Retrospective characterisation and outcome of canine idiopathic mesenteric purulent lymphadenitis and lymph node abscesses at a teaching hospital from 2005 to 2015

Retrospective characterisation and outcome of surgical treatment for cervical lymph node abscessation in 15 dogs

CASE HISTORIES

Medical records of a private referral hospital (Veterinary Emergency Clinic, Toronto, Canada) and a university teaching hospital (Louisiana State University, Baton Rouge, LA, USA) were reviewed, using the search terms lymphadenectomy, lymph node extirpation, cervical lymphadenitis, and lymph node abscessation. Dogs (n = 15) with a diagnosis of cervical lymph node abscessations confirmed through histopathology that underwent surgery for treatment from January 2015-May 2022 were included in the study. Long-term follow-up data was obtained by an in-person visit or telephone interview with each owner. Dogs that met the inclusion criteria were of various breeds with a median age of 6 (min 0.5, max 12) years. All cases presented with cervical swelling and lethargy, with inappetence and fever in 5/15 dogs. The range of duration of clinical signs prior to treatment was 1-3 weeks. Seven dogs were treated with a short course of antibiotics, with or without prednisone, without successful resolution, before referral.

CLINICAL FINDINGS

Diagnostic imaging using CT or cervical ultrasound revealed enlargement of unilateral mandibular and retropharyngeal lymph nodes with regional cellulitis and oedema in four dogs, enlargement of unilateral retropharyngeal lymph nodes with regional cellulitis in eight dogs, and a right ventral cervical abscess infiltrating the right medial retropharyngeal lymph nodes with oedema in one dog. Unilateral or bilateral cervical lymph node abscessation was diagnosed by lymphadenectomy and histopathology of affected lymph nodes. Bacterial cultures from samples of excised lymph nodes were positive in six cases.

TREATMENT AND OUTCOME

Cervical exploration and lymphadenectomy were performed in all cases. Thirteen dogs received antibiotics along with surgical treatment. Resolution was defined as absence of cervical swelling or enlarged lymph node(s) at the time of long-term follow-up (median 300 (min 240, max 1,072) days). Most patients had resolution of clinical signs following surgical excision of affected lymph nodes. Two dogs had complications including recurrence of clinical signs and development of open wounds following surgery. Their clinical signs resolved following additional administration of antibiotics.

CONCLUSIONS AND CLINICAL RELEVANCE

All dogs in this series had lymphadenectomy of abscessed lymph nodes and showed resolution of clinical signs with a favourable outcome. As 13/15 dogs also received antibiotics in conjunction with surgical treatment, appropriate use of antimicrobials may also play a role in treatment of this disease process.

Mesenteric lymph node abscesses due to Escherichia coli in a cat

A 3-year-old, castrated male mixed-breed cat presented with an almost 2-year history of chronic loose stools. On radiography and ultrasound examination, there were two masses in the centre of the abdomen. Contrast-enhanced computed tomography revealed that the masses were enlarged mesenteric lymph nodes with fluid accumulation. Percutaneous lesion drainage yielded pus-like fluid. Fluid cytology revealed numerous neutrophils and Gram-negative rods. Pus culture identified Escherichia coli as the causative organism. Consequently, mesenteric lymph node abscesses were definitively diagnosed. Since computed tomography showed that the abscesses adhered to the surrounding tissues, it was difficult to remove them surgically. With drainage and antimicrobial therapy, the mesenteric lymph nodes gradually decreased in size. However, loose stools persisted. The cat's diet was changed to a hydrolysed diet, and the clinical symptoms improved, suggesting food-responsive enteropathy. This may be an underlying disease of lymph node abscesses. Lymph node abscesses limited to the mesenteric lymph nodes rarely occur in veterinary medicine, and this is the first report in cats.