Preparation for the initial contact time with the client and patient should begin with a system of record keeping. Ambulatory records are usually more flexible than “in-house” hospital admission forms. Both field and clinic forms should include designated spaces for the client or agent’s address and phone number. An area for the complete signalment (name, sex, breed, color, age, reproductive status), including an estimated weight, should be provided. If the patient is unnamed, as with foals, it should be listed in the dam’s name with the year of birth (e.g., Curious ’06). The sire’s name should not be used because more than one foal per year would be expected from a stallion’s crop. Whenever surrogate mares produce multiple foals from a single embryo transfer dam, a new system of naming and identification will have to be incorporated. Additional identification of the patient may include a lip tattoo, freeze brand, or microchip number and, if available, should be noted in the horse’s record. Thoroughbred racehorses are tattooed under the lip with a letter, denoting the year foaled, followed by four or five numbers. Thoroughbreds foaled in 1997 have “A” as the first character in their tattoo, followed by those foaled in 1998 with a “B” as the first letter, and so on. Once the end of the alphabet is reached, the process is repeated. Numbering and lettering schemes used for lip tattoos and freeze marks vary, depending on breed registry, so one should consider breed or discipline carefully when using the number for aging or identification purposes. As of 2013, horses competing in U.S. Equestrian Federation (USEF)-sanctioned events for the first time will be required to have microchips as part of their passport identification. ISO 11784– and ISO 11785–compliant microchips (resQ, Bayer Healthcare, LLC, Shawnee Mission, Kan; HomeAgain/Digital Angel) must be used, the same as those required by the U.S. Department of Agriculture’s voluntary Animal Disease Traceability program (previously National Animal Identification System).¹ Microchips should be located on the near side of the horse, in the nuchal ligament, approximately 3 to 4 cm below the crest, in the middle third of the neck.

Equine Insurance

If the animal is insured, this should be documented, preferably with the insurer’s telephone number. In addition, the type of insurance should be noted (e.g., mortality and/or surgical and medical). It is the client’s or his or her agent’s responsibility to notify the insurance company representative whenever an animal insured for full mortality contracts an illness or sustains an insult, life-threatening or not, that requires a veterinary examination. If the patient is insured, it is considered a professional courtesy for the veterinarian to also communicate directly with the insurance company, especially with a life-threatening illness. Also, permission from the insurance company is required whenever a general anesthetic, surgical procedure, or euthanasia is to be performed. Whenever euthanasia is requested, the insurance company may require a second opinion from an adjusting veterinarian. If a direct representative from the insurance company cannot be contacted immediately, the clinician must exercise professional judgment in assuming the responsibility for a humane or critical decision. The client or agent should be in agreement with the decision, and all communications and pertinent data should be documented in the medical record, including a signed euthanasia consent form, if applicable. If a necropsy is to be performed, it should preferably be in the presence of another veterinarian from a different practice. The American Association of Equine Practitioners (AAEP) provides an insurance pamphlet as a guide to veterinarians.²

History

The medical history should be directed to the clinical problem. The “herd health” of the stable or farm can be assessed briefly as depicted by the vaccination and parasite control program and visually by the condition of other horses residing on the premises. The patient’s individual problems should be determined according to such factors as clinical history of onset, feed and water consumption, fevers, and decrease in performance. In essence, the clinician must effectively zero in on the problems at hand, which may affect multiple body systems.

The diet (e.g., supplements, grazing environment), stall or housing schedule, and medical problems concerning other animals on the premises, which may coincide with a group incidence of the client’s complaint, should be determined. When contagious disease is a concern, travel history by the patient or stable mates including recent additions to the farm should also be considered.

When a veterinarian is dealing with neonates, the reproductive and foaling history of the mare may be important in establishing an early diagnosis. Any compromise during a mare’s gestational period (e.g., systemic disease, general anesthesia, or administration of certain medications), foaling, or lactation; placental abnormalities; and any problems that occurred during previous pregnancies should be questioned and considered to be important, pertinent historical data. In some circumstances, the foal’s breed should be considered and the possibility of genetic disease transmission by the dam and/or sire should be investigated (e.g., combined immunodeficiency in Arabians).

A description of the types of medication used before hospitalization may aid in determining if “masking” agents have inadvertently been administered. Tranquilizers or sedatives, which can cause confounding clinical signs of hypotension, bradycardia, lethargy, weakness, and ataxia, are frequently given for the horse’s safety during transport. In many instances a van driver or hauler is unaware of medications used or the patient’s medical condition. Sedatives (e.g., xylazine) and analgesics such as flunixin meglumine, administered by owners or farm staff in the hours or days prior, may mask signs of pain or colic and alter interpretation of the severity of the horse’s condition on arrival. Failure of such an analgesic to abolish clinical signs may necessitate hospital or clinic admission for further evaluation or surgical consultation. Conversely, the failure of other previous medical treatments can aid in the initial selection of more appropriate therapeutic planning. Knowledge of the quantity and interval of administered drugs is pertinent information as well, particularly in hypovolemic animals given drugs known to be nephrotoxic (e.g., phenylbutazone).

Physical Examination

The extent of the physical examination will be subject to the condition of the patient, the environment where the examination is conducted (field vs. hospital), the equipment at hand, and the ancillary personnel available for restraint and procedural purposes. In a hospital setting the clinician should have immediate access to most of the equipment and diagnostic instrumentation listed in Box 2-1. The physical examination sheet should provide a systematic list of the organ systems being evaluated. Vital signs (temperature, pulse, and respiratory rate) should be documented in the “calm” animal, if possible (Table 2-1). Abnormal findings are described in an appropriate space provided, usually below the body systems checklist. Using the same numeral for each body system throughout the examination process and in problem identification is useful for future caseload recall, especially if a computer is used and codes can be applied to clinical findings and diagnosis. At the completion of the physical examination, the major problems identified are listed, and appropriate laboratory tests can be requested. The final diagnosis is seldom determined at the time of the initial examination; however, the final diagnosis represents the final assessment and should be filled in at the appropriate time (e.g., hospital discharge).

A general evaluation of the equine patient should be made from afar. This is particularly important for neonates at the side of their dams. The initial observations of body condition, posture, weakness, lethargy, incoordination, lameness, and musculoskeletal asymmetry are more easily observed a slight distance away from the patient. The integumentary system can usually be quickly evaluated as to the type, distribution, and number of lesions and site and layer of involvement. However, subtle lesions of petechia and ecchymosis cannot be visualized in the integument because the hair coat and pigment hide lesions that are obvious in other species, such as purpura of nonpigmented humans and pigs. In these instances the mucous membranes must be examined as an extension of the integumentary system. If obvious multiple lesions of the skin are present, documentation is usually expedited by photographing or drawing a picture of the horse and indicating the distribution on the drawing including both sides (see Chapter 11). Gross generalized distortions (e.g., anasarca) may be viewed as lesions of possibly more than one body system (integumentary and circulatory).

Abnormalities in demeanor and mentation can be assessed by watching the horse’s initial response to the environment and again once the physical examination and interaction with the patient begins. Whatever the approach, the physical examination should be systematic and orderly, so as not to miss subtle features in the face of obvious abnormalities. In general, most examinations start at the head, so as not to startle the horse or foal and to prevent possible injury to the veterinarian who may be unfamiliar with the horse’s temperament or previous handling experience. Evaluation of facial symmetry and cranial nerve function can be accomplished with minimal handling or manipulation. The eyes can be examined by a rapid visual assessment using a penlight. The cornea and cranial and caudal lens capsules can be evaluated by horizontally moving the penlight and noting the crossing light reflexes. Pupillary constriction to light and the “menace” response should be observed, although these reflexes may be significantly slower or absent in the neonate. An ophthalmoscope retinal examination should be performed whenever the eyes represent the primary complaint, and fluorescein dye should be used for the detection of corneal ulcers before the installation of other ophthalmic agents. Blindfolding of one eye at a time may aid in the assessment of unilateral blindness and should be conducted in a safe area with “blunt” devices contrived as an obstacle course.

Evaluation of the circulatory system starts with assessment of heart rate, rhythm, and any presence of murmurs. Mucous membrane color, capillary refill time, scleral injection, palpable changes in the temperature of the ears and extremities, jugular pulsation, and pitting subcutaneous edema are the most common obvious circulatory physical examination parameters. The heart should be auscultated bilaterally, and murmurs graded according to intensity (I to VI or I to V), character, the valve site, and phase of the cardiac cycle. Cardiac arrhythmias usually necessitate an electrocardiogram (ECG), except in the case of type II atrioventricular block, a normal finding commonly observed in clinically asymptomatic horses. Type II heart block in normal horses can usually be obliterated by exciting the horse with a threatening gesture or trotting the horse a few steps to increase the heart rate. In addition to electrocardiography, transcutaneous ultrasound examination of the heart and pericardium and transrectal evaluation of the caudal aorta and iliac arteries for intraabdominal thrombotic lesions can be used.³ If procedural assessments of blood pressure are necessary, a manometer for central venous pressure or a sphygmomanometer with Doppler ultrasound is used on the base of the tail in foals⁴ and adults.⁵

The respiratory system is similar to the circulatory system in that the breathing rate and mucous membrane color are important assessments. A quick visual assessment of the alar folds may identify conformational abnormalities or indicate severe compromise (e.g., nostril flaring). Respiratory effort and the phase of increased work should be assessed (e.g., increased expiratory effort with “heaves”). Nasal airflow can be determined by wetting the hands and holding them gently over the nostrils so that both intensity and equality of air movement can be assessed. The color (e.g., blood tinged), character, and amount of any nasal discharge should be noted and indicated whether it is present in one or both nostrils. A penlight can be used to visualize the internal nares (septal mucosa). Smelling the breath for fetid or necrotic odors (ozena) is similarly important, and endoscopic evaluation of the upper airways should be an adjunct to abnormal clinical findings. Percussion of the sinuses should be performed for detection of dullness, suggesting a possible mass (e.g., ethmoid hematoma), sinusitis, or the presence of fluid within the sinus cavity. In addition, the head should be carefully examined ventrally and caudally for the presence of lymphadenopathy. Auscultation should be of both the upper (larynx and trachea) and lower airways. In horses with equivocal lower airway findings, a rebreathing bag can be used to accentuate abnormal sounds by increasing the respiratory rate and volume of inspired air. The interpretation of lung sounds has been described elsewhere,⁶ and the clinician should make an effort to auscultate dorsal and ventral regions of the thorax bilaterally and document findings as to the location or absence of sounds and the phase of respirations involved. Coughing in horses with upper and lower respiratory disease is variable.

Percussion of the thorax is a reliable clinical tool and should be performed in cases of suspected abscess, tumor, or pleural effusion. A pleximeter and tablespoon are the only tools required, although some clinicians are adept at direct finger percussion of the chest. In foals, percussion can be performed by placing a stethoscope on one side of the chest and reaching over the back of the foal to manually percuss the opposite side. Fractured ribs may be recognized in the neonatal foal as palpable asymmetry or a bony crepitus (“clicks”), often with edema of the sternum or elbow coinciding with the fractured side. Horses with pleuropneumonia may exhibit a reluctance to move (pleurodynia) similar to that seen in horses with laminitis, which is a possible sequela to endotoxemia caused by gram-negative bacterial pneumonia.⁷

Ultrasound has revolutionized the clinical evaluation of the thoracic cavity. Unfortunately, the familiarity of clinicians in thoracic interpretation is directly related to access and frequency of ultrasound use. However, subtle pneumonia, abscess, and pleural effusion represent definitive objective findings and can be identified rapidly with little or no stress to the patient.⁸ Because radiographic changes often lag behind clinical disease, serial examinations via ultrasound may be a more accurate way of monitoring response to treatment. In fact, ultrasound examinations may eliminate the need for chest radiographs in numerous cases, thereby increasing efficiency and decreasing client costs.

A systematic approach should always be used when examining the horse for gastrointestinal disease. Although the majority of emergencies and referrals are related to colic or acute intestinal disease, the clinician should resist the temptation to focus only on the abdomen, so that important clinical signs relating to other problems are not missed (e.g., gastric ulceration, botulism). If a clinical complaint involving the abdomen is present or in suspected cases of intestinal displacement, obstruction, or volvulus, the gastrointestinal system is initially examined with bilateral auscultation of intestinal sounds by dividing the abdomen into four quadrants. Intestinal borborygmi vary by location and in the cecum and ascending colon propulsive contractions tend to occur in waves, with periods of quiescence, over several minutes. In general, small intestinal sounds are the least dramatic, heard in the area of the left flank. In addition, the abdomen should be auscultated ventrally for sounds similar to “ocean waves” or sand pouring on itself, indicative of the presence of sand within the gastrointestinal tract.⁹ The presence of increased (hypermotile), reduced, or absent borborygmi (ileus) should be considered important features of the physical examination. It is helpful to document the activity or lack thereof in each of the four abdominal quadrants, especially in hospitalized patients where different clinicians may be monitoring the patient over several days. In cases in which the gastrointestinal tract is the site of the primary lesion, checking for gastric reflux and performing a rectal examination are required elements. Although only about 40% of the gastrointestinal tract can be reached by palpation, it is a valuable technique that can quickly identify surgical cases and affect survival.¹⁰ Clinicians should strive to become adept at rectal palpation and regard the procedure as a premier diagnostic skill while respecting the risks involved for the patient and veterinarian.

The patient should be observed for the presence of normal prehension, eating, and drinking whenever dysphagia is present or neurologic dysfunction is suspected. A subjective assessment of tongue strength and tone can be made by carefully grasping the tongue. Normal horses will pull against the hand and, once the tongue is released, replace it immediately in the mouth. The evaluation of the gastrointestinal system should also include a dental examination for the presence of malocclusion and dental abnormalities (e.g., missing or damaged teeth, tooth root abscess) that can affect prehension or mastication. Use of a dental speculum is required for safe and complete examination of the dental arcade and adjacent soft tissues. Accurate notation of affected teeth should be made in the medical record using a universally accepted identification system such as a numeric system in which the horse’s head is divided into four quadrants, with each tooth described by its own number (e.g., two central upper incisors on horse’s right and left would be 101 and 201, respectively). Clinicians should also become adept at dental age determinations, albeit with an awareness of its limitations and subjectivity.¹¹ Nasogastric intubation is useful in evaluating dysphagia and esophageal blockage (choke) and determining the presence or absence of gastric reflux. In addition, the volume and character (e.g., color, pH, presence of blood or toxic plant material) of reflux obtained can be rapidly evaluated and may aid in the diagnosis.

The use of long endoscopes (e.g., 2 to 3 m) is valuable in the visual assessment of the esophagus and stomach with lesions such as esophageal stricture and gastric ulceration. For a diagnostic endoscopic examination of the stomach, it is recommended that the patient be muzzled or held off feed for at least 10 hours to allow complete visualization of the stomach.¹²

Ultrasound evaluation of the abdomen in conjunction with aspiration and analysis of visualized abdominal fluid may quickly reveal peritonitis, uroperitoneum, hemorrhage, ascites, visceral rupture, or abdominal masses. In adults, palpable abdominal masses and enlarged lymph nodes can usually be scanned transrectally.

The urogenital system can be examined by manual palpation, rectal palpation, vaginoscopic (speculum examination) viewing, endoscopy, and ultrasound. The caudal portion of the left kidney is easily palpated in most horses. Uterine and catheterized samples should be obtained (e.g., cultures, urinalysis) before any contaminating invasive procedures (e.g., rectal palpation) are performed and before fluid therapy is initiated. Sphincter tone may be subjectively or objectively (urethral pressure profile) assessed in horses with urinary incontinence or stranguria. Horses with incontinence often demonstrate “scalding” of the perineum, and hind legs and foals with a patent urachus may dribble urine from a moist umbilical stump.

The neurologic system examination should involve a consistent procedure for all patients with nervous system disorders (see Chapters 8 and 35). The patient’s attitude, posture, and head carriage should be assessed from afar. The cranial nerves should be evaluated, followed by examination of the spinal reflexes and tail tone. Sensory deficits should be noted at this time. Conscious proprioception and postural responses (e.g., placement, hemi-hopping, sway) can then be assessed before observing the patient in locomotion. Notes regarding symmetry, ambulation, paresis, muscle atrophy, and upper and lower motor neuron deficits should be documented to aid in determining the sites for any additional ancillary tests such as radiographs, cerebral spinal fluid collection, or myelogram. Blindfolding should be conducted in a safe area, especially for patients with vestibular disease. An area of incline is useful for evaluating the locomotor deficits, especially when the horse is led with the head elevated.

The lymphatic system is usually evaluated merely by recording any obvious lymphadenopathy. This can be regional or local (as in strangles) or generalized (cutaneous lymphosarcoma) and may be appreciated on rectal examination. Lymphangitis or the presence of edema should also be noted.

For the internist, evaluation of the musculoskeletal system usually involves a rudimentary examination of the site and appearance of the disease processes. Primary lameness is more commonly evaluated by clinicians familiar with diagnostic nerve blocks, arthrocentesis methods (e.g., septic arthritis in foals), and radiographic findings. It should be noted that acute (caused by fracture) or chronic lameness can coexist with primary neurologic disorders (e.g., equine protozoal myeloencephalitis). Therefore, when warranted, the patient should receive a cursory neurologic evaluation (see Chapter 8) in conjunction with the musculoskeletal examination. Conversely, all horses presented with systemic illness (pneumonia, colitis) should also be evaluated for signs of laminitis in all four feet because this complication is often the limiting factor for the horse’s survival. Visual inspection of the hoof wall and sole may indicate previous laminitic episodes and should be documented because this may increase the patient’s risk and lower the threshold for repeat episodes. Careful palpation of the lower limbs may indicate increased intensity of digital pulses or changes in the coronary band that may be related to the “sinker” syndrome (distal phalangeal displacement).¹³ If laminitis is present as a complicating factor, the clinician should be able to add to the clinical prognosis by using Obel grading (1 to 4).

Once a patient has been admitted to the clinic or hospital, well-organized flow charts should be used for monitoring and assessing the patient.

Use of Ancillary Equipment in the Examination Procedure

Advancing technologies are allowing the practitioner or clinician to add to or replace many physical examination procedures with techniques capable of providing more rapid diagnostic information or direct therapeutic intervention. Ultrasound of the chest for the definitive diagnosis of a pleural effusion is an example of an objective procedure that may obviate many of the traditional physical examination procedures used for the clinical diagnosis of pleuropneumonia (e.g., auscultation, percussion). Though less commonly used by the internist, the advent of portable digital radiography has dramatically improved the efficiency of obtaining quality films without additional trips and repeated exposure of staff and patient.

The size of equipment is a determining factor in whether or not a diagnostic tool is suitable for the examination area. For example, equipment such as computerized axial tomography scanners, magnetic resonance imaging (MRI) units, and nuclear scintigraphy units do not currently fit into the space available in most hospital physical plants. Large, modular ultrasound machines can be cumbersome in small areas, although units available for field reproductive use (linear or sector scanners) are appropriate for any area, including vehicle transport. The choice of ultrasound equipment is an individual decision based on need, budget, and available units. Security should also be a consideration in stocking an examination area with equipment and medications. The clinical examination areas of most facilities tend to be high-traffic regions; this may be a primary reason for not stocking certain pieces of equipment in both university practices and private facilities.

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