Jugular Vein Phlebectomy in Two Horses with Septic Thrombophlebitis Unresponsive to Medical Treatment

Introduction
Intravenous catheters provide continuous, secure access for the administration of therapeutic agents to horses. However, they can be associated with complications such as thrombosis and septic thrombophlebitis, requiring medical treatment with appropri- ate antimicrobials and anti-inflammatories. in rare cases, thrombophlebitis is unrespon- sive to medical treatment.

Case details
Two 5 year old mares with a previous history of colic were presented for unilateral jugu- lar phlebitis that developed from 3 to 7 days after catheter removal. one case presented a swollen and hot right jugular vein from the head to the chest and fever, the other horse exhibited a large mass in the left mid-jugular area with head edema, fever, and a systolic heart murmur. no abnormality was noticed on cardiac ultrasound examination. this mare had already been treated with several antibiotics (successively 5 to 7 days of oxytetracycline, gentamicine, enrofloxacine, and ceftiofur) before referral. ultrasono- graphic examination revealed a thrombus over the entire diameter of the vein as a heterog- enous cavitating mass with multiple hyperechoic spots in one case, and a thrombus obstructing half of the jugular vein cranially to a mass filled with a hypoechogenic homoge- nous fluid content in the second case. a coagulase positive Staphylococcus and Strep- tococcus equi zooepidemicus were cultured from one blood aspiration, respectively, which were sensitive to usual antimicrobials. the suspected anaerobic bacteria was not cultured.

Treatment and outcome
Treatment was initiated with cefquinome and rifampicine (1 mg/kg intramuscularly twice a day and 5 mg/kg orally twice a day, respectively) in the most severe case, in order to achieve an excellent diffusion in a purulent abscess, and cefquinome and met- ronidazole (1 mg/kg intramuscularly twice a day and 15mg/kg orally four times a day, respectively) in the mare with supposed anaerobic infection. in spite of local (topical cream containing lidocaine, prednisolone and dimethylsulfoxyde) and systemic therapy, both cases got worse. a venous punction to evacuate the serosanguineous fluid inside the mass was performed for the first mare, but it filled again quickly and ultrasound examination confirmed a fistula between the vein and the perivenous mass. a phlebotomy and a debridement were performed and a draining tract was created. Healing was complete within 13 days. in the other horse, necrotic tissue, purulent material around the vein and the extensive thrombus were removed and a sterile maggot therapy was initiated for three days. the opened surgical wound healed within 20 days.

Conclusions
When no response is achieved with appropriate antimicrobials, surgical treatment is necessary to avoid life-threatening complications such as endocarditis, pulmonary embolism, bacteremia and septicaemia. Standing jugular phlebotomy is a simple and effective method for removing infected clots and resolving septic jugular thrombophlebitis and can be performed on a standing horse.