Horse with heaves....not so fast!

A middle-aged draft gelding presented for a complaint of difficulty breathing for several months duration. The increased respiratory rate began during the late summer months and was presumed to be likely Heaves/COPD. As the ambient temperature cooled during the fall and winter months, the gelding's respiratory efforts remained elevated. He was referred to PHD Veterinary services to confirm the diagnosis of Heaves/COPD. At presentation, the gelding displayed a significant abdominal component during inspiration and expiration. However his lung sounds were relatively normal. The typical crackles and wheezes that are common in horses with Heaves/COPD were not present. The gelding was slightly under weight and the rest of the physical exam was normal. A bronchio-alveolar lavage (BAL) was performed through a bronchoscope. Upon inspection of the larynx, it was noted that there was minimal if any movement of either arytenoid cartilage (Figure 1).     The image below was taken during inspiration when the airway should be at its maximum diameter. Due to the apparent bilateral paralysis, the gelding's airway consisted of a small slit which would be similar to trying to breath through a straw. The BAL procedure was performed and the cytology results were normal which completely ruled Heaves/COPD. 

The figure below is that of a normal larynx during inspiration with functioning arytenoid cartilages. Note the size of the airway compared to the above image. 

                        

The image below is that of a "roarer" in which the left arytenoid cartilage is completely paralyzed and not moving. This type of condition and varying degrees of paralysis are most common in horses. Bilateral paralysis is rare and carries a worse prognosis. The cause of the paralysis is unknown and management of horses with bilateral arytenoid paralysis is limited.  Permanent tracheostomy is a recommended procedure and will allow the horse to return to a normal respiratory rate and comfortable life in the pasture. 

There are many horses with increased respiratory effort during the warm summer months in the Southeastern USA that suffer from Heaves/COPD. A large percentage of these horses are treated empirically with medications and management practices.  However, this case highlights the importance of diagnostic imaging of the airway to help confirm the diagnosis, especially in those horses that are not responding as expected to medical treatment. 

The Benefits of Platelet Rich Plasma (PRP)

Platelet Rich Plasma (PRP) treatment has been used in modern medicine since the 1990s. It was originally used to facilitate wound healing in humans after oral surgery. Platelet-rich plasma is a blood product that has a high concentration of platelets, growth factors and cytokines that enhance healing of bone and soft tissue. 

In human medicine, PRP has been implemented in the treatment of nerve injuries, tendinitis, osteoarthritis, bone repairs, plastic surgery, and oral surgery. In horses, veterinarians are using PRP for the treatment of tendon/ligament injuries and osteoarthritis. 

The following images are from 2 different cases in which treating with PRP made a significant difference in the quality of tendon repair. In the first case, a 6 year old Saddlebred mare presented for acute lameness at a show that was associated with soft tissue swelling over the flexor tendons. Ultrasound of the limb noted significant swelling of the superficial digital flexor tendon (SDF) and a core-like lesion (Figure 1) that appears as a black circular structure within the SDF tendon. This lesion extended 4-5cm in length. These findings were consistent with moderate to severe tendinitis of the SDF tendon.

Figure 1

The tendon was treated with approximately 10cc of PRP product by injecting the core lesion via ultrasound guidance. The area of interest was treated in multiple sites. In addition, the mare was treated with forced rest, daily ice therapy and extra-corporeal shockwave treatment (3X). The tendon was re-ultrasounded 6 weeks post PRP injection (Figure 2). The core-like lesion was filled in and the over-all cross sectional area (CSA) of the tendon was significantly reduced.

Figure 2

The second case was a 14 year old Fresian gelding that presented for a chronic (2-4 months) history of forelimb lameness. The lameness blocked out to the proximal metacarpal region which is just below the carpus (knee). The ultrasound exam of this area noted an enlarged SDF tendon with a CSA that was over 3X the normal size (Figure 3) . In addition, there was evidence of fiber disruption and edema present within the tendon. The area of interest was treated with approximately 10cc of PRP product that was injected at multiple sites. In addition, the gelding was treated with forced rest, ice therapy, and extra-corporeal shockwave treatment.

Figure 3

The SDF tendon was re-ultrasounded 4 weeks after PRP and the CSA of the tendon was greatly reduced (Figure 4). There appeared to be better fiber alignment and the gelding's lameness was greatly improved.

Figure 4

Both of these cases are good examples of the benefits of PRP treatment. However, it is important to note that forced rest and a controlled rehabilitation program are critical components to a successful outcome. Current PRP technology allows for on-site treatment and there are a variety of products available to the veterinarian for the production of PRP. The quality of product is directly correlated to the high concentration of platelets and the low concentration of white cells. More recently, practitioners are using PRP treatments in horses that have arthritis as a healthy alternative to cortisone treatment.