions
Q.1. Hypothermia is characterized by
a) Vasodilatation b) Vasoconstriction c) Both D) None of these
Q.2. Hyperthermia is characterized by
a) Vasodilatation b) Vasoconstriction c) Both D) None of these
Q.3. Most of the animals in hyperthermia have body temperature above
a) 420 C b) 1070F c) Both d) None of these
Q.4. Causes of hyperthermia are
Fescue toxicity b) high ambient temperature c) Porcine stress syndrome d
d) All of these
Q.5. Hyperthermia causes failure of
a) Respiratory system b) Circulatory system c) Nervous system d) All of these<br>
slide10. Thanks<br>
Associate Professor
Department of Veterinary Medicine
VMD, BVC, BASU, Patna Department of Veterinary Medicine
Bihar Veterinary College, BASU, Patna<br>
slide2. Hyperthermia is a state of elevated core temperature that raise rapidly above 400C, secondary to failure of thermoregulation caused by excessive heat production or absorption or deficient heat loss
Etiology
High environmental temperature
Severe muscular exertion (specially in high humidity)
Fatty animal/animals with heavy hair coat
Confined with inadequate ventilation (during transportation)
Dehydration – insufficient tissue fluids to accommodate heat loss by evaporation
Neurogenic hyperthermia- Damage to hypothalamus eg. spontaneous haemorrhage<br>
slide3. Hyperkalaemic periodic paresis in horse
Fescue toxicity (Neotyphodium coenophialum toxin) in ruminants and horses
Administration of tranquilizing drugs to sheep in hot weather
Specific mycotoxins e.g. epidemic hyperthermia by Claviceps purpurea and Acremonium coenophialum
Malignant hyperthermia in the porcine stress syndrome<br>
slide4. Pathogenesis Increased Ambient temperature Increased metabolism and muscular activity Hyperthermia Multi-organ failure Fall in blood pressure Decrease in
Cerebral blood flow
Cardiac blood flow
Gut blood flow
Renal blood flow Increased gut epithelial membrane permeability Brain damage Circulatory failure Digestive failure Renal failure Peripheral vasodilatation Death
(Respiratory failure) Release endotoxin<br>
slide5. Clinical signs
The first observable clinical reaction when temp. exceeds 39.50 C (1030F)- Increased thirst
Most cases temp. exceeds 420 C (1070F) may reach upto 43.50 C (1100F)
Increased heart and respiratory rates with weak pulse of large amplitude
Respiratory rate above 70 beats/min indicates heat stress
Laboured, shallow and irregular respiration
The pulse becomes very rapid and weak
Sweating and salivation- initially followed by marked absence of sweating (anhidrosis)<br>
slide6. The animal seeks cool place
Animal may be restless but soon become dull, stumbles while walking and tends to lie down
Abortion in pregnant animals
Death in most of the species when the core body temp. exceeds the normal value by approximately 5 0 C (80F)
Clinical pathology
Horse- typical hyponatraemic dehydration and azotaemia
Necropsy findings
Vasodilatation
Slow and incomplete blood clotting
Early rigor mortis and putrefaction
No constant or specific histopathological changes<br>
slide7. Treatment
The presence of adequate drinking water together with shade and proper ventilation
Affected animal should be immediately placed in shade and hosed on the midline of the back
Fans should be placed in front of the animal to enhance evaporation and cooling
Cooled water, with or without water
Placement of wet sheets or towels over the head or neck is not recommended as they provide unneeded insulation
Intravenous fluid (0.9% NS) administration
Cold water enema
In very severe cases of hyperthermia, very cold water (2-80 C) should be applied and immediately scraped off<br>
slide8. Prevention and Control
Shade should be in north-south orientation will permit drying
The efficiency of metal shades can be increased by painting metal shade white on the topside and black on the underside
Provide cool clean water and plenty of trough space for drinking
Use shades and intermittent sprinkler system
Enhance airflow by fans
Minimize handling during periods of greater heat stress
Select cattle based on breed and coat characteristics
Use tranquilizing drugs (chlorpromazine) for confinement of animal in high temp. and humidity<br>
slide9. Multiple choice questions
Q.1. Hypothermia is characterized by
a) Vasodilatation b) Vasoconstriction c) Both D) None of these
Q.2. Hyperthermia is characterized by
a) Vasodilatation b) Vasoconstriction c) Both D) None of these
Q.3. Most of the animals in hyperthermia have body temperature above
a) 420 C b) 1070F c) Both d) None of these
Q.4. Causes of hyperthermia are
Fescue toxicity b) high ambient temperature c) Porcine stress syndrome d
d) All of these
Q.5. Hyperthermia causes failure of
a) Respiratory system b) Circulatory system c) Nervous system d) All of these<br>
slide10. Thanks<br>