Preventing haemorrhage in equine guttural pouch mycosis.

Guttural Pouches:

• They are diverticulae of the eustachian tubes in horses.
• Their exact function remains unclear. Some proposed functions include:
  • Cooling the blood flowing through the internal carotid artery, which in turn cools the brain.
  • Equalizing air pressures across the tympanic membrane.
  • Acting as a resonating chamber for vocalization.
• They contain many vital nerves and blood vessels, which are susceptible to injury during infections.

Infections:

• The pouches can suffer from various microbial infections.
• Streptococcus equi (var equi), also known as strangles, is a notable infection.
• The mucosa can be affected by all respiratory viral infections.
• They are also prone to mycotic (fungal) infections, particularly from Aspergillus species.
• It’s unclear why these fungi affect some horses’ guttural pouches and not others, and why they prefer certain parts of the pouch.

Observations and Trends:

• Over the past 20 years, the prevalence of guttural pouch mycosis has decreased in the UK.
• This reduction is possibly linked to changes in equine husbandry, like the shift from hay to haylage and the use of non-straw bedding.
• The author speculates that the fungal challenge level might play a role in the development of guttural pouch mycosis.

Complications:

• One severe consequence of the mycosis is the infection reaching the underlying nerves, causing neurological damage.
• It can also cause erosion of the arteries, leading to severe or even fatal hemorrhage.
• Previous treatments for arterial hemorrhage included ligation of the arteries, but this could sometimes lead to further hemorrhage.
• Newer treatments involve inserting balloons or embolic catheters to prevent hemorrhage, but these are expensive and require specialized equipment and training.

Alternative Treatments:

• There’s a salvage procedure involving ligation of the common carotid artery and topical antimycotic therapy, which, while less effective than the newer treatments, still offers a better outcome than leaving the condition untreated.
• The study by Cousty and others suggests that the use of topical antimycotic treatments and lesion debridement might speed up the resolution of the infection.

Conclusions:

• While the newer treatments are preferable, the salvage procedure can be a viable alternative, especially in cases where the newer treatments are not feasible.
• Topical antimycotic therapy should be considered for all cases of guttural pouch mycosis unless there’s strong evidence against its efficacy.

This text sheds light on the mysterious and complex nature of the guttural pouches in horses and the challenges faced in treating infections associated with them.