Focal peritarsal cellulitis with long digital extensor tenosynovitis

Abstract

Summary This study reviews seven cases of focal peritarsal infection with long digital extensor tendon sheath (LoDETS) tenosynovitis, which presented to the same metropolitan equine practice over a 3‐year period (2016‐2019). All horses presented with acute‐onset severe hindlimb lameness, in combination with swelling and pain of the dorsal tarsus. In all cases, tarsal ultrasound demonstrated diffuse thickening of subcutaneous tissues and increased hypoechoic fluid volume in the LoDETS. Sampling and analysis of the LoDETS fluid demonstrated increased nucleated cell count, neutrophil percentage or total protein, consistent with sepsis in 6/7 cases. No bacterial organisms were identified on cytology or culture. Treatment consisted of systemic and local antimicrobial therapies, nonsteroidal anti‐inflammatory drugs and hand walking. Treatment duration ranged from 15 to 33 days. Lameness resolved in five cases; the remaining two cases were euthanised due to complicating factors prior to resolution of lameness. The study demonstrates the use of ultrasound and synovial fluid analysis in the diagnostic work‐up of suspected cases of focal peritarsal infection and identifies concurrent sepsis of the LoDETS as a novel finding. The prognosis for resolution of peritarsal cellulitis with concurrent sepsis of the LoDETS is considered good, with early diagnosis and appropriate antimicrobial treatment.

Identifying bacterial infections in synovial structures—When will the Cavalry arrive?

“…Results demonstrated a greater than 70% contribution of obligate anaerobes to the bacterial populations identified in samples. Could undiscovered obligate anaerobes have played a contributory role in the demise of Case 6 in Kalka et al (2022)? Going one step further, metagenomic NGS (mNGS) is the ability to sequence nucleic acids present in a sample and identify specific bacteria, fungi, archaea and viruses through mapping to reference databases.…”

“…Presented in this issue, Kalka et al . (2022) discuss a series of seven challenging cases diagnosed with focal peritarsal cellulitis and long digital extensor tenosynovitis. Aspects of these fascinating cases have been presented for us that may directly influence the way we practice veterinary medicine and the information we can offer to our clients helping them to make informed decisions.…”