Subcutaneous Pythiosis in a Horse

.A 10 year-old warmblood gelding presented to PHD veterinary services for the complaint of a swollen left front fetlock that was associated with a chronic draining wound. The recent history included a biopsy of the wound and diagnosis of pythiosis per histopathology. The gelding was treated with a single dose of a systemic pythiosis vaccine. In Figures 1 and 2 the yellow arrows are pointing to the firm swelling that is directly on the backside (palmar aspect) of the fetlock joint. In addition, the red arrow in Figure 2 corresponds to the chronic draining wound. The gelding was sensitive to direct pressure over the swelling, passive flexion of the fetlock and was mildly lame at the trot.
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Figure 1

Figure 2

An ultrasound exam was performed of the area in question. The firm swelling consisted of multiple fluid filled structures along with focal areas of apparent mineralization. The structure appeared embedded within the distal annular ligament; however the superficial flexor tendon (SDF) and the deep digital flexor tendon (DDF) appeared to be normal. In Figure 3 the yellow arrows are highlighting the fluid filled structures. This case is a very unusual presentation for pythiosis in a horse. The majority of cases present with an external lesion as seen in Figure 4. As external lesions there are several treatment options which involve aggressive surgical de-bulking and various topical medications. The pathogen responsible for this condition is found in stagnant water and invades superficial abrasions that might be present any where on the horse. Hence the lower limbs are most commonly affected but it has been diagnosed in the naso-pharynx and GI track of horses.

Figure 3

Figure4

Because of the complicated location of the lesion in this horse, we elected to treat with a potent anti-fungal medication known as Amphotericin B. The medication was administered through a vein in the lower limb using regional limb perfusion. This technique maximizes the local perfusion of the soft tissues with the medication and minimizes the systemic effect of the medication. 

Figure 5

The lesion was re-evaluated 30 days after the initial treatment and there was approximately 40-50% reduction in size of the lesion. However, after 60 days, the lesion appeared to resume growth and a second treatment with Amphotericin B was recently administered. In addition, the gelding as received 2 vaccines against the pythiosis and will likely receive another. Because of the location, surgery is not an option for this horse hence the systemic therapy is our best option at this point. The case is on -going and the blog will be updated as we go!!

Figure 6

Severe Navicular Disease in a Horse

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.A 10 year-old thoroughbred gelding presented to PHD veterinary services for the complaint of intermittent forelimb lameness. The gelding was purchased several months following a prepurchase exam performed by a local veterinarian. The buyer opted for NO radiographs at the time of the prepurchase considering that the horse was sound. Unfortunately, within several months after purchase, the gelding developed a lameness in the right front foot which was intermittent. The client contacted  PHD veterinary services for foot radiographs and a lameness exam. The lameness exam noted NO lameness in the forelimbs but rather a mild to moderate lameness in both hind limbs after flexing the upper limbs (hocks/stifles). The gelding was not positive to hoof testers in either forelimb. A radiographic exam was elected to document the palmar angle and sole thickness in both front feet. The image in Figure 1 is a lateral image of the right front foot and Figure 2 is a lateral image of the left front foot. The yellow arrows are highlighting the navicular bone of each foot.

Figure 1

Figure 2

Interestingly, the lateral image of the suspect foot (right front) appeared normal however the lateral radiograph of the left front foot was highly abnormal. The navicular bone of the left front foot was flattened and completely sclerotic when compared to the navicular bone of the right front.foot. Additional views of the navicular bone are imaged in Figures 3 and 4.  In Figure 3, the skyline projection of the navicular bone suggests severe deterioration of the bone and what appears to be a chronic fracture of the navicular bone (yellow arrow). The flexor surface of the navicular bone is very irregular.

Figure 3

In Figure 4, the distal border of the navicular bone is imaged. The yellow dotted line outlines the navicular bone and the yellow arrows are pointing to the many dark circles which are consistent with areas of lysis and/or cyst formation. The findings in Figures 3 and 4 are consistent with SEVERE degeneration and likely chronic fracture of the navicular bone. 

Figure4

These findings are NOT consistent with the physical exam findings of a sound horse or the history unless this horse has had the nerves, which provide innervation to the foot, surgically transected (nerved). At the time of the exam, the gelding did demonstrate sensation to the skin along the heel bulbs however there were small scars consistent with a previous surgery over the neuro-vascular bundles. Considering how normal the right front navicular bone appears, the degeneration of the left front navicular bone is most likely due to a septic process from a penetrating foreign body that resulted in infection of the navicular bone or a traumatic fracture. Regardless of the cause, these radiographic findings are suffice to retire this horse from forced exercise and hope that he remains comfortable for an extended period of time. This case represents another example of the benefit of simple foot radiographs as part of all prepurchase exam.

Ionophore-free Horse Feed Mills

The two bags of horse feed shown below were produced in IONOPHORE-FREE mills!! Why is this important??  In the past year there has been at least two well publicized cases of horses ingesting feed that was contaminated with a common supplement for cattle known as ionophores. The first case involved a barn full of horses in south Florida which ingested contaminated feed. Initially, three horses died however the remainder of the 22 horses were expected to eventually die due to the toxin in their feed.http://www.sun-sentinel.com/local/broward/fl-sick-horses-davie-20141121-story.html  The story is heart breaking however it could have been prevented.

 Recently, there was another reported incident of horses becoming ill and dying from contaminated feed. http://www.poisonedpets.com/deadly-horse-feed-still-sale-adm-alliance-refuses-pull-feed/ . Once again, the feed appeared to be contaminated with the supplement for cattle, ionophores. Ionophores are extremely toxic to horses and attack the muscle of the heart. If the horse does not succumb initially, it is likely that the diseased heart muscle will slowly weaken resulting in heart failure and death.. How can horse owners and trainers avoid the possibility of such a tragic occurrence?? By purchasing horse feed from ionophore-free mills. Most feed companies produce feed for various types of livestock including cattle and horses. In addition, it is common practice for some feed companies to produce cattle and horse feed in the same facility. These feed companies practice techniques to "flush" the cattle supplements out of the system prior to producing the horse feed. Clearly, there is room for error. The solution is to buy feed from documented, ionophore-free mills. If your horse feed representative is not capable of saying the words "ionophore-free mill" then its time for a change in feed!!!

Proximal Suspensory Desmitis in a Horse

A 10 year-old warm-blood gelding presented to PHD veterinary services for the complaint of forelimb lameness. During the lameness exam, it was noted that the gelding was moderately lame in the right front limb and the lameness appeared worse when the horse was lunged at the trot in a circle to the left. Palpation of the limb noted only mild response to pressure over the proximal suspensory ligament (back side of the limb, just below the carpus). A series of nerve and joint blocks were performed to isolate the source of the lameness. Once the proximal suspensory ligament was "blocked" the horse's lameness improved significantly. Therefore, an ultrasound exam was performed of the soft tissue structures of the right limb with emphasis on the proximal suspensory ligament. Figures 1 and 2 correspond to the proximal suspensory ligament. The yellow line outlines the body of the proximal suspensory ligament in cross-section and the blue arrows a bright (hyperechoic) lesion within the suspensory ligament. The area of increased brightness or echogenicity is consistent with an enthysophyte. In addition, the enthysophyte was surrounded by an area of decreased echogenicity consistent with edema or active inflammation. An enthysophyte is a abnormal bony projections at the site of attachment between a tendon/ligament at bone. In this case, between the proximal suspensory ligament and the third metacarpus (cannon bone).

Figure1

Figure 2

In a similar case, the horse was subjected to a CT (computed tomography) exam and the enthysophytes appear as small, spikes (blue arrows) which are projecting into the body of the suspensory ligament (yellow outline). From this view is understanding why these horses have chronic and recurring forelimb lameness issues. The presence of enthysophytes tends to worsen the prognosis with regards to return to "full" work.

Figure3

The above mentioned gelding was treated with rest, multiple PRP (platelet rich plasma) injections, and shockwave treatment. He is currently sound however his prognosis remains guarded for full return to work and show.

Eye Lid Tumor in a Donkey

A 2 year-old female donkey presented to PHD Veterinary services for the complaint of multiple tumors surrounding the left and right eye. The tumors have been present for several months and have been treated by surgical debulking and intra-lesional injections with a variety of chemotherapy agents. However, the tumors continue to return. There is a golf ball size tumor just below the right eye and the left eye is nearly closed due to the tumor's involvement of the entire eye lid!
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The plan for this donkey involves biopsy of the tumors followed by local treatment with an immune stimulant that contains mycobaterial cell wall extract. PHD veterinary services will be working with Dr. Brendan Mangan from Affiliated Veterinary Specialist in Gainesville, Florida. Dr. Mangan is a board certified ophthalmologist with extensive experience treating such cases! Dr. Mangan suspects that these tumors are sarcoids and not squamous cell carcinomas. Certainly, an unusual presentation for sarcoids in a young donkey!! Dr. Mangan submitted several core biopsies this week for confirmation and began treatment with the mycobaterial cell wall extract.

After the initial treatment with the immune stimulant, Dr. Mangan plans to surgically remove the tumors surrounding both eyes! Thereafter, it is likely that the injection of the local immune stimulant will be repeated along with focal cryotherapy. The biopsy results and follow-up pics will be added to this post next week so stay tuned!!!

Sarcoids in a Horse

The following images represent 3 different cases of sarcoid tumors in horses. The images in Figure 1 and 2 are that of sarcoid tumors on a horse's hind limb. The tumors had been removed several times before however they continue to re-develop. The sarcoid tumors in this case have been treated by surgical resection and a topical anti-sarcoid medication called Xxterra. This gelding will require additional surgical debulking and more aggressive post-operative treatment with cryotherapy AND chemotherapy agents. Prognosis is guarded due to the large tumor size and the location of the sarcoid tumors.
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Figure 1

Figure 2

In Figures 3,4 and 5, the sarcoid tumor in this horse is located along the sheath of the gelding and is flatter compared to the sarcoid tumors in the horse in Figures 1 and 2. This sarcoid was treated with multiple injections of a chemotherapy agent known as cisplatin. There was minimal response to the chemotherapy agent hence this sarcoid tumor will likely require surgical debulking followed by additional chemotherapy treatment.

Figure 3

Figure 4

Figure 5

The gelding in Figure 6 and 7 was suffering from a horrible sarcoid that weighed more than 2 pounds and was dangling from his right ear. The sarcoid was removed by surgical debulking and the ear was treated with both injectable cisplatin and cryotherapy (liquid nitrogen). The image in Figure 7 is several months after the initial surgical debulking. To date, there does NOT appear to be any re-development of the sarcoid tumor.

Figure 6

Figure 7

These 3 cases represent the diversity of the appearance and location of sarcoid tumors in horses!  However, what they have in common is the aggressive and persistent nature of sarcoid tumors in horses. As such, the take home message of these cases is that sarcoid tumors should be identified EARLY and treated as AGGRESSIVELY as possible. There is no ONE treatment that is typically suffice for treatment but rather a combination of surgical debulking, chemotherapy and cryotherapy!

Gastric ulceration in Horses

Two adult horses presented to PHD Veterinary Services this Fall/winter for very different complaints yet the same disease process. Horse #1 was a 10 year-old gelding that presented for the complaint of rearing under saddle and refusing to go forward. Horse #2 was a 5 year-old mare that presented for the complaint of recurrent low grade colic after eating. A gastroscopy was performed on both horses and both horses were diagnosed with gastric ulcers. In Figure 1, the area of ulceration is within the blue circle and the ulcerated tissue is highlighted by the red arrows. The ulcers in Figure 1 correspond to the horse which was rearing and the ulcers scored a 3 out of 5 with 5 being severe. In Figure 2 and 3, the ulcers appear less severe (score 2/5) and correspond to the horse that was demonstrating abdominal pain after eating. Interestingly, the gastric ulcers in the horse that was rearing under saddle appear worse than the horse with recurring symptoms of colic.
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Figure 1

Figure 2

Figure 3

 In Figure 4, a "normal stomach" is imaged through gastroscopy. The horse's stomach can be divided into the glandular stomach (darker red tissue) and the non-glandular stomach (lighter tissue). The junction of the two types of tissue (yellow arrows) is called the margo plicata. Most gastric ulcers in horses occur at the margo plicata and in the non-glandular stomach immediately adjacent to the margo plicata.

Listed below are a list of clinical symptoms which can fit with gastric ulcers in horses:

1- Recurring colic
2: Weight loss and failure to thrive
3: Poor performance
4: Sudden change in behavior
5: Unwilling to go forward
6: Rearing under saddle
7: Increased sensitivity to brushing/touching of abdominal and flank area
8: Repeated straining to urinate: parking-out for geldings and tail flagging for mares

The take home message is that gastric ulcers can present in many different ways and should always be considered when evaluating horses for performance/behavior issues.

Chronic Foot Abscess in a Horse

A fifteen year old gelding presented to PHD veterinary services for the complaint of recurrent foot abscesses. Over the past 2 months, the gelding has suffered from 2 abscesses in the same foot. Physical exam revealed a draining abscess from the outside (lateral) margin of the sole and the horse was lame at the walk. A radiographic study of the foot was performed. In Figure 1, the lateral view of the foot is represented. There is no evidence of laminitis and there appears to be adequate sole depth (>1cm). However, careful examination of the palmar (bottom) portion of the coffin bone revealed an area of radiolucency in the bone (yellow circle and yellow arrows).

Figure 1

In Figure 2, the same radiolucency can be seen in the outside (lateral) portion of the coffin bone (yellow arrows and circle) AND is associated with the radiolucency (blue arrows)  immediately below it which is the current abscess that is draining from the bottom of the foot.

Figure 2

In Figure 3, the downwardly projected radiograph clearly identifies the defect within the coffin bone (yellow arrow and yellow circle).  In addition, the full extent of the abscess is noted by the blue arrows which nearly encompass the entire lateral aspect of the sole. The "black hole" noted inside the yellow circle corresponds to a region of the coffin bone which as been invaded by infection or possibly a tumor. The most likely scenario is a chronic abscess which has resulted in osteomyelitis (bone infection) of the coffin bone. Further diagnosis and treatment will involve a veterinary surgeon and exploration of the coffin bone defect. 

Figure 3

 Typically, foot abscesses do NOT result in a bone infection. However, if the initial abscess is not treated aggressively with disinfecting foot soaking and proper bandaging, it is possible to have such a complication. I typically recommend 7 days of epsom salt solution soaking along with bandaging the foot with a variety of "packing" material. In the case of large sub-solar abscesses, I strongly recommend the use of a hospital plate or specialized boot.

Hock Arthritis in a Horse

A 14 year-old gelding presented to PHD veterinary services for the complaint of left hind limb lameness. The lameness had been noted for 6 months with minimal clinical improvement after several months of pasture rest. On presentation the gelding was a grade 3/5 lame in the left hind limb when trotted in a straight line. Flexion of the lower limb and upper limb did NOT worsen the lameness. In addition, the lameness did NOT worsen when lunged in either direction. Physical exam of the left hind limb did not identify any swelling or joint effusion however the gelding's range of motion of the hock joint was reduced. Radiographic evaluation of the limb was elected as the best option for identifying the source of lameness in this horse.  In Figure 1 and 2, the lower hock joints are identified as the following: PIT= proximal intertarsal joint, DIT= distal intertarsal joint, and TMT= tarsal metatarsal joint. 

Figure 1

Figure 2

In Figure 3, the lower hock joints are circled in blue and the yellow arrows are highlighting areas of significant arthritis across the front of the lower hock joints. For comparison, in Figure 4, the right hock is imaged in a radiograph and there is no evidence of arthritis in any of the hock joints.

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Figure 4

In Figure 4, the front of the lower hock joints appear disfigured (yellow arrows) by the advanced arthritis present. In addition, there is evidence of arthritis in the most proximal hock joint (tibio-tarsal joint) which significantly worsens the prognosis for this horse (Figure 4, red arrow).

Figure 4

The cause of such advanced arthritis in only one hock suggests trauma or a previous infection. Unfortunately, the full history of this horse was not available. Recommendations included a daily anti-inflammatory medication and intra-articular therapy with corticosteroids. Prognosis is guarded for soundness due to the involvement of the tibio-tarsal joint and the degree of arthritis noted in the lower hock joints.

Fractured Tail Bone in a Horse

A seven year-old gelding presented for a history of recent trauma via a pasture mate over the region of the tail head. The gelding was able to move his tail however there was firm swelling around the region and he was tender to palpation (Figure 1 and 2). Physical exam performed 2 weeks after the injury was first noted revealed moderate swelling yet no pain on palpation. In addition, the tail had a normal range of motion and there was normal tail anal tone.
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Figure 1

Figure 2

A radiographic exam was performed and a mildly displaced fracture of the first coccygeal bone was identified. In Figure 3, the vertebrae in the center of the image has what appears to be a cap on the spinous process which represents the mildly displaced fracture. In Figure 4, the coccygeal vertebrae in question is magnified and the fractured bone is highlighted with the red arrows. The yellow arrow in Figure 4 identifies the fracture line through the spinous process of the first coccygeal vertebrae.

Figure 3

Figure 4

The fracture will heal with time and there should not be any negative, long term effects from this injury. However, there remains a concern of the development of a sequestrum (de-vitalized bone) at the fracture site. A sequestrum would develop if the fracture resulted in loss of blood supply to the fractured fragment. This would result in the likely development of a draining fistula as the body attempts to reject the sequestrum. The gelding will be given several weeks of rest and relaxation before returning to light riding. A follow-up radiographic exam will be performed in 2-4 months.