Phenobarbital-responsive sialadenosis in dogs: case series

Severe Bilateral Sialadenitis of the Mandibular and Parotid Salivary Glands with Severe Panniculitis in a 2-Year-old Standard Poodle

A 2-year-old male neutered Standard Poodle weighing 17.9 kg was presented to their primary care veterinarian for enlarged bilateral submandibular swellings following an interdog altercation sustained in the previous weeks. Cytology performed following fine-needle aspirates of the regions of swelling was inconclusive, and the patient was treated empirically with Clavaseptin. Despite treatment, the submandibular swellings continued to enlarge, and right-sided intermittent epistaxis was reported. On biochemical profile, there was mild hypercalcemia and mild hyperglobulinemia. The computed tomography (CT) findings were indicative of severe multifocal sialadenitis with severe regional cellulitis and inflammatory lymphadenopathy. Histopathology and cytology results described mixed inflammation of the salivary gland. Methenamine silver staining and Fite's acid-fast staining were negative. Aerobic and anaerobic cultures were negative. Targeted, next-generation DNA sequencing detected no known fungi or bacterial pathogens. These findings were consistent with the diagnosis of severe bilateral mandibular sialadenitis, panniculitis, and lymphadenopathy. The patient was prescribed enrofloxacin, clindamycin, phenobarbital, and prednisolone for 1 month. One week after initiating treatment, the patient had a significant reduction in size of the salivary glands. CT imaging was helpful in the diagnosis of this patient and allowed the clinician to identify which submandibular anatomical structures were abnormal, guiding subsequent diagnostic decisions to provide medical management to resolve the condition.

Clinical and CT sialography findings in 22 dogs with surgically confirmed sialoceles

Sialoceles are an uncommon canine salivary gland disease, and complete surgical resection is important for a positive outcome. Radiographic sialography has been described as a diagnostic test for presurgical planning; however, superimposition artifacts may limit the diagnosis and detection of all affected glands. Computed tomographic (CT) sialography is a promising technique for delineating the salivary gland apparatus. The aims of this retrospective, observational study were to describe clinical and CT sialographic findings in a group of dogs with confirmed sialoceles, to determine the sensitivity of CT sialography for detecting affected salivary glands using surgery as the reference standard and to determine interobserver agreement for CT sialographic assessments. Dogs were included if they underwent a CT sialography study followed by surgical resection of the diseased gland(s) and histopathological analysis. Computed tomography sialography studies of dogs with surgically confirmed sialoceles (n = 22) were reviewed by a European College of Veterinary Diagnostic Imaging (ECVDI)-certified radiologist and an ECVDI resident. Interobserver agreement was calculated using Cohen's kappa statistics. CT sialography results were compared to surgical findings to determine sensitivity. Contrast leakage was detected in 12 of 22 dogs (54.5%), with intrasialocele leakage being most frequently observed (7/12, 58.3%). There was substantial agreement (κ = 0.70) between reviewers identifying diseased glands, substantial agreement (κ = 0.62) on the diagnostic quality, and no to slight agreement (к = 0.13) in the detection of contrast leakage. The overall sensitivity of CT sialography to detect surgically confirmed diseased glands was 66.7% (95% confidence interval: 48.8-80.8). In conclusion, these findings support the use of CT sialography as an adjunct diagnostic test for treatment planning in dogs with sialoceles.

Successful treatment of a dog with phenobarbital-responsive sialadenosis and an oesophageal stricture

Background

Phenobarbital‐responsive sialadenosis (PRS) can cause nausea and vomiting, and is rarely reported in dogs.

Objectives

An 8‐year‐old neutered, male Pomeranian dog was presented to our teaching hospital with vomiting that began 2 years ago. The clinical signs repeatedly improved and deteriorated despite treatment.

Methods

The only abnormality found on physical examination was salivary gland enlargement, and no specific findings were observed on blood analysis and imaging tests. The results of the fine needle aspirate cytology from the salivary glands revealed possible sialadenosis. Phenobarbital was prescribed, and the patient's symptoms resolved. However, upon discontinuing drug, the patient's clinical signs recurred and did not improve even after re‐introduction of phenobarbital and the addition of other anticonvulsant drugs. An oesophageal stricture was observed on an oesophagram, and fibrosis was confirmed endoscopically. A balloon dilation was performed to expand the stenosis.

Results

After the first procedure, the patient's clinical signs initially improved, but relapsed 2 weeks later. A total of three oesophageal dilation procedures were performed using a sequentially larger diameter balloon. After the third procedure, the patient's clinical signs were managed without recurrence. The cause of recurrent gastrointestinal signs following the initial successful treatment of phenobarbital‐responsive sialadenosis was due to oesophageal stricture formation.

Conclusions

This case report demonstrates the successful management of PRS with subsequent oesophageal stricture formation in a dog.