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2016 American Animal Hospital Association Conference

Clinician's Brief

July 2016

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Intervertebral Disk Disease

Intervertebral disk disease is most commonly characterized by intervertebral disk herniation (IVDH), which is caused by either disk extrusion or protrusion. Disk extrusion occurs from the complete tearing of the annulus fibrosus with displacement of the nucleus pulposus in the vertebral canal or intervertebral foramen; disk protrusion is caused by partial tearing of the inner layers of the annulus fibrosis with displacement of the nucleus pulposus into the torn region. IVDH diagnosis requires advanced imaging (eg, MRI, CT, myelogram) but can be suggested by radiographs showing suspicious signs (eg, an opacity in the vertebral canal, narrowed articular facet space and/or foramen, narrowed or wedged disk spaces). 

Medical vs surgical treatment of IVDH depends on clinical status, financial feasibility, and the degree of changes seen on imaging. Medical management is recommended for cases with spinal pain +/- mild paresis or ataxia. Multimodal therapy involves analgesia, anti-inflammatory, and muscle relaxant therapy. Surgical intervention is usually reserved for patients that have not responded well to medical management or that have more severe clinical signs. Deep pain sensation is the primary predictor for motor function retention: Animals with intact deep pain sensation have an 80% to 90% chance of regaining motor function, whereas animals lacking deep pain sensation only have a 50% chance. Discussing supportive care and husbandry requirements with the owner is essential, especially in severe cases, as inappropriate bladder management can cause significant morbidity.—Isaacs A

Central Sensitization & Osteoarthritis: Treating Chronic Pain 

Central pain sensitization occurs when nociceptive neurons in the dorsal horn of the spinal cord become sensitized by peripheral tissue damage or inflammation; this causes those neurons to become hyperresponsive. Osteoarthritis (OA), a primary cause of chronic pain in dogs, is characterized by cartilage damage, joint capsule thickening, remodeling of subchondral bone leading to sclerosis, and osteophyte formation. Inflammatory mediators produced by damaged chondrocytes can cause pain. Treating OA pain requires a comprehensive approach using medications, exercise, and weight management. Nonsteroidal anti-inflammatory drugs (NSAIDs) are the mainstay. Animals with refractory OA pain may benefit from a multimodal analgesic approach; following are some of the options and developments discussed. Amantadine is an N-methyl-D-aspartate (NMDA) receptor antagonist that reduces CNS hyperresponsiveness, which allows other analgesics to function more effectively. Gabapentin helps reduce neuropathic and other chronic pain. Grapiprant is a new drug that specifically targets the EP4 receptor; it blocks prostaglandin E2 from binding and subsequently blocks the pain response. Resiniferatoxin targets TRPV-1 (specific afferent sensory neurons) and allows selective nerve destruction. Shockwave therapy and pulsed magnetic field therapy have been studied as means of targeting cartilage defects in severe OA cases.—Stramel DP

Finicky Felines: Anorexia in Cats 

Anorexia, commonly seen in feline medicine, is a nonspecific clinical sign caused by many diseases. It can lead to alterations in metabolism, wound healing, and immune impairment. True anorexia (ie, loss of appetite for food) should be distinguished from hyporexia (ie, reduced appetite), as anorexia requires more aggressive treatment. Anorexia and hyporexia can be caused by disease, diet changes, and stressors. When treating these patients, it is crucial to know the Resting Energy Requirement (RER) and to adjust the amount fed according to fluctuations in body weight (BW) and body condition score (BCS). Multiplying the RER by an illness factor is no longer recommended. BW and BCS should be noted on admission and updated frequently. Food intake, vomiting, and bowel movements should be monitored. If an adult cat is eating <85% of its RER, is anorexic for >3 days, or has rapidly lost >10% of its BW, nutritional intervention is indicated. In kittens, nutritional intervention should begin after 24 hours of anorexia. 

Clinician's Brief

When intervention is required, the clinician should choose either simple intervention involving enhancing smell and palatability through temperature and food choices, syringe feeding (limited utility), or feeding through a nasogastric/nasoesophageal tube if support is required for <7 days. For animals requiring support for >1 week, an esophagostomy tube is preferable. Metoclopramide, maropitant, prochlorperazine, chlorpromazine, mirtazapine, and cyproheptadine are commonly used as antiemetics and appetite stimulants in cats.—Little S

Acid Suppressants in Organ Failure & Inflammation 

There are no prospective studies evaluating the benefit of acid suppressants in dogs and cats, and thus there are no current guidelines for their use in these patients. Some preliminary, anecdotal evidence supports using proton pump inhibitors in patients with gastroduodenal ulceration, reflux esophagitis, and exercise-induced gastritis. Patients with advanced renal disease may be prone to gastric mineralization, gastric gland atrophy, and hypergastrinemia, but data are lacking. 

The author administers acid suppressants to patients with advanced renal disease when they are anorexic or vomiting or have GI bleeding. Acid suppression should be considered in patients with advanced liver disease that are at risk for gastric ulceration, although further evidence is needed. Acid suppression in pancreatitis patients is controversial but may be beneficial if persistent vomiting causes esophageal mucosal injury. Although an intragastric pH >6.8 promotes platelet aggregation and clot formation in patients with GI bleeding, the efficacy and optimal dose of acid suppressant therapy is unknown in patients with thrombocytopenia-induced GI bleeding. The author uses acid suppressants to treat only those critically ill patients that have continuous vomiting or regurgitation and/or suspected compromise of the gastric mucosal barrier. Side effects of acid suppression are few. No published studies have evaluated the effects of prolonged drug use in small animals.—Tolbert K

Advances in Veterinary Oncology

The past 10 years in veterinary medical oncology have seen many advances in the standard of care. The author discussed diagnostic advances in detecting pulmonary metastasis through CT; advances in diagnostic imaging used for feline vaccine-associated sarcomas; testing for the ABCB1 gene that is associated with increased drug sensitivity; and dexrazoxane use for the attenuation of the side effects of adriamycin and doxorubicin. Updates to lymphoma therapy, including evaluation of the CHOP protocol and results of L-asparaginase efficacy studies, were reviewed. The author also covered toceranib, a kinase inhibitor, for treating mast cell tumors; the melanoma vaccine in dogs; fine-needle aspiration of nonpalpable lymph nodes for evaluating metastasis of carcinomas and sarcomas; and the success of maropitant treatment for chemotherapy-associated vomiting.—Bergman PJ

Belly Aching: Acute Abdominal Emergencies

Clinical signs of acute abdomen, defined as sudden onset of abdominal pain, frequently include vomiting, diarrhea, abdominal distention, postural changes, lethargy, weakness, and shock. Clinicians often must determine if and when surgery is necessary. A thorough physical examination is required. Clinical signs such as tachycardia, pale mucous membranes, slow capillary refill time, and weak pulses indicate shock. A minimum blood work database—including packed cell volume and total solids, serum chemistry profile, urine dipstick and specific gravity, and serum electrolytes—may answer key questions.

Abdominal radiographs are critical to screen for free gas, free fluid, organ displacement, enlarged organs, or a distended stomach and intestines. Ultrasound is a valuable tool in the acute abdomen workup. Abdominocentesis should be performed if the cause is not obvious. Simple fluid cytology may indicate presence of intracellular bacteria, a sign of septic peritonitis and a clear indication for surgery. Other key findings from lavage or abdominal fluids may include: decreased glucose or increased lactate relative to peripheral blood (suspicious for septic peritonitis); bilirubin (indicative of biliary tree rupture); increased creatinine and potassium relative to peripheral blood (indicating urine); amylase (pancreatitis); or alkaline phosphatase (intestinal ischemia). For the surgical patient, surgical preparation of a wide area and a long ventral midline incision are critical. Surgical exploration should be detailed and methodical. Tissue integrity, blood supply, and areas of hemorrhage must be fully assessed and addressed. Lavage and suction must occur before closure.—Barr J, Peycke LE

Presurgical Stabilization of Emergent Patients

The risk of anesthesia can be higher than normal for critically ill patients, which have a diminished ability to physiologically compensate. The clinician should correct abnormalities such as shock, abnormal lab results, or physical deficiencies before anesthesia. Immediate attention should be paid to the patient’s airway, breathing, and circulation. Oxygen therapy has no contraindications or short-term side effects. If the animal is in shock, fluids should be administered, typically starting with one-fourth of a shock dose over 5 to 10 minutes, with frequent reassessment of the patient. Hypertonic saline and hetastarch are useful when serum protein is low or when pulmonary contusions or head trauma are present.

Packed RBCs, devoid of plasma and its colloid oncotic pressure, are useful for avoiding volume overload in cases of life-threatening anemia. RBCs are usually given after initial attempts at volume resuscitation are complete. Glucocorticoids are contraindicated except for possibly at physiologic doses in steroid-deficient patients in septic shock. Hypoglycemia is life-threatening and must be corrected before anesthesia. Potassium derangements, particularly life-threatening because of their arrhythmogenic potential, should be addressed promptly. Pleural space disease can impair ventilation, thus necessitating thoracocentesis and oxygen therapy. Clinical signs associated with pulmonary contusions may be alleviated with supplemental oxygen; however, their presence may be an indication to delay surgical intervention. When treating critically ill patients, it is important to identify, anticipate, and treat problems while minimizing anesthetic risk and using appropriate anesthetic protocols.—Barr J

The Ownership Proposition

The responsibility of ownership requires great consideration. There can be substantial personal and financial rewards; however, risk and sacrifice are required. A practitioner can start a new practice or buy a practice; both options involve significant consideration to create a profit-building enterprise. The purchase price of a practice has critical impact on the practice’s success because if a business is oversold, the profits may be insufficient to cover the debt, which exposes the new owner to even more significant financial strain. An independent practice valuation can provide a potential buyer an assessment of the practice’s profitability and thus some insight into the risks of ownership. Practice ownership also requires a great deal of time, foresight, and responsibility. Owner understanding of the strengths and limitations of any practice will not only help that practice succeed but eventually lead to a unique financial and professional opportunity. It is essential to have an interest in business management and a willingness to acknowledge and seek advisors for unfamiliar aspects of the business.—Mamalis LA, Hargrove M

Closing the Expectation Gap 

An expectation gap is the difference between what an employer asks of team members and what the team members actually do. This gap exists in the workplace because employers fail to communicate expectations and employees are not engaged in their work. By creating a manageable number of clear, relevant objectives, employers allow employees to understand why tasks were created and how their work benefits the company as a whole. This then leads to an engaged team. A clearly stated, original, meaningful mission statement can define a practice’s relevance regarding animal care, client care, and employee relations. It is also important to hire team members with skills specific to the positions they fill. With detailed job descriptions that accurately define expectations, team members will be better able to fulfill their roles using their unique skill sets. Regular performance reviews should be carried out in a celebratory, not critical, manner. Done correctly, reviews should help improve both the employee and the business. Regular team meetings can help keep the practice moving toward its goals and mission.—Halow B

Preparing for the Truly Unexpected

Many clinics have emergency strategies in place. However, certain incidents (eg, agricultural or industrial accidents, radioisotope-related events) are considered so unlikely that most clinics have no plans for them. The fertilizer plant explosion in West, Texas, in 2010 is an example of such a disaster. Given the proximity of residential areas, schools, and a nursing home, the disaster affected many more citizens than plant workers and first responders. Deaths were secondary to fractures and injuries; many other traumatic injuries were described. The Texas A&M Veterinary Emergency Team (VET) dispatched to handle veterinary patients reported similar injuries in their patients.

Unanticipated emergencies and disasters can affect any veterinary clinic. The area where a clinic is located should be appraised for possible risks and evacuation considerations. City and county emergency management coordinators can be a useful resource when determining risks. When developing an evacuation plan, it is essential to consider patient, client, and team capacity; transportation needs; drivers; equipment, supplies, and drugs needed; and multiple evacuation destinations. The Texas A&M VET and the Texas and American Veterinary Medical Associations have resources available to help practices develop emergency plans. Texas A&M VET offers a template on its website (vetmed.tamu.edu/VET) to help practices gather and organize information for emergency plans.—Zoran DL

For global readers, a calculator to convert laboratory values, dosages, and other measurements to SI units can be found here.

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