Atypically located arachnoid cyst in a five-year-old cat.

Arachnoid cysts are cystic lesions that occur in spinal or intracranial locations in the leptomeningeal space. Four intracranial cases have been described in cats, three of which were diagnosed by imaging techniques alone. We now report the clinical, gross and histopathological findings in a 5-year-old, male-neutered European Shorthair cat that presented with chronic, asymmetrical encephalopathy. Using magnetic resonance imaging, a focal, fluid-filled cavity that did not show contrast enhancement was identified in the left temporal and piriform lobes. Necropsy confirmed the presence of a cystic, meningeal cavity filled with clear, serous fluid. Histologically, the cyst had an irregular, hypereosinophilic surface and single psammoma bodies with moderate perivascular oedema in the adjacent neuroparenchyma. Immunohistochemical evidence of meningeal tissue surrounding the cyst confirmed the diagnosis of an arachnoid cyst, which should be considered as a differential diagnosis of intracranial, fluid-filled cavities.

Complex central nervous system malformations in a Dutch Warmblood foal.

A neonatal Dutch Warmblood colt was evaluated for inability to stand, incoordination and intention tremor. Despite partial improvement in clinical signs during the first 4 days of hospitalization, neurological deficits remained. Magnetic resonance imaging identified a unilateral infratentorial arachnoid cyst-like lesion with ipsilateral compression and displacement of the cerebellar hemisphere, absent corpus collosum, polymicrogyria, suspect leukoencephalopathy, and noncompressive occipitoatlantal malformation. Improvement in clinical signs during the first 6 months of life suggests that horses can survive with complex congenital neurological malformations, but prognosis for athletic performance is poor. The accessibility of magnetic resonance imaging should improve the diagnostic accuracy of central nervous system disorders in neonatal foals in which congenital malformations are suspected. Euthanasia often is elected in foals with suspected congenital central nervous system disorders because of poor prognosis for athletic performance, limiting understanding of clinical progression in these cases.

Surgical techniques used in the management of intra-arachnoid diverticula in dogs across four referral centres and their immediate outcome.

OBJECTIVES: To report the surgical techniques being used to treat single focal spinal intra-arachnoid diverticula in dogs, their complications and immediate postoperative outcomes. MATERIALS AND METHODS: Retrospective multi-centre case series across four referral centres. RESULTS: Fifty-seven dogs were included in the study. The most common type of surgery was durectomy (28 dogs) followed by marsupialisation (11 dogs), durotomy alone (seven dogs), shunt placement (six dogs) and stabilisation (five dogs). A higher proportion of intra-arachnoid shunt dogs became unable to walk in the immediate postoperative period (24 hours postsurgery) (4/6, 66%) compared to all dogs five of 57, 9% (2/7 durotomy alone, 3/28 durectomy alone). Of the nine dogs with immediate postoperative deterioration, seven had improved, walking without assistance, by 3 to 5 weeks postoperatively. CLINICAL SIGNIFICANCE: This study does not identify an influence of surgical technique on short-term outcome. Dogs with a thoracolumbar intra-arachnoid diverticulum that undergo a shunt placement are likely to deteriorate neurologically in the immediate 24-hour postoperative period but appear to improve by 3 to 5 weeks after surgery. Further work is required to evaluate whether one surgical technique is superior for preventing or reducing long-term relapse.

Retrospective evaluation of surgical outcomes after closure of durotomy in eight dogs affected by spinal subarachnoid diverticulum.

Background: Canine spinal subarachnoid diverticulum has been studied since 1968 and a few advancements have been made with regard to the treatment of this disease. Several surgical techniques have been proposed which include durectomy, fenestration, and/or marsupilization with the latter two regarded as the more favorable surgical treatments. Aim: In this retrospective study, we evaluated the closure of the durotomy incision in the treatment of canine spinal subarachnoid diverticulum. Methods: We retrospectively evaluated eight dogs with clinical signs and magnetic resonance imaging findings consistent with spinal subarachnoid diverticulum located in the cervical and thoracolumbar area. This was to determine whether the fenestration with closure of durotomy was superior to the marsupialization technique. In all dogs, fenestration and removal of subarachnoid adherences alongside closure of the durotomy were carried out. Results: Mild post-operative deterioration was observed in all dogs. Follow-up from 7 to 36 months indicated a satisfactory outcome. Conclusion: We conclude that the closure of durotomy has similar short-term and long-term outcomes compared to the previous reported studies. These results suggest that the closure of durotomy is a viable technique for spinal subarachnoid diverticulum.

Two different indications of ventriculoperitoneal and cystoperitoneal shunting in six dogs.

In this study we described two different indications of ventriculo- and cystoperitoneal shunting (VPS, CPS) procedures in six dogs, including their clinical data and magnetic resonance imaging (MRI) examinations. One dog had moderate and two dogs had severe congenital hydrocephalus, one was presented with intracranial pressure elevation due to meningoencephalitis of unknown origin (MUO) associated with congenital hydrocephalus, and two with quadrigeminal cysts (QC). VPS procedures were done in four and CPS in two dogs, using low-pressure valve systems. The follow-up period ranged from 1 to 6 months and control MRI scans were also made. Significant improvement was detected in five cases during the short-term follow-up period (1 month) and in four cases in the medium-term follow-up (2-6 months). Major complications were found in two cases: one dog with acute-hypertensive hydrocephalus died one week after surgery, and in another case development of a chronic subdural haematoma and hygroma caused death 3 months after the surgery. Minor complications (e.g. subdural hygroma) were found in two cases. In cases of severe hydrocephalus or intracranial cysts, higher-pressure valve systems are recommended in order to prevent subdural hygroma. Transient postoperative clinical signs usually resolve within one week after the surgery.

Short- and long-term outcome and magnetic resonance imaging findings after surgical treatment of thoracolumbar spinal arachnoid diverticula in 25 Pugs.

BACKGROUND: There is a successful outcome after surgical management of spinal arachnoid diverticula (SAD) in up to 82% of cases. HYPOTHESIS/OBJECTIVES: We hypothesized that Pugs have favorable short-term and poor long-term prognosis after surgical treatment of thoracolumbar SAD. The aim of the present investigation was to describe clinical findings, short- and long-term outcomes, and follow-up magnetic resonance imaging (MRI) findings in Pugs with thoracolumbar SAD. ANIMALS: Twenty-five client owned Pugs with 12-month follow-up information after surgical treatment of thoracolumbar SAD. METHODS: Multicenter retrospective case series. All medical records were searched for Pugs diagnosed with SAD. Data regarding signalment, history, surgical procedure, outcome, histopathology, and follow-up MRI results were extracted. RESULTS: Mean age at presentation was 7.32 (range 2-11) years, 80% were males. Short-term outcome was available in 25 dogs, and improvement was confirmed in 80% of dogs. Long-term outcome was available in 21 dogs, and deterioration was confirmed in 86% of cases, with late-onset recurrence of clinical signs after initial postsurgical improvement affecting 85% of Pugs. A moderate correlation (r = 0.50) was found between duration of clinical signs and outcome. In 8 dogs with deteriorating clinical signs, follow-up MRI revealed regrowth of the SAD in 2 cases, new SAD formation in 2 cases, and intramedullary T2W hyperintensity/syringomyelia in 6 cases. CONCLUSIONS AND CLINICAL IMPORTANCE: This study suggests that Pugs with thoracolumbar SAD do not have a favorable long-term prognosis after surgical treatment for reasons yet to be determined.

Caudal lumbar spinal cysts in two French Bulldogs.

BACKGROUND: Spinal cysts are rare findings in veterinary medicine, but they are increasingly recognized due to the availability of advanced imaging techniques. Extradural meningeal cysts in French Bulldogs have not been reported previously and arachnoid cysts (diverticula) have not been reported at the caudal lumbar (L6-L7) region in dogs. CASE PRESENTATION: Two French Bulldogs, aged 5 and 8 years, were referred for evaluation of lower back pain and bilateral hind limb neurological deficits. Neurologic examination revealed ataxia and postural deficits in both dogs. Magnetic resonance imaging (MRI) showed cauda equina compression due to a cyst-like lesion at the level of L6-L7 in both cases. The dogs underwent dorsal laminectomy and the meningeal cyst was completely removed in one dog and in the other dog the spinal arachnoid diverticula was marsupialized. In Case 1, histopathology of the cysts was performed and MRI was repeated. Both dogs were pain free during follow-up evaluations. CONCLUSIONS: Based on radiological, intra-operative and histopathological findings, the first case was diagnosed as a meningocele connected by a pedicle to the caudal tip of the dural sac forming a dural diverticulum categorized as an extradural spinal cyst type Ib, and Case 2 as a type III intradural arachnoid diverticula. It is concluded that spinal cysts should be included in the differential diagnosis of cauda equina syndrome and lower back pain in French Bulldogs. Results of these cases may be useful for diagnostic and treatment management.

Clinical Application of 3D-CISS MRI Sequences for Diagnosis and Surgical Planning of Spinal Arachnoid Diverticula and Adhesions in Dogs.

OBJECTIVE: Abnormalities within the spinal arachnoid space are often treated surgically, but they can be challenging to detect with conventional magnetic resonance imaging (MRI) sequences. 3D-CISS sequences are considered superior in evaluating structures surrounded by cerebrospinal fluid (CSF) due to the high signal-to-noise ratio, high contrast-to-noise ratio and intrinsic insensitivity to motion with minimal signal loss due to CSF pulsations. Our objective was to describe findings and advantages in adding 3D-CISS sequences to routine MRI in patients affected by spinal arachnoid diverticula (SAD) or arachnoid adhesions. MATERIAL AND METHODS: This article is a retrospective review of medical records of 19 dogs admitted at Fitzpatrick Referrals between 2013 and 2017 that were diagnosed with SAD and confirmed surgically. Inclusion criterions were the presence of clinical signs compatible with compressive myelopathy and an MRI diagnosis, which included the 3D-CISS sequence. Our database was searched for additional 19 dogs diagnosed with other spinal lesions other than SAD that had the same MR sequences. All MR images were anonymized and evaluated by two assessors. CONCLUSION AND CLINICAL RELEVANCE: 3D-CISS sequence appears to improve confidence in diagnosing and surgical planning (Mann-Whitney U-test: p < 0.0005), delineating SAD from other changes associated with abnormal CSF hydrodynamics and providing more anatomical details than conventional MRI sequences. The clinical data in combination with imaging findings would limit over interpretation, when concurrent pathology within the arachnoid space is present.

A retrospective study of quadrigeminal arachnoid cysts diagnosed by Magnetic Resonance Imaging and Computed Tomography in 26 dogs / Estudo retrospectivo de cistos aracnoides da cisterna quadrigeminal diagnosticados pela ressonância magnética e tomografia computadorizada em 26 cães

Arachnoid cysts are accumulations of cerebrospinal fluid that occur within the arachnoid membrane due to the splitting or duplication of this structure. The aim of this retrospective study is to report the occurrence of this condition in 26 dogs, as well as to describe the findings of computed tomography imaging and magnetic resonance image scans and to correlate these with the clinical signs. A prevalence of the condition was observed in males, predominantly in the small breeds Miniature Pinscher and Shih Tzu, with age raging from 2 months to 9 years. The mainly clinical signs observed in these dogs were seizures and cerebellar ataxia. The study concluded that in 17 dogs the quadrigeminal arachnoid cyst was regarded as an incidental finding, in 6 dogs this condition was regarded as the determinant cause of the clinical signs, and in 3 dogs some clinical signs were associated with arachnoid cyst, but they also presented clinical signs involving others sites of intracranial lesion. (AU)

Cistos aracnoide são acúmulos de líquido cefalorraquidiano que ocorre dentro da membrana aracnoide devido à divisão ou duplicação desta estrutura. O objetivo desse estudo retrospectivo é relatar a ocorrência dessa condição em 26 cães, assim como descrever os aspectos de imagem pela tomografia computadorizada e ressonância magnética e correlacionar com os sinais clínicos. No estudo observamos a prevalência em machos, em raças de pequeno porte, com predomínio de Pinscher miniatura e Shih Tzu, com idade variando de dois meses a nove anos. Os principais sinais neurológicos observados nestes animais foram crises epiléticas e ataxia cerebelar. Foi possível concluir que em 17 cães o cisto aracnoide quadrigeminal foi considerado um achado incidental, em seis cães essa condição foi considerada a causa determinante dos sinais clínicos, e em três cães alguns sinais estavam associados com o cisto aracnoide, porém esses animais apresentaram sinais clínicos relacionados a outros sítios de lesão intracraniana.

Late-onset recurrence of neurological deficits after surgery for spinal arachnoid diverticula.

Spinal cord dysfunction secondary to spinal arachnoid diverticula (SAD) has been widely reported in the veterinary literature and there is some suggestion that surgical treatment may provide better outcomes than medical treatment. Despite this, previous reports have mentioned cases with recurrence of clinical signs following surgical treatment but the cause for this has not been further investigated. The medical records of seven dogs and one cat which presented for investigation of recurrence of neurological deficits at least six months after surgery for SAD were retrospectively reviewed. Median time to relapse of the neurological deficits was 20.5 months after surgery. On repeated imaging, 3/8 cases showed clear regrowth of diverticulum, 2/8 cases showed dorsal compression at the previous laminectomy site (presumed to be the laminectomy membrane), and 3/8 cases showed herniation of the spinal cord through the laminectomy defect associated with a stellate appearance to the spinal cord with small multiloculated areas of dilation of the subarachnoid space. Repeat surgical intervention was most successful in the cases where SAD recurrence was identified while medical treatment resulted in either subtle improvement or stabilisation on the clinical signs, sometimes followed by slow deterioration.

Prevalence of neurological disorders in French bulldog: a retrospective study of 343 cases (2002-2016).

BACKGROUND: French Bulldog (FB) has significantly gained in popularity over the last few years, and seems to be frequently affected by various neurological conditions. The purpose of this retrospective study was to report the prevalences of neurological diseases in a large population of FB, presented with neurological signs between 2002 and 2016, and for which a definitive diagnosis was established. A secondary objective was to identify epidemiological characteristics regarding specific diseases in this singular breed. RESULTS: During the study period, 533 FBs were presented for neurological signs, representing 18.7% of all admitted FBs (N = 2846). In total, 343 FBs with definitive diagnosis were included in this descriptive epidemiological study. Hansen type I intervertebral disk herniation (IVDH) was by far the most common neurological disorder (45.5% of all cases). The IVDH location was cervical in 39.8%, and thoracolumbar in 60.2% of cases. The median ages for cervical and thoracolumbar IVDH were 4.2 and 4 years, respectively. C3-C4 was the most commonly affected disk (57.8% of cervical IDVH) all locations combined. Spinal arachnoid diverticulum (SAD) was detected in 25 FBs, representing the second most common myelopathy (11.3%). A concurrent spinal abnormality was identified in 64.0% of SAD cases. Brain tumours represented 36.8% of encephalopathies, with glioma (confirmed or suspected) being the most common. Meningoencephalitis of unknown origin (MUO) represented 25.0% of brain disorders, females less than 5.5 years being more likely to be affected. Aside from central nervous system conditions, otitis interna associated with peripheral vestibular signs and bilateral congenital deafness (associated with white coat) were also common. CONCLUSIONS: The findings of this study suggest that FB seems to be prone to several neurological diseases. IVDH is clearly predominant in FB and cervical location seems more represented than in other breeds. FBs affected by IVDH tend to be younger than previously described, either for both cervical and thoracolumbar locations. Thoracic SAD was the second most common myelopathy, with a concurrent spinal anomaly identified in two thirds of the cases. MUO was more likely to affect young to middle-aged females. These findings could be of interest for owners, breeders, practicing veterinarians and insurance companies.

Cisto aracnoide medular em um cão: relato de caso / Arachnoid cyst in a dog: case report

O cisto aracnoide medular (CAM) é uma doença que pode ocorrer em humanos e animais, podendo causar sinais clínicos neurológicos. A origem dessa enfermidade ainda é desconhecida assim como sua patofisiologia. Acredita-se que pode ser congênita ou adquirida. Até o momento, não foi verificada predileção por raça, sexo ou idade. O objetivo deste trabalho é relatar um caso de CAM lombar em um cão com 13 anos de idade, que causou paralisia dos membros pélvicos. Ao exame clínico, o paciente apresentava dor lombar na palpação epaxial, incontinência urinária e fecal, com paraplegia de membros pélvicos. A sintomatologia progrediu durante oito meses, com histórico de trauma. Na mielografia, foi identificado um CAM na região lombar (L1-L2) lateralizado para a esquerda. O tratamento instituído foi a laminectomia e a durectomia. A paciente apresentou melhora dos sinais clínicos após 11 dias da realização da cirurgia. O tratamento cirúrgico obteve bons resultados para essa enfermidade. O CAM pode ocorrer em cães geriátricos ou com paraplegia de membros, assim deve ser incluído na lista de diagnóstico diferencial das mielopatias lombares compressivas.(AU)

Medullary arachnoid cyst (MAC) is a disease that occurs in humans and animals, and may cause neurological clinical signs. The origin of this disease, as well as its pathophysiology, are still unknown. It is believed that it can be congenital or acquired. No predilection for race, sex, or age has been verified. The aim of this paper is to report a lumbar MAC case in a dog at 13 years of age that caused paralysis of the pelvic limbs. At the clinical examination the patient had back pain on the lumbar region, urinary and fecal incontinence, and paraplegia on the pelvic members. The symptoms were progressing for eight months with history of trauma. In myelography a MAC in the lumbar region (L1- L2) lateralized to left was identified. For treatment laminectomy and durectomy were established. The patient showed improvement of clinical signs eleven days after surgery. The surgical treatment achieved good results for this type of disease. MAC can occur in geriatric or member paraplegia dogs, so it must be included in the differential diagnosis list of the lumbar compressive myelopathy.(AU)

Spinal Arachnoid Diverticula: Outcome in 96 Medically or Surgically Treated Dogs.

BACKGROUND: Little is reported about the role of medical management in the treatment of spinal arachnoid diverticula (SAD) in dogs. OBJECTIVES: To describe the outcome of 96 dogs treated medically or surgically for SAD. ANIMALS: Ninety-six dogs with SAD. METHODS: Retrospective case series. Medical records were searched for spinal arachnoid diverticula and all dogs with information on treatment were included. Outcome was assessed with a standardized questionnaire. RESULTS: Fifty dogs were managed medically and 46 dogs were treated surgically. Dogs that underwent surgery were significantly younger than dogs that received medical management. No other variables, related to clinical presentation, were significantly different between both groups of dogs. The median follow-up time was 16 months (1-90 months) in the medically treated and 23 months (1-94 months) in the surgically treated group. Of the 38 dogs treated surgically with available long-term follow-up, 82% (n = 31) improved, 3% (n = 1) remained stable and 16% (n = 6) deteriorated after surgery. Of the 37 dogs treated medically with available long-term follow-up, 30% (n = 11) improved, 30% (n = 11) remained stable, and 40% (n = 15) deteriorated. Surgical treatment was more often associated with clinical improvement compared to medical management (P = .0002). CONCLUSIONS AND CLINICAL IMPORTANCE: The results of this study suggest that surgical treatment might be superior to medical treatment in the management of SAD in dogs. Further studies with standardized patient care are warranted.

Intracranial Intra-arachnoid Diverticula and Cyst-like Abnormalities of the Brain.

Primary intracranial cystic or cyst-like lesions include intra-arachnoid, epidermoid, dermoid, and choroid plexus cysts. Differentiation of these cystic lesions can usually be accomplished by imaging studies alone; however, some cysts are similar in appearance and require histopathology for definitive diagnosis. Clinical signs often reflect the location of the cysts within the intracranial cavity rather than the type of cyst. If clinical signs are significant and progressive, surgical removal is warranted and may be successful, although cystic contents could be harmful if allowed to contact surrounding brain parenchyma or meninges.

Cystic Abnormalities of the Spinal Cord and Vertebral Column.

Cystic lesions of the vertebral column and spinal cord are important differential diagnoses in dogs with signs of spinal cord disease. Synovial cysts are commonly associated with degenerative joint disease and usually affect the cervical and lumbosacral regions. Arachnoid diverticulum (previously known as cyst) is seen in the cervical region of large breed dogs and thoracolumbar region of small breed dogs. This article reviews the causes, diagnosis, and treatment of these and other, less common, cystic lesions.