A Hanoverian horse needed to be put on oxygen because of breathing difficulties after a wound to its front, above its right leg, developed potentially fatal complications.
The case report, described in the Veterinary Medicine and Science journal, highlights the potential risks associated with wounds in the axillary region – the space that lies between the inside of the upper limbs and the body wall.
Lacerations in this region occur frequently in horses, Linda Marie Schoen and her fellow researchers from Justus Liebig University Giessen in Germany noted. They can be caused by running into objects, being impaled by sharp objects, or kick injuries from other horses.
Depending on the size and depth of the wound, air can be trapped during movement of the limbs and migrate within the body, causing problems that can be life-threatening.
The yearling colt was referred to the university clinic for evaluation and management of a cut to the right axillary region, which appeared to be about 3cm deep. The exact age of the wound could not be determined. No therapeutic steps had been undertaken before referral.
The horse had a heart rate of 44, a respiratory rate of 12, and an elevated rectal temperature of 39.2°C. His mucous membranes were pink with a capillary refill time of under 2 seconds. Airway sounds in both lung fields were normal.
Beyond the 10cm by 4cm wound, a layer of air was beneath the skin, known as subcutaneous emphysema, was evident over the right and left thoracic walls.
An x-ray of the chest from the right side showed typical signs of pneumomediastinum – a condition in which air is present in the mediastinum (the space in the chest between the two lungs).
The wound edges were swollen, irregular, partly dried superficially, and had detached from the subcutaneous tissue. It was cleaned and treated, with packing and bandaging applied. Due to skin loss, a complete closure of the wound was not possible. The horse received a tetanus jab, the anti-inflammatory painkiller flunixin-meglumine, and a course of the antibiotic cefquinome.
Within 12 hours of hospitalisation, the colt’s temperature fell to 37.8°C and remained within normal limits. The area of air under the skin continued to increase in subsequent days around the thorax, up to the 12th rib. Additionally, both sides of the neck and head began to show evidence of air under the skin upon palpation.
On the fifth day, the horse’s respiration rate rose significantly and a shallow pattern was noticed. An arterial blood gas analysis revealed low oxygen levels. A global respiratory insufficiency was diagnosed.
The respiratory distress and the increasing air under the skin prompted a repeat chest x-ray. It revealed signs typical of a bilateral pneumothorax – collapsed lungs due to air in the space between the lungs and chest wall.
Additionally, peritoneal air pockets were suspected in the upper abdominal cavity. The clinical team diagnosed a pneumoperitoneum – air in the abdominal cavity.
The horse was put on oxygen and a bilateral thoracentesis was performed under local analgesia by inserting a teat cannula through the chest wall into the pleural space. Air was evacuated using a 100ml syringe until the horse showed no further respiratory distress. His respiratory rate fell to 16 breaths a minute.
The horse’s condition continued to be monitored by x-ray, and air evacuation was repeated two days later after the horse’s respiratory rate climbed to 28.
The horse was discharged after 21 days. At that time, low-grade signs of pneumoperitoneum were still evident on radiographs of the cranial abdomen. However, his blood oxygen levels were normal.
One month after discharge, the wound had reportedly fully healed. A telephone interview with the owner a year after discharge revealed no impairment of gait or respiratory function, nor other abnormalities. The owner was able to start training the horse.
Discussing the case, the authors said the complications that arose were most likely the result of being unable to achieve airtight closure of the wound.
The nature of the wound and its location potentially impaired its airtight closure. Discharge from the wound had also compromised the function of the dressings.
They said the use of an active suction drainage system might have been a more appropriate alternative treatment option. The use of a vacuum-assisted closure system was another possible alternative.
“In conclusion, management of an axillary wound with extensive skin loss, by sealing and packing it and restriction of movement might not be sufficient to prevent the development of pneumoperitoneum, which has to be considered as a potential complication after this type of laceration.”
Radiography is the diagnostic method of choice to detect pneumoperitoneum in horses, they said.
The case report team comprised Schoen, Mohammed Al Naem, Michael Röcken and Florian Geburek.
Schoen, L. M., Al Naem, M., Röcken, M., & Geburek, F. (2022). Pneumoperitoneum as an uncommon complication after an axillary laceration in a horse. Veterinary Medicine and Science, 8, 546– 552. doi.org/10.1002/vms3.718