DOI

https://doi.org/10.1136/vetreccr-2017-000448

原文網(wǎng)址

https://bvajournals.onlinelibrary.wiley.com/doi/abs/10.1136/vetreccr-2017-000448

Successful medical management of an epidural abscess in a?dog

一例犬的硬膜外膿腫的成功保守治療

Nora Romero-Fernandez,?Roberto José-López,?Alexane Durand,?Rodrigo Gutierrez-Quintana

First published: 13 June 2017

https://doi.org/10.1136/vetreccr-2017-000448

Abstract 摘要

A seven-month-old entire male dobermann presented with acute onset neck pain and left thoracic limb lameness. The dog had a similar episode eight weeks before presentation that responded to meloxicam. A cervical spinal epidural abscess secondary to?Staphylococcus pseudintermedius?bacteraemia was diagnosed following investigations, including MRI of the cervical vertebral column and blood cultures. Treatment with cephalexin, gabapentin and meloxicam was started. The dog was doing clinically well one month later. A control MRI and radiographs of the cervical vertebral column showed evidence of discospondylitis and resolution of the primary lesion, therefore the treatment course with cephalexin was continued. Three months after initial presentation the clinical signs had resolved, radiographs showed improvement of the discospondylitis and antibiotics were stopped. Seven months later the dog continued doing well with no relapse.

SUMMARY 總結(jié)

A seven-month-old entire male dobermann presented with acute onset neck pain and left thoracic limb lameness. The dog had a similar episode eight weeks before presentation that responded to meloxicam. A cervical spinal epidural abscess secondary to Staphylococcus pseudintermedius bacteraemia was diagnosed following investigations, including MRI of the cervical vertebral column and blood cultures. Treatment with cephalexin, gabapentin and meloxicam was started. The dog was doing clinically well one month later. A control MRI and radiographs of the cervical vertebral column showed evidence of discospondylitis and resolution of the primary lesion, therefore the treatment course with cephalexin was continued. Three months after initial presentation the clinical signs had resolved, radiographs showed improvement of the discospondylitis and antibiotics were stopped. Seven months later the dog continued doing well with no relapse.

Back ground?背景

Spinal epidural abscesses (SEAs) are rarely reported in veterinary medicine (Cherrone and others 2002, Schmiedt and Thomas 2005, Linon and others 2014). Infection results from haematogenous bacterial spread or direct local extension (Cherrone and others 2002, Lavely and others 2006, Song and others 2015, Monteiro and others 2016). The most common bacteriae isolated as the causative agent for spinal epidural infections in human beings and dogs are Staphylococcus and Streptococcus species (Linon and others 2014, Cherrone and others 2002, Monteiro and others 2016, Schmiedt and Thomas 2005). Epidural infections can present as a diffuse purulent exudate in a natural cavity without a capsule (empyema) or in a newly formed cavity (abscess) (Lavely and others 2006, Remedios and others 1996). The former is uncommonly reported in the veterinary literature and the latter has only rarely been described (Cherrone and others 2002, Linon and others 2014, Nykamp and others 2003, Schmiedt and Thomas 2005, Lavely and others 2006, De Stefani and others 2007, Granger and others 2007, Escriou and others 2011, Linon and others 2014, Song and others 2015, Monteiro and others 2016). Although both terms are distinct, they are usually used interchangeably in the literature. Clinical signs are commonly non-specific, and neurological signs may initially be absent (Linon and others 2014). The imaging test of choice for the diagnosis of SEA is MRI (Remedios and others 1996, Cherrone and others 2002, Nykamp and others 2003). Although historically myelography has been the most widely used diagnostic tool (Schmiedt and Thomas 2005). The current treatment of choice is surgical drainage and decompression (Lavely and others 2006, Granger and others 2007), although medical management has recently been described (Escriou and others 2011, Song and others 2015, Song and others 2015, Monteiro and others 2016) suggesting non-surgical treatment should also be considered an option.?

This case report describes the successful medical management and MRI features at initial presentation and follow-up of a cervical SEA in a dog.?

Case presentation?病例就診表現(xiàn)

A seven-month-old entire male dobermann presented to the Neurology Service of the University of Glasgow for investigation of acute onset neck pain and left thoracic limb lameness. The dog had one episode of left thoracic limb lameness two months before presentation that responded well to meloxicam.?

Physical examination showed mild to moderate prescapular lymphadenomegaly and was otherwise unremarkable. Orthopaedic examination was unremarkable. Neurological examination showed normal mentation. The dog was ambulatory with intermittent left thoracic limb lameness. Cranial nerve examination was within normal limits. Proprioception was normal in all four limbs. A reduced withdrawal reflex was noted on the left thoracic limb when assessing the spinal reflexes. Marked pain was elicited on manipulation of the neck. The neuroanatomical localisation was left brachial plexus or lateralised C6-T2 spinal cord segments.?

Investigations?檢查

Complete blood count, biochemistry profile, clotting times and buccal mucosal bleeding time were unremarkable. MRI of the cervical vertebral column was performed using a 1.5-Tesla unit (Siemens Magnetom Essenza; Frimley). T2-weighted (T2w) and T1-weighted (T1w) images were acquired in the sagittal plane. Transverse T2w, T1w and T2* images were also obtained. Postcontrast T1w images were acquired in the sagittal and transverse planes after intravenous administration of gadolinium (0.1mmol/kg; Gadovist, Bayer). MRI showed a left-sided well defined small and ovoid extradural (epidural) T2w and T2* hyperintense mass lesion outlined by a hypointense halo, dorsal to mid-C6 vertebral body (Fig 1). The lesion was isointense to hypointense in the centre relative to spinal cord parenchyma on T1w images, with a surrounding mildly hyperintense peripheral rim, which was markedly enhancing on T1w postcontrast sequences. The lesion was causing a moderate mass effect with moderate spinal cord compression and right dorsolateral displacement. The caudal half of the C6 vertebral body and the left C6 transverse process were hypointense on T1w sequences relative to adjacent normal vertebrae and showed marked diffuse contrast enhancement. There was marked enhancement of C6 and cranial C7 hypaxial muscles just adjacent to the ventral vertebral bodies, more pronounced on the left.?

FIG 1: Parasagittal T2w (a), T1w (b), T1w postcontrast (c), and transverse T2w (d), T1w (e) and T1w postcontrast (f) MRIs?demonstrating a T2w hyperintense and T1w isointense to slightly hypointense extradural mass with a contrast medium-enhanced peripheral rim (arrows), moderately compressing the spinal cord at the level of the?mid-C6 vertebral body. Note also the enhancement of the caudal half of the?C6 vertebral body, C6 left transverse process and the hypaxial muscles from C6 to C7 on T1w postcontrast images.

A cerebrospinal fluid (CSF) sample was obtained but marked iatrogenic blood contamination precluded reliable interpretation of analysis results. Two blood sample cultures?taken from different veins (right and left saphenous veins, 10minutes apart) were positive for Staphylococcus pseudintermedius and serologies for Toxoplasma gondii and Neospora caninum were negative.

Differential diagnosis?鑒別診斷

Differential diagnoses after general and neurological examination included inflammatory/infectious process (eg, meningitis, neuritis, discospondylitis), traumatic injury, congenital vertebral malformation or haemorrhage causing spinal cord or nerve root compression, and less likely neoplasia (eg, lymphoma). An infectious condition was considered most likely following MRI (ie, epidural abscess with early physitis/osteomyelitis), likely secondary to haematogenous spread infection or to unidentified foreign body migration. Less likely differential diagnoses included focal epidural haemorrhage or an epidural cystic lesion.

Treatment?治療

The patient was admitted and treated with meloxicam (0.1 mg/ kg orally every 24 hours), methadone (0.26 mg/kg intramuscularly every 6 hours) and gabapentin (10.5 mg/kg orally every 8 hours). After MRI, CSF analysis and sampling for blood cultures, a course of cephalexin (19.7 mg/kg, orally every 8 hours), metronidazole (15.8 mg/kg orally every 12 hours) and omeprazole (1 mg/kg orally every 12 hours) was started in addition to the former treatment. After 12 days the dog was discharged and continued on gabapentin, cephalexin and meloxicam.

Outcome and follow-up 結(jié)果與后續(xù)跟進(jìn)

A complete clinical recovery was seen at re-examination six weeks after initial presentation and gabapentin and meloxicam were stopped. General and neurological examinations were within normal limits. Lateral radiography of the cervical vertebral column showed fairly well defined rounded lytic lesions in C6/7 end plates (larger in caudal C6) with surrounding sclerosis and narrowing of the intervertebral disc space (Fig 2). These findings were consistent with discospondylitis, which was not present at the time of diagnosis. Follow-up MRI including a sagittal short tau inversion recovery (STIR) sequence, showed complete resolution of SEA (Fig 3a). The C6/7 end plates were hypointense on T2w and T1w sequences, hyperintense on STIR and showed diffuse contrast enhancement (Fig 3b–d). The intervertebral disc space was markedly narrowed with mild focal T2w and STIR hyperintensity of the intervertebral disc mildly extending into the end plates. These findings confirmed the radiographic changes. Follow-up radiographs of the cervical vertebral column three months after initial diagnosis showed improvement of the lytic changes with increased sclerotic changes and, therefore, antibiotics were stopped. At telephonic?follow-up with the owner seven months later, no further clinical signs were reported.

FIG 2: Lateral radiographic view of the caudal cervical vertebral?column six weeks after initial presentation revealing well?defined rounded lytic lesions in C6/7 end?plates, larger in caudal C6 (arrow), with surrounding sclerosis and narrowing of the intervertebral disc space.

FIG 3: Follow-up MRI performed six weeks after initial diagnosis. Transverse T2w image at the level of?the mid-C6 vertebral body demonstrating complete resolution of the epidural lesion (a); and midsagittal STIR (b), T1w (c) and T1w postcontrast (d) images illustrating the observed discospondylitis. Note the C6/7 end?plates appear hyperintense on STIR, hypointense on T1w and markedly enhancing on T1w postcontrast images. Note the narrowing of the intervertebral disc space with focal STIR hyperintensity of the disc mildly extending into the end?plates.

Discussion 討論

Epidural empyema is an uncommon diagnosis in dogs, and SEA has only rarely been described (Remedios and others 1996,?Schmiedt and Thomas 2005, Linon and others 2014, Song and others 2015). Clinical signs are often non-specific and include pyrexia, spinal pain and/or neurological dysfunction that may be progressive, however the lesions may be subclinical (Linon and others 2014).?

MRI has recently been reported as the imaging test of choice for the diagnosis of SEA (Nykamp and others 2003, Schmiedt and Thomas 2005, Song and others 2015). In the present case, a lesion consistent with SEA was identified by MRI, in addition to positive blood cultures with a pathogen commonly involved in this type of lesion (Staphylococcus species). Discospondylitis has been described as a cause of SEA or diagnosed concomitantly to it. In this case, however, no obvious signs of typical discospondylitis were observed on initial MRI, although there were some imaging features indicative of C6 vertebral osteomyelitis and physitis (Jimenez and O'Callaghan 1995). Thus, it could have been possible that an early stage discospondylitis was developing at the time of initial MRI, and postcontrast fat suppression T1w or STIR sequences would have aided its diagnosis.?

The current treatment of choice is surgical drainage and decompression (Remedios and others 1996, Lavely and others 2006). Successful medical management has been recently described in veterinary medicine suggesting that non-surgical treatment should also be considered (Granger and others 2007, Escriou and others 2011, Song and others 2015, Monteiro and others 2016).?

This case report describes a case of SEA treated medically with complete resolution of the clinical signs and epidural lesion. To the authors’ knowledge there are only eight previous cases described in the veterinary literature of spinal epidural infections and successful medical management, of which only two were described as abscesses (Remedios and others 1996, Song and others 2015) as opposed to empyemas/infections (Escriou and others 2011, Monteiro and others 2016). In one case the abscess was localised at the level of the lumbosacral junction (Remedios and others 1996) and in the other it extended from the foramen magnum to C2 (Song and others 2015).?

Therefore, this case report supports the emerging idea that medical treatment for SEA, as well as in spinal epidural empyemas, should be considered an option for suitable cases.?

Unfortunately, there is no reported criterion in the veterinary literature to differentiate the cases that may only be treated medically from the ones that may require surgical treatment. The human literature describes medical approach as a reasonable option in the following scenarios: if decompressive laminectomy is declined by the patient or is contraindicated due to high operative risk, if paralysis has been present for over 24–36hours (making paralysis unlikely to be reversed), in cases of panspinal infection in which surgery may cause instability of the vertebral column or in neurologically intact patients (Darouiche 2006). However, these recommendations should be carefully considered in veterinary patients, and the treatment modality should be selected based on the history, clinical signs and imaging findings.?

The authors' criteria to decide to pursue medical instead of surgical treatment was based on the fact that the patient was ambulatory and that no deterioration was noted after starting medical therapy. The authors therefore believe that selected cases may be managed medically, mainly those with no or mild neurological deficits, especially when the history is not rapidly progressive and an early response to treatment with no further deterioration is shown. In these cases, close monitoring is essential and referral to a specialist centre is indicated in progressive or severely affected cases.

Contributors?

All authors listed have contributed significantly to the work, have read the manuscript, attest to the validity and legitimacy of the data and its interpretation, and agree to its submission to Veterinary Record Case Reports.?

Competing interests?

None declared.?

Provenance and peer review?

Not commissioned; externally peer reviewed.?

Data sharing statement?

No additional data are available. ? British Veterinary Association (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.?

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