Fractured Coffin Bone in a Horse

The radiographic images below are from a horse that presented for a 2 week history of non-weight bearing lameness in a forelimb. The horse had been treated for a suspect abscess with minimal clinical improvement. Interestingly, the horse was minimally responsive to hoof tester exam.

Figure 1

In the lateral radiograph (Figure 1) there is no obvious explanation for the lameness. However in the subsequent radiographs (Figures 2-4) the cause for the lameness is evident. A large fracture of the coffin bone is apparent. The fracture extends from the toe region all the way through the joint!

Figure 2

 In Figures 3 and 4, the fracture line appears to encompass the entire length of the coffin bone. The prognosis for future soundness depends on whether the fracture communicates with the coffin joint. If it does, the prognosis for soundness is poor due to the likelihood of developing of advanced osteoarthritis. This type of fracture will eventually heal with the correct shoeing and adequate rest. However, the prognosis for return to soundness is guarded due to the severity of this fracture!

Figure 3

Figure 4

Contracted Heels in a Horse

The foot in the first two images (Figure 1 and 2)  belongs to a horse with chronic heel pain. As a result of the chronic pain, the horse's heels are severely contracted and the base of the frog has atrophied (shrunk). In Figure 2, the width of the frog is highlighted by the blue line and the length of the frog is in yellow. Normally, the width of the widest portion of the frog is 2/3 of the total length of the frog (Figure 3).

Figure 1

Figure 2

 

Figure 3

In Figure 5 and 6, a normal foot demonstrates the normal ratio between the length of the base of the frog and the over all length of the frog.This is in stark contrast to the foot in Figures 1 and 2. Normally, a horse's foot lands heel first and transfers the ground forces from the base of the frog/digital cushion thru the body of the frog. As such, the frog and digital cushion play and important role as a shock absorber.  If the base of the frog is abnormally atrophied OR the frog is NOT making contact with the ground, the ground forces are transferred to the sole and wall of the foot creating a scenario for pain over the sole and bars of the foot. This may result in further heel contracture and continued foot pain!!

Figure 4

 

Figure 5

 The development of contracted heels and an atrophied frog can be due to poor conformation and/or chronic heel pain. The chronic pain prevents the horse from fully loading the heel region and engaging the frog properly.One of the most common conditions that results in heel contracture due to chronic heel pain is in horses with navicular syndrome. Unfortunately there is no magic treatment or shoeing that will significantly reduce heel contracture in these horses. In addition, once the base of the frog atrophies as in Figure 1, it is not likely that a normal frog will ever develop. Regardless, it is important to determine if these horses have heel pain and to treat accordingly. In my experience, shoeing these horses with a full pour-in pad or a frog-support pad is key to promote normal engagement of the frog. In addition, maximizing the "break-over" will allow these horses to land heel first yet shorten the time spent weight bearing over the heel region and thus reduce heel pain. An example of such a shoeing is in Figure 6. This shoe is known as a "Roller-motion" shoe which has maximum break-over built into the toe region of the shoe. In addition, a medium-grade pour-in pad has been included for the entire length of the frog.

Figure 6

Squamous Cell Carcinoma in a Horse

The images below are from 3 different horses with the same disease. Squamous cell carcinoma is a type of cancer that tends to affect the lightly pigmented areas of horses. These areas include the penis (Figures 3-4), sheath (Figures 1-2), muzzle (Figures 5), anus, and the eye lids. Diagnosis should be confirmed via a biopsy and histopathology. This type of cancer does not commonly metastasize to other regions of the body but is locally aggressive. As such, early intervention is the most important component to effectively treating this cancer.

Figure 1

Figure 2

Once the diagnosis of squamous cell carcinoma (SCC) has been confirmed it is my opinion that surgical resection of the tumor should be attempted. This is easier said than done and in some cases surgical removal is not a reasonable option. In some cases, if the lesion is small yet not surgical, cryotherapy with liquid nitrogen can be highly effective. Cryotherapy is recommended for carcinomas near the muzzle and on the penis.  Once the tumor has been removed or if it is not surgical, I recommend proceeding with intra-lesional chemotherapy agents to attack any remaining cancerous cells. It is common to repeat the intra-lesional chemotherapy treatment multiple times.

Figure 3

Figure 4

 It is very important to aggressively treat SCC! The horse in Figure 5 was treated with only surgical resection. Within months of surgery, the tumor returned and invaded the oral cavity. There were no more options for this horse. Horses with SCC need to be treated early and repeatedly until there is no evidence of any remaining cancerous tissue!!

Figure 5

Severe Roaring in a Horse!!

A teen-age mare presented for respiratory noise during exercise and poor performance. The mare had made noise during exercise for the past 2-3 years WITHOUT poor performance. Interestingly, the mare has always been resistant when cantering to the RIGHT! Recently, it was noted that the mare demonstrated signs of exercise intolerance at the canter. During the exam, the mare was asked to canter on a lunge line and she carried her head to the outside of the circle with her nose turned up. After 1-2 minutes of cantering to the right, it became increasingly more difficult for her to catch her breath and she would occasionally cough/gag violently!. 

Figure 1

 The mare was scoped immediately after exercise and complete paralysis of the left arytenoid was discovered (Figures 1-2). During inspiration, the left arytenoid was across mid-line (yellow line) and obstructing at least 50% of the mare's airway (Figure 2).  It is highly likely that during heavy exercise, the increased negative pressure during inspiration would cause the paralyzed arytenoid to completely cover the airway and prevent the mare from breathing! 

Figure 2

In addition, while scoping the horse, the mare tended to displace her soft palate in such a position that the epiglottis was trapped below (Figures 3-4). When this occurred, the mare instantly began to cough/gag until she corrected the displacement! Displacement of the soft palate is not always associated with arytenoid hemipligia but when it does occur may worsen the exercise intolerance.

Figure 3

The prognosis for this mare is dependent on additional evaluation by an equine surgeon and the recommended surgical procedure. If she is a good candidate for surgery and the surgery is a success, there is a good likelihood that she will return to work and perform significantly better than before.

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Hind Limb Proximal Suspensory Ligament Desmitis in a Horse

A 15 year-old mare presented for a 3 week history of rear-limb lameness that was associated with a "drop" of the rear fetlock joint. On presentation there was moderate swelling of the lower limb, just below the hock joint and the mare was lame at the walk. In addition, there was a 90 degree drop of the fetlock/pastern axis as noted in Figure 1.

Figure 1

The primary mechanism involved in "suspending" the fetlock joint and maintaining the proper fetlock/pastern axis is the suspensory ligament (Figure 2). The suspensory ligament originates just below the hock (red arrow) and initially is one structure (body) that travels down the back of the lower limb (yellow arrow). Approximately half way down the canon bone the suspensory ligament splits into a medial (inside) and lateral (outside) branch. The suspensory branches attach to the sesamoid bones which are located just behind and below the fetlock joint. As such, the suspensory ligament helps "suspend" the fetlock joint and a  proper fetlock/pastern axis.

Figure 2

An ultrasound exam was performed to evaluate the entire suspensory ligament. The origin or proximal suspensory ligament is imaged in cross-section in Figures 3-6. The proximal suspensory ligament of the affected limb is grossly enlarged (yellow circle) and the fiber pattern is a mixed pattern with significant edema and evidence of active inflammation! There is a black and grey swirl pattern noted in the proximal suspensory ligament (tissue inside the yellow circle) of the affected limb which is indicative of severe changes.

Figure 3

Figure 4

 When compared to the normal limb, the significant increase in the size of the proximal suspensory ligament is evident. In this case the affected suspensory ligament was 2x the "normal" size. These ultrasound findings confirm the diagnosis of proximal suspensory desmitis of the hind limb. The prognosis for this injury is poor for return to riding and guarded for return to pasture soundness. Once the fetlock has "dropped" the physical changes to the suspensory ligament CANNOT be reversed!! Treatment is aimed at slowing the progress of the condition and attempting to provide pain relief to the horse. In my experience, corrective shoeing is the MOST important aspect of managing this condition.

Figure 5

  

Figure 6

A "fish tail" bar shoe is strongly recommended for this condition. The shoe should be set extra full such that approximately 1.5 to 2 inches of shoe extended BEHIND the heel bulb. Any kind of a wedge is CONTRAINDICATED in this condition! In addition, daily treatment with ice packs over the proximal suspensory ligament followed by topical Surpass cream are indicated to reduce inflammation and provide pain relief. With corrective shoeing, adequate pain relief, and supervised turn-out, these horses may return to pasture soundness however such a condition carries a guarded prognosis.

Figure 7

Pyloris of a Horse of course!!

The endoscopic images in the following figures are of a horse's pyloris. This is the portion of the stomach that creates a valve and allows gastric fluids and contents to enter the small intestines. The very first region of the small intestines is known as the duodenum. In Figure 1, the pyloric sphincter is open and a small amount of feed material is noted around the edges of the sphincter. In Figure 2, the pyloris is nearly completely closed. The movement of material through the pyloris is controlled via rhythmic contractions or peristalsis of the stomach's muscular wall.

Figure 1

Figure 2

In Figure 3-6, there are very important abnormalities noted around the pyloric sphincter. In Figure 3 and 4, there is evidence of active bleeding from ulcerations around the pyloric sphincter! These ulcerations are likely to be a source of significance discomfort in the horse and would contribute to signs of gastric ulcer disease. It is possible and common to examine a horse's stomach and miss these lesions if the horse is not properly fasted prior to the gastroscopy and the pyloric sphincter is not visualized. This can be quite difficult in some equine patients!! The pyloric sphincter essentially controls the rate of gastric emptying hence any inflammation in this area will likely SLOW the rate of gastric emptying and result in an abnormal build-up of gastric fluid/content within the stomach.

Figure 3

Figure 4

 In Figures 5-6, there is a significant amount of hyperemia around the pyloric sphincter which corresponds to active inflammation. The degree of clinical signs may vary significantly from horse to horse however it is highly likely that horses with these types of lesions will have clinical signs consistent with gastric ulceration and WILL require the proper medical management! These type of lesions may be caused by excessive use of non-steroidal anti-inflammatory agents such as banamine and phenylbutazone. Diagnosis is dependent on a COMPLETE gastroscopy and I typically recommend a follow-up gastroscopy after treatment to verify complete resolution of the pyloric sphincter ulcerations!!

Figure 5

Figure 6

Fractured Patella in a Horse

A teenage gelding presented for sudden non-weight bearing lameness in the right hind limb. There was a history of a "kick" from another horse but the exact location of the kick was not witnessed. On presentation, there was a basketball-size swelling centered on the stifle and the horse was very painful. He was not willing to walk on the limb. The initial radiographs were not conclusive due to the severe swelling and a follow-up exam was performed 10 days later. On presentation, the gelding was walking on the limb but was very resistant to have the limb flexed at the stifle/hock. There was minimal swelling compared to previous exam.
Figure 1 is a lateral radiograph of the patella. The yellow lines corresponds to bone fragments that are noted along the edges of the patella.

Figure 1

In order to better assess the patella, a special "sky line" projection is required and was especially difficult in this horse because he was resistant to having the stifle flexed! However, it proved to be the most important radiographic view. In  Figure 2, the patella is imaged and a distinct line can be noted traveling through the body of the patella. In Figure 3, the "line" is highlighted in red and is consistent with a complete or near-complete fracture of the patella. In Figure 4, a normal patella is imaged for comparison to the fractured patella.

Figure 2

Figure 3

The degree of fracture appears complete or near-complete which significantly worsens the prognosis. There are cases of patella fracture in horses that are described in the literature that have healed after several months of stall rest. However, there is minimal discussion regarding the future of these horses with regards to as equine athletes. The prognosis for this horse to return to work is poor and his outcome is yet to be determined.

Resolved Fibrosarcoma in a horse!

Several months ago I presented a case involving a gelding that presented for lameness and soft tissue swelling along the outside of the right knee (carpus). The gelding was lame at the walk and hesitant to flex the limb at the carpus. Ultrasound exam revealed a well demarcated soft tissue mass (dark tissue inside blue circle) that was centered over the carpus (Figures 1-3). The histopathology report was consistent with a fibrosarcoma.

Figure 1

Because the tumor was located immediately adjacent to the joint capsule of the carpus, surgical removal was considered high risk. As such, the tumor was injected with a chemotherapy agent called Cisplatin via ultrasound guidance. The tumor was injected twice, approximately 30 days apart. There was a moderate reduction in the size of the tumor just 3 weeks after the first injection and the gelding was no longer lame at the walk and was more willing to flex the limb at the carpus.

Figure 2

Figure 3

 The gelding's limb was evaluated 4 weeks after the second Cisplatin treatment. There was no evidence of the fibrosarcoma on the outside of the carpus AND under the skin (Figure 5). The ultrasound exam only noted normal subcutaneous tissue and joint capsule between the ultrasound probe and the carpus. The gelding was sound at the walk, trot, canter and has returned to full work!! The case is a good example of the benefits of intra-lesional injection of tumors that are non-operable with chemotherapy agents. There are several chemotherapy agents available and the procedure can be performed at the barn with ultrasound guidance.

Figure 4

Pleuropneumonia in a Horse

A 17 year-old gelding QH presented for a 3 week history of intermittent fever and coughing.

History:

The gelding had been treated with 3 different antibiotics over the past 3 weeks and there were no improvements in clinical signs. The problem started after the horse had been transported approximately 12 hours via truck and trailer. Within 24 hours of arriving to the show grounds the gelding was sick!

Physical exam:

When I examined the horse, the gelding was in distress! His heart rate was 80 bpm, respiratory rate was 60-70 bpm (shallow) and his body temperature was 102 degrees. Auscultation of the thorax noted lung sounds (sound of air moving in and out of lungs) on both sides of the horse only ABOVE the level of the shoulder but lung sounds were absent or muffled below the level of the shoulder. Suspecting pleuropneumonia, I performed a trans-thoracic ultrasound exam. A significant amount of fluid was noted in the pleural space along with large fibrin tags and multiple abscesses! ( Figure 1-3).

 

 

 

 

 

Figure 1

 In the video clips below, the fibrin tags can be seen "floating" in the excessive fluid within the pleural space. In addition, the fluid appears as "cellular" suggesting a heavy component of fibrin and purulent debris (pus).

In Figure 2-3, large abscesses are noted adjacent to the body wall. Ultimately, these abscess would need to be exteriorized through a rib resection in order for the horse to completely heal. Unfortunately, the ultrasound findings combined with the severe physical distress were very poor prognostic indicators and the owner elected humane euthanasia!  There was near zero chance that this horse could have been saved regardless of the medical and surgical intervention provided!

Figure 2

Figure 3

Pleuropneumonia in also called pleurisy and refers to bacterial infection of the pleural cavity and the surrounding soft tissue structures. This condition is VERY deadly and originates from bacterial colonization of the lower airway! The condition is more common in young horses that are transported long distances on a regular basis. Hence the term "shipping fever". A common belief is that horses which are transported with their head tied and a bag of hay in front of them are predisposed because they are not able to properly clear their airway of airborne debris and pathogens. Normally, horses eat with their head down which minimizes the passage of unwanted matter down their trachea and into their lungs.  This condition can be treated effectively if diagnosed early, i.e, within 1-2 days of clinical signs! Aggressive medical treatment is a must and includes IV antibiotics, chest drainage/lavage, and supportive care. One of the most painful horses I witnessed as a resident was a young filly with pleurisy!! Looked like a bad case of colic but was in fact pleuropneumonia!!

Aortic Valve Insufficiency in a Horse

Figure 1

Figure 2A and 2B

 The image in Figure 1 is of a horse's heart taken via trans-thoracic ultrasound. Specifically, the ultrasound probe is centered on the aortic valve. The horse presented for a prepurchase exam and a loud murmur was detected during the physical exam. There was no history of exercise intolerance nor was there evidence of heart failure during the physical exam. The murmur was best described as diastolic (during the filling phase) and included a high musical pitch at the end of the murmur. During the cardiac ultrasound exam, color flow doppler was imaged (Figure 1) to determine the flow of blood across the aortic valve. Normally, the color of the blood flow will be blue or red depending on whether the blood is moving towards or away from the ultrasound probe. When there is a "leaky" valve or a valve that is "insufficient" the color of the blood flow is bright yellow, white or orange. This color flow pattern is consistent with turbulence across the valve due to blood traveling "backwards" through the valve. In Figure 2, the red arrow identifies the normal direction of blood flow through the aortic valve. In Figure 3 a small white line is highlighted by the yellow arrows. This white line corresponds to one of the 3 valves that make up the aortic valve. In this horse, the aortic valve is thickened resulting in a "leaky" valve. The "leakiness" can be noted in Figure 4 as bright yellow and white blood flow in the opposite direction of normal blood flow across the aortic valve. The thickened valve likely vibrates as the jet of blood flows "backwards" causing the musical heart murmur!  Aortic insufficiency is the most common type of heart murmurs in horses and is often benign during the early phases of development. However, if the horse lives long enough, the aortic insufficiency can lead to heart failure in the horse. As such, heart murmurs in horses should not be dismissed as "normal" and inconsequential but should be carefully documented via ultrasound exam!!

Figure 3

Figure 4

Chronic Obstructive Airway Disease in a Horse

The endoscopic image in Figure 1 is from within a horse's trachea. In Figure 1, the endoscope is positioned just in front of the main bifurcation of the trachea where it splits into the right and left bronchi (Figure 2) . This is just in front of the horse's heart also known as the carina! The purpose of passing an endoscope down to this level of the horse's respiratory tract is to evaluate for the accumulation of debris (feed material, pus and/or blood) and to perform a diagnostic procedure called a bronchoalveolar lavage (BAL). In this particular case, the horse presented for a chronic cough and exercise intolerance.

Figure 1

Figure 2

As the endoscope was passed down the trachea there was a moderate amount of white foamy fluid along the ventral aspect of the trachea (Figure 2 and 3). This debris is consistent with sputum that originates within the lung tissue and is coughed into the trachea. This finding can be consistent with either pneumonia (bacterial infection) or an allergic airway condition that is also known as COPD/Heaves! To determine the cause of the sputum, a BAL is performed. In this procedure, the endoscope is passed into the primary bronchi until it is lodged within the bronchi. At this point a small volume of sterile saline is passed into the bronchi through the scope and then collected via aspiration. The fluid is analyzed to determine the percentage of different cell types and from this data, it can be determined if the horse has an infection or allergic airway disease.

Figure 2

Figure 3

The importance of determining which disease process is causing the sputum is that treatment for allergic airway disease involves systemic corticosteroid administration which will lower the horse's immune system and significantly worsen any bacterial infection the horse may have!! Hence, it is key to perform the BAL  prior to any treatment to determine if the horse needs antibiotics or steroids or maybe antibiotics plus steroids!! The BAL can be performed stall-side with a sedated horse.