Laminitis in a horse!!

 The following radiographs are from a gelding that has been lame for nearly 1 year. The gelding has been treated for laminitis/founder and despite efforts by the farrier and veterinarian, the gelding's conditions has worsened. He is non-weight bearing on one forelimb at the time of my exam. The right front foot is imaged in Figure 1 and the left front foot in Figure 2. In Figures 3 and 4 the palmar angle (angle "A") is measured in both front feet. The palmar angle corresponds to the angle that the bottom or palmar surface of the coffin bone makes with the horizon. In both front feet, the palmar angle measures approximate +23-25 degrees. Normally, the palmar angle may range between zero to +5 degrees. Abnormal palmar angles may be negative or greater than +7-8 degrees. However, even though the right and left front feet share the same palmar angle, it is for two very different reasons!

Figure 1 (Right front)

Figure 2 (Left front)

Figure 3 (Right front)

Figure 4 (Right front)

The most likely causes for an increased palmar angle include coffin bone rotation and coffin joint contracture. The difference between these two conditions is key to making the correct diagnosis. In the case of laminitis, the coffin bone rotates under the influence of the deep digital flexor tendon and due to a lack of attachment between the coffin bone and the lamina (i.e. laminitis). In Figure 5, the degree of coffin bone "rotation" is estimated based on the difference between angles "A" and "B". Normally, the hoof wall (red line over "A")  is parallel with the coffin bone (red line over "B"). When these two lines are parallel, the angles equal each other and there is zero degrees of coffin bone rotation. Therefore, the problem with the left front limb in Figure 5 is laminitis and secondary coffin bone rotation.

Figure 5 (Left front)

The right front foot has zero degrees of coffin bone rotation however the palmar angle is the same as in the left front foot. This due to coffin joint contracture and is the definition of a "Club foot". In Figure 6, the lines corresponding to the hoof wall and coffin bone are parallel and as such angle  "A" equals angle "B". Figure 7 diagrams the concept of coffin joint contracture that results in an angle of contracture (angle "A"). Typically, a club foot or coffin joint contracture does not result in non-weight bearing lameness but rather a life long commitment to proper shoeing and trimming. In this case, first glance of the radiographs might be deceiving because both front feet have an abnormal palmar angle, but it is the left front foot with the coffin bone rotation and life threatening laminitis! The deep digital flexor tendon was transected in the left front limb and follow-up radiographs will follow!
To be continued......

Figure 6 (Right front)

Figure 7 (Right front)

Equine Hock Arthritis

Figure 1

The radiograph above (Figure 1) is of a horse's hock or tarsus. This view is also known as the "Lateral" view or side view. The equine hock joint is made up of 4 individual joints which are labelled above. The bottom two joints are also known as the distal hock joints and include the distal inter-tarsal joint (DIT) and the tarsal metatarsal joint (TMT). When "injecting" hocks, these are the most common joints treated and are often referred to as the "upper and lower hock joints". Degenerative joint disease (DJD) or osteo-arthritis is most common in the distal hock joints and  often results in poor performance plus/minus lameness. Bog spavin is the term that refers to increased joint fluid within the tibiotarsal joint. This is the "high motion" joint of the hock and is NOT commonly injected with "hock injections". However if increased fluid is noted, a radiographic exam is definitely indicated prior to instituting a treatment plan. Generally speaking, arthritis of the distal hock joints is more acceptable and can be managed with intra-articular therapies. However, arthritis of the tibiotarsal joint and/or the proximal inter-tarsal joint is more concerning and is reason for concern when predicting future performance.

Figure 2

In Figure 2 and 3, there are radiographic changes that indicate osteo-arthritis of the tarsal metatarsal joint space. These changes were noted during a prepurchase exam of a 5 year old horse. The horse was sound during the exam and did NOT respond to hock/stifle flexion. The million dollar question is what to recommend to the buyer based on these findings. In my clinical experience, most horses with these changes will eventually need intervention via intra-articular cortisone injections. I believe that horses with these changes are MORE likely to need hock injections than those with "normal" radiographs. However, these findings are not necessarily a negative prognostic indicator with regards to the horse's future performance. 

With management, i.e, hock injections, these horses can compete at the highest level and succeed!  As such, these findings do NOT constitute a FAILING grade during the prepurchase exam however the buyer needs to be prepared for the strong likelihood of routine "maintenance". This can easily result in hundreds to thousands of dollars per year that should be considered into the price of the horse. 

Figure 3

Proximal Suspensory Desmitis in a Horse

The ultrasound images below are from a teenage gelding that presented for a 3 month history of mild, forelimb lameness. The lameness would improve with rest but would return soon after the gelding was returned to work. On physical exam, the proximal suspensory palpated sensitive, just below the carpus (knee) of the right forelimb. The gelding was not lame in a straight line however when lunged in a circle to the left, a mild lameness (2/5) was noted in the right forelimb. The lameness improved approximately 50% after blocking the lower limb however when the proximal suspensory ligament was blocked, the gelding was sound. Ultrasound exam of the tendons and ligaments revealed a focal area of decreased echogenicity (dark spot) which was consistent with inflammation and edema within the proximal suspensory ligament. 

Figure 1

Figure 2

In Figure 1, there is a cross sectional image of the superficial flexor tendon (SDF), deep digital flexor tendon (DDF), distal check ligament, and the proximal suspensory ligament. This image was made approximately 10cm below the knee or carpus. In Figure 2, the same area is imaged in cross section and in longitudinal plane. The same lesion (dark spot) can be seen in both images which is consistent with a "real" lesion versus an artifact. In the longitudinal view (right image in Figure 2), the origin of the suspensory is highlighted by the blue arrows and the edema is noted by the dark fibers just above the blue arrows. In Figure 3, the cross sectional image is slightly obliqued to visualize the inside or medial aspect of the limb. The lesion within the suspensory ligament is more apparent in this image and is represented by the dark blue circle within the yellow circle (suspensory ligament) in Figure 3.

Figure 3

Figure 4

The history and lameness exam findings are "classic" for a forelimb proximal suspensory ligament injury. Often the lameness is most noticeable when the affected limb is on the outside of the circle and the lameness will improve temporarily with rest. The prognosis for this injury is "good" however will require rest, ice therapy, corrective shoeing and a specific rehabilatory program. Adjunct therapies include shockwave treatment and platelet rich plasma (PRP) injections.

Gastric Ulcers in a horse

The endoscopic images below are from a teenage gelding that presented for a complaint of aggressive  behavior while grooming. The gelding was not displaying any classic signs of colic nor was there a decline in food intake or a report of weight loss. When the stomach was examined, several bleeding ulcers were noted surrounding the pyloric sphincter. This region of the stomach includes the passage from the stomach into the small intestine. The gelding was treated with 45 days of Gastrogard and returned to normal behavior.

 The important message from this case is that gastric ulcers in horses can present like most anything! Classically, they present as low grade colic associated with feeding plus or minus weight loss. However, in my experience clinical signs associated with gastric ulcers have included poor performance, dull hair coat, excessive water intake, sour behavior under saddle, aggressive behavior while being groomed, colic, parking out, frequent posturing to urinate, teeth grinding, and weight loss.

I strongly recommend a gastric exam which includes visualization of the pyloris to determine if gastric ulcers are the source of the clinical complaint. This involves 24 hrs of fasting and a trained clinician with a 3 meter gastroscope. If ulcers are discovered, the only treatment proved to be effective is Gastrogard medication for at least 30 days! I typical recommend 30 days of a full dose followed by 2 weeks of a half dose.

Guttural Pouch Mycosis in a horse!!

The endoscopic images in Figure 1 and 2 are that of a normal guttural pouch in a horse. There are 2 guttural pouches in the horse and their role is not clearly defined. However, there are several very important structures which course through the guttural pouches. These include large veins and arteries plus critical cranial nerves (Figure 2) . Each guttural pouch is divided into a medial and lateral compartment by a unique bone named the stylohyoid bone. This bone articulates with the base of the skull, just below the ear drum and is part of the support structure for the tongue and larynx! As such, when the horse moves its tongue the articulation between the stylohyoid bone and the base of the skull moves as well. The large blood vessels located within the guttural pouch are important for bringing oxygenated blood to the brain and draining deoxygenated blood from the brain. Equally important are the cranial nerves that course through the guttural pouches. These nerves are essential for a proper swallowing reflex, sensation to the face, and balance.

Figure 1

Figure 2

The endoscopic images in Figures 3-5 are from a gelding that presented for a history of purulent nasal discharge that responded to antibiotic treatment. The endoscopic exam was requested as a follow-up to make sure there was nothing lurking in the horse's upper airway. When the right guttural pouch was entered, a large white plaque was noted covering the entire stylohyoid bone. There was minimal discharge within the pouch and there appeared to be mold covering the surface of the plaque!!

Figure 3

Figure 4

In Figures 4 and 5, the proximity of the fungal plaque with the large blood vessels and important nerves can be seen. Normally, fungi seek out vascular tissue and slowly erode the walls of vessels which can result in low grade bleeding and if it is a large artery, sudden death!! Commonly, horses with fungal infection or mycosis of the guttural pouch present with a history of a bloody nose (epistaxis), however this horse did not. When the plaque was disturbed with the scope, the underlying tissue was exposed and the inflammation was evident.  A bacterial and fungal culture was performed on the fluid recovered during the guttural pouch lavage and a fungi was recovered yet the identity is still being worked out. This condition is difficult to treat and is currently being managed with systemic antifungals and guttural pouch lavage. Stay tuned!!!!

Figure 5

Dysphagia and Aspiration Pneumonia in a horse!!

The endoscopy images below were from a young gelding that presented for a history of coughing while eating. In addition, an intermittent nasal discharge was present and the gelding was described as a "hard keeper". In Figure 1, a small amount of feed material was noted along the floor of the soft palate, just in front of the epiglottis. In addition, feed particles were noted on the epiglottis and the walls of the pharynx. These findings alone are not 100% indicative of a dysphagic (difficulty swallowing) horse however, generally speaking there should NOT be any feed material in the pharynx or larynx. 

Figure 1

When the endoscope was passed through the larynx into the trachea (wind pipe) copious amounts of feed material mixed with mucus was noted on the walls of the trachea. In Figure 2, green and brown feed material  can be seen adhered to the wall of the trachea. As the endoscope was pass further down the trachea, feed material mixed with mucus remained present in significant amounts. 

Figure 2

At the very end or deepest region of this image (Figure 3) is the primary bifurcation of the trachea which occurs just in front of the heart. The presence of feed material at this level of the airway is consistent with aspiration and a trans-tracheal wash was performed to confirm pneumonia.  

Figure 3

Dysphagia and aspiration pneumonia are quite uncommon in horses and may be secondary to a neuropathy affecting the nerves that control the swallow reflex. The most common disease processes in horses that may affect these nerves include equine protozoal myeloencephalitis (EPM), cervical spine trauma, trauma to the guttural pouches, temporohyoid osteopathy (THO), strangles, encephalitis, and basisphenoid bone fracture. Unfortunately, the prognosis is poor for horses with this condition. The likelihood that they will recover their normal swallow reflex, regardless of the cause, is low!  In addition, the aspiration pneumonia that results from the dysphagia  is a recurring problem that typically results in their failure to thrive!

Cervical Spine Fracture

The radiographic images below are from a young gelding that was found by the owner walking "strangely" in the pasture. There was a large swelling present along the neck region, just behind the right ear and the gelding was having difficulty raising his head above the horizon. There was no knowledge of recent trauma. When examined, the gelding WAS walking and the "strange" gait was better described as moderate ataxia in all  limbs. The gelding was able to elevate his head with assistance but there was minimal lateral movement of this cervical spine. 

The radiographic exam revealed a catastrophic fracture of cervical spine #2 (C2), also known as the axis. The fracture line (yellow line) appears to travel directly through the spinous process of  C2 and through the body of C2. Centered in the body of the cervical spine is the vertebral canal which houses the spinal cord. Typically, an injury to this region of the spine results in trauma to the spinal cord and varying degrees of neurologic deficits. 

Due to the severity of the fracture in this case, one might have predicted that the trauma to the spinal cord would have resulted in severe neurologic deficits such as complete recumbency or even sudden death! Although the gelding was still standing, there was significant instability of the cervical spine and the prognosis for life was poor, hence humane euthanasia was elected. 

Very sad case!!

Illegal Equine Supplements!!!!

Carolina Gold

Magnesium Sulfate

The supplements imaged above are both considered "performance enhancing" drugs and are banned from use in horses of all disciplines!! Why am I posting this information you ask? Please take a moment to read the story about "Humble" the pony that was recently published in The New York Times. This pony died suddenly at a major horse event after being administered an injectable "supplement" by the horse trainer. A published medication sheet indicated that the pony was treated with Estrone, Depo Provera, Banamine, and Dexamethasone multiple times in the 48 hrs preceding his sudden death! The medication that was administered just prior to the pony's sudden death was not listed and remains unknown. 

http://www.nytimes.com/2012/12/28/us/ponys-death-draws-notice-to-drugs-in-show-ring.html

If this story does not upset you then read about all group of polo ponies that died due to an over-dose of a supplememt called Biodyl. This supplement contains vitamine B12, selenium, potassium, and magnesium. Oddly enough, this supplement is very popular in the illegal sport of rooster fighting!!

http://www.nytimes.com/2009/04/24/sports/othersports/24polo.html

These stories are examples of the gross and inappropriate actions by horse trainers and veterinarians with regards to the type and frequency of medications given to show horses. Some supplements are "home made" such as Carolina Gold and there is no telling what substances are mixed into the bottle. Other supplements are FDA approved medications such as Magnesium Sulfate which are used in appropriately in horses to enhance performance. Too often, the result of excessive use is sudden death due to cardiovascular collapse.

http://www.chronofhorse.com/article/intravenous-injection-magnesium-sulfate-isn%E2%80%99t-just-illegal%E2%80%94it%E2%80%99s-dangerous 

I urge to know exactly what your horses are being treated with and ask the question "why". Please read below about the product called "Carolina Gold". Although this drug has not been associated with sudden death, it is illegal and its use may result in hazardous riding conditions!

The active ingredient in "Carolina Gold" is known as Gabapentin or "GABA".  When administered, it acts as an inhibitory neurotransmitter and therefore has the potential to be anxiolytic, analgesic, anticonvulsant, and sedative. In human medicine, GABA containing drugs are prescribed for epilepsy and neuropathic pain. Adverse side effects include dizziness  fatigue  and drowsiness, to name a few.

In veterinary medicine it has been used sparingly to control seizures in foals. In addition, it has been classified as a class 3 performance enhancing drug by the Association of Racing Commissioners International. Interestingly, this product was introduced into the performance horse world as a means to "calm" horses just before entering the show arena! In February of last year, the USEF officially banned this product from you in performance horses.

http://www.dressage-news.com/?p=14964

Long toe/Under run heel!!

The image below is of a horse's foot that is suffering from a conformational problem known as "long toe-under run heels". This horse tends to grow significant amount of hoof wall within 4-5 weeks without growing normal heel. Although the heel regions grow, they tend to roll under the center of the hoof. As such, this horse and others like him are prone to heel pain and poor performance. In Figure 1 the center of rotation is marked by the blue line. Ideally, the length of foot that is in front of the blue line and behind should be equal. This would result in a horse that is balanced "cranial to caudal" with respect to the center of rotation. 

Figure 1

As the amount of foot behind  (B) or caudal to the center of rotation decreases compared to "A" there is  a significant increase in the amount of force that is applied across the heel regions. This results in the rolling under or "under run heels" that is imaged in Figure 1 and 2. When this horse is trimmed, the hoof wall needs to be trimmed back to the widest portion of the frog.  This may seem counter intuitive due to the apparent "lack of heel" however it is necessary to achieve "normal" heel growth. 

Figure 2

The radiograph below is that of horse that has heel pain and is lame when trotted in a small circle in both directions. The hoof tester exam noted a strong positive response across the bar region of both heels. Notice that the length of "B" is significantly shorter than "A". In order to correct this problem, corrective shoeing is a must!  The process begins with a balanced trim that includes lowering the heels to the widest portion of the frog. This is followed by applying a shoe that either has built-in break over such as a natural balance/equilibrium shoe or break over is increased manually be rolling the toe. In addition  the shoe is set extra full in an attempt to increase the length of "B" and hence support the caudal aspect of the foot. 

Figure 3

In Figure 4 the horse has been trimmed and re-set. Notice that the length of  "B" is nearly the same as "A". This horse is quite close to being balanced with regard to the center of rotation (blue line) and within 4-5 days returned to complete soundness. Finally, these horses that tend to have a long toes and under run heels need to be trimmed and re-set every 4-5 weeks. It is quite common that these horses are sound for the first 4 weeks after the farrier visit yet their performance begins to diminish as 5 to 6 weeks pass before they are trimmed and re-set. Although radiographs are not necessary to diagnose this problem, they are helpful for quantifying the extent of imbalance and documenting improvement after shoeing. 

Figure 4

Round Two!! Pharyngeal Phythiosis

Figure 1

The endoscopic image in Figure 1 is from a middle aged quarter horse that presented for abnormal noise during exercise. The entire pharynx is obstructed by multiple granulomas.  Initial biopsy results were consistent with pythiosis and the gelding was treated with systemic anti-fungal medication for several months. 

Figure 2

Recheck endoscopy after 45 days revealed a significant improvement (Figure 2) ; however, treatment was discontinued prematurely and a final endoscopy was not performed.

Figure 3

Over 1 year after the initial presentation, the abnormal noise returned along with bloody nasal discharge. The pale yellow nodules have increased in size and number. Multiple small yellow granuoles are noted through out the pharynx and there is evidence of mild bleeding. The horse will again be treated with systemic anti-fungal medication. A follow up exam to follow!!