Medical Directors’ Notes
Thank you for making this year’s CE in the City a great success!
We had over 250 attendees, provided 24 hours of high quality and clinically applicable CE and raised over $8,000 for NYSAVE.
Next year will mark the tenth anniversary of CE in the City, so be on the lookout for more information on an exciting event. We’ve already started planning and hope to make it the best yet.
In the meantime, if you have a topic you would like to learn more about, we are happy to provide CE to Your Door for you and your staff with complimentary breakfast, lunch or dinner. Just contact Dr. David Wohlstadter or Jen Anderson-Khan to set a date.
Marc Greenberg, DVM, DACVS-SA
Timothy Rocha, DVM, DACVIM-Oncology
Tiger in Your Waiting Room: Understanding Feline Aggression
Jill Sackman, DVM, DACVS, PhD
BluePearl in Michigan
By nature cats prefer not to fight! Domestic cats are solitary hunters. Social behaviors have evolved in cats to avoid conflict; this strategy is very different from humans and dogs. Once cats are aroused, they have very poor skills for resolving conflict, unlike dogs.
Passive avoidance is a cat’s first response to an uncomfortable situation; just leave the room. Setting a household up for peaceful feline living includes enriching the environment with an abundance of toys, resting places, litter boxes, food and water bowls distributed throughout the house; there is no need for anyone to fight over anything.
When dealing with feline behavioral health, always ask, “Am I meeting the needs of this animal based upon his/her behavioral evolution and natural needs?” The answer is often “no.” Many home environments are sterile and non-stimulating for cats. Treatment of aggression in cats frequently includes environmental enrichment, providing opportunities for cats to exercise their predatory behavior with acceptable toys, etc.
To ensure healthy behavior and treatment for many forms of aggression in cats, it is important to first look at the home environment. Start by making the cat’s indoor space more like a natural space. Suggestions include visual stimulation with fish tanks, bird feeders outside windows, even robotic prey-like toys (www.Hexbugs.com). Add perches and cat trees; introduce novel toys (wand toys are particularly interesting); and satisfy the predatory need of cats. Hunting instincts can be satisfied by putting dry food in puzzle feeder balls or tubes instead of dishes.
Reading Feline Body Language
Unfortunately, humans don’t often do a great job reading feline body language in order to de-escalate a stressed or aggressive cat. Understanding feline body language can help with avoiding conflict, its escalation and aggression.
Cats use a combination of visual, olfactory and audible communication to communicate and to avoid confrontation. Threatening feline body postures include hissing, piloerection, arching of the back and side presentation. Ear position is also a helpful stress barometer. Cats that are restricted in movement (i.e. cages, transport boxes) may choose to fight when unable to flee. The ability to get away, hide under something or jump up high can influence the expression of the aggressive responses.
The most frequent basis for aggression from cats to people revolves around fear, anxiety, frustration and misdirected predatory behavior. Fearful cats learn that aggressive stances are effective at maintaining distance between them and people, and the behavior can evolve to a preemptive strategy. Repeated unpleasant interactions in a veterinary hospital contribute to the development of negative behavior in these cats.
Play-based aggression may arise from predatory play, which is an integral part of feline behavior and learning. Treatment is focused on finding outlets for play and directing the cat toward appropriate activities and toys. Playing with hands should be discouraged.
Redirected aggression occurs when a cat faces an agitating circumstance and is unable to vent aggression. Stimuli include loud noises, odor of another cat, unfamiliar people or environments and pain. Agitated cats should be placed in a darkened room with food, water and litter box and left there with the door closed. If the aggression was directed at another unsuspecting feline, very SLOW reintroduction must be done.
Punishment is contraindicated in all cases as this will lead to a worsening of the behavior. Medication may be warranted and may include pheromones, nutraceuticals and drugs such as fluoxetine. Always evaluate the cat for medical problems first, followed by evaluation of the home environment before turning to medication.
Recognizing and Treating Heat Stroke in Dogs
John C. Gicking, DVM, DACVECC
BluePearl in Florida
Heat stroke in canines occurs when the core body temperature exceeds 105.8° F (41° C) and central nervous system dysfunction occurs. This will occur either when animals are exposed to high temperatures (classical heat stroke) or if physical exertion causes the creation of excessive body heat (exertional heat stroke). In both situations, the body’s normal cooling mechanisms are overwhelmed. Unlike humans, dogs do not sweat; instead, panting causes heat to be ‘blown off’ from the nasal passages and oral mucosa through evaporation. This mechanism quickly loses efficiency as environmental temperature and humidity increases.
Pathophysiology and presentation
The high temperatures cause problems in almost every organ system in the body. The most obvious is dysfunction to the brain as heat stroke patients present with anything from depression to seizure activity, or even comatose. Very often, patients will be coagulopathic and thrombocytopenic from direct consumption of clotting factors and platelets; this can even be a lead to the dreaded syndrome of disseminated intravascular coagulation (DIC). Acute kidney injury is also common in these patients due to direct effects of heat on the kidneys as well as shock and thrombosis. A large amount of fluid may be lost quickly through panting and vomiting, or diarrhea may occur worsening fluid deficits.
The diagnosis of heat stroke may be readily apparent with a high body temperature and a patient who is mentally abnormal. The dog may stumble, act drunk, be mentally dull or even have seizure activity, and possibly even present comatose. If the patient presents a considerable time after the heat stroke event has passed, the body temperature may be normal or even low. Patients will often present in some form of shock with signs of cardiovascular compromise. Vomiting and diarrhea are common. If coagulopathy and/or thrombocytopenia are present, ecchymotic and/or petechial hemorrhages may be seen. Melena and/or hematochezia may occur.
First aid and treatment
Steps taken prior to presentation at the veterinary clinic may be life saving. Moving the pet to a cool area, wetting down the skin with cool (not ice) water, and using a fan to increase airflow can bring down the body temperature rapidly and effectively. Use of ice or freezing cold water should be avoided as it will cause peripheral vasoconstriction (thus slowing heat conduction) and can cause cutaneous injury with prolonged contact. It must be stressed that the provision of first aid in the field should not delay the presentation to a veterinarian for further evaluation and treatment. Delays such as this have been shown to have a negative effect on outcome.
Once presented to the veterinary clinic almost all heat stroke patients will benefit from being treated with IV fluids to restore or maintain hydration and perfusion. Depending on the pet’s clinical state, the following may be needed: blood products to treat coagulopathy or anemia, medications to treat seizures, gastric protectants, and broad-spectrum antibiotics. Many cases may require hospitalization for several days depending on the severity.
Pets who are at risk for heat stroke include working dogs, dogs that are athletes, brachycephalic breeds, pets with respiratory problems, or overweight animals. Patients who have suffered a heat stroke in the past appear to be at a higher risk for further heat stroke incidents. A key to avoiding heat stroke is providing counseling to owners about these risks and to avoid activities during the warmest times of the day or even year.
The prognosis for an individual animal who suffers a heat stroke is dependent upon the severity of the incident. Risk factors for death due to heat stroke include hypoglycemia at presentation, coagulopathy at presentation, delayed time to presentation for emergency care, obesity, and an increased creatinine (>1.5g/dL) after 24 hours of treatment.
In conclusion, heat stroke is a multisystemic disorder that carries with it the possibility of death and significant morbidity. Awareness of the risks, recognition of the signs, and the provision of first aid all go a long way to prevent heat stroke. If a pet is suspected to have had a heat stroke, presentation and evaluation by a veterinarian as soon as possible is essential. Aggressive, intensive therapy may be needed as severely affected pets are critically ill and are at high risk for mortality.
BluePearl critical care teams are prepared to accept your most critical of cases.
Autologous Blood Transfusions in an Emergency Setting
Beth Guerra, DVM
BluePearl in Washington
One of the problems plaguing the veterinary profession is the availability of blood products in an emergency setting. With a dearth of well-established blood banks, most emergency clinics rely on national suppliers or in-house blood donors. For general practices, the options may be more limited.
The most common causes of thoracic and abdominal hemorrhage are vascular trauma, ruptured neoplasia or coagulopathy (usually rodenticide). In a critical setting, there may be a limited amount of time to locate a blood product, perform a cross match or adequately warm the product to the appropriate temperature. An autologous blood transfusion (ABT) involves re-infusing the patient’s blood quickly in an emergency setting. This can be done in-house with equipment that is usually on hand, and once the procedure is established, can require minimal personnel.
The technique can involve direct aspiration from a body cavity or aspiration into a sterile canister during surgery. In the former, centesis is usually performed using a large-gauge needle attached to an extension line and a three-way stopcock. The blood is collected into large syringes or a sterile collection bag. A 210 micron Hemo-Nate® filter is used on the end of the tubing introduced into the patient catheter. The blood is usually drawn straight from the patient’s body cavity and then infused directly back through the IV. For larger volumes, citrate anticoagulant (at the ratio of 0.14ml/ml of blood) can be added to the collection vessel, usually syringes, and blood can be collected in several syringes sequentially before infusing back into the patient.
During surgery, blood can be collected directly from the body cavity using a Poole suction tip with the pressure set at less than 100mmHg to avoid stress to the RBCs. The suction tip should be kept well below the level of the blood to avoid aspiration of excessive air. The blood can be collected into a sterile suction canister, then transferred to either an empty blood collection kit bag or an empty sterile fluid bag with an IV administration set containing a 210 micron filter.
A third method of collection was just described in the November 2016 issue of JVECC. Blood can be collected from the abdomen during surgery using catheter tip syringes, which can then be passed to an assistant. Luer tip syringes can be inserted into the catheter tip to withdraw the blood and then hooked to a filter and the blood administered to the patient.1
The benefit of ABT is obvious: an immediate source of normothermic, compatible blood with no risk of transfusion reactions. It is also much more cost effective compared to banked products, and there is no risk of disease transmission or degradation of 2,3-DPG associated with stored products. The risks include contamination during collection, air embolism or hemolysis of RBCs (either during suctioning or prolonged contact with a serosal surface). Rarely, hypocalcemia can be seen if a large amount of citrate anticoagulant is used.
A recent retrospective study in JVECC2 identified 25 dogs receiving ABTs. The hemorrhage was localized to abdominal (76%), thoracic (20%) and both (4%). Of the dogs with vascular trauma (56%), the most common causes were GDV with rupture of short gastric vessels, post-op OVH/neuter complications and blunt force trauma. For dogs with rupture neoplasia (32%), sites included renal, splenic or unidentified intrathoracic. The dogs with coagulopathy (12%) were exclusively brodifacoum. In this study, the median transfused volume was 29ml/kg, with the largest volume transfused in ruptured neoplasms. Additional blood products, such as whole blood or FFP, were given in 68% of the cases. It was noted that there was no significant association between survival and etiology of hemorrhage. Investigations in humans have failed to demonstrate an increased metastatic rate with ABTs in patients with ruptured neoplasia; in this study, most of the dogs already had evidence of metastasis at time of ABT.
If your clinic does not have an in-house blood bank, or when products are scarce, ABT can be considered as an alternate source of blood. Establishing ready-made kits and training technical staff in these procedures can make the process routine.
1) Robinson DA, Kiefer K, Bassett R, Quandt J. Autotransfusion in dogs using a 2-syringe technique. J Vet Emerg Crit Care. 2016: 26: 766-774.
2) Higgs VA, Rudloff E, Kirby R, Linklater AKJ. Autologous Blood Transfusion in dogs with thoracic or abdominal hemorrhage: 25 cases. Vet Emerg Crit Care. Nov/Dec 2015;25(6):731-8.
Understanding How Cataracts Form and Treatment Methods
Anja Welihozkiy, DVM, DACVO
BluePearl in Florida
The crystalline lens is an avascular, transparent and highly structured “fine-tuning” refractive tissue that focuses light rays on the retina, which is the beginning of image transmission to the brain. The lens is composed of mostly water and protein arranged in a manner that keeps it transparent, thereby enabling light to pass through it.
Any opacity within the lens or its associated lens capsule that is causing loss of transparency is termed a cataract. Cataracts are among the most common intraocular lesions in dogs and are the leading cause of vision loss in this species.
Cataract formation results from denaturation and clumping of lens proteins causing an opacity within the lens that obstructs light from passing and being focused on the retina. They are frequently progressive. As the opacity progresses, a loss of visual acuity occurs. People with cataracts report a loss of sharpness to the image they are seeing, less contrast between objects, and less vivid colors. A glare is sometimes described and probably occurs due to the scattering of light in different directions by the abnormal lens. Ultimately, vision will be lost.
Most cataracts in dogs are inherited and can occur at any age. The cataract may develop rapidly over weeks, or slowly over years, and occur in one or both eyes. Different breeds of dogs have different characteristics of cataract development.
The second most common cause of cataracts in dogs is diabetes mellitus. Over 75% of diabetic dogs will develop blinding cataracts within the first year of diagnosis; 60% of dogs have cataracts at initial diagnosis of diabetes mellitus. Diabetic cataracts can develop VERY fast – sometimes within a few days – and may be considered medical and surgical emergencies in certain situations.
The third most common cause of cataracts in dogs is a toxic reaction in the lens secondary to an underlying primary ocular disease or (much less commonly) due to a drug reaction. These are called “toxic cataracts.” Toxic cataracts caused by ocular disease are quite common in dogs and can be caused by
- Retinal degeneration, especially progressive retinal atrophy (PRA)
- Uveitis (intraocular inflammation) of any cause, including trauma
- Glaucoma (increased intraocular pressure) of any cause.
Cataracts can also develop due to penetrating trauma (cat scratches to the lens), nutritional deficiencies (puppies on an artificial milk-replacer diet), age-related onset of cataract formation (senile cataract) and many other potential causes, such as birth defects, infection and radiation therapy to the head. Discussion of these causes is beyond the scope of this article.
Once a lens has developed a cataract, there is no known medical method to increase transparency in the lens. Immature, mature and hypermature cataracts can be removed surgically via phacoemulsification. The sooner a cataract is removed the better the postoperative outcome. A cataract becomes surgical if it is deemed progressive and is starting to cause visual behavior changes (vision loss).
A small incision is made in the cornea, and an opening is created in the anterior lens capsule. Phacoemulsification is then performed during which a special probe ultrasonically emulsifies and removes the cataract (all of the lens contents inside the capsule). After the cloudy lens is removed, the empty lens capsule remains and is called the capsular bag. An artificial replacement lens, called an intraocular lens, or IOL, is placed in the bag to refocus the light onto the retina. The eye is closed with small absorbable sutures.
The success rate of uncomplicated cataract surgery with intraocular lens implantation in dogs is approximately 90-95%. Short and long-term complications include glaucoma, uncontrolled uveitis and retinal detachment, with a prevalence from 5-10%. Not having a cataract removed can also cause the same complications as described above, even to a higher percentage rate. Regardless of whether or not a patient receives cataract surgery, long-term topical anti-inflammatory treatment is necessary to control intraocular inflammation.
What is lenticular sclerosis (nuclear sclerosis)?
Lenticular sclerosis is a normal, age-related clouding of the lens of the eye, which is not a cataract. Lens epithelial cells located on the anterior lens capsule are continually producing new protein fibers compressing older fibers in the center of the lens. The denser lens center causes light to scatter giving the lens a hazy grayish-blue appearance to the observer. Unlike cataracts, light can still penetrate the lens to reach the retina producing a visible tapetal reflection. Lenticular sclerosis is not believed to significantly affect vision, and therefore treatment is not recommended.
Canine Laryngeal Mass? Consider a Thyroid Tumor
The presence of a firm mass in the ventral cervical neck region overlying the larynx of dogs should make you suspicious for a thyroid tumor. Few other tumor types develop in this location. The mass is most commonly an incidental finding by the pet owner or noted on physical exam. Less frequently, owners will note a laryngeal stridor. Unlike cats with thyroid tumors, clinical signs of hyperthyroidism are uncommon. Most thyroid tumors in dogs are nonfunctional, but also more aggressive. Up to 40% of dogs with thyroid tumors may demonstrate evidence of metastasis on thoracic radiographs at time of diagnosis. Approximately 80% of canine thyroid tumors will eventually metastasize.
Ultrasound or CT scanning of the neck region is performed to assess the tumor’s invasiveness. In our experience, thyroid aspiration cytology, which can be quite bloody, will provide a definitive diagnosis in the majority of patients. The absence of other cell types can effectively exclude other possible causes for the mass.
Surgery is the best treatment option for thyroid tumors. Survival times of up to 3 years can be achieved when the mass is freely moveable and 6 to 12 months if it has invaded into the surrounding tissues. The proximity of these tumors to major blood vessels and nerves in the cervical neck region can make surgical resection challenging.
Radiation therapy has also proven effective for treating thyroid tumors and is a good adjunctive choice for tumors that cannot be completely resected. Radiation therapy slowly kills cancer cells so it can take 8 to 22 months for the mass to decrease in size. This is not a quick enough option for dogs if the mass is obstructing breathing.
Radioactive iodine has also been used to treat some dogs with thyroid tumors. It can be effective against metastatic or residual thyroid neoplasia with survival times of 2 years being reported. However, unlike cats with hyperthyroidism, most dogs do not trap the iodine in their thyroid tumors, which is required for the treatment to be effective. Technetium scanning is performed to determine whether radioactive iodine treatment could be effective. Dogs require much higher doses of radioactive iodine than cats, and therefore are quarantined longer.
Should you suspect the presence of a thyroid tumor, BluePearl oncology services are available for consultations or to answer any questions you might have.
BluePearl is strongly committed to the veterinary community. One of the ways we demonstrate this commitment is through our continuing education program, which is subsidized in part by our Partners in Education.
All BluePearl lectures are free and include a light dinner at 7:00pm. Presentation begins at 7:30 pm.