Pain and Stress by Dr. Ali Hassan Awan.pptx

Pain and stress in animals can significantly affect their behavior, physiology, and overall well-being. Common signs include changes in eating habits, vocalization, and physical posture. Addressing these issues promptly through proper veterinary care and environmental modifications is crucial for maintaining their health and quality of life.

1. Pain and Stress Ali H assan 2023-Mphil-1123 PG Clinic-II

2. Introduction What is PAIN? “Unpleasant sensory and emotional experience associated with actual or potential damage” Pain is a distressing sensation arising from stimulation of specific end-organs in particular parts of the body and perceived in the thalamus and cerebral cortex.

3. Pain assessment Pain is assessed in animals by three methods : O bservation of behavior M easurement of physiological parameters, including heart rate, blood pressure, sweating and polypnea , that indicate sympathetic activation . M easurement of the plasma concentration of factors that indicate sympathetic activation, such as plasma cortisol, epinephrine, norepinephrine and non-esterified fatty acid concentrations.

4. Etiology Pain sensations are aroused by different stimuli in different tissues and the agents that cause pain in one organ do not necessarily do so in another. In animals there are three types of pain: 1. Cutaneous (or superficial) 2. Visceral 3. Somatic (or musculoskeletal)

5. Cutaneous or superficial pain is caused by agents or processes that damage the skin, such as burning, freezing, cutting and crushing. Fire burns, frostbite, acute mastitis, laminitis, infected surgical wounds, foot rot, crushing by trauma, conjunctivitis and foreign body in the conjunctival sac are all common causes of pain. Examples of visceral pain include: Inflammation of serosal surfaces, as in peritonitis , pleurisy and pericarditis Distension of viscera, including the stomach , intestines, ureters and Bladder, Swelling of organs as in hepatomegaly and splenomegaly. Inflammation as in nephritis, peripelvic cellulitis and enteritis Stretching of the mesentery and mediastinum . Muscular pain can be caused by lacerations and hematomas of muscle, myositis and space-occupying lesions of muscle. Osteomyelitis , fractures, arthritis, joint dislocations , sprains of ligaments and tendons are also obvious causes of severe pain .

6. Types of Pain in Pets Acute pain Chronic pain Cancer pain Neuropathic pain Acute pain: Acute pain is a recent, noticeable response to something that happens suddenly. Common causes of acute pain include trauma, bruising, crushing injuries, cuts, or other body injuries. Postsurgical or procedural pain also is considered acute

7. Continue… Common signs of acute pain may include: Behavior changes such as hiding or resisting handling Limping  Guarding a body part such as paw or tail Licking , biting, or rubbing the affected area Chronic pain : Chronic or persistent pain can be stressful to pets and decreases their overall quality of life and wellness. Chronic pain is typically a dull, ongoing pain. Osteoarthritis, or joint disease, is a common source of chronic pain.

8. Continue… Chronic pain signs may include: Decreased appetite Changes in breathing patterns or increased panting when at rest Changes in movement or posture Decreased interest in long walks or games of fetch Behavior changes such as irritability  Cancer pain: Cancer pain can be acute and chronic . A primary bone tumor is the most common pain-causing cancer, but any type of tumor can be associated with pain.

9. Continue… Common signs of cancer pain may include : Decreased appetite Lethargy Weight loss  Wounds that do not heal Limping that occurs without an injury  Abdominal swelling Swollen joints Abnormal bleeding

10. Continue… Neuropathic pain: Neuropathic pain can occur from an injury or disease that affects a pet’s nerves or nerve function within the spinal cord. Common signs of neuropathic pain may include: Limping or dragging of limbs Shaking or twitching skin Muscle atrophy Inappropriate elimination  Decreased appetite Vocalization

11. Pain pathway

12. Clinical signs The general clinical findings of pain are described here and the indications of pain associated with individual body systems or organs are described within each category. 1. Physiological response: The severity of the pain determining the degree of response: Tachycardia Polypnea Pupillary dilatation Hyperthermia Sweating .

13. Continue… 2. Behavioral pain: These include abnormal posture and gait when the pain is musculoskeletal. The gait abnormalities include lameness , a shuffling gait and rapid shifting of weight from one leg to another. The behavioral responses to pain may also include unrelated activities such as rolling , pawing, crouching or grinding of teeth when the pain is visceral . Moaning, grunting and grinding of the teeth ( odontoprisis or bruxism) are generally indicative of pain.

14. Signs of abdominal pain

15. Elicitation of pain by the veterinarian This is an essential part of a clinical examination . The techniques include the following: Pressure by palpation , including firm ballottement with the fist and the use of a pole to depress the back in a horse or to arch the back upwards from below in a cow. Pressure by compression , as with hoof testers for detecting the presence of pain in the hoof. Movement by having the animal walk actively or by passively flexing or extending limbs or neck. Stimulation of pain related to coughing by eliciting the cough reflex.

16. Species General behavior Appearance Physiology Dog Bites, scratches, guards; whimpers or howls; growls; quiet, submissive; or more aggressive to handling Stiff, moves less or lies still; "hangdog" look; tail between legs Shivers; pants; urinates Horse Reluctant to be handled; decreased activity; disrupted feeding; restlessness or depression; reluctance to move; unusual limb position Anxious appearance; dilated pupils; flared nostrils; glassy eyes; lowers head Sweats Cat Quiet; hisses or spits; hides; licks excessively; limps; guards limbs; stilted gait; reduced appetite; escape response to handling Apprehensive facial expression; tucks-in limbs; hunches head/neck; ungroomed; flattens ears; cringes Indicators of Pain

17. D uration of pain Duration of pain can be the result of natural recovery or of surgical or medical correction of the problem. Constant pain results from a static state whereas periodic or intermittent pain is often related to periodic peristaltic movement. In humans and in companion animals some importance also attaches to observing the time of onset of pain, whether it is related to particular functions or happenings and whether the patient gains relief by adopting particular postures or activities.

18. Treatment Several aspects concerning the relief of pain in agricultural animals are important. Treatment of the causative lesion is a major priority, but the treated lesion may remain painful for varying lengths of time. Relief and the control of pain should be a major consideration and the following principles require consideration Relief of pain is a humane act. Improved , less painful methods of castration , dehorning, tail-docking, Mules operation in sheep, spaying cattle and treating painful lesions of the hooves of farm animals must be explored and implemented. Surgical operations such as laparotomies must be performed using appropriate analgesia.

19. Continue .. 2 . Analgesia may obscure clinical findings that may be necessary to observe , properly diagnose or maintain surveillance of a case. This is of major importance in equine colic. 3 . Control of pain is necessary to prevent animals from inflicting serious self-injury associated with uncontrollable behavior as a result of severe visceral pain. 4 . Analgesics for visceral pain are readily available and relatively effective.

20. Analgesia The analgesic agents and techniques available include the following : Surgical procedures, e.g. neurectomy by section of peripheral nerves, as practiced in horses Local destruction of peripheral nerves by chemical means, e.g. the epidural injection of agents such as ethyl alcohol may prevent straining Local destruction of peripheral nerves by thermal means, e.g. cautery of the wound edge after gouge dehorning in calves.

21. Analgesic agents There are five main types of analgesic agent administered parenterally or topically to large animals : Local anesthetic agents such as lidocaine, mepivacaine and bupivacaine . NSAIDs such as flunixin meglumine , ketoprofen , phenyl butazone and meloxicam. -agonists such as xylazine and detomidine . Opioids such as morphine, fentanyl, butorphanol and buprenorphine. Vanilloids such as capsaicin.  

22. Continue… 1. Local anesthetic agents : Lidocaine , mepivacaine and bupivacaine exert their analgesic effect by addressing both the first pain and second pain after injury by blocking the voltage-gated sodium channels in peripheral nerves, thereby preventing propagation of depolarization. The main advantages of local anesthetic agents are their cost and predictable and local effect. The main disadvantage is short duration of action.

23. Continue.. 2 . NSAIDS : NSAID has excellent anti inflammatory , antipyretic and analgesic properties , and is the preferred NSAID for acute soft tissue or visceral pain, although it is also efficacious against musculo - skeletal pain. Flunixin meglumine provides excellent analgesia in equine colic and postsurgical pain. In a comparison of three NSAIDs used to minimize postsurgical pain in horses, flunixin meglumine (1 mg/kg BW), phenylbutazone (4 mg/kg BW ) or carprofen (0.7 mg/kg BW) were administered once intravenously.

24. Mode of Action NSAIDs inhibiting cyclooxygenase enzyme in the pain pathway to inhibit the formation of prostaglandins hence, inhibiting pain.

25. Cont … Xylazine : Xylazine was shown to be the most effective analgesic for the relief of experimentally induced superficial, deep and visceral pain in ponies when it was compared to fentanyl, meperidine (pethidine ), methadone, oxymorphone and pentazocine . However , its short duration of action and the accompanying sedation and decrease gastrointestinal motility and increased urine formation limit its use to short-term analgesia.

26. Cont … Vanilloids : Capsaicin is derived from hot chili peppers (Capsicum annum) and is the main vanilloid used in horses. Capsaicin induces a transient primary hyperalgesia that is followed by a sustained period of desensitization that is species-, age-, dose and route-of-administration-dependent. The major clinical disadvantage of using capsaicin is the initial transient primary hyperalgesia.

27. In general, local anesthetic agents, agonists and opioids are used to provide short-term analgesia (hours), and parenteral NSAIDs and topical vanilloids are used to provide long-term analgesia (days to months).   The main routes used for administration of analgesics have been local infiltration, subcutaneous , intramuscular and intra venous . Other routes, including the oral, epidural , intra-articular and topical. Administration routes

28. Xylazine and lidocaine given as epidural analgesia abolished pain Xylazine in the epidural space has also been used to provide analgesia for the castration of bulls. In the horse epidural analgesia using a combination of butorphanol and local anesthetics has been used to provide perineal analgesia.

29. Supportive therapy The application of moist heat to a local lesion causing pain is effective and makes medical sense. Its value depends on how frequently and for how long it can be applied. Providing adequate bedding is important for an animal that is recumbent for long periods or that is likely to injure itself while rolling. The provision of adequate amounts and quality of feed and water is essential, especially if the animal is immobilized and because appetite is often poor. Rubber floors and walls , as in recovery wards, are effective but are usually available only for short periods. Distracting a horse with colic by walking it continuously is a common practice to prevent the animal from behavioral activities such as rolling.

30. Stress Stressors are environmental factors that stimulate homeostatic, physiological and behavioral responses in excess of normal. The most objective measure of the presence and magnitude of stress is the plasma cortisol concentration . Stress is a systemic state that develops as a result of the long-term application of stressors. It includes pain.

31. Stress-provoking factors  may come from the outside, such as the environment and psychological or social situations of the body or from the inside, for example, illnesses or medical procedures. Physical , chemical and other perceived  stressors can affect animals  and cause primary, secondary, and whole-body responses. Stress response  may depend on their species, breeds and living conditions. Stress is a physical or mental factor that causes tension in the body or mind of both people and animals.

32. Lead to the development of psychosomatic disease Increase susceptibility to infection Represent an unacceptable level of consideration for the welfare of animals Reduce the efficiency of production Importance of stress

33. Classification

34. Causes For animals, a satisfactory environment is one that provides thermal comfort, physical comfort, control of disease and behavioral satisfaction. Road transportation Climate Excessive physical effort Pain Crowding Presence or absence of bedding . Housing & Nutritional deficiencies

35. Heat stress High temperature accompanied by high relative humidity imparts heat stress to the animals. The productive and reproductive traits were also affected by heat stress. In males, the sperm maturation and libido are affected with reduced testosterone concentration ( Kastelic et al. 2001). In female animals, various stages of the oestrus cycle are affected. High temperature also decreased milk yield and milk composition in dairy cattle. Heat stress is also responsible delayed embryonic development and caused embryonic mortality.

36. Stress and road transportation The response of different farm animal species to the effects of road transportation has been examined . The effects of road transportation on cattle varies according to age: the transportation of 1-3-week-old calves for up to 18 hours was not as stressful as in older calves. During transportation , plasma cortisol concentrations and serum creatine kinase activities increase . Based on the physiological measurements and subjective measurements of behavior, a I5 -hour transportation period under good conditions is not unacceptable with regard to animal welfare. There was no indication that road transport was a risk factor for pulmonary disease.

37. Continue … Based on plasma cortisol concentrations, confinement of young bulls on a truck and motion are considered stressful factors in road transport. Transport stress increases fecal, urine and tissue Losses. Major stress may be related to the handling of the animals during loading and unloading.

38. Clinical pathology The direct criterion of stress is the assay of plasma ACTH; stress may be indirectly assayed using plasma cortisol concentration , which is a less expensive. Salivary cortisol concentration is a good indicator of stress in sheep . During prolonged periods of road transportation of cattle and sheep, there are significant changes in serum concentrations of total proteins, non – esterified fatty acids (NEFAs), glucose, creatine kinase , - hydroxybutyrate and urea. These changes can be used to assess the degree of stress and the deprivation from feed and water during transportation . Physical stress such as fatigue or exercise will result in increases in creatine kinase. Psychological stressors such as fear result in elevations of cortisol and corticosterone.  

39. Management of stress The widespread public debate about the welfare of food-producing domestic animals dictates that veterinarians, animal scientists and the livestock industry must develop systems of handling and housing that will minimize stressors. In addition to housing, handling and experimental intervention, it will also be important to give due care to the appropriate selection and use of anesthetics and analgesics when pain is being inflicted, as in dehorning and castration. Many countries now have codes of practice for the handling and transportation of animals . Welfare is determined by the length of the trip and the conditions under which animals are transported, including stocking density, ventilation, temperature and humidity, noise and vibration.

40. How to manage animal stress? Animals can experience stress for several reasons: fatigue or injury; hunger, thirst or temperature changes; unfamiliar people, handling, changes in environment or surroundings, etc. Efficient , experienced, calm  livestock handling , using recommended techniques and facilities, and taking measures to eliminate pain and accidental injury all play a role in  reducing animal stress . Stress may be managed by providing adequate nutrition and hydration in each case, with proper management practices, such as  shelters, ventilation and health care. Avoiding handling the animals as much as possible.

41. References Veterinary medicine by   D. C. Blood  (Author),  J. A. Henderson  (Author ). https ://daradia.com/pain-pathway / https:// link.springer.com/article/10.1007/s00423-004-0468-9 https://animalemergencycare.net/understanding-4-types-of-pain-in-your-pet / https:// academic.oup.com/ilarjournal/article/41/2/62/746988