Sarcoid Tumor in a Horse

A middle-aged gelding presented to PHD Veterinary services for the removal of a large tumor from the base of the right ear (Figures 1 and 2). Two years prior, a smaller tumor was surgically removed from the same ear. The histological report was consistent with a sarcoid tumor. At the time of the original surgery, several sarcoids were removed from different areas including the pectoral region and groin area. The recurring sarcoids were treated with intra-lesional chemotherapy, cryotherapy, topical medications and systemic herbal remedies. At presentation, a large, lobulated tumor was "hanging" from the base of the right ear. There was mild hemorrhage and evidence of moderate necrosis of the tumor. The gelding was resistant to manipulation of the tumor however gentle palpation of the ear noted that the tumor was NOT attached to the cartilage portion of the ear but only the skin and immediate subcutaneous tissues.

Figure 1

Figure 2

The gelding was rendered unconscious via injectable anesthetics and the tumor was removed through a large incision (Figure 3 and 4). Moderate hemorrhage was encountered confirming that the tumor was highly vascular. The incision was partially closed with sutures and the horse was recovered from anesthesia. Examination of the tumor after removal noted it consisted of 3 individual masses and weighed more than one pound (Figure 5).

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Figure 4

Figure 5

This case represents an extreme example of recurrent sarcoids in a horse. Per the owner, the previous management of the sarcoids were initially effective however in time the tumors returned. The removal or de-bulking of the ear-based tumor will most likely not be sufficient in keeping the sarcoid tumor from removal. Aggressive therapy involving intra-lesional chemotherapy agents and cryotherapy will be employed to keep these tumors from continuing the develop!!

Figure 6

 Fast forward 6 weeks and the surgical wound is in the process of healing nicely (Figure 6), however there are several small sarcoids along the tip of the ear and also within the surgical site that are inflamed and beginning to grow. Follow-up treatment included the injection of cisplatin directly into the small sarcoids. Unlike the initial procedure which was done under anesthesia, the cisplatin injection was performed with sedation and a local "block" of the ear. Two weeks after the cisplatin injection, the small sarcoids along the tip of the ear are shrinking however the sarcoids within the surgical site remain inflamed  (Figure 7).

Figure 7

 Hence, the small sarcoids were treated with cryotherapy and the picture in Figure 8 was approximately 2 weeks post cryotherapy. The initial surgical site is a scar and all of the small sarcoids are regressing nicely. This horse will be monitored very carefully to make sure that any new sarcoid growth is treated aggressively!! This case represents an excellent example of the need for early, aggressive and multi-drug treatment of sarcoids in horses.

Figure 8

Atrial Fibrillation in a Horse

 An 18 year-old gelding presented for a pre-lease exam. The horse was sound and displayed no clinical abnormalities. However, when the heart was auscultated the heart rhythm was abnormal. Normally, a horse's heart sounds like two distinct sounds, otherwise known as the "lub-dub". These two sounds correspond to the opening and closing of specific heart valves during contraction and filling of the heart's chambers . There are actually 4 heart sounds but typically we only describe the "lub-dub". In a normal horse, the number of lub-dubs that are counted in a minutes range between 28-40 lub-dubs or beats per minute and they should be equally spaced in time. The electrocardiogram (EKG) in Figure 1 is that of a normal horse. The red arrows correspond to the contraction of the ventricles and the green arrows correspond to the contraction of the atrial. Normally, the atria contract first followed by the contraction of the ventricle. The blue arrow corresponds to the time between ventricle contractions which should equal the heart rate or number of lub-dubs auscultated in a period of time. Notice that the blue arrows are equal in length between heart beats AND that there is one green arrow for every red arrow!!

Figure 1

The lub-dubs for this particular horse were irregular and there was no predictability of their irregularity hence the heart rhythm was described as "irregularly, irregular". This type of heart arrhythmia is consistent with a condition known as atrial fibrillation. In Figures 2 and 3 notice that the blue arrows which correspond to the time between heart beats vary significantly. Equally important, there appears to be many more green arrows (Figure 3) than red arrows. This would suggest that the atria is contracting more often than the ventricles, hence the term atrial fibrillation!!

Figure 2

Figure 3

 Atrial fibrillation in horses is not uncommon and young horses with this condition are often asymptomatic. Thoroughbreds are diagnosed most often and when it is diagnosed in younger horses, the cause for the arrhythmia is often not determined. However, in older horses underlying heart disease is often associated with atrial fibrillation.  The most common clinical complaint would be exercise intolerance and decline in performance. In addition, an elevated resting heart rate may be indicative of early congestive heart failure as well as persistently distended jugular veins (Figure 4). Diagnosis of atrial fibrillation requires an EKG and a cardiac ultrasound is recommended to determine if there is underlying heart disease. Often a 24 hr halter monitor (Figure 5) may be used to better describe the horse's 24 hr cardiac cycle. There are several methods available to try and "convert" a horse with atrial fibrillation. However, it is important to first determine that cardiac disease nor electrolyte disturbances are the root of the problem. The methods include various medications and electrical cardi-conversion.  Prognosis for horses with atrial fibrillation depends on whether the horse has underlying cardiac disease. In the case of cardiac disease, the prognosis is poor; however, in young horses with idiopathic atrial fibrillation, the prognosis can be good for full return to work as a sport horse!! This case re-inforces the need for a solid physical exam on a regular basis to make sure this type of disease does not go undetected!!
  

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Superficial Flexor Tendonitis in a Horse

A middle-aged gelding presented to PHD veterinary services for tendonitis of the superficial flexor tendon (SDF). The tendonitis was a result of an tendon-sheath penetrating injury and was associated with a severe tendon sheath infection. The tendon sheath infection was treated aggressively and effectively by an equine surgeon. An ultrasound exam was performed along the plantar aspect of the hind fetlock and a large, core-like lesion was identified (Figure 1, black area within red circle). The lesion consisted of disrupted tendon fiber and edema. Several options were considered to help the "healing process" involving the SDF tendonitis. These included extra corporeal shock wave treatment, platelet rich plasma (PRP) injection, stem cell injection, and/or concentrated bone marrow injection. The decision was made to treat the lesion by injecting a mixture of concentrated bone marrow mixed with PRP product. The bone marrow was collected from the horse's sternum and concentrated on site (Figure2). In addtion, a blood sample was collected from the horse and PRP was harvested on site. The PRP was mixed with the concentrated bone marrow and then injected into the lesion via ultra-sound guided technique.

Figure 1

Figure 2

In addition to the PRP+bone marrow injection, the horse was fitted with a corrective shoe that provided significant heel extension (Figure 3 and 4). This type of shoe is also known as a "fish tail" show and will reduce the "load" across the fetlock joint by supporting the lower limb. Horses recovering from tendon sheath infections and SDF tendonitis tend to avoid fully loading the back of the foot which may result in lower limb contracture. The fish tail shoe allows the horse to fully load the foot in a more comfortable fashion. The horse was walked daily and otherwise kept in stall confinement. In addition, the leg was treated daily with cold compresses.

Figure 3

Figure 4

Approximately 30 days after the PRP+bone marrow injection, the horse's limb was re-ultrasounded. There has been significant "filling in" of the lesion (Figure 5). Although the area that was the lesion (red circle) remains identifiable, there has been a significant improvement in tendon fiber alignment and the edema (black) has nearly completely resolved! Although this represents a tremendous amount of improvement in just 30 days, there remains a significant period of rehabilitation before the ultimate out come of this case can be reported.  This case provides an example of a regenerative therapy that combines PRP and progenitor stem cells (bone marrow) for the treatment of tendonitis! The advantages of this approach versus stem cell treatment include reduced cost, on site harvesting and same-day treatment.

Figure 5

Ethmoid Hematoma versus Paranasal Sinus Cyst in a Horse

Two horses presented to PHD Veterinary services for the same complaint of "no air moving through one of the horse's nasal passages!" Both horses had a history of mild to moderate nasal discharge that had increased slowly over the past 6 months. On presentation, a simple evaluation of air passing through the nasal cavities revealed that there was NO air moving through the affected side on each horse however, endoscopic exam revealed a unique problem in each horse.

Figure 1

 In Figure 1, a smooth, white soft tissue mass was identified within 2 inches of the opening of the nasal cavity. This soft tissue mass was completely obstructing the nasal passage. In addition, when the scope was passed through the unaffected side, the soft tissue mass was noted to be extending into the naso-pharynx suggesting that the soft tissue mass extended through out the entire nasal passage (Figure 2). In Figure 2, the white wall of tissue noted along the right side of the image is the soft tissue mass as it extends into the naso-pharynx.The soft tissue mass is most likely consistent with a paranasal sinus cyst however surgical removal will be required to confirm the diagnosis. These types of cysts develop in young horses and grow slowly over months and years until a clinical problem develops. Surgical removal provides complete resolution of these types of cysts!!

Figure 2

Figure 3

In the second horse, a large golden-colored soft tissue mass was identified in the region of the nasal passage closest to the naso-pharynx. There was more discharge associated with this soft tissue mass and small areas of hemorrhage were noted. The soft tissue mass was completely obstructing the nasal passage and was originating from the ethmoid turbinate region which most likely classified it as a ethmoid hematoma!! These types of tumors typically present with a complaint of a unilateral bloody nasal discharge for months before they completely obstruct the nasal passage. However, they can be fast growing tumors and require an aggressive approach to eradicate. Treatment may involve either surgical removal or repeated injections of formalin. It has been my experience, having injected several horses for YEARS, that the tumors tend to return with this approach! Hence, I recommend surgical removal when first diagnosed, especially if the tumor is invading the sinus cavity or the naso-pharynx.

IIeal Hypertrophy in a Horse

A 10 year old Paso fino mare presented for recurrent colic for several months duration. The mare had a long history of being a "hard keeper" but in the past 3-4 months had begun to colic after each feeding. The mare was fed a diet of senior feed plus free-choice coastal bermuda grass hay. The mare was referred to PHD Veterinary services for a gastroscopy (stomach scope). The mare presented with a body condition score of 3 out of 9. The client reported that the mare had a good appetite yet shortly after eating, the mare would develop signs consistent with abdominal discomfort! The gastroscopy was normal therefore we opted to ultrasound the mare's abdomen.  In Figure 1 there is a cross-sectional image of a loop of intestine (black circle) that is grossly abnormal. The lumen (center) is completely filled in with soft tissue(grey area). The filled in center in Figure 1 corresponds to thickening of the small intestine which likely results in delayed passage of ingesta. Interestingly, there was only 1 very distinct area of the small intestine that scanned abnormally thick. However, there were several loops of small intestine that were dilated and had diminished peristalsis (Large black circles in Figure 2).

Figure 1

Figure 2

The ultrasound findings were consistent with a focal area of thickened small intestine and a large area of dilated small intestine. The dilated small intestine were likely "up stream" from the thickened small intestine and were as a result of partial obstruction of the thickened small intestine. Based on these findings, the mare was referred for abdominal exploratory surgery. During the abdominal exploration, a very thick region of the small intestine was identified. This region corresponded to the ileum which is the very final section of the small intestine. Approximately 12 inches of ileum were grossly thickened resulting in minimal lumen formation for passage of ingesta (Figure 3). Normally, the ileum is a wide-open tube as depicted in Figure 4!! Unfortunately, due to the severity of the condition, poor prognosis, and financial limitations, the mare was euthanized on the surgical table. Ileal hypertrophy has been reported in horses consuming coastal bermuda grass hay and it is theorized that some horses develop an "allergic" response to coastal hay resulting inflammation of the ileum and ultimately gross thickening. More commonly, colic symptoms associated with coastal hay is due to poor quality hay rather than ileal hypertrophy. However, any horse with chronic colic symptoms that is consuming coastal bermuda grass hay should be evaluated for this condition. 

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Extensor Process Fracture in a Horse

A teen-age gelding presnted for the complaint of forelimb lameness. The gelding had been purchased approximately 6 months prior and the prepurchase exam performed did NOT include a radiographic exam. The gelding was mildly lame in a straight line however the lameness was significantly worse when lunged in a small circle. Through a series of nerve blocks it was determined that the lameness was originating from the foot and a radiographic study was performed. The radiographic images in Figure 1-3 are lateral views of the foot in question. Two abnormalities are noted by the yellow and blue arrows in Figure 2. The blue arrow corresponds to a chip fracture of the extensor process of the coffin bone and the yellow lines correspond to extensive mineralization of the cartilage of the foot (side bone).

Figure 1

Figure 2

 In Figure 3, the extensor process chip fracture is magnified. It is likely that this chip fracture was present at the time of purchase and would have been discovered had the client opted for a radiographic exam of the forelimb feet.  In my opinion, this radiographic finding would have been reason enough the FAIL the horse at the time of prepurchase exam.  In addition to the extensor chip fracture, moderate "side bone" development is evident in the lateral view and the dorsal-palmar view (Figure 4). Typically, side-bone does not present a clinical problem however does consist of an abnormal finding and in this horse the side bone is more pronounced along the inside versus the outside of the foot. The asymmetry of the side-bone may be more clinically relevant that bilateral side-bone that is symmetrical.

Figure 3

Figure 4

The horse was treated with intra-articular corticosteroid and is approximately 75% improved with respect to lameness. The long term prognosis for this horse is guarded due to fracture of the extensor process of the coffin bone. This case represents yet another example of the need for at least foot radiographs at the time of prepurchase exam.

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

Recurrence of Pharyngeal Pythiosis in a Horse

The image in Figure 1 is that of a "normal" larynx and pharynx in a horse. In Figure 2-4, the pharynx is filled with granulomas that are nearly completely obstructing the larynx. The images in Figures 2-4 belong to a middle-aged quarter horse mare that has been treated several times over 2 years for pythiosis of the pharynx. After each treatment with systemic anti-fungal medication, the granulomas shrink in size and the hemorrhagic discharge stops (Figure 4) . However, once the medication stops, the granulomas slowly begin to re-grow and the discharge returns. The image in Figure 4 was taken approximately 12 months prior to Figures 2 and 3. Although the granulomas are present and there is some drainage, the over-all condition of the pharynx is better than what we see in Figures 2 and 3!

Figure 1

Figure 2

Figure 3

Figure 4

 The most likely scenario in this case is that the pythiosis pathogen resides within the granulomas and although they shrink and appear to become inactive, the pathogen persists. Once the medication is stopped, the pathogen is allowed to multiply and the granulomas grown unabated!  Pythiosis was once believed to be a fungi put is now described as an algae that lives in stagnant water throughout the southeastern United States. The pathogen gains access to the horse through small wounds in skin or mucosa. I have diagnosed pharyngeal pythiosis in over a dozen horses in the past 10 years. Every case has involved horses with access to free standing water and all have responded favorably to the systemic anti-fungal. The case imaged in the figures above has been refractory and proven difficult to completely resolve!!

Sabulous Cystitis in a horse!

The sample of urine in Figure 1 was collected from a gelding with the history of persistent urine dribbling or urinary incontinence.  The gelding was 20 years old and otherwise normal. A rectal exam revealed a large, distended urinary bladder that was so distended it hung over the brim of the pelvis!! The urine sample was milky and when allowed to settle there was a large concentration of sediment in the urine! These findings are consistent with sabulous cystitis in a horse!!

 

Figure 1

In Figure 2, the urinary bladder of the horse is labelled with the letter "B" and typically resides within the pelvis, immediately below the rectum. Emptying of the bladder or urination is a two-part process that involves relaxation of the bladder sphincter and simultaneous contraction of the bladder wall. This process is controlled by two distinct components of the nervous system which work together to empty the bladder and to keep urine in the bladder in between periods of voiding.

Figure 2

In the case of sabulous cystitis, the part muscle layer within the urinary bladder wall loses tone and does not contract properly during urination. As such, the bladder tends to remain full and will eventually over-distend. Fortunately for the horse, once the bladder over-distends, it begins to leak urine through the bladder sphincter and the horse dribbles urine on a regular basis. If the sphincter did NOT leak, the bladder would distend and ultimately rupture resulting in a medical/surgical emergency!! As a result of the over-filling, sediment tends to accumulate within the urinary bladder resulting in chronic irritation of the bladder lining and ultimately cystitis. The cause for the loss of bladder wall tone is unknown and there has been no proven treatment for this condition.These cases become management cases which includes regular "lavage" of the urinary bladder, systemic antibiotics for cystitis, and a reduction in any feed or supplements containing calcium.

Foundered Horse with Inadequate Shoeing!

A 10 year-old Arabian cross gelding presented for shifting foot lameness and pounding digital pulses. There was no history of laminitis/founder. The horse was not willing to walk on concrete and was a grade 3/5 lame in both front feet on soft ground. Physical exam noted a prominent fat pad over the tail head and the development of a cresty neck! A radiographic exam was performed on both front feet to determine the severity of the gelding's condition.

Figure 1

Figures 1-3 correspond to the lateral projection of the right front limb. There is a clear explanation for the shifting leg lameness and pounding digital pulses. In Figure 2, the yellow dotted lines correspond to the dorsal hoof wall and the dorsal border of the coffin bone. In a normal horse, these two lines are parallel. However, in the case of laminitis/founder with coffin bone rotation the yellow lines are NOT parallel. The small blue triangles labelled A and B correspond to the angles of the yellow lines with the horizon (red line). In this horse, angle A does NOT equal angle B. These findings confirm the diagnosis of laminitis with coffin bone rotation. The difference between angle A and B corresponds to the degrees of coffin bone rotation and in this case that number was 10-12 degrees. The left front limb was similar.

Figure 2

In addition, the gelding's cranial to caudal balance is extremely poor. The yellow line in Figure 3 corresponds to the "center of rotation" and in a normal horse should divide the foot evenly in half. As such, there should be equal amount of ground contact (red lines) in front of the yellow line (cranial) and behind the yellow line (caudal). In this horse, the amount of ground contact behind the yellow line is nearly zero compared to that in front of the yellow line. This is due in part to the extremely long "toe" and the shoe placement. The extremely long toe and cranial shoe placement adds significant leverage on the toe which will aggravate the laminitis and increase the horse's level of pain!. Initial management of this case involved removing the shoes and significantly reducing the length of the toe. In addition, a blood sample was tested for insulin resistance and the horse was confirmed to be suffering from insulin resistance secondary to metabolic syndrome. The gelding was treated with the appropriate diet, stall confinement, pain medication, and medical management for insulin resistance. Stay tuned for follow-up.....

Figure 3