Treatment of pythiosis in equine limbs using intravenous regional perfusion of amphotericin B.

Abstract

OBJECTIVE: To evaluate the effects of intravenous regional limb perfusion (IRLP) administration of amphotericin B in horses to treat pythiosis after surgical excision and thermocautery. STUDY DESIGN: Case series. ANIMALS: Horses (n = 12) with Pythium insidiosum infection of the distal aspect of the thoracic or pelvic limbs. METHODS: After surgical excision of granulation tissue and thermocautery, 50 mg amphotericin B was administered by IRLP through a catheter placed in a superficial vein of the affected limb next to the lesion after placing a tourniquet above the injection site. The lesions and locomotor system were evaluated before treatment and at 7, 14, 21, 28, 35, and 60 days. RESULTS: Ninety-two percent of horses treated with amphotericin B had complete lesion resolution 35 or 60 days after 1 or 2 IRLP treatments, respectively. IRLP induced limb edema and pain during regional palpation in 42%, and inflammation of the injection site in 33% of horses; however these signs resolved after 14 days. CONCLUSIONS: IRLP administration of amphotericin B was effective for treating pythiosis in equine limbs, resolving infection with manageable side effects.