Retrospective evaluation of the clinical presentation, magnetic resonance imaging findings, and outcome of dogs diagnosed with intracranial empyema (2008-2015): 9 cases

Bacterial meningitis secondary to otogenic infection in 10 French bulldogs: A retrospective case series

Background

There is limited published information to guide the clinical management of bacterial meningitis/encephalitis in dogs.

Methods

This was a retrospective case series comprising 10 French bulldogs from two referral centres. The cases were diagnosed with bacterial meningitis/encephalitis suspected secondary to otogenic infection based on detection of abnormal fluid/soft tissue opacity within the middle/inner ear, associated meningeal/intracranial involvement through MRI, the findings of cerebro-spinal fluid (CSF) analysis suggestive of sepsis and/or clinical improvement following antibiosis.

Results

Ten dogs were included (three female and seven male), with a median age of 60 months. Dogs presented with acute onset (median 2 days), progressive history of vestibular signs and/or intra-oral or cervical pain. Five dogs had gross signs of concurrent otitis externa. Common MRI findings included material within the tympanic bulla with adjacent meningeal enhancement. Analysis of CSF documented pleocytosis in all eight dogs, intracellular bacteria seen in three with positive bacteriological culture in two dogs. One dog was euthanised following diagnosis. Nine remaining dogs received antimicrobial therapy and six underwent surgical management. Three dogs treated surgically were neurologically normal within 2 weeks and the remaining three improved. Two dogs treated medically improved and one had complete resolution reported within a 4-week follow-up period. Study limitations include its retrospective nature and small sample size with minimal longer term follow-up.

Conclusions

Bacterial meningitis/encephalitis in French bulldogs can require both medical and surgical treatment to achieve a favourable outcome.

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.

Intracranial Subdural Fluid Accumulation Associated with a Choroid Plexus Carcinoma in a Dog

Choroid plexus tumors are commonly described as intraventricular mass lesions and account for 7-10% of intracranial, primary tumors in dogs. A 3-year-old Shetland sheepdog was presented with a history of slowly progressive lethargy, vision impairment and cognitive deficits. On magnetic resonance imaging, a subdural fluid accumulation (SFA) overlying and compressing the left parietotemporal lobe as well as multifocal changes consisting of cyst-like lesions, supposed intra-axial brain lesions and mild, multifocal meningeal thickening and generalized contrast enhancement were identified. Cerebrospinal fluid (CSF) analysis showed a mononuclear pleocytosis with negative results for infectious agents. The dog was treated with prednisolone followed by burr hole craniotomy with puncture of the SFA, which macroscopically appeared to be CSF-like fluid. After initial improvement, the dog deteriorated despite continuation of prednisolone and cytarabine therapy and was euthanized four weeks after surgery. Histopathology was consistent with a disseminated, neuroinvasive choroid plexus carcinoma (CPC) that involved the entire neuroaxis including the meninges of the brain and spinal cord. Immunohistochemical examination showed a strong Kir7.1 and a heterogenous cytokeratin-immunoreactivity in neoplastic cells. In conclusion, a CPC should be considered as a possible cause of a SFA even in the absence of an intraventricular mass lesion.

Clinical Presentation, MRI Characteristics, and Outcome of Conservative or Surgical Management of Spinal Epidural Empyema in 30 Dogs

Spinal epidural empyema (SEE) represents a neurological emergency in veterinary medicine, but information on this condition is limited to date. This retrospective case series study describes the clinical and magnetic resonance imaging (MRI) features, and the outcome of conservative or surgical management of SEE in 30 dogs diagnosed with SEE from September 2015 to March 2020 at one referral neurology centre. The most frequent clinical sign was pain 28/30 (93%), and 22/30 (73%) showed neurological signs with ambulatory paraparesis/tetraparesis 15/30 (50%), monoparesis 1/30 (3.3%), non-ambulatory paraparesis 3/30 (10%), or paraplegia 3/30 (10%). MRI was valuable for the diagnosis and in the follow-up. In this group of dogs, 24/30 (80%) were conservatively treated and 6/30 (20%) were surgically treated. The outcome was considered favourable in all dogs: 20/30 (66.6%) achieved full recovery (3 surgically treated and 17 medically treated) and 10/30 (33.3%) dogs had an improvement in the neurological signs with residual ambulatory paresis (3 surgically treated and 7 medically treated). Surgical treatment showed better short-term (7 days) outcomes than medical treatment in non-ambulatory paraparetic or paraplegic dogs (33%). Nevertheless, this study suggests that a good recovery may be achieved with conservative treatment even for non-ambulatory or paraplegic dogs. Further prospective studies, with a standardised protocol of diagnostic tests and a homogeneous distribution of conservatively and surgically treated dogs, are needed to establish treatment guidelines.

Patterns of bacterial culture and antimicrobial susceptibility test results for dogs with retrobulbar abscesses: 133 cases (2002-2019)

OBJECTIVE

To evaluate patterns of bacterial culture and antimicrobial susceptibility test results for dogs with retrobulbar abscesses and generate recommendations for empirical antimicrobial selection.

ANIMALS

133 dogs examined between 2002 and 2019.

PROCEDURES

Records were retrospectively reviewed to determine type of bacterial culture, number and type of bacterial isolates, antimicrobial susceptibility test results, concurrent and recent antimicrobial exposure, effect of culture results on antimicrobial regimen, and outcome.

RESULTS

Aerobic culture alone was performed in 37 dogs, and aerobic and anaerobic culture was performed in 96 dogs. Isolates were recovered from 96 dogs, with multiple isolates recovered from 54 (56%) of those dogs. Of the 69 dogs for which both aerobic and anaerobic culture was performed and at least 1 isolate was obtained, 34 (49%) had purely aerobic infections, 15 (22%) had mixed aerobic and anaerobic infections, and 20 (29%) had purely anaerobic infections. Pasteurella spp (n = 26), Streptococcus spp (20), and Escherichia coli (12) were the most common aerobic isolates. Bacteroides spp (n = 22), Actinomyces spp (10), and Fusobacterium (10) spp were the most common anaerobic isolates. Susceptibility test results led to changes in the antimicrobial regimen in 37 of 80 (46%) dogs. Of the 76 dogs for which outcome information was available, 78 (97%) recovered.

CLINICAL RELEVANCE

Multipathogen and anaerobic infections were common in dogs with retrobulbar abscesses. Susceptibility data supported the use of amoxicillin-clavulanate or a combination of clindamycin and enrofloxacin as first-line treatments. Additional study is needed to characterize anaerobic antimicrobial susceptibilities and to compare results of susceptibility testing with in vivo responses to antimicrobial administration.

Cerebrospinal fluid analysis lacks diagnostic specificity in dogs with vestibular disease

BACKGROUND

Although, vestibular syndrome is a common neurological presentation, little is known about the diagnostic value of cerebrospinal fluid (CSF) analysis in vestibular syndrome in dogs.

METHODS

Medical records were retrospectively reviewed, and dogs with vestibular disease that had undergone magnetic resonance imaging of the head, CSF analysis and were diagnosed with central or peripheral vestibular syndrome were included. Disorders affecting the central vestibular system included meningoencephalitis of unknown origin (MUO), brain neoplasia, ischaemic infarct, intracranial empyema or metronidazole toxicity. Disorders affecting the peripheral vestibular system included idiopathic vestibular disease, otitis media/interna or neoplasia affecting the inner ear structures. Total nucleated cell concentration (TNCC), total protein concentration (TP) and cytologic assessment were recorded.

RESULTS

A total of 102 dogs met the inclusion criteria. The sensitivity and specificity of increased CSF TNCC to differentiate central from peripheral vestibular syndrome was 49% and 90%, while the sensitivity and specificity of increased TP was 58% and 39%, respectively. The TNCC and TP in dogs with MUO were significantly higher than in dogs with idiopathic vestibular disease (p = 0.000 and p = 0.004). MUO was associated with lymphocytic pleocytosis, while idiopathic vestibular disease and ischaemic infarct were associated with the presence of activated macrophages or normal cytology (p = 0.000).

CONCLUSION

Although consistent CSF abnormalities were observed in dogs with MUO, CSF analysis did not allow reliable differentiation between central and peripheral vestibular syndrome. CSF analysis is not reliable as the sole diagnostic technique in dogs with vestibular disease.

[Canine meningoencephalitis and meningitis: retrospective analysis of a veterinary hospital population]

OBJECTIVE

Characterization of the etiology of meningoencephalitis and meningitis in dogs through an analysis of a veterinary hospital population.

MATERIAL AND METHODS

Retrospective study (2011-2016) with evaluation of clinical and diagnostic data of dogs with cerebrospinal fluid (CSF) pleocytosis (> 5/µl). Only dogs with cytological evaluation of CSF or pathological examination of CNS were included. Results of CSF cytology and examination for infectious diseases were reviewed.

RESULTS

A total of 62 dogs met the inclusion criteria. 14.5 % (n = 9) were classified as reactive CSF pleocytosis due to other structural CNS disease, such as neoplasia or infarct. Meningoencephalitis or meningitis of unknown origin was diagnosed in 56.5 % (n = 35). In 29.0 % (n = 18), investigations for infectious diseases or presence of bacteria in CSF cytology (n = 5) indicated an infectious etiology. This infectious etiology appeared reliable in 6 dogs (9.7 %) based on the examination findings, in 9 dogs (14.5 %), there was only a suspicion of infectious meningoencephalitis or meningitis and in 3 dogs (4.8 %), the findings were of uncertain significance.

CONCLUSION

The most common cause of CSF pleocytosis was meningoencephalitis or meningitis of unknown origin. Nevertheless, there was evidence of a possible infectious etiology in 29 % of the dogs. For a reliable diagnosis, it is important to assess the CSF cytology and to conduct investigations for infectious diseases.

CLINICAL RELEVANCE

Meningoencephalitis or meningitis of unknown origin requires immunosuppressive therapy. Therefore, CSF cytology and investigations for infectious diseases are important for an exclusion of infectious meningoencephalitis or meningitis.