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Red Maple Toxicity
by Dr. Kathy Samley
Red maple leaves (Acer rubrum) are toxic to horses. The fresh leaves themselves are safe, but they become toxic after the leaves have wilted. The wilted leaves can remain toxic for up to 30 days. Red maple leave toxicity is common in the fall when the leaves begin to wilt and accumulate on the ground.
A 1000# horse will develop clinical signs after ingesting at least 1.5 lbs of wilted red maple leaves. A toxic component of red maple leaves damages the horse’s red blood cells. The red blood cells eventually become lysed, which causes the horse’s packed cell volume (percentage of red blood cells in the blood) to decrease rapidly as the red blood cells are destroyed. Hemoglobin, a component of red blood cells, is filtered out by the kidneys into the urine and causes the urine to turn a dark red color. Hemoglobin is damaging to kidneys, leading to acute renal failure. Common clinical signs of red maple toxicity in horses are depression, jaundice, fever, dark red urine, and colic.
A physical exam is important to assess the status of the horse. Bloodwork and urinalysis can be used to confirm the diagnosis as well as assess how far the toxicity has progressed. Horses with hemolytic anemia due to red maple toxicity have hemoglobinemia (red-tinged serum), as well as signs of hemoglobin in their urine. Bilirubin will be elevated in the blood due to the hemolysis. Kidney values (BUN and creatinine) are often elevated depending on the amount of renal compromise.
If you suspect your horse has ingested red maple leaves a veterinarian should be called as soon as possible. If in the acute phase, activated charcoal may be administered through a nasogastric tube in order to help absorb the toxins. In most cases, hospitalization is necessary as the horse usually requires close monitoring, IV fluids, and critical care. A blood transfusion is often necessary if the horse’s packed cell volume is extremely low. Intravenous fluids are important to diurese the kidneys if they are showing signs of damage from hemoglobin. Vitamin C, vitamin E, and selenium can help treat the oxidative damage from the toxins.
Prognosis is guarded to poor, as horses can develop many secondary complications including acute renal failure, colic, and laminitis. Hospitalization and intensive care provide the best possibility of recovery. Early diagnosis and treatment is critical.
Equine Kissing Spine
By Laura Wodzinski, DVM, cVMA
In horses, kissing spine, more formally known as overriding dorsal spinous processes (ORDSP), is a condition where the spacing between the dorsal spinous processes (DSP) in the horse’s back vertebrae are narrowed and there is associated back pain. Thoroughbreds are overrepresented in the breeds commonly affected. In a study performed by Dr. Tracy Turner, DVM, DACVS, DACVSMR, dressage horses were the most commonly affected discipline with eventing horses being second. There is speculation that the appearance of kissing spine in these horses could be due to overuse of the back during collection and lateral movements causing inflammation and pain at the sight of impingement.1 In this article, you will learn how kissing spine is typically diagnosed and the various treatment options available.
The diagnosis of kissing spine is made after a thorough lameness evaluation and lateral radiographs of the spine. It is important to note that the presence of kissing spine radiographically without clinical signs of back pain is not necessarily a concern, however the horse may be predisposed to back pain in the future.1 Clinical signs of back pain include resistance to digital pressure over the back and epaxial muscles. Signs of discomfort including ears pinned, tail switching, and/or kicking out often accompanies this resistance. The horse may travel with his head in the air with a stiff back or may have some difficultly bending to one side. The more severely affected horse may progress to rearing or bucking.
Radiographs of the dorsal spinous processes show a narrowed space between the vertebrae with sclerosis, or increased bone density due to bony remodeling, on the adjacent touching sides. The most common location for ORDSP is the caudal thoracic vertebrae, where the seat of the saddle sits, between T13-T18 vertebrae. 1 Other diagnostic modalities used are nuclear scintigraphy, more commonly known as a bone scan, where the affected spinous processes will have a greater radiopharmaceutical uptake.2 Thermography can also be used to identify kissing spine by displaying specific thermal heat patterns.1 This tool may help differentiate between kissing spine and other causes of back pain. 1
There are several treatment options for kissing spine from physiotherapy management to surgery. Exercises to stretch the back include walking and trotting in a “long and low” frame and adding in ground poles to encourage further stretching. Additionally, stretches that include lateral bending and stretching their neck to their knees can be helpful in opening up the DSP spaces. Proper saddle fit is essential to the continued comfort of a horse’s back. Mesotherapy is another treatment where a combination of anti-inflammatories and LRS solution is injected with multiple very small intradermal needles over the back and croup. 1 Extracorporeal shockwave therapy (ESWT) can be used over the dorsal spinous processes and epaxial musculature to promote healing in the region. ESWT is a non-invasive technique that sends shock waves to a specific area to promote blood flow, increase the production of natural healing factors, and increases blood vessel formation.3
Injections with corticosteroid between the affected dorsal spinous showed improvement in 55% of horses. 1 Several surgical procedures have been described to physically open up the space between the dorsal spinous processes. Dr. Coomer from Cotts Equine Hospital in the United Kingdom developed a method where the interspinous ligament, the ligament that connects the spinous processes to one another, is cut to increase the spacing between the vertebrae. 4 In his study, Coomer found that 89% of horses treated medically had initial resolution of back pain versus 95% of horse treated surgically. None of the surgical cases had a recurrence of clinical signs and radiographs following surgery revealed a significantly widened interspinous space. 4 Visit the New England Equine Facebook page to see images from a recent kissing spine case!
There are many causes of back pain in the horse. Kissing spine is easily seen with radiographs and can be treated in a variety of ways to improve the comfort of the horse.
1. Turner, Tracy A,. "Overriding Spinous Processes (“Kissing Spines”) in Horses: Diagnosis, Treatment, and Outcome in 212 Cases." WOUND & ORTHOPEDIC MANAGEMENT AAEP Proceedings 57 (2011)
2. DVM, Kenneth Marcella. "Kissing Spines in Veterinary Equine Patients: Easy to Diagnose, Complicated to Treat." Dvm360.com. N.p., 17 Dec. 2014. Web. 08 May 2017.
3."Extracorporeal Shockwave Therapy." Large Animal Hospital. N.p., n.d. Web. 08 May 2017.
4. Coomer RP, McKane SA, Smith N, et al. A controlled study evaluating a novel surgical treatment for kissing spines in standing sedated horses. Vet Surg 2012;41(7):890-897.
Roaring (laryngeal hemiplegia)
Dr. Kathy Samley, DVM
What is it?
Laryngeal hemiplegia, commonly called "roaring" is a disease of the upper airway in horses. The larynx is the opening to the trachea, and consists of several pieces of cartilage. The arytenoid cartilages open to allow air into the trachea, and close during swallowing to prevent food and liquid from getting into the trachea. Laryngeal hemiplegia occurs when there is degeneration of the nerve that innervates the muscles of the larynx, preventing the arytenoid cartilage from opening properly. This prevents proper airflow into the trachea and causes a noise heard during exercise. This decrease in airflow can also lead to exercise intolerance. Laryngeal hemiplegia usually only affects one arytenoid, with the left side affected in 95% of cases. The specific cause of the nerve degeneration is unknown but there are likely genetic and acquired components that contribute.
The two main signs of laryngeal hemiplegia are upper respiratory noise during exercise and poor performance. The severity of laryngeal hemiplegia is graded on a scale of 1-4, with 4 being complete paralysis of the arytenoid. The volume and severity of the upper respiratory noise and the amount of exercise intolerance can vary based on the grade of the laryngeal hemiplegia.
Laryngeal hemiplegia is diagnosed through upper airway endoscopy. A small camera is passed up the horse's nares to the level of the larynx. The arytenoid cartilages are examined through several respiratory cycles to assess their movement. The horse cannot be sedated for this procedure, as sedation makes it difficult to properly assess arytenoid function. There are several other conditions that can cause upper respiratory noise in horses, so the larynx and surrounding structures are closely examined for any abnormalities. After a baseline examination, a post-exercise endoscope exam is often performed. The horse is exercised for several minutes and the scope is passed again to assess the function of the arytenoids immediately after vigorous exercise.
Laryngeal hemiplegia is typically a surgical condition and is corrected via a prosthetic laryngoplasty, "tieback," procedure. Two strong sutures are placed through the arytenoid cartilage and attached to one of the other laryngeal cartilages. The sutures help to abduct the arytenoid cartilage, opening up the airway. The laryngeal saccule is removed in order to further stabilize the tieback and decrease upper airway noise. This procedure has a good prognosis for return to athletic function. Additionally, horses with lower grades of laryngeal hemiplegia have shown improvement after several treatments of electroacupuncture.
These images show a before (left) and after (right) a tieback procedure. The left image is from a horse with grade 4 left laryngeal hemiplegia. Note how the left arytenoid cartilage is deviated to the center of the larynx, partially obstructing the trachea. After surgery, the left arytenoid is held open which allows normal airflow.
Effects of Equine-Facilitated Psychotherapy on Post-Traumatic Stress Symptoms in Youth
Research Published in Journal of Child and Family Studies:
Effects of Equine-Facilitated Psychotherapy on Post-Traumatic Stress Symptoms in Youth
Chagrin Falls, Ohio, April 20, 2017– The findings from Tufts University’s equine-facilitated psychotherapy research studying effects on youth with Post-Traumatic Stress Disorder (PTSD) Symptoms was just published in the Journal of Child and Family Studies. The project was funded by Horses and Humans Research Foundation and lead by Principal investigator Megan K. Mueller, Ph.D.
Equine-assisted therapy has become an increasingly popular complementary mental health treatment approach, but there is limited empirical research assessing the effectiveness of this practice. In particular, equine-facilitated psychotherapy has many potential benefits for the treatment of trauma in youth. The purpose of the proposed study was to investigate changes in levels of post-traumatic stress symptomatology and levels of the human-animal bond in children and adolescents ages 10–18 over the course of a 10-week equine-facilitated psychotherapy (EFP) intervention.
Youth in the treatment group participated in 10 weekly two hour EFP sessions, and were compared on changes in post-traumatic stress symptoms with a control group of participants who continued to receive the already existing traditional therapeutic services provided by their treatment facility or outpatient therapist.
Findings suggested a significant decrease in post-traumatic stress symptoms across the intervention for both the treatment and control group, but the treatment group did not decrease significantly more than the control group. These findings suggest that EFP may be an effective additional treatment modality for post-traumatic stress symptoms, but there was no evidence from this initial study that EFP was significantly more effective than traditional office-based therapy. Further research and discussion of the relative benefits of EFP compared to traditional treatment modalities is warranted.
Paul Haefner PhD, of the Horses and Humans Research Foundation board of directors, stated “This research project was exceptionally significant because it put Equine Facilitated Psychotherapy on the map. It shows that this professionally facilitated treatment is a viable option. It gives us an important recognized tool when working with troubled youth who urgently need a treatment option that will help them progress during vulnerable time in their lives.”
Mission: Through sustained investment in rigorous research, HHRF serves as a catalyst to advance global knowledge of horse-human interactions and their impact on health and wellness.
Horses and Humans Research Foundation (HHRF) is dedicated to funding research to investigate the equine-assisted activities and therapies field. Since its founding, HHRF has awarded over $500,000 in professional research efforts led by eleven research teams in the United States, Canada and Germany. HHRF is a non-endowed foundation dependent solely on donations. To make a donation and/or learn more about this and other Horses and Humans Research Foundation projects visit http://www.horsesandhumans.org
Equine Acupuncture - A Scientific Approach
Written by intern Dr. Laura Wodzinski
New England Medical & Surgical Center
Acupuncture has been a part of Traditional Chinese Medicine for over 5,000 years and has grown in popularity in western medicine in the last few decades.2 With more evidence-based research emerging in human and veterinary medicine proving its effectiveness, it is becoming more recognized as a valid treatment modality in medicine. The World Health Organization has concluded that acupuncture is a valuable therapy in treating several human diseases. But how does this seemingly “voodoo” therapy of needling work?
The exact mechanism of acupuncture has yet to be discovered in the last 5,000 years, however numerous responses to needling have been documented in thousands of evidence-based studies. One of the most common uses of acupuncture treatments is for chronic pain. To explain a mechanism of how acupuncture can provide analgesia in chronic pain, consider this: You are chopping up apples to feed you horse the perfect bite-sized portions, when you accidently slice you finger with the knife. Your first reaction will be an involuntary reflex originating from a fast nociceptive fiber signal to your brain telling you to pull your hand away. The second reaction is to grip your cut finger an apply pressure. The pressure provides pain relief by activating mechanoreceptors found under the skin and the original sharp pain ceases. The brain is only able to handle one source of pain at a time, as described by the Gate Control Theory of Chronic Pain. With the pressure applied, the body is able to down regulate the sharp pain from the cut and allow your body’s “internal pharmacy” to be activated.3,6 In chronic pain, the fibers are thick and slower transmitting fibers that cause a more dull and throbbing pain. In contrast, sharp pain is associated with fast conductive fibers that transmit messages to the brain very quickly to create a response that will protect the body. When acupuncture needles are inserted into the skin and tissues, they cause micro-inflammation at the site and stimulate the fast fibers to carry signals to the brain, overriding the slow, chronic pain fiber messages.3 With this new, fast signal from the acupuncture, the brain is able to activate its neurochemical pharmacy to produce substances such as endorphins, serotonin, and opioids that make the animal feel good and down regulate pain. This process is known as neuromodulation.
The Central Nervous System (CNS) has a major role in the effects of acupuncture. By placing needles in acupuncture points, or areas that are richly supplied with nerve endings, it causes stimulation that creates a signal that is transmitted to the spinal cord, and then the brain. Once at the brain, key centers including those responsible for digestion, cardiopulmonary function, and the endocrine system are affected and a response can be created. Recent studies have used functional magnetic resonance imaging (fMRI) to evaluate the effect of specific acupuncture points and their direct effect on areas of the brain.2 In addition to direct nerve stimulation, the needle engages with collagen fibers, connective tissue matrix, and vessels under the skin that with manipulation of the needle causes activation of mechanoreceptors (a receptor that respond to pressure and transmit messages to the CNS), nociceptors (sensory receptors), vasodilation, and tissue biochemistry changes.1
Another use for acupuncture is relieving trigger points. A myofascial trigger point is described as: “a hyperirritable spot in skeletal muscle that is associated with a hypersensitive palpable nodule in a taut band.”1 Most humans can find these in their neck and shoulders after being hunched over a computer all day. In the equine patient, these trigger points can be associated with lameness, weakness, sore backs, and decreased flexibility. Excessively strenuous activities, repetitive strains, or even stall rest can precipitate the development of triggers points in addition to disturbances such as poor shoeing and an improperly fitted saddle. 1 Acupuncture works right at the site of the maximum soreness by inserting the needle directly into the center of the trigger point, and twisting it back and forth until the muscle fibers release. Localization of trigger points is done in our animal patients by palpating tight bands and watching the animals’ response in the form of a twitch or avoiding the pressure. Trigger points can form in any muscle at either the muscle belly or the myotendinous junction. They are not necessarily correlated with acupuncture points.
How can acupuncture be used to treat my horse?
In the equine patient, acupuncture can be used for a variety of musculoskeletal issues such as back pain, neck stiffness, laminitis, poor saddle fit and much more. Acupuncture treatments typically start with a “scan” of points that consists of running an acupuncture pen (or needle cap or Sharpie in a lot of cases!) over the horse to determine areas of sensitivity. Over sensitive areas, the horse will often flinch or move away from you, indicating there is some level of soreness at that site. This soreness can be due to a primary problem, or can be secondary muscle soreness from compensating for lameness somewhere else in the body. Regular acupuncture treatments can reduce muscle soreness during increased work or even improve comfort during their routine show schedule. Back soreness is a common condition that acupuncture can improve whether it is from an ill-fitting saddle or kissing spine lesions. Regular acupuncture treatments may even extend the interval between kissing spine treatments or mesotherapy.
Another common use for acupuncture in the equine patient is colic. Ileus, or decreased or absent gastrointestinal motility, is a common complication following colic surgery that can significantly compromise the recovery of the horse. The motility of the gastrointestinal tract is influenced by the sympathetic nervous system, the “flight or fight” response, and the parasympathetic nervous system, the “rest and digest” portion of the nervous system.4 Acupuncture aims to manipulate these systems through neurotransmitters acting on the autonomic nervous system to promote intestinal motility. Acupuncture should be considered and adjunctive treatment to colic with Western medicine therapies and diagnostics being performed first.
Reproductive disorders in both mares and stallions can be treated with acupuncture through neuro-hormonal regulation, pain relief, and smooth muscle contractions. In the stallions, issues including loss of libido, infertility, and poor semen quality can be improved using acupuncture. 5 In mares, cycle issues including failure to ovulate, sporadic heat cycles, or anestrus can be better regulated through acupuncture via mediation of the nerves that regulate and control the reproductive tract and the pituitary gland which influences hormone secretion. 5 Additionally, acupuncture’s effect on smooth muscle contractions can aid in the eliminate of fluid in the uterus and urine pooling that could compromise conception.5
Although seemingly abstract, acupuncture is a science-proven treatment modality that can help in a variety of diseases, most notably chronic pain. I recommend acupuncture treatment to my clients with the caveat that, like some pharmaceutical medications we take, acupuncture may not work for all animals or people or may take several treatments to see an effect. This treatment modality has very few negative side effects, is minimally invasive, and may have a profound positive response in your equine athlete- what are you waiting for?
1. Robinson, Narda G. "One Medicine, One Acupuncture." Animals 2.4 (2012): 395-414. Web.
2. Dorsher, Peter T. "Neuroembryology of the Acupuncture Principal Meridians." Medical Acupuncture (2017)
3. Sypniewski, Lara. "Dog Acupuncture." TEDxOStateU. 07 Feb. 2017. YouTube. Web. 07 Feb. 2017.
4. Story, Melinda. "Equine Gastrointestinal System." Medical Acupuncture for Veterinarians. Colorado, Fort Collins. 07 Feb. 2017. Lecture.
5. Holt, Timothy. "Veterinary Medical Acupuncture and Reproduction." Medical Acupuncture for Veterinarians. Colorado, Fort Collins. 07 Feb. 2017. Lecture.
6. ABPP, William W. Deardorff PhD. "Modern Ideas: The Gate Control Theory of Chronic Pain." Spine-health. N.p., n.d. Web. 08 Feb. 2017.
Lauren Hughes, DVM
Anaplasmosis is an infectious disease affecting horses most commonly during tick season. A majority of cases are reported in California but it has also been identified all over the United States and worldwide including right here in New England. Knowledge of this disease and early recognition can greatly improve the prognosis for your horse.
This disease can affect horses of all ages and the clinical presentation can vary greatly depending on the duration of illness. Horses with Anaplasmosis can display a large variety of clinical signs ranging from a high fever (103-105 F), depression, decreased appetite, mild limb swelling, reluctance to move, icterus, and in rare cases incoordination/ataxia. The fevers are normally highest in the first few days of infection but can persist up to 12 days. Icterus, a build up of bilirubin, leads to a yellowing most commonly appreciated on the sclera of the eyes and oral mucous membranes. It is important that your veterinarian perform bloodwork while working up a horse with icterus as any disease process affecting the liver can also lead to icterus and should be ruled out in a case of Anaplasmosis.
Anaplasmosis is a tick borne disease caused by the bacterium Anaplasma phagocytophilum. This bacteria is carried by the deer tick, the same tick that carries and spreads Lyme disease. A horse becomes infected with the bacteria through the bite of a tick and it enters the blood stream where it lives within white blood cells. The organism acts to cause destruction of red blood cells, white blood cells and platelets and low levels of these cells are often seen on bloodwork when working up a horse with Anaplasmosis.
There are multiple ways to diagnose this disease with the most definitive being identification of the organism within the white blood cells on a blood smear. Even in cases of active infection, the bacteria may only infect a small number of cells so it is not always visualized. Titers can also be performed to assess immune response and confirm exposure to the bacteria. Lastly polymerase chain reaction (PCR) tests can be performed to recognize the DNA of the bacterium. Routine blood work may also be consistent with the disease process and show decreased red blood cell, white blood cell and platelet levels. In many cases it is difficult to obtain an immediate diagnosis so treatment if often initiated prior to confirming infection.
Early recognition of the disease and treatment with appropriate antibiotics often leads to a good prognosis and full recovery. Administration of a tetracycline antibiotic can be done intravenously or orally and can include oxytetracycline, doxycycline or minocycline depending on the individual case. In most cases fever and other clinical signs will dramatically improve within 48 hours of initiating antibiotics. Some horses with a mild form of the disease may recover without treatment but can also relapse within a few weeks so treatment is highly recommended. Banamine or other anti-pyretics are often used to help control the fever.
More severe cases with neurologic signs often require supportive care and may benefit from corticosteroid treatment.
Prognosis is excellent if the disease is recognized early and treatment is initiated. In more severe cases where neurologic signs develop additional treatment may be needed and permanent injury may occur due to incoordination/ataxia. Fatality is rarely reported due to this disease unless secondary complications occur.
There is currently no vaccine for this disease. Immunity is acquired after infection and normally lasts around two years following an active infection. The most important aspect of disease prevention is tick control by routinely checking your horses for ticks and removing them. Topical products are also available that can help against ticks.
If you have any questions or concerns regarding Equine Anaplamosis do not hesitate to contact the doctors of New England Equine Medical & Surgical Center.
Fig 1. Icteric Sclera: https://s-media-cache-ak0.pinimg.com/originals/3b/f8/bf/3bf8bfdcfba519c86e25c93dba303247.jpg
Fig 1. Icteric MM: https://www.vetstream.com/images-equis/thumbs/21_165672-thumb.jpg
Fig 2. Bloodsmear: https://anokaequineblog.files.wordpress.com/2014/03/morula.jpg
Merck Vet Manual. Webpage. <http://www.merckvetmanual.com/mvm/generalized_conditions/ equine_granulocytic_ehrlichiosis/overview_of_equine_granulocytic_ehrlichiosis.html>.
Reed, Bayly and Sellon. Equine Internal Medicine- 3rd Edition. St Louis: Elsevier, 2010. Print