Streptococcal Meningoencephalomyelitis in 3 Dogs

Abstract

A n 8-year-old male Boxer was examined because of a history of acute depression and abnormal posture. The patient was treated with dexamethasone and penicillin G and 1 day later a right-sided head tilt was noticed. The Boxer had a history of chronic interdigital dermatitis.Abnormalities detected in general clinical examination were dehydration (9%), pain around the right ear, and mild interdigital dermatitis. The dog was depressed and disoriented. Head tilt to the right and generalized vestibular ataxia was noticed with drifting and falling to the right side. Dog was paretic in all 4 limbs and proprioceptive positioning was decreased in the rear. All spinal reflexes and perception of noxious stimuli were normal. Spontaneous left horizontal jerk nystagmus and ventral strabismus on the right eye were observed. Menace reaction and palpebral reflex were markedly decreased on the right side. Noxious stimulation of nasal mucosa on the right side elicited almost no response. Neurologic examination primarily indicated involvement of the right brainstem at the cerebellopontine angle evidenced by the presence of a right-sided central vestibular syndrome and a right facial and trigeminal nerve dysfunction (maxillary and possibly ophthalmic branches). Tetraparesis indicated involvement of both sides of the brainstem.No significant hematologic abnormalities were noted, except that the erythrocyte sedimentation rate was markedly increased (12 mm/30 minutes, 37/60, 100/120; reference range (RR): 1/30, 2/60, 4/120). The most important serum biochemistry abnormality was severe hyperglobulinemia (58.7 g/L; RR: 31-35 g/L). No abnormalities were found either on otoscopic examination under general anesthesia or on radiographic evaluation of the tympanic bullae. The atlanto-occipital collection of cerebrospinal fluid (CSF) yielded a gray-yellowish and somewhat thick fluid. The CSF showed marked pleocytosis (700 cells/mm 3 ; RR: Ͻ5 cells/ mm 3 ) and increased protein concentration (Pandy's reaction, ϩϩϩϩ positive; normal: negative). The predominant cell population was neutrophils (94%), which were moderately to severely degenerated, including many cells that displayed karyolysis and karyorrhexis. Bacterial cocci were frequently observed within neutrophils. Bacteriologic cul- From the Department of Clinical Studies, Section of Clinical AnimalNeurology (Cizinauskas, Fatzer, Jaggy) The dog was gradually rehydrated and treatment with metronidazole (20 mg/kg IV q12h) and cefazolin (20 mg/ kg IV q8h) as well as buprenorphin (0.01 mg/kg q6h) was initiated. Additional supportive therapy included oxygen administration, frequent patient turning, and regular bladder expression. The dog's clinical condition deteriorated rapidly within 24 hours, progressing to stupor. Bilateral ventral strabismus and absent menace reactions and palpebral reflexes suggested progression of the lesion in the brainstem. The owner elected to euthanize the dog.Splenomegaly was found on postmortem examination. On macroscopic examination, the brain and cervical spinal c...

Central nervous system infection withStaphylococcus intermediussecondary to retrobulbar abscessation in a dog

“…Bacteria are cultured from CSF of dogs with bacterial CNS infections at a relatively low rate, 4,5,8,9,11 and in one study of histopathologically confirmed cases of canine bacterial meningoencephalomyelitis, CSF culture was positive in only one of eight samples 4 . This is likely due to the small number of bacteria present in the CSF 3,11 . In this case, Staphylococcus intermedius was isolated, an organism only reported to be isolated from the CSF of a dog once before 1 …”

“…Bacterial CNS infections are life‐threatening and should be treated rapidly and aggressively 5,7–9,36,37 . Appropriate antibacterial therapy is based on culture and susceptibility but it is often necessary to institute therapy before culture results are available or if culture results prove negative 3,5,8,9,11,12 . In these instances, an antibacterial agent should be chosen that has a broad spectrum of activity, particularly against those organisms most frequently isolated 1,8,9 .…”

“…Antibacterials that have the ability to cross the blood–brain barrier should be selected, although meningeal inflammation may allow a wider range of antibacterials to reach therapeutic concentrations within the CNS 2,5,8,9 . Amoxicillin/clavulanate, metronidazole, and enrofloxacin were initially selected before a definitive diagnosis was made to give a broad‐spectrum bactericidal therapy for a suspected retrobulbar abscess 3,8,38 . Culture and susceptibility suggested amoxicillin/clavulanate to be an appropriate choice.…”

“…High doses of corticosteroids can cause suppression of the hypothalamic–pituitary axis, and there is a risk of development of hypoadrenocorticism with sudden treatment withdrawal. The use of corticosteroids in dogs with bacterial CNS infections remains controversial 1–3,7,36,37 . In this case, it is likely that immunosuppressive doses of corticosteroids used in the absence of antibacterial therapy facilitated the extension of retrobulbar infection into the cranial vault resulting in CNS infection.…”

“…Bacteria implicated in central nervous system (CNS) infections in the dog include Staphylococcus , Streptococcus , Pasteurella , Actinomyces , Nocardia , Prevotella , Peptostreptococcus , Fusobacterium , Eubacterium , and Bacterioides species 1–7 . Bacteria may enter the cranial vault from direct access, extension from adjacent structures, or hematogenously 4,7–12 .…”