Cerebral Ventriculitis Associated with Otogenic Meningoencephalitis in a Dog

Otogenic Meningitis or Meningoencephalitis in 30 Dogs: Association Between Neurological Signs, Magnetic Resonance Imaging Findings, and Outcome

This retrospective study aimed to assess the accuracy of neurological examination in identifying intracranial extension of ear infection in dogs and to investigate the clinical data that may potentially aid in its diagnosis and prognosis. Dogs diagnosed with meningitis or meningoencephalitis due to an intracranial extension of otitis media-interna were included, and the relationship of MRI findings with neurological examination, clinical data, and outcome was studied. Thirty dogs were included, with 96% corresponding to brachycephalic breeds and a mean age of 7.5 years. The neurological examination was accurate in localizing the lesion in the central nervous system in 33% of dogs. Dogs with brainstem parenchymal involvement in magnetic resonance imaging (MRI) had a longer recovery (21 days). Recovery was complete in 28% of cases, with dogs more likely to have persistent neurological deficits when parenchymal and/or meningeal involvement was observed on imaging. MRI did not show intracranial extension in 20% of cases despite inflammatory cerebrospinal fluid (CSF). This study supports the conclusion that intracranial extension of otogenic infection is possible in dogs without central nervous system signs. When otitis media-interna is diagnosed, MRI and CSF studies should be recommended, especially for chronic or recurrent cases and in brachycephalic breeds.

Suspected bacterial ventriculitis in a nine-month-old Goldendoodle

Bacterial ventriculitis is an uncommon, often fatal complication of intracranial bacterial infection. This case report describes a nine-month-old spayed female Goldendoodle that presented with a history of acute onset generalised seizures. The initial clinical examination, neurological examination and minimum database laboratory tests were unremarkable, and the dog was diagnosed with probable idiopathic epilepsy. Three weeks thereafter, the patient developed breakthrough clustering orofacial and generalised seizures. Magnetic resonance imaging (MRI) findings were consistent with bacterial ventriculitis. Broad-spectrum antibiotic and supportive therapy was initiated pending cerebrospinal fluid (CSF) analysis, serology and bacterial culture; however, the patient died eight hours after initiating treatment. To our knowledge, this is the first case report of suspected bacterial ventriculitis in a dog in South Africa and describes its atypical clinical presentation, progression and unique MRI findings.

Bacterial identification in cerebrospinal fluid of domestic species with neurologic signs: a retrospective case-series study in 136 animals (2005-2021)

Central nervous system (CNS) infections comprise life-threatening clinical conditions in domestic species, and are commonly related to severe sequelae, disability, or high fatality rates. A set of bacterial pathogens have been identified in central nervous infections in livestock and companion animals, although the most of descriptions are restricted to case reports and a lack of comprehensive studies involving CNS-related bacterial infections have been focused on a great number of domestic species. In this scenario, we retrospectively investigated selected epidemiological data, clinical findings, bacteriological culture, and in vitro susceptibility patterns of 136 nonrepetitive neurologic cases in domestic species (2005-2021). Bacterial isolates were recovered from 25% (34/136) of the cerebrospinal fluid (CSF) sampled. The isolates were obtained from cattle (9/136 = 6.6%), dogs (7/136 = 5.1%), horses (6/136 = 4.4%), goats (3/136 = 2.2%), pigs (3/136 = 2.2%), sheep (3/136 = 2.2%), cats (2/136 = 1.5%), and asinine (1/136 = 0.7%). Among animals with bacterial isolation, Staphylococcus aureus (6/34 = 17.6%), Escherichia coli (5/34 = 14.7%), Staphylococcus beta-hemolytic (5/34 = 14.7%), and Trueperella pyogenes (3/34 = 8.8%) were predominant, in addition to a miscellaneous of other bacteria isolated in minor frequency, e.g., Corynebacterium pseudotuberculosis, Enterobacter cloacae, Mannheimia haemolytica, Pseudomonas aeruginosa, and Streptococcus equi subsp. equi. In vitro susceptibility tests of isolates revealed that amoxicillin/clavulanic acid (11/13 = 84.6%), cephalexin (9/11 = 81.8%), and florfenicol (9/12 = 75%) were the most effective antimicrobials. Conversely, isolates exhibited resistance mainly to tetracycline (6/10 = 60%), penicillin (6/11 = 54.5%), and trimethoprim/sulfamethoxazole (5/11 = 45.5%). Also, multidrug resistance to ≥ 3 classes of antimicrobials was found in 23.5% (8/34) strains. Data relative to the outcome was available in 79.4% (27/34) of animals that had bacterial isolation, and from these, the lethality rate was 92.6% (25/27). Incoordination (14/34 = 41.2%), recumbency (11/34 = 32.4%), apathy (10/34 = 29.4%), anorexia (9/34 = 26.5%), blindness (7/34 = 20.6%), seizure (6/34 = 17.6%), limb paresis (5/34 = 14.7%), head-pressing (4/34 = 11.8%), and nystagmus (3/34 = 8.8%) were the most frequent clinical signs. A variety of bacterial pathogens were identified in the CSF of domestic species showing neurologic signs, with a predominance of staphylococci, streptococci, and enterobacteria. High lethality of cases, poor in vitro efficacy of conventional antimicrobials, and a high in vitro multidrug resistance pattern of isolates were seen. Our results contribute to etiological characterization, antimicrobial resistance patterns, and clinical-epidemiological findings of bacterial infections in domestic species with neurological signs.

Clinical presentation, treatment, and outcome of 24 dogs with bacterial meningitis or meningoencephalitis without empyema (2010-2020)

BACKGROUND

Bacterial meningitis (BM) and meningoencephalitis (BMEM) are associated with high case fatality rates and neurologic sequelae in people, but limited data exists on outcome in dogs.

HYPOTHESIS/OBJECTIVES

To report the clinicopathologic features, treatment and outcome of BM/BMEM in dogs, with a focus on clinical presentation, relapse and long-term neurological deficits.

ANIMALS

Twenty-four client-owned dogs diagnosed with BM/BMEM without empyema.

METHODS

Retrospective case series of dogs diagnosed with BM/BMEM from 5 veterinary referral hospitals between January 2010 and August 2020.

RESULTS

Twenty-four dogs were included. Median duration of clinical signs was 2 days (range ≤24 hours to 30 days) and signs recorded included pyrexia (3) and cervical hyperesthesia (10). Neurological deficits were present in 18 dogs including altered mentation (12), ataxia (8), nonambulatory status (8), head tilt (8), and cranial nerve deficits (13). Intracellular bacteria were visualized on cerebrospinal fluid (CSF) analysis in 15/24 dogs, with positive CSF bacteriological culture in 8/21. Otitis media/interna (OMI) was diagnosed in 15/24 dogs, of which 6/15 dogs underwent total ear canal ablation and lateral bulla osteotomy. Twenty dogs survived to hospital discharge. Median duration of antibiotic administrations was 8 weeks (range, 2-16 weeks). Glucocorticoids were administered to 15 dogs. Median follow-up time was 92 days (range, 10-2233 days). Residual neurological deficits were reported in 9 dogs, with a single case of suspected relapse.

CONCLUSIONS AND CLINICAL IMPORTANCE

Clinical signs were variable in dogs with BM/BMEM, the nidus of bacterial infection was often OMI and the majority of dogs made a full recovery with treatment.

Bilateral tympanokeratomas (cholesteatomas) with bilateral otitis media, unilateral otitis interna and acoustic neuritis in a dog

Background

An aural cholesteatoma, more appropriately named tympanokeratoma, is an epidermoid cyst of the middle ear described in several species, including dogs, humans and Mongolian gerbils. The cyst lining consists of stratified, keratinizing squamous epithelium with central accumulation of a keratin debris. This case report describes vestibular ganglioneuritis and perineuritis in a dog with chronic otitis, bilateral tympanokeratomas and presumed extension of otic infection to the central nervous system.

Case presentation

An 11-year-old intact male Dalmatian dog with chronic bilateral otitis externa and sudden development of symptoms of vestibular disease was examined. Due to the dog’s old age the owner opted for euthanasia without any further examination or treatment and the dog was submitted for necropsy. Transection of the ears revealed grey soft material in the external ear canals and pearly white, dry material consistent with keratin in the tympanic bullae bilaterally. The brain and meninges were grossly unremarkable. Microscopical findings included bilateral otitis externa and media, unilateral otitis interna, ganglioneuritis and perineuritis of the spiral ganglion of the vestibulocochlear nerve and multifocal to coalescing, purulent meningitis. A keratinizing squamous epithelial layer continuous with the external acoustic meatus lined the middle ear compartments, consistent with bilateral tympanokeratomas. Focal bony erosion of the petrous portion of the temporal bone and squamous epithelium and Gram-positive bacterial cocci were evident in the left cochlea. The findings suggest that meningitis developed secondary to erosion of the temporal bone and ganglioneuritis and/or perineuritis of the vestibulocochlear nerve.

Conclusions

Middle ear tympanokeratoma is an important and potentially life-threatening otic condition in the dog. Once a tympanokeratoma has developed expansion of the cyst can lead to erosion of bone and extension of otic infection to the inner ear, vestibulocochlear ganglion and nerve potentially leading to bacterial infection of the central nervous system.

Electronic supplementary material

The online version of this article (10.1186/s13028-018-0386-4) contains supplementary material, which is available to authorized users.

Pyogenic Ventriculitis and Ventricular Empyema associated with Staphylococcus pseudintermedius in a Puppy

A 40-day-old male, blue heeler puppy with hindlimb ataxia, nystagmus, apathy, motor incoordination and hyperaesthesia of the forelimbs died 3 days after the onset of clinical signs. Significant gross findings included cerebellar herniation, cerebral oedema and dilation of the third and right lateral cerebral ventricles due to the accumulation of a purulent exudate. Histopathological examination revealed pyogenic ventriculitis and purulent meningoencephalitis. Pure colonies of a coagulase-positive Staphylococcus were isolated from the purulent cerebral exudate. A polymerase chain reaction assay that targeted the 16S rRNA gene of bacteria amplified the desired product from bacterial colonies. Direct sequencing revealed the organism to be Staphylococcus pseudintermedius. Phylogenetic analyses showed that the organism was antigenically similar to Staphylococcus intermedius and Staphylococcus delphini, being part of the S. intermedius group of bacteria. These findings confirmed the participation of S. pseudintermedius in the development of the pathological manifestations and lesions observed in this puppy.