Efficacy of frameless stereotactic radiotherapy for the treatment of presumptive canine intracranial gliomas: A retrospective analysis (2014-2017).

The use of conventional multi-fractionated radiotherapy for the treatment of glial tumours is well documented in the literature. Recently, stereotactic radiotherapy (SRT) has become more widely available allowing for hypo-fractionated protocols; however, its usefulness in the treatment of canine intracranial gliomas is largely undetermined. We conducted a retrospective analysis, including 21 dogs diagnosed with presumptive intracranial gliomas treated with one or more courses of three fractions of 8 to 10 Gy CyberKnife SRT. The objective of this study was to evaluate the efficacy, safety and prognostic factors associated with the use of SRT for the treatment of canine intracranial gliomas. Overall MST for all dogs was 636 days (d). Dogs treated with one course of the described SRT protocol had a MST of 258 days while those treated with >1 course had a MST of 865 days (P = .0077 log rank, 0.0139 Wilcoxon). Dogs treated with one course of SRT who received adjuvant chemotherapy had a MST of >658 days and lived significantly longer than those who did not receive chemotherapy (MST, 230 days) (P = .0414 log rank, 0.0453 Wilcoxon). The most common adverse event included presumptive transient demyelination in 3/21 dogs, which was treated successfully with corticosteroids in all patients. This study provides evidence that SRT is effective in prolonging survival in dogs with intracranial gliomas, and may provide similar results to conventional fractionated protocols, while decreasing the number of hospital visits and anaesthetic episodes. Additionally, it appears that patients can be safely treated with multiple rounds of SRT resulting in improved survival times.

Histopathologic characteristics of biopsies from dogs undergoing surgery with concurrent gross splenic and hepatic masses: 125 cases (2012-2016).

OBJECTIVE: To investigate the histopathologic characteristics of concurrent splenic and liver masses in dogs undergoing splenectomy and liver mass biopsy/resection. Medical records of 125 client-owned dogs found to have splenic mass or masses and a liver mass or masses during surgery were examined. Signalment (age, sex, breed), body weight, and results of histopathology were recorded for all dogs. RESULTS: Twenty-seven percent (34/125) of the dogs in this study had no evidence of malignancy in either the liver or the spleen. Sixty of 125 dogs (48.0%) had malignancy in the spleen and liver, and 56 (56/60, 93.3%) of those dogs had the same malignancy in both organs. Signalment was similar to that in other reports of splenic pathology. In this clinical population of dogs, 27% of dogs with concurrent gross splenic and liver masses discovered intraoperatively had benign lesions in both locations and therefore had a favorable prognosis.

Transnasal, Endoscopically Guided Skull-Based Surgery by Pharyngotomy for Mass Removal from the Sphenopalatine Sinus in a Horse.

OBJECTIVE: To report a transnasal, endoscopically guided ventral surgical approach for accessing the cranial and caudal segments of the sphenopalatine sinus for mass removal in a horse. STUDY DESIGN: Case report. ANIMAL: Adult horse with acute onset blindness referable to a soft tissue mass within the sphenopalatine sinus. CLINICAL REPORT: A 7-year-old Warmblood gelding presented with a history of running into a fence and falling. No neurologic signs were identified at initial examination but acute blindness was noted 3 weeks later. On computed tomography (CT) the sphenopalatine sinus was filled with a large homogeneous mass with poor contrast enhancement that extended dorsally with thinning to the dorsal cortex of the sphenoid bone, just rostral to the entrance of the optic canals into the cranial cavity. Surgical access to the sphenopalatine sinus was achieved using a transnasal, endoscopically guided ventral pharyngotomy approach and the mass lesion was removed. A presumptive diagnosis of chondroma was made based on histopathology. The horse recovered well from surgery, and although it has not regained vision as of 6.5 years postoperatively, the disease has not progressed. CONCLUSION: Transnasal, endoscopically-guided ventral surgical access to the sphenopalatine sinus is possible in horses and may improve access in horses with disease extending caudally beyond the palatine portion of the sinus. Use of smaller diameter or specialized instruments, such as various endoscopic bone cutting instruments, and CT image guidance may improve sinus access by this route.

Characteristics and Survival of 121 Cats Undergoing Excision of Intracranial Meningiomas (1994-2011).

OBJECTIVE: To report clinical features and outcomes of cats undergoing excision of intracranial meningiomas. STUDY DESIGN: Retrospective, multicenter case series. SAMPLE POPULATION: One hundred and twenty-one cats. METHODS: Signalment, clinical signs, duration of clinical signs, preoperative drug therapy, diagnostic imaging reports, surgery, histopathology, and outcome were collected from records of cats undergoing excision of intracranial meningiomas. Survival estimates were made using Kaplan-Meier analysis. RESULTS: There were 76/121 neutered males and 83/121 domestic short-hairs. Body weight ranged from 1.5-8.7 kg (median 5.0 kg). Age at diagnosis ranged from 3-18 years (median 12 years). Clinical signs included changes in behavior, ataxia, seizures, visual deficits, circling, and paresis. Duration of neurologic signs ranged from <1-23 months (median 1.25 months). At the time of writing, 13 cats were alive, 54 were dead or euthanatized, and 54 were lost to followup. Seven cats (13% of cats that died; 6% of all cats) died or were euthanatized in the immediate postoperative period (<1 month post-surgery) and 9 cats (17% of all cats that died; 7% of all cats) died from causes related to the meningioma but outside the immediate perioperative period. The median survival time for all cats was 37 months (95% confidence interval 28-54 months). CONCLUSION: Cats undergoing excision of intracranial meningiomas had a low perioperative mortality and a long-term prognosis of more than 3 years.

Medical infrared thermal imaging of cats with hyperthyroidism.

OBJECTIVE: To determine the usefulness of medical infrared thermal imaging (MITI) as a screening tool for hyperthyroidism in cats, evaluate the need for hair clipping over the ventral aspect of the neck to achieve optimal images, and determine whether there is a change in thermal patterns at 1 and 3 months after radioactive sodium iodide I 131 treatment. ANIMALS: 17 cats with and 12 control cats without hyperthyroidism. PROCEDURES: All cats underwent MITI first with the hair present and then after the hair was clipped. Each cat with hyperthyroidism was subsequently appropriately treated SC with radioiodide; reevaluations, including MITI before and after hair clipping and measurement of serum thyroxine concentration, were performed 1 and 3 months after treatment. RESULTS: The MITI had 80.5% and 87.5% accuracy in differentiating hyperthyroid cats from clinically normal cats before and after the hair over the ventral aspect of the neck was clipped. Among cats with an initial serum thyroxine concentration > 4.0 µg/dL, the success rate for MITI-detected response to radioiodide treatment at the 1-month reevaluation was 92.86% in unshaved cats and 85.71% in shaved cats. The success rate for MITI-detected response to radioiodide treatment at the 3-month reevaluation was 100% in unshaved and shaved cats. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that MITI was successful in differentiating between hyperthyroid cats and clinically normal cats and identifying patients with thyroxine concentration within reference interval after radioactive sodium iodide I 131 treatment.

Severe hyperthermia, hypernatremia, and early postoperative death after transethmoidal cavitron ultrasonic surgical aspirator (CUSA)-assisted diencephalic mass removal in 4 dogs and 2 cats.

OBJECTIVE: To report clinical findings including severe hyperthermia and hypernatremia after transethmoidal Cavitron ultrasonic surgical aspirator (CUSA)-assisted diencephalic mass removal. STUDY DESIGN: Retrospective case series. ANIMALS: Dogs (n = 4) and 2 cats. METHODS: Medical records (1997-2003) of dogs and cats that had transethmoidal CUSA-assisted diencephalic mass removal were reviewed. Retrieved data were: history, signalment, blood work, neurologic examination findings, MRI results, histopathology, postoperative complications, pre- and postoperative medical therapy, and outcome. RESULTS: Tumor types included: meningioma (n = 3), choroid plexus papilloma (1), astrocytoma (1), and pituitary macroadenoma (1). Median onset of hyperthermia was 3.5 hours (range: 1-6 hours) after extubation; median high temperature at onset was 40.3°C, (range: 39.6-41.7°C). Median onset of hypernatremia (median, 172 mmol/L; range: 168-196 mmol/L) was 4.5 hours (range: 1-9 hours) after extubation. Median time of death after hyperthermia was 10.5 hours (range: 6-13 hours) and after extubation was 13.5 hours (range: 11-15 hours). CONCLUSIONS: Transethmoidal CUSA-assisted diencephalic mass removal is associated with early postoperative hyperthermia, hypernatremia, and death, and cannot be recommended.

Spinal cord nephroblastoma in dogs: 11 cases (1985-2007).

OBJECTIVE: To evaluate clinical features and outcome of dogs with a confirmed spinal cord nephroblastoma and to describe the use of Wilms tumor-1 (WT-1) immunohistochemical staining to confirm a diagnosis of nephroblastoma in dogs. DESIGN: Retrospective case series. Animals-11 dogs with a spinal cord nephroblastoma. PROCEDURES: Medical records of dogs with a spinal cord nephroblastoma were reviewed. Information extracted included signalment, history, clinical signs, results of diagnostic testing, tumor location, treatment, and outcome. The diagnosis was confirmed through histologic review and WT-1 immunohistochemical staining of a tumor sample. In dogs with negative results for staining with WT-1, staining for cytokeratin, vimentin, and glial fibrillar acidic protein was performed. RESULTS: 11 dogs had a spinal cord tumor with a histologic appearance and immunohistochemical staining consistent with a nephroblastoma. Positive results for staining with WT-1 were detected in 9 of 11 dogs. Age at admission ranged from 5 to 48 months (median, 14 months). Nine dogs were female. All had progressive paraparesis, paraplegia, or ataxia. Duration of clinical signs ranged from 2 to 60 days (median, 14 days). Median survival time was 30 days from the time of diagnosis. Median survival time in dogs treated via surgical resection was 70.5 days. CONCLUSIONS AND CLINICAL RELEVANCE: The prognosis for dogs with a spinal cord nephroblastoma appeared to be poor, although combined surgical resection and radiation therapy may provide a good functional outcome. Results for staining with WT-1 can be used to support a diagnosis of nephroblastoma.

Surgical treatment of a meningoencephalocele in a cat.

OBJECTIVE: To report the clinical signs, imaging findings and surgical treatment of a meningoencephalocele in a cat. STUDY DESIGN: Case report. ANIMAL: Domestic shorthaired cat, 4 months old. METHODS: A parietal meningoencephalocele was identified and characterized by magnetic resonance and computed tomography (CT) imaging. The abnormal tissue was excised and submitted for histopathology, and the meningeal and skull defects were reconstructed. RESULTS: The cat made a full recovery and the episodes of aggression, restlessness and apparent discomfort that occurred before surgery ceased after surgical treatment. The cat was clinically normal 1 year postoperatively. CONCLUSION: Surgical management of meningoencephalocele in cats may be a viable treatment option.

Mycophenolate mofetil treatment in dogs with serologically diagnosed acquired myasthenia gravis: 27 cases (1999-2008).

OBJECTIVE-To compare clinical outcome in dogs with serologically diagnosed acquired myasthenia gravis (MG) treated with pyridostigmine bromide (PYR) with that of dogs treated with mycophenolate mofetil (MMF) and PYR (MMF + PYR). DESIGN-Retrospective case series. ANIMALS-27 dogs. PROCEDURES-Medical records from August 1999 through February 2008 were reviewed to identify dogs with serologically diagnosed acquired MG treated with PYR or MMF + PYR. Data collected for each dog included signalment, whether the dog had megaesophagus or pneumonia (or both), thyroid hormone concentration, remission, time to remission, and survival time. Rates for detection of clinical signs and survival time were compared. Survival time was estimated via the Kaplan-Meier method. Influence of drug treatment protocol on likelihood of remission, time to remission, and survival time was examined. Effects of MMF treatment, megaesophagus, pneumonia, and low serum thyroid hormone concentration on time to remission and survival time were also analyzed. RESULTS-12 dogs were treated with PYR, and 15 were treated with MMF + PYR. Mortality rates were 33% (PYR) and 40% (MMF + PYR). There was pharmacological remission in 5 and 6 dogs in the PYR and MMF + PYR groups, respectively. No significant differences were detected between treatment groups for remission rate, time to remission, or survival time. Megaesophagus, pneumonia, and low serum thyroid hormone concentration had no significant effect on time to remission or survival time for either treatment group. CONCLUSIONS AND CLINICAL RELEVANCE-The results did not support routine use of MMF for the treatment of dogs with acquired MG.

Intracranial arachnoid cysts in dogs.

Intracranial arachnoid cyst (IAC) is an infrequently reported developmental disorder seen primarily in small-breed dogs. It usually occurs in the caudal fossa, in the region of the quadrigeminal cistern. Although still considered uncommon, IAC is being recognized more frequently in veterinary medicine, coinciding with the increased availability of magnetic resonance imaging. In this article, clinical information from previously reported cases of canine IAC is combined with additional case information from our hospitals. Similar to IAC in people, it is thought that canine IAC is often an incidental finding. When IAC is responsible for neurologic disease in dogs, generalized seizures and cerebellovestibular dysfunction are the most common clinical presentations. Medical therapy of IAC focuses on management of increased intracranial pressure and seizures, if the latter are part of the clinical complaints. Surgical therapy of IAC involves either cyst fenestration or shunting the excess fluid to the peritoneal cavity

Imaging features of atlanto-occipital overlapping in dogs.

The imaging features of four dogs with atlanto-occipital overlapping are described. This malformation appeared to play a role in the development of neck pain, ataxia, variable cerebellar involvement, medullary kinking, and possibly syringomyelia. Using cervical radiographs, three of the four dogs were initially diagnosed with an atlanto-axial malformation. Because this disorder could not account for all clinical signs, magnetic resonance and computed tomography images were also acquired. These provided a more complete evaluation of the craniocervical junction, allowing detection of atlanto-occipital overlapping, medullary kinking, occipital dysplasia, abnormalities of the dens, and syringomyelia in these dogs. Head position during imaging affected the degree of atlanto-occipital overlap. These findings emphasize the need to modify the currently accepted imaging recommendations for dogs with head and neck pain and/or cranial cervical myelopathy. We suggest that the entire craniocervical junction be evaluated, even if atlanto-axial subluxation has already been detected. Moreover, we propose that atlanto-occipital overlapping is a perhaps underrecognized disorder that can influence the clinical signs and therapeutic outcome of dogs with anomalies of the craniocervical junction.

The seizuring cat. Diagnostic work-up and therapy.

PRACTICAL RELEVANCE: Although seizures occur less commonly in cats compared with dogs, they are one of the most common forms of neurological disease in the feline patient. Cats may experience both focal (partial) and generalized seizures and causes are divided into primary disorders, in which there is no underlying cause (ie, idiopathic epilepsy), and secondary disorders. Cats with secondary seizure disorders have either an underlying structural lesion or metabolic disease. PATIENT GROUP: Seizures affect cats of all ages. Cats with idiopathic epilepsy tend to be younger (approximately 3.5 years) than cats with secondary seizure disorders (approximately 8 years). AUDIENCE: This review of feline seizures is directed at all veterinarians who treat cats, both in an emergency setting as well as in general practice. CLINICAL CHALLENGES: Refractory seizures are often a diagnostic and therapeutic challenge. A systematic approach to the seizuring cat is described, easing the task of diagnosing the cause of the seizures. In addition, novel antiepileptics are discussed, which can be used as add-on drugs in challenging feline seizure cases. EVIDENCE BASE: Compared with the canine counterpart, the literature regarding treatment of feline seizures is less established. Recent clinical trials and studies are focusing on new treatment options for feline seizures. Specifically, these studies, some of which are ongoing, have led to the use of levetiracetam, zonisamide and pregabalin as add-on antiepileptics in cases that are refractory to phenobarbital.

Case report --surgical stabilization of a craniocervical junction abnormality with atlanto-occipital overlapping in a dog.

A 3-year-old male neutered Pomeranian presented with severe, poorly localizable pain that was unresponsive to a combination of oral medications (gabapentin, tramadol, prednisone, and methocarbamol) and a fentanyl patch. A Chiari-like malformation with associated syringomyelia was evident on magnetic resonance imaging (MRI). In addition, overlapping of the dorsal arch of C1 and the dorsal aspect of the foramen magnum was suspected from the MRI scans and verified via computed tomography, suggesting a condition similar to basilar invagination/impression in people. At surgery, a combination of foramen magnum decompression with cranioplasty and stabilization of the atlanto-occipital junction was performed. The atlanto-occipital junction was stabilized using an adaptation of a procedure used in people for basilar invagination/impression. Over the next several months, the dog's clinical signs improved dramatically, allowing substantial reduction of oral pain medications. This is the first report of surgical stabilization for atlanto-occipital overlapping in a dog.

Craniotomy with cystoperitoneal shunting for treatment of intracranial arachnoid cysts in dogs.

OBJECTIVE: To describe a technique of decompressive craniotomy with cystoperitoneal shunt (CPS) placement for treatment of canine intracranial arachnoid cyst (IAC), and to evaluate outcome in 4 dogs. STUDY DESIGN: Retrospective study. ANIMALS: Dogs (n=4) with IAC. METHODS: Medical records of dogs diagnosed with IAC by magnetic resonance imaging (MRI; 3 dogs) or computed tomography (CT; 1 dog) were evaluated. All dogs had varying degrees of neurologic dysfunction before surgery. A combined lateral (rostrotentorial)/suboccipital craniotomy was performed sacrificing the transverse sinus on the operated side. The rostral (ventricular) end of a low-pressure valve shunt (3.0 mm outer diameter, 7.0 cm length) was placed transversely into the cyst cavity; the distal end was placed in the peritoneal cavity. All dogs were rechecked at various intervals by >or=1 of the authors either directly, by telephone consultation with owners, or both. Three dogs were imaged postoperatively (CT-1 dog; MRI-1; ultrasonography-1). RESULTS: Intraoperative complications were limited to excessive transverse sinus hemorrhage requiring blood transfusion in 1 dog. There were no postoperative complications. Clinical signs of neurologic dysfunction resolved in 3 dogs and improved substantially in 1 dog. The latter dog required long-term, low-dose corticosteroid therapy. No dogs required repeat surgery. Mean follow-up time was 23.8 months (range, 12-43 months). Collapse of the intracranial cyst was verified in 3 dogs with repeat imaging. In 2 dogs, there was no evidence of the cyst on CT or MRI; in the third dog, a small amount of fluid was demonstrated rostral to the cerebellum on ultrasonography, but there was no identifiable cyst. In 1 dog, the rostral aspect of the shunt had shifted; however, this was not associated with any clinical deterioration. CONCLUSION: Craniotomy with CPS placement was well tolerated and resulted in sustained improvement or resolution of dysfunction. Cyst decompression was verified in 3 dogs that were re-imaged. None of the patients required re-operation. Excessive transverse sinus hemorrhage is a potential danger that may necessitate blood transfusion. Other IAC patients treated with this method will need to be evaluated to fully evaluate its effectiveness. CLINICAL SIGNIFICANCE: Craniotomy with CPS placement may be an effective treatment method for dogs clinically affected with IAC.

Foramen magnum decompression with cranioplasty for treatment of caudal occipital malformation syndrome in dogs.

OBJECTIVES: To describe a cranioplasty procedure used in conjunction with foramen magnum decompression (FMD) for the treatment of canine caudal occipital malformation syndrome (COMS), and to evaluate the clinical outcome. STUDY DESIGN: Prospective clinical study. ANIMALS: Dogs (n=21) with COMS diagnosed by magnetic resonance imaging (MRI). METHODS: After FMD, titanium screws were placed around the perimeter of the foramen magnum defect and a skull plate fashioned from titanium mesh and polymethylmethacrylate was attached to the back of the skull, using the titanium screws as anchor posts. Follow-up was obtained by direct examination by the authors, telephone interviews with owners and referring veterinarians, and a questionnaire sent to owners of surviving dogs designed to assign objective measures of response to surgical intervention. Surgical success was defined as improvement in >or=1 aspects of clinical dysfunction (e.g. scratching, pain) postoperatively. Owner-assigned pre- and postoperative quality-of-life (QOL) scores (1-5) for surviving dogs were compared using a Wilcoxon's signed rank test for paired data (P

Procarbazine as adjunctive therapy for treatment of dogs with presumptive antemortem diagnosis of granulomatous meningoencephalomyelitis: 21 cases (1998-2004).

BACKGROUND: Granulomatous meningoencephalomyelitis (GME) is an idiopathic inflammatory disease of the central nervous system. Remission often is short-lived in dogs treated with glucocorticoids. Procarbazine is T cell-specific and crosses the blood-brain barrier. HYPOTHESIS: Dogs with presumptive antemortem diagnosis of GME given procarbazine as adjunctive therapy to prednisone will have improved long-term outcome compared with dogs given no treatment or glucocorticoids alone. ANIMALS: Two groups were studied: (1) Dogs with presumptive antemortem diagnosis of GME treated with procarbazine and prednisone (n = 21); (2) Dogs that had a histologic diagnosis of GME at postmortem examination and received no treatment (n = 11). METHODS: Dogs with presumptive GME treated with procarbazine were identified retrospectively from medical records of 2 veterinary referral hospitals. Selection criteria required all dogs have a neurologic examination, blood work, cerebrospinal fluid analysis, and brain imaging (MRI or CT). RESULTS: Median survival time for all dogs studied was 5.0 months. Median survival time for dogs treated with procarbazine was 14.0 months and for untreated dogs, 0.73 months. Treatment with procarbazine was significantly correlated with survival time (P < .001). Procarbazine was the only independent predictor of survival. Prednisone was reduced in dosage or discontinued in 17 dogs. Adverse reactions to procarbazine therapy included myelosuppression in 7 dogs and hemorrhagic gastroenteritis in 3 dogs. CONCLUSION: These data suggest that procarbazine treatment of presumptive GME may result in greater improved long-term outcome than has been previously reported for glucocorticoid treatment alone and may complement other immunomodulatory therapies. Procarbazine-treated dogs must be monitored for adverse reactions.

Foramen magnum decompression for treatment of caudal occipital malformation syndrome in dogs.

A method for foramen magnum decompression (FMD) in dogs with caudal occipital malformation syndrome (COMS) and results for 16 dogs are described. In brief, a dorsal approach to the caudal portion of the occiput and arch of the atlas was made, and a high-speed drill was used to remove a portion of the occiput in the region of the foramen magnum and the dorsal aspect of C1. The meninges that were exposed were removed or marsupialized to surrounding tissues. Foramen magnum decompression was performed in 16 dogs. No intraoperative complications occurred, and postoperative complications occurred in only 2 dogs after initial surgery and in 1 of these dogs after follow-up surgery. In both dogs, postoperative complications after the initial surgery resolved without additional treatment. One dog was nonambulatory tetraparetic after follow-up surgery and died of a suspected ruptured viscus 9 days after surgery. Four dogs developed evidence of scar formation at the surgery site and required additional surgery. Overall, 14 dogs survived, 1 died, and 1 was euthanatized. Clinical signs resolved in 7 of the 14 dogs that survived, improved in 6, and did not change in 1. Results suggest that FMD may be an effective treatment for dogs with COMS, especially if performed early in the course of the disease.

Intracranial Toxoplasma gondii granuloma in a cat.

An 8-year-old cat with recent-onset generalized seizures was diagnosed with a right forebrain mass using magnetic resonance imaging. The mass was excised and upon histologic and immunohistochemical examination shown to be a Toxoplasma gondii granuloma. Serology supported active T gondii infection. The cat was treated with phenobarbital to control seizures. After definitive diagnosis of toxoplasma granuloma, clindamycin was administered for approximately 1 month. Seizures recurred 8 months after initial presentation, and the cat was euthanased at the owner's request. This is a previously unreported manifestation of feline central nervous system toxoplasmosis. When a mass lesion is present in the brain of a cat and serologic test results support active infection with T gondii, toxoplasma granuloma must be a differential diagnosis. If the patient is suffering from clinical disease, surgical resection of the mass (if possible) can be complimented with medical treatment until definitive diagnosis is obtained. Immunocompromising factors should be identified and addressed if possible.

A retrospective comparison of cervical intervertebral disk disease in nonchondrodystrophic large dogs versus small dogs.

Medical records of 144 small-breed dogs (< or =15 kg) and 46 medium- to large-breed dogs (>15 kg) with surgically confirmed, Hansen type I, cervical intervertebral disk extrusions were reviewed. The most common clinical presentation was cervical hyperesthesia. The most common sites affected were the second (C(2)) to third (C(3)) cervical intervertebral disk space in small-breed dogs and the sixth (C(6)) to seventh (C(7)) cervical intervertebral disk space in the larger dogs. Following surgery, 99% of the dogs had resolution of cervical hyperesthesia and were able to ambulate unassisted. Seven (4%) dogs required a second surgery; four of these were large-breed dogs.