1. SPORTS MEDICINE THE EXHAUSTED HORSE SYNDROME
Poor race performance syndrome
Synchronous diaphragmatic flatter

2. THE EXHAUSTED HORSE SYNDROME
Exhaustion is a result of brief maximal exercise or protracted (prolonged) sub­maximal exercise.

3. produces severe metabolic lactic acidosis
With maximal exertion in race­horses, there is rapid depletion of readily available muscle energy stores (creatine phosphate, ATP)
produces severe metabolic lactic acidosis

4. minimal changes in acid‑base status or lactic acid concentration.
With protracted submaximal or endurance exercise, energy is supplied by aerobic metabolism of both fatty acids and carbohydrates
minimal changes in acid‑base status or lactic acid concentration.

5. Etiology and pathogenesis
occurs mostly during summer season, when the temp. and humidity are elevated.

6. high-intensity short exercise.
2 types of exercise
The syndrome is associated with 2 types of exercise and
high-intensity short exercise.
prolonged submaximal exercise:

7. High-intensity short exercise:
rapid depletion of the phosphagen pool of muscle cells (creatine phosphate and ATP) and accumulation of lactate
Accumulation of lactate reduces the muscle pH from normal (7.0 – 7.1) to 6.3 or lower
Inactivation of muscle metabolizing enzymes, thus reducing the availability and production of ATP
Interfering with Ca availability by actomyosin, reducing the contractile efficiency.

8. Prolonged submaximal exercise
1- Sweating
large volumes of fluid may be lost via this route producing dehydration and reduction of exercise performance
Horse sweat is hypertonic, and sodium and chloride are the major ionic constituents
the major signs resulting from the loss of sodium and associated fluid are due to decreased circulatory function and poor organ perfusion .
Loss of potassium ions in the sweat may occur and contribute to the exhaustion but usually transient because of the compensatory release from other cells.
Oxygen with Ca in Mitochondria required for oxidative phosphorylation of ADP to ATP so reduction of oxygen or calcium produce exhaustion

9. Prolonged submaximal exercise
2- Depletion of intramuscular glycogen store during prolong submaximal exercise contributes to increasing the exhaustion

10. Profuse sweating

11. Clinical signs
There are variations in the severity of signs of exhaustion in individual horses.
All affected horses will have elevated rectal temperatures and pulse and respiratory rates, and variable dehydration on arrival.
The most reliable quantitative guides to impending exhaustion are pulse and respiratory recovery rates.
The pulse and respiratory rates take 30 minutes after rest and must return to acceptable levels, usually 60 to 70 per minute and 40 per minute, respectively.
Severely affected horses are usually severely depressed with little interest in food or water despite apparent dehydration.
Pulse pressure and jugular distensibility are often markedly decreased.
Capillary refill time is prolonged and cardiac irregularities.
Muscle cramps (lactic acid) and spasms are often evident.
Diminution or absence of intestinal sounds.

12. Diagnosis Case history Clinical Signs Lab Diagnosis Hyponatremia
Hypochloremia
Metabolic acidosis (lactic acidosis)
Hemoconcentration

13. Treatment --- step 1 1
Horses manifesting depression and persistently elevated pulse and respiratory rates as their only problems
Respond to rest, cooling out, and access to salt, clean feed, and water.
If there is no improvement in 30 minutes, they should receive fluids orally or intravenously.

14. The rectal temp. should return to normal within 15-30 Min
cold water is applied by a hose, sprayer, sponge, or towels over the large vessels of the distal extremities, head and neck, and over the jugular veins. .
Treatment
Step 2 2
The rectal temp. should return to normal within Min
Cautions !
Use an open area with free circulation of air, in a breeze or in front of a fan.
Avoid pouring very cold water over the large muscle masses to avoid inducing muscle spasms
Cold alcohol leg wraps are also useful in dissipating heat

15. severe exhaustion requires prompt and vigorous fluid therapy
Treatment step 3 3
severe exhaustion requires prompt and vigorous fluid therapy
Restoration of effective circulating blood volume by IV injection of saline (provides Na+ and Cl-).
Correction of electrolyte deficits by IV saline with addition of K+.
The use of non-steroidal anti-inflammatory drugs is controversial because they may produce toxicity in dehydrated, volume-depleted horses. However, they may be used after rigorous fluid therapy for their anti-inflammatory, analgesic and anti-pyretic effect.
Provision of readily metabolizable energy as glucose

16. Questions