Dr Michael Porter DVM
Guttural pouch infection in a horse.
A yearling quarter horse presented for a 30 day history of unilateral nasal discharge. The colt was not febrile, ate with a good appetite and there was a milky discharge from the left nostril only! Endoscopic exam of the guttural pouches revealed muco-purulent discharge within the left guttural pouch (Figure 1 and 2). Careful exam of the wall lining the guttural pouch revealed many small pustules (Figure 2). The colt was diagnosed with a guttural pouch infection and the fluid was analyzed for the presence and type of bacteria!
As a rule, these findings should always be considered as a likely case of equine strangles until prove otherwise. There were not enlarged lymph nodes detected within the guttural pouch of this colt and there were no other symptoms that would have suggested a case of equine strangles. Regardless, it was assumed until proven otherwise! The culture was positive for streptococcus equi zooepidemicus which is NOT the bacteria associated with equine strangles. As such, this horse was treated by lavaging the guttural pouch and the symptoms resolved.Typically, these horses do NOT respond to systemic antibiotics but will resolve with repeated lavaging of the guttural pouches. Occasionally, administration of penicillin gel directly into the guttural pouch may effective!! In my experience, >90% of the cases I diagnose with a guttural pouch infection are positive for the bacteria that causes equine strangles also known as Streptococcus equi equi
therefore, these cases are treated as highly infectious until the culture results are confirmed.