Clinical presentation, diagnostic findings and outcome of dogs undergoing surgical resection for intracranial meningioma: 101 dogs.

BACKGROUND: Meningioma is the most common primary brain neoplasm in dogs. Further information is required regarding the expected long-term prognosis of dogs following the surgical resection of an intracranial meningioma together with the influence of adjunctive therapies. Whilst there have been several studies reporting the long-term outcome of intracranial meningioma resection following surgery alone, surgery with the use of an ultrasonic aspirator, surgery combined with radiotherapy and surgery combined with the addition of hydroxyurea, it is currently unclear which type of adjunctive therapy is associated with the most favourable outcomes. The objective of this study is to describe the presentation and outcome of dogs undergoing surgery for the resection of an intracranial meningioma and the effect of clinical factors, adjunctive therapies and meningioma histopathological subtype on the long-term outcome. RESULTS: A hundred and one dogs that had intracranial surgery for meningioma resection were investigated from four referral centres. 94% of dogs survived to hospital discharge with a median survival time of 386 days. Approximately 50% of dogs survived for less than a year, 25% survived between 1 and 2 years, 15% survived between 2 and 3 years and 10% survived for greater than 3 years following discharge from hospital. One or more adjunctive therapies were used in 75 dogs and the analysis of the data did not reveal a clear benefit of a specific type of adjunctive therapy. Those dogs that had a transfrontal approach had a significantly reduced survival time (MST 184 days) compared to those dogs that had a rostrotentorial approach (MST 646 days; p < 0.05). There was no association between meningioma subtype and survival time. CONCLUSIONS: This study did not identify a clear benefit of a specific type of adjunctive therapy on the survival time. Dogs that had a transfrontal approach had a significantly reduced survival time. Intracranial surgery for meningioma resection offers an excellent prognosis for survival to discharge from hospital with a median long term survival time of 386 days.

Clinical features, treatment and outcome of discospondylitis in cats.

OBJECTIVES: There is a paucity of information on feline discospondylitis. This study aimed to describe the signalment, clinical and laboratory findings, aetiological agents, treatment and outcome in cats affected by discospondylitis. METHODS: This was a retrospective review of the medical records of cats diagnosed with discospondylitis at four referral institutions. RESULTS: A total of 17 cats were identified. Most were domestic shorthair cats (76.5%) and male (58.8%), with a median age of 9 years (range 0.9-14) and a median duration of clinical signs of 3 weeks (range 0.3-16). All cats presented with spinal hyperaesthesia; 3/17 had pyrexia. Neurological dysfunction was found in 64.7% of cats, which was indicative of a T3-L3 or L4-S2 spinal segment, associated nerve root or associated nerve neurolocalisation. Haematology, serum biochemistry and urinalysis revealed occasional inconsistent non-specific changes. All cats underwent urine culture; 9/17 cats also had a distinct tissue cultured. Positive bacterial cultures were obtained in two cats (11.8%) for Staphylococcus species (urine, blood and intradiscal fine-needle aspirate) and Escherichia coli (urine); both presented with multifocal discospondylitis. Treatment was non-surgical in all cats, with sustained antibiotic therapy for a median of 3 months (range 1-9). Analgesia provided included non-steroidal anti-inflammatory drugs, alone or in combination with gabapentin. Restricted exercise was advised for a minimum of 4 weeks. Outcome information available in 12 cats was excellent in terms of pain control and neurological function in 10 cats (83.3%) at the time of stopping antibiotics. Recurrence occurred in one case, which had received a single antibiotic for 6 weeks, and relapsed 4 months after presentation. One other case failed to improve and was euthanased during the course of hospitalisation. CONCLUSIONS AND RELEVANCE: Feline discospondylitis is uncommon and no obvious signalment predisposition was found in this study. Spinal hyperaesthesia was universally present, with neurological dysfunction also highly prevalent. Bacterial culture was unrewarding in most cases. Amoxicillin-clavulanic acid or cephalosporins are reasonable choices for first-line antibiotics. Prognosis was favourable, with no long-term evidence of recurrence in cats on sustained antibiotic therapy, for a mean duration of 3 months.

Phenotypic characterisation of paroxysmal dyskinesia in Sphynx cats.

OBJECTIVES: The aim of this study was to identify the phenotypic features of a paroxysmal dyskinesia observed in Sphynx cats. METHODS: The owners of affected Sphynx cats were invited to provide video footage of abnormal episodes for review. Those that demonstrated episodes consistent with paroxysmal dyskinesia were then invited to complete an online questionnaire designed to allow further characterisation. RESULTS: Ten Sphynx cats were included in the study. All affected cats were <4 years of age at the onset of the episodes (range 0.5-4.0). The episodes had a duration of <5 mins in 9/10 cats (range 0.5-10), while episode frequency was variable between and within individual cats. The episodes were characterised by impaired ambulation due to muscle hypertonicity, most commonly affecting the hips and pelvic limbs (9/10) and shoulders and thoracic limbs (8/10). The head and neck (6/10), tail (5/10), and back and abdomen (3/10) were also involved in some cats. Sudden movement, excitement and stress were identified as possible triggers for the episodes in three cats. Therapeutic intervention was not attempted in 7/10 cases, although two cats were reported to become free of the episodes while receiving acetazolamide. The two cats that were followed beyond 2 years from onset entered spontaneous remission. None of the owners believed that the abnormal episodes had affected the quality of life of their cat. CONCLUSIONS AND RELEVANCE: The phenotype of paroxysmal dyskinesia in Sphynx cats presented in this study appears to share similarities with paroxysmal kinesigenic dyskinesia described in human classification systems. Some cats appear to achieve episode freedom spontaneously. Subsequent research should focus on evaluating response to treatment and determining an underlying genetic cause.

1.5 Tesla Magnetic Resonance Imaging Features of Canine Intracranial Intra-axial Hematomas.

The differentiation of solitary intra-axial hematomas from hemorrhagic neoplasms based on their magnetic resonance imaging (MRI) features is challenging. The treatment and prognosis for these two disease entities are vastly different and distinction between them is often based on MRI findings alone. The aim of this study was to describe the 1.5 tesla MRI features of canine intra-axial hematomas and correlate these findings with the evolution of hemorrhages described in human brains. Retrospective evaluation of patient details, clinical signs, and MRI findings of dogs with intra-axial hematomas that were histopathologically confirmed or determined via repeat MRI study and/or resolution of neurological signs. Ten dogs met the inclusion criteria. All 10 hematoma lesions were determined to be 2-7 days in age. On MRI, all 10 hemorrhagic lesions were comprised of two distinct regions; a relatively thin T1-weighted (T1W), T2-weighted (T2W) and gradient echo (GRE) hypointense (9/10) peripheral border region and a large central region that was heterogenous but predominantly T1W, T2W and GRE hyperintense (8/10). The peripheral border region was complete in its integrity in all 10 cases on T2W and GRE sequences. Contrast enhancement was present in (6/10) hematoma lesions and was always peripheral in nature with no evidence of central enhancement associated with any of the lesions. An intra-axial hematoma should be suspected in solitary hemorrhagic space occupying lesions that have a complete hypointense peripheral rim, elicit a peripheral contrast enhancement pattern, and display the expected temporal pattern of hematoma evolution.

Imaging features of discospondylitis in cats.

OBJECTIVES: This study describes the imaging features of feline discospondylitis on MRI, comparing them with CT and radiographic findings where available. METHODS: The medical records of cats diagnosed with discospondylitis, presented to three referring institutions, were reviewed. MRI, CT and radiographic features were assessed by two of the authors independently. RESULTS: Fourteen sites of discospondylitis were retrospectively identified in 13 cats. The L7-S1 intervertebral disc space (IVDS) was affected in 7/14 (50%) cases. Characteristic MRI features included a hyperintense nucleus pulposus signal on T2-weighted (T2W) imaging (n = 10/14 [71%]) and short tau inversion recovery (STIR) imaging (n = 11/13 [85%]), with contrast enhancement in all (n = 11/11); involvement of adjacent vertebral endplates (n = 11/14 [79%]) and hyperintense neighbouring soft tissue on T2W (n = 11/14 [79%]) and STIR (n = 10/13 [77%]), with contrast enhancement in all (n = 11/11); and the presence of spondylosis deformans (n = 10/14 [71%]). Other features included narrowed or collapsed IVDS (n = 8/14 [57%]), contrast enhancement of vertebral bodies (n = 5/11 [46%]), epidural space involvement (n = 5/14 [36%]), compression of the spinal cord or nerve roots (n = 5/14 [36%]), paraspinal abscessation (n = 3/14 [21%]) and meningeal signal intensity abnormalities with contrast enhancement (n = 5/6 [83%]). These latter findings may indicate secondary focal meningitis. Radiographs were available covering five sites (in four cats) and CT covering three sites (in two cats). The most common radiological features were collapse or narrowing of the affected IVDS (80%) and endplate erosion (60%). No changes suggestive of discospondylitis were identifiable on radiography or CT in two sites (one cat), despite being identifiable on MRI. Repeated radiography in one case did not reveal complete radiological resolution following 9 months of treatment. CONCLUSIONS AND RELEVANCE: The results of this study indicate consistent MRI features of feline discospondylitis that should be considered in the diagnosis of this condition.

Long-term outcome of cats with acquired myasthenia gravis without evidence of a cranial mediastinal mass.

BACKGROUND: Acquired myasthenia gravis (AMG) is increasingly recognized in cats, yet information regarding the natural history of the disease, treatment, and outcome including occurrence of immune and spontaneous remission remains limited. OBJECTIVE: To determine the long-term outcome of cats with AMG without evidence of a cranial mediastinal mass (CMM). ANIMALS: Eight cats diagnosed with AMG without evidence of a CMM. METHODS: Retrospective case series. The medical records of cats diagnosed with AMG between 2005 and 2018 from 2 veterinary referral hospitals were reviewed for inclusion. Inclusion criteria consisted of a diagnosis of AMG, thoracic imaging, serum biochemistry including measurement of creatine kinase, and a CBC. Exclusion criteria were the presence of an identifiable CMM, or administration of methimazole or carbimazole. RESULTS: All cats had an excellent long-term outcome, achieving immune remission within 6 months of diagnosis, including 4 cats that did not receive any treatment and whose natural course of disease involved spontaneous remission. Clinical presentation was heterogeneous, and skeletal muscle weakness and fatigability induced or exacerbated by the wheelbarrow exercise stress test were the most consistent abnormalities associated with AMG. CONCLUSION AND CLINICAL IMPORTANCE: Cats diagnosed with AMG without evidence a CMM have a favorable outcome and frequently achieve immune remission. Moreover, the natural history of AMG in cats includes spontaneous remission when there is no evidence of a CMM. Attempting to rule out the presence of a CMM therefore refines prognosis, and treatment is not always necessary in this disease population.

Interleukin-6 is increased in plasma and cerebrospinal fluid of community-dwelling domestic dogs with acute ischaemic stroke.

Inflammatory cytokines are potential modulators of infarct progression in acute ischaemic stroke, and are therefore possible targets for future treatment strategies. Cytokine studies in animal models of surgically induced stroke may, however, be influenced by the fact that the surgical intervention itself contributes towards the cytokine response. Community-dwelling domestic dogs suffer from spontaneous ischaemic stroke, and therefore, offer the opportunity to study the cytokine response in a noninvasive set-up. The aims of this study were to investigate cytokine concentrations in plasma and cerebrospinal fluid (CSF) in dogs with acute ischaemic stroke and to search for correlations between infarct volume and cytokine concentrations. Blood and CSF were collected from dogs less than 72 h after a spontaneous ischaemic stroke. Infarct volumes were estimated on MRIs. Interleukin (IL)-2, IL-6, IL-8, IL-10 and tumour necrosis factor in the plasma, CSF and brain homogenates were measured using a canine-specific multiplex immunoassay. IL-6 was significantly increased in plasma (P=0.04) and CSF (P=0.04) in stroke dogs compared with healthy controls. The concentrations of other cytokines, such as tumour necrosis factor and IL-2, were unchanged. Plasma IL-8 levels correlated significantly with infarct volume (Spearman's r=0.8, P=0.013). The findings showed increased concentrations of IL-6 in the plasma and CSF of dogs with acute ischaemic stroke comparable to humans. We believe that dogs with spontaneous stroke offer a unique, noninvasive means of studying the inflammatory processes that accompany stroke while reducing confounds that are unavoidable in experimental models.

Levetiracetam in the management of feline audiogenic reflex seizures: a randomised, controlled, open-label study.

Objectives Currently, there are no published randomised, controlled veterinary trials evaluating the efficacy of antiepileptic medication in the treatment of myoclonic seizures. Myoclonic seizures are a hallmark of feline audiogenic seizures (FARS). Methods This prospective, randomised, open-label trial compared the efficacy and tolerability of levetiracetam (20-25 mg/kg q8h) with phenobarbital (3-5 mg/kg q12h) in cats with suspected FARS that experienced myoclonic seizures. Cats were included that had ⩾12 myoclonic seizure days during a prospective 12 week baseline period. This was followed by a 4 week titration phase (until a therapeutic serum concentration of phenobarbital was achieved) and a 12 week treatment phase. Results Fifty-seven cats completed the study: 28 in the levetiracetam group and 29 in the phenobarbital group. A reduction of ⩾50% in the number of myoclonic seizure days was seen in 100% of patients in the levetiracetam group and in 3% of patients in the phenobarbital group ( P <0.001) during the treatment period. Levetiracetam-treated cats had higher freedom from myoclonic seizures (50.0% vs 0%; P <0.001) during the treatment period. The most common adverse events were lethargy, inappetence and ataxia, with no difference in incidence between levetiracetam and phenobarbital. Adverse events were mild and transient with levetiracetam but persistent with phenobarbital. Conclusions and relevance These results suggest that levetiracetam is an effective and well tolerated treatment for cats with myoclonic seizures and is more effective than phenobarbital. Whether it will prevent the occurrence of generalised tonic-clonic seizures and other forebrain signs if used early in the course of FARS is not yet clear.

Audiogenic reflex seizures in cats.

OBJECTIVES: This study aimed to characterise feline audiogenic reflex seizures (FARS). METHODS: An online questionnaire was developed to capture information from owners with cats suffering from FARS. This was collated with the medical records from the primary veterinarian. Ninety-six cats were included. RESULTS: Myoclonic seizures were one of the cardinal signs of this syndrome (90/96), frequently occurring prior to generalised tonic-clonic seizures (GTCSs) in this population. Other features include a late onset (median 15 years) and absence seizures (6/96), with most seizures triggered by high-frequency sounds amid occasional spontaneous seizures (up to 20%). Half the population (48/96) had hearing impairment or were deaf. One-third of cats (35/96) had concurrent diseases, most likely reflecting the age distribution. Birmans were strongly represented (30/96). Levetiracetam gave good seizure control. The course of the epilepsy was non-progressive in the majority (68/96), with an improvement over time in some (23/96). Only 33/96 and 11/90 owners, respectively, felt the GTCSs and myoclonic seizures affected their cat's quality of life (QoL). Despite this, many owners (50/96) reported a slow decline in their cat's health, becoming less responsive (43/50), not jumping (41/50), becoming uncoordinated or weak in the pelvic limbs (24/50) and exhibiting dramatic weight loss (39/50). These signs were exclusively reported in cats experiencing seizures for >2 years, with 42/50 owners stating these signs affected their cat's QoL. CONCLUSIONS AND RELEVANCE: In gathering data on audiogenic seizures in cats, we have identified a new epilepsy syndrome named FARS with a geriatric onset. Further studies are warranted to investigate potential genetic predispositions to this condition.

Extramedullary spinal cysts in dogs.

OBJECTIVE: To (1) synthesize the terminology used to classify extramedullary spinal cysts in dogs to clarify some of the commonly reported misconceptions, and (2) propose a classification scheme to limit confusion with terminology. STUDY DESIGN: Literature review. METHODS: An online bibliographic search was performed in January 2013 for articles relating to extramedullary spinal cysts in dogs using PubMed (http://www.pubmed.gov/) and Google Scholar (http://scholar.google.com/) databases. Only peer-reviewed clinical literature describing cystic lesions pertaining to the spinal cord and associated structures was included. RESULTS: From 1962 to 2013, 42 articles were identified; 25 (95 dogs) reported meningeal cysts, 10 (24 dogs) described 60 extradural cysts, 3 reports (18 dogs) described discal cysts or acute compressive hydrated nucleus pulposus extrusions (HNPE). Spinal cysts were categorized by location based on cross-sectional imaging as meningeal or extradural non-meningeal. Sub-classification was then performed based on surgical findings and pathology. Meningeal cysts included arachnoid diverticulae and Tarlov (perineural) cysts. Extradural non-meningeal cysts included intraspinal cysts of the vertebral joints, ligaments and discs. Discal cysts also fit this category and have been reported extensively in humans but appear rare in dogs. CONCLUSIONS: Extramedullary spinal cysts should be first classified according to location with a sub-classification according to pathologic and surgical findings. Previous canine cases of discal cysts appear to represent a different disease entity and the term acute compressive HNPE is therefore preferred.

Feline ischaemic myelopathy with a predilection for the cranial cervical spinal cord in older cats.

All previous studies on feline ischaemic myelopathy (IM) have reported an acute onset of a single event with no recurrence of clinical signs. This study aimed to evaluate clinical and long-term follow-up data in cats presumptively diagnosed with cervical IM in the territory of the ventral spinal artery (VSA). Eight cats (four females and four males) were included with a mean age of 14 years and 2 months. Neurological status at the time of presentation ranged from ambulatory tetraparesis to tetraplegia with nociception present. Six cats had marked cervical ventroflexion. All eight cats were diagnosed with one or more concurrent medical conditions, including chronic kidney disease (n = 2), hypertrophic cardiomyopathy (n = 2) and hypertension (n = 6). Median time to ambulation was 5.7 days (range 2-14 days). Long-term follow-up ranged from 7 months to 3 years and 3 months (median 1 year and 2 months). Five cats had no reported recurrence of clinical signs and 3/8 had a chronic relapsing disease course. One cat had an acute recurrence of clinical signs 4 months after the first event and was euthanased. Two cats had acute onsets of suspected intracranial infarctions, one of which had further suspected intracranial infarcts every 3 months and was euthanased after one of these. This study highlights the importance of performing ancillary diagnostic tests in older cats presenting with IM, particularly when VSA embolisation is suspected.

Imaging diagnosis-magnetic resonance imaging features of a cerebral hemangioblastoma in a dog.

The magnetic resonance (MR) imaging features of a cerebral hemangioblastoma in a 9-year-old dog are described. Imaging revealed a well-defined contrast-enhancing lesion of the rostral forebrain that appeared extraparenchymal. Histopathology of the excised mass showed clusters of small blood vessels interspersed with interstitial cells staining positive for neuronal specific enolase, features consistent with a cerebral hemangioblastoma; the mass also appeared intraparenchymal after further immunohistochemistry study. This neoplasm should be considered a rare differential diagnosis for intracranial masses in dogs.

Concurrent medical conditions and long-term outcome in dogs with nontraumatic intracranial hemorrhage.

Nontraumatic intracranial hemorrhage is bleeding originating from the brain or surrounding structures. It results from blood vessel rupture and may be primary or secondary in origin. The magnetic resonance imaging (MRI) characteristics of 75 dogs with nontraumatic intracranial hemorrhage were reviewed to determine signalment; intracranial compartment involved, size and number of lesions; type and prevalence of concurrent medical conditions; and long-term outcome. Hemorrhagic lesions were intraparenchymal (n = 72), subdural (n = 2) or intraventricular (n = 1). Thirty-three of 75 dogs had a concurrent medical condition. A concurrent condition was detected in 13 of 43 dogs with a single lesion ≥5 mm and included Angiostrongylus vasorum infection, intracranial lymphoma and meningioma. Of the 20 dogs with multiple lesions ≥5 mm, 7 had A. vasorum infection, 2 had hemangiosarcoma metastasis, 5 had suspected brain metastasis, and 1 was septicemic. Of the 12 dogs with multiple lesions, 2 had hyperadrenocorticism, 2 had chronic kidney disease, and 1 had hypothyroidism. Of these five dogs, all were hypertensive and four died within 12 months. No dog had a single lesion <5 mm. Long-term outcome was favorable in 26 of 43 dogs with single lesions ≥5 mm, 6 of 20 dogs with multiple lesions ≥5 mm, and 8 of 12 dogs with multiple lesions <5 mm. A. vasorum infection was the most common concurrent condition in dogs with nontraumatic intracranial hemorrhage (16/75), with an excellent outcome in 14 of 16 dogs. Prognosis in nontraumatic intracranial hemorrhage is reported in terms of concurrent medical conditions and the number and size of lesions.

Neurological lameness in the cat: common causes and clinical approach.

PRACTICAL RELEVANCE: Neurological causes of lameness are infrequently seen in cats but they are an important consideration when an obvious orthopaedic cause cannot be identified. Monoparetic cats are also frequently presented for veterinary investigation with the main complaint being lameness. CLINICAL CHALLENGES: Neurological causes of lameness may be difficult to determine without access to advanced imaging modalities, electrodiagnostics or cerebrospinal fluid analysis. AUDIENCE: This review, aimed at all veterinarians who treat cats, sets out to describe the specific approach to cats with lameness that cannot be attributed to an orthopaedic cause. It describes the diagnosis and management of the most common neurological conditions responsible for lameness or monoparesis in cats.

Head trauma in the cat: 1. assessment and management of craniofacial injury.

PRACTICAL RELEVANCE: Feline trauma is commonly seen in general practice and frequently involves damage to the head. CLINICAL CHALLENGES: While craniofacial injuries following trauma vary widely in severity, affected cats can often be severely compromised in terms of their neurological, respiratory and cardiovascular status, and their management can be challenging in both the short and long term. They need prompt stabilisation and careful monitoring in the initial period to maximise prospects of a successful outcome. Many cats with severe facial trauma will require surgery to stabilise skull fractures or address injuries to the eyes, with its inherent issues surrounding pain management, ensuring adequate nutrition and the necessity for ongoing hospitalisation. DIAGNOSTICS: Cats with head trauma benefit from imaging of the injured areas as well as thoracic radiography. Imaging the skull can be challenging and is best performed under general anaesthesia. In unstable patients this can be delayed to prevent any associated morbidity. EVIDENCE BASE: The clinical evidence base relating to injury to the feline head is limited, despite its relative frequency in general practice. This review focuses on the initial approach to craniofacial (in particular, ocular and jaw) trauma, and outlines simple techniques for management of soft tissue and bone injuries. Much of the information is based on the authors' clinical experience, as there is a paucity of well-described clinical case material.

Head trauma in the cat: 2. assessment and management of traumatic brain injury.

PRACTICAL RELEVANCE: Feline trauma patients are commonly seen in general practice and frequently have sustained some degree of brain injury. CLINICAL CHALLENGES: Cats with traumatic brain injuries may have a variety of clinical signs, ranging from minor neurological deficits to life-threatening neurological impairment. Appropriate management depends on prompt and accurate patient assessment, and an understanding of the pathophysiology of brain injury. The most important consideration in managing these patients is maintenance of cerebral perfusion and oxygenation. For cats with severe head injury requiring decompressive surgery, early intervention is critical. EVIDENCE BASE: There is a limited clinical evidence base to support the treatment of traumatic brain injury in cats, despite its relative frequency in general practice. Appropriate therapy is, therefore, controversial in veterinary medicine and mostly based on experimental studies or human head trauma studies. This review, which sets out to describe the specific approach to diagnosis and management of traumatic brain injury in cats, draws on the current evidence, as far as it exists, as well as the authors' clinical experience.

Brain abscess in seven cats due to a bite wound: MRI findings, surgical management and outcome.

UNLABELLED: PRESENTATION AND LESION LOCALISATION: Seven adult domestic shorthair cats were presented with a 1- to 6-day history of progressive neurological signs. A focal skin puncture and subcutaneous swelling over the dorsal part of the head were detected on physical examination. Neurological examination indicated lesion(s) in the right forebrain in four cats, multifocal forebrain in one cat, left forebrain in one cat, and multifocal forebrain and brainstem in the remaining cat. In all cats, magnetic resonance imaging revealed a space-occupying forebrain lesion causing a severe mass effect on adjacent brain parenchyma. CLINICAL APPROACH AND OUTCOME: All cats were managed with a combination of medical and surgical treatment. At surgery a small penetrating calvarial fracture was detected in all cats, and a tooth fragment was found within the content of the abscess in two cats. The combination of surgical intervention, intensive care and intravenous antimicrobials led to a return to normal neurological function in five cats. PRACTICAL RELEVANCE: As this series of cases indicates, successful resolution of a brain abscess due to a bite injury depends on early recognition and combined used of antimicrobials and surgical intervention. A particular aim of surgery is to remove any skull and foreign body (tooth) fragments that may represent a continuing focus of infection.