Feline coronavirus antibody titer in cerebrospinal fluid from cats with neurological signs.

To investigate the utility of cerebrospinal fluid (CSF) anti-feline coronavirus (FCoV) antibody test for diagnosis of feline infectious peritonitis (FIP), the antibody titers were tested in CSF and sera from 271 FIP-suspected neurological cats. CSF antibody was detected in 28 cats, which were divided into 2 groups; 15 with CSF titer of 1:80 or lower and 13 with CSF titer of 1:640 or higher. In the latter group, reciprocal serum titer/reciprocal CSF titer was 8 or lower, which is extremely lower than normal range (256-2048), and FCoV RNA was detected in all of 11 CSF samples assayed by RT-PCR. Our findings indicate that CSF titer of 1:640 or higher may be served as a candidate for the index for diagnosing FIP.

Clinical reasoning in feline epilepsy: Which combination of clinical information is useful?

We sought to identify the association between clinical risk factors and the diagnosis of idiopathic epilepsy (IE) or structural epilepsy (SE) in cats, using statistical models to identify combinations of discrete parameters from the patient signalment, history and neurological examination findings that could suggest the most likely diagnosis. Data for 138 cats with recurrent seizures were reviewed, of which 110 were valid for inclusion. Seizure aetiology was classified as IE in 57% and SE in 43% of cats. Binomial logistic regression analyses demonstrated that pedigree status, older age at seizure onset (particularly >7years old), abnormal neurological examinations, and ictal vocalisation were associated with a diagnosis of SE compared to IE, and that ictal salivation was more likely to be associated with a diagnosis of IE than SE. These findings support the importance of considering inter-ictal neurological deficits and seizure history in clinical reasoning.

Diagnostic utility of cerebrospinal fluid immunocytochemistry for diagnosis of feline infectious peritonitis manifesting in the central nervous system.

Objectives The aim of the study was to evaluate whether an ante-mortem diagnosis of central nervous system (CNS) feline infectious peritonitis (FIP) is possible via immunocytochemical staining (ICC) of feline coronavirus antigen (FCoV) within macrophages of cerebrospinal fluid (CSF). Methods Prospectively, CSF samples of 41 cats were investigated, including cats with histopathologically confirmed FIP and neurological signs (n = 10), cats with confirmed FIP without CNS involvement (n = 11), cats with neurological signs but another confirmed CNS disease (n = 17), and cats without neurological signs and a disease other than FIP (n = 3). ICC staining of CSF macrophages was performed in all cats. Sensitivity, specificity, positive (PPV) and negative predictive values (NPV) of CSF ICC were calculated. Results Of 10 samples from cats with CNS FIP, eight had detectable CSF macrophages, seven of which were positive for FCoV. Ten of 11 samples from cats with confirmed FIP without neurological signs had macrophages in the CSF, with all 10 being ICC-positive. In cats with other CNS disorders, 11/17 had macrophages, two of which stained positively. In cats with diseases other than FIP and without neurological disorders, 2/3 revealed macrophages, with one cat showing positive ICC staining. Diagnosis of FIP via CSF ICC had a sensitivity of 85.0% and a specificity of 83.3%. PPV and NPV were 85.0% and 83.3%. Conclusions and relevance CSF ICC is a highly sensitive test for ante-mortem diagnosis of FIP manifesting in the CNS. However, CNS ICC specificity is too low to confirm FIP and the method should only be applied in conjunction with other features such as CSF cytology. CNS ICC could be helpful to discover pre-neurological stages of CNS FIP.

Eosinophilic meningomyelitis associated with T-cell lymphoma in a cat.

A 12-year-old cat was presented for evaluation of progressive tetraparesis. Magnetic resonance imaging of the cervical spine demonstrated T2-hyperintensity, and contrast enhancement within the C4-C7 spinal cord, with marked meningeal contrast enhancement and segmental nerve root thickening. Lumbar cerebrospinal fluid contained 407 total nucleated cells/µL, with 99% eosinophils. The cat transiently improved with prednisolone, clindamycin, and ivermectin therapy, but subsequently worsened and was euthanized. Necropsy revealed an asymmetric infiltration predominantly of the white matter, meninges, and nerve roots of the C4-C6 spinal cord segments by an unencapsulated, poorly demarcated neoplasm composed of atypical lymphocytes admixed with eosinophils, causing perivascular hemorrhage and lytic necrosis. The neoplastic cells were immunoreactive for CD3, ultimately confirming T-cell lymphoma.

Biomarkers for neural injury and infection in small animals.

Cross-sectional imaging techniques have facilitated diagnosis of central nervous system (CNS) diseases. However, there is still frequently a lack of definition of the cause of neurologic lesions, because tissue sampling from the pathologic site is often difficult and there are few clinical diagnostic tools to assist diagnosis. Biomarkers can assist in understanding the cause, diagnosis, severity, and prognosis for neural injury. Integration of conventional testing and new diagnostic techniques will overcome shortcomings in understanding infectious diseases of the CNS. Diagnostic tests may be limited by poor positive and negative predictive values, which must be recognized when interpreting test results.

CNS disease in the cat: current knowledge of infectious causes.

PRACTICAL RELEVANCE: Neurological disease is a relatively common reason for referral, constituting approximately 10% of the feline referral caseload. Nearly one-third to one-half of these cases may be infectious in origin. As such, an awareness of infectious diseases causing central nervous system (CNS) signs in cats, and their clinical diagnosis and management, is relevant to anyone dealing with cats on a regular basis. GLOBAL IMPORTANCE: Some conditions (eg, rabies) are more common in certain countries than others. Conditions such as feline infectious peritonitis (FIP) and toxoplasmosis are of global significance. PATIENT GROUP: Many infectious diseases may affect any feline population. Some, such as FIP, are more common in pedigree households, whereas others such as toxoplasmosis, feline immunodeficiency virus (FIV) or feline leukaemia virus (FeLV) infections, are more likely to affect a single cat with an outdoor lifestyle. EQUIPMENT: All patients benefit from thorough history taking and clinical, neurological and ophthalmic examinations, which all require minimal equipment. Infectious diseases may often be diagnosed on blood samples; however, definitive diagnosis may require more extensive investigation involving cerebrospinal fluid analysis or advanced imaging necessitating access to computed tomography or magnetic resonance imaging. EVIDENCE BASE: The information in this review, which summarises current knowledge of infectious diseases affecting the CNS, is collated from publications on the infectious diseases comprising previous research papers, review articles, case series, case reports and textbooks, supplemented by the clinical experience of the authors.

Neuromuscular disorders in the cat: clinical approach to weakness.

PRACTICAL RELEVANCE: Weakness is a relatively common clinical presentation in feline medicine and can be caused by primary neuromuscular disease or by diseases of other body systems affecting the neuromuscular system secondarily. Successful work-up relies on a thorough clinical and neurological examination, and logical problem solving, based on an understanding of the underlying neuroanatomical and pathophysiological mechanisms. CLINICAL CHALLENGES: Feline neuromuscular diseases can be a diagnostic challenge. On initial inspection, the presenting signs can mimic disorders of other body systems, particularly cardiovascular, pulmonary and orthopaedic disease, or may be confused with systemic illnesses. Additionally, because many different pathologies of the feline neuromuscular system converge to a similar clinical phenotype, further diagnostic steps such as electrodiagnostics, cerebrospinal fluid analysis, and muscle and nerve biopsies must be considered even after neuromuscular dysfunction has been identified. AUDIENCE: This review provides a framework for the clinical approach to the weak cat and gives a practical summary of neuromuscular diseases for the general practitioner and specialist alike. EVIDENCE BASE: Many diseases affecting the feline neuromuscular system have been well described in the veterinary literature, mostly based on retrospective case reports and series. The evidence base for the treatment of feline neuromuscular diseases remains very limited.

Presumptive meningoencephalitis secondary to extension of otitis media/interna caused by Streptococcus equi subspecies zooepidemicus in a cat.

A 5-year-old castrated male domestic longhair cat was presented with neurological signs consistent with a central vestibular lesion and left Horner's syndrome. Computed tomography images revealed hyperattenuating, moderately contrast-enhancing material within the left tympanic bulla, most consistent with left otitis media/interna. Marked neutrophilic pleocytosis was identified on cerebrospinal fluid analysis. Streptococcus equi subspecies zooepidemicus (SEZ) was isolated from the cerebrospinal fluid. Intracranial extension of otitis media/interna is relatively infrequent in small animals. There are no reports of otitis media/interna caused by SEZ in dogs or cats. This is the first report of otitis media/interna and presumptive secondary meningoencephalitis caused by SEZ in a cat.

Clinical signs, imaging features, neuropathology, and outcome in cats and dogs with central nervous system cryptococcosis from California.

BACKGROUND: Cryptococcus spp. is a fungal pathogen with a predilection for the central nervous system (CNS). OBJECTIVES: To compare the clinical, advanced imaging, and neuropathologic findings in dogs and cats with CNS cryptococcosis, and to evaluate outcome of treatment in these animals. ANIMALS: Twenty-six cats and 21 dogs with CNS cryptococcosis. METHODS: Medical records were reviewed for clinical findings and results of CNS imaging. Archived cerebrospinal fluid and CNS tissue specimens were reviewed for pathology. Findings in cats were compared with those in dogs and the effects of variables on survival were determined by survival curve analysis. RESULTS: When present, pain was localized to the cervical region in dogs and was generalized or localized to the thoracolumbar spine or pelvic limbs in cats. Magnetic resonance imaging (MRI) findings were variable but correlated with CNS histopathological findings of meningitis, meningitis with gelatinous pseudocyst formation, and granulomatous mass lesions. Peripherally enhancing brain lesions were seen only in cats. Histopathologically, the inflammatory response was milder in cats compared with dogs. Remissions of ≥1 year occurred in 32% of treated animals. Altered mentation was associated with negative outcome. Glucocorticoid use after diagnosis was associated with improved survival in the first 10 days. CONCLUSIONS AND CLINICAL IMPORTANCE: Lesions seen on MRI reflected neuropathological findings and were similar to those reported in human patients. The immune response to infection may differ between cats and dogs, or relate to the infecting cryptococcal species. Long-term (>6 month median survival time) survival may be possible in animals surviving ≥4 days after diagnosis.

The function, composition and analysis of cerebrospinal fluid in companion animals: part II - analysis.

Accurate analysis of cerebrospinal fluid (CSF) provides a wide range of information about the neurological health of the patient. CSF can be withdrawn from either of two cisterns in dogs and cats using relatively safe techniques. Once CSF has been collected it must be analysed immediately and methodically. Evaluation should consist of macroscopic, quantitative and microscopic analyses. As part of a quantitative analysis, cell counts and infectious disease testing are the most important and potentially sensitive indicators of disease. Although certain pathologies can be described, microscopic analysis will rarely be specific for any disease, emphasising the adjunctive nature of this diagnostic modality.

Bartonella species antibodies and DNA in cerebral spinal fluid of cats with central nervous system disease.

Bartonella species infection is associated with central nervous system (CNS) disease in some humans and cats but the diagnosis is difficult to confirm with blood or serum test results. In this retrospective study of 100 client-owned cats, serum and cerebral spinal fluid (CSF) were assayed for Bartonella species IgG antibodies and CSF was assayed for Bartonella species DNA. Bartonella species IgG antibodies were detected in serum of 36 cats, Bartonella species C-values>1 (suggesting antibody production by the CNS) were detected in CSF of 11 cats, and B henselae DNA was amplified from the CSF of 10 cats. While the clinical significance of these findings cannot be assessed without a control group, the development of neurological signs in some cats inoculated with B henselae and the results of this study warrant prospective evaluation of the association of Bartonella species with feline CNS disease.

Results of magnetic resonance imaging in 14 cats with meningoencephalitis.

Medical records and magnetic resonance (MR) images of 14 cats with inflammatory diseases affecting the central nervous system (CNS) were reviewed retrospectively. Cases included eight cats with feline infectious peritonitis and two cats with toxoplasmosis. Abnormalities affecting the CNS were observed in MR images in 10 (71%) cats. Intracranial lesions appeared as slightly hypointense foci in T1-weighted images in two (14%) cats, as hyperintense foci in T2-weighted images in seven (50%) cats and as hyperintense foci after intravenous administration of a gadolinium-based contrast medium in 10 (71%) cats. In six cats with lesions in T1- and/or T2-weighted images, additional lesions were visible in T1-weighted images obtained after gadolinium-based contrast medium administration. In three cats, lesions were visible only after contrast medium administration. In our study, MR imaging (MRI) did not appear to detect all cases of CNS inflammation in the population of cats with inflammatory cerebrospinal fluid (CSF); however, MRI adds information about the sites and morphology of intracranial lesions that should help to distinguish between neoplasia and inflammatory conditions and, possibly, between different inflammatory conditions.

Value of a single-shot turbo spin-echo pulse sequence for assessing the architecture of the subarachnoid space and the constitutive nature of cerebrospinal fluid.

Three case history reports are presented to illustrate the value of the single-shot turbo spin-echo pulse sequence for assessment of the subarachnoid space. The use of the single-shot turbo spin-echo pulse sequence, which is a heavily T2-weighted sequence, allows for a rapid, noninvasive evaluation of the subarachnoid space by using the high signal from cerebrospinal fluid. This sequence can be completed in seconds rather than the several minutes required for a T2-fast spin-echo sequence. Unlike the standard T2-fast spin-echo sequence, a single-shot turbo spin-echo pulse sequence also provides qualitative information about the protein and the cellular content of the cerebrospinal fluid, such as in patients with inflammatory debris or hemorrhage in the cerebrospinal fluid. Although the resolution of the single-shot turbo spin-echo pulse sequence images is relatively poor compared with more conventional sequences, the qualitative information about the subarachnoid space and cerebrospinal fluid and the rapid acquisition time, make it a useful sequence to include in standard protocols of spinal magnetic resonance imaging.

Fungal infections of the central nervous system in the dog and cat.

Fungal infections of the central nervous system (CNS) in dogs and cats are uncommon. The purpose of this paper is to review the clinical signs, diagnostic tests, and therapeutic options of fungal infections of the CNS in the dog and cat. Clinical signs are dependent on lesion location and are often multifocal. Extraneural involvement is common. Antemortem diagnosis can be difficult and is definitively made via cytology, biopsy, or culture of an affected organ or cerebrospinal fluid (CSF). Magnetic resonance imaging can support a diagnosis and may assist in therapeutic decisions. Fungal serology can support a diagnosis when direct visualization of the organism is not possible. Long-term azole maintenance therapy is suggested to enhance survival and prevent relapse. Serial cerebrospinal fluid evaluation and magnetic resonance imaging may identify early relapse.

Ophthalmomyiasis (interna posterior) of the posterior segment and central nervous system myiasis: Cuterebra spp. in a cat.

A unilateral ophthalmomyiasis posterior in a 5-year-old female spayed Domestic Long-haired cat of a third or fourth stage instar Cuterebra spp. larvae is reported. The cat was presented for depression and anorexia. The organism was found on physical examination at presentation. The cat was euthanized because of the worsening systemic condition. The larva was demonstrated by histopathology with coagulation necrosis and hemorrhage of the optic nerve, retina and choroid, and anterior uveitis. No significant cerebrum and anterior brain stem lesions were found.

Inflammatory cerebrospinal fluid analysis in cats: clinical diagnosis and outcome.

The medical records of 62 cats with clinical signs of central nervous system disease and accompanying inflammatory cerebrospinal fluid (CSF) analysis were examined retrospectively to determine if signalment, clinical signs, CSF analysis and ancillary testing could accurately predict the type of central nervous system disease that was present. An inflammatory CSF was defined as one in which a total nucleated cell count was greater than 5 cells/microl or one in which the total nucleated cell count was normal but the nucleated cell differential count was abnormal. Sex, degree of CSF inflammation, neuroanatomical location and systemic signs provided little contributory information to the final diagnosis. In 63% of the cases a presumptive diagnosis could be made based on a combination of clinical signs, clinicopathological data and ancillary diagnostic tests. CSF analysis alone was useful only in the diagnosis of cats with feline infectious peritonitis, Cryptococcus species infection, lymphoma and trauma. Overall, despite extensive diagnostic evaluation, a specific diagnosis could not be made in 37% of cats. The prognosis for cats with inflammatory CSF was poor with 77% of cats surviving less than 1 year.

Infectious diseases of the central nervous system.

Neurologic disease is seen commonly in cats, with infectious causes accounting for 30-45% of cases. However, since a specific infection cannot be identified in 12-40% of these cases, it is essential that we try to understand these cases better in the hope that we can eventually identify the cause(s), and so determine how best to treat and/or prevent them.

Cerebral phaeohyphomycosis caused by Cladosporium spp. in two domestic shorthair cats.

Two domestic shorthair cats presented for clinical signs related to multifocal central nervous system dysfunction. Both cats had signs of vestibular system involvement and anisocoria, and one had generalized seizure activity. Cerebrospinal fluid analysis revealed a neutrophilic pleocytosis with protein elevation in one cat and pyogranulomatous inflammation in the second. Electroencephalography and brain-stem auditory-evoked potentials in the first cat confirmed cerebral cortical and brain-stem involvement. Euthanasia was performed in both cats, and postmortem diagnoses of phaeohyphomycosis secondary to Cladosporium spp. were made based on histopathology and fungal culture in both cats.

Cerebral cryptococcal granuloma in a cat.

A 7-year-old cat was presented for seizures. Cerebrospinal fluid cytology and serology were consistent with a diagnosis of toxoplasmosis. The cat was treated with clindamycin but seizures continued and additional neurological signs developed over 6 months. A mass lesion was identified in the left cerebral hemisphere using magnetic resonance imaging (MRI). The lesion enhanced after gadolidium and a tumour was considered likely. Histologically, the lesion proved to be a cryptococcal granuloma and retrospective serology confirmed that the cat had cryptococcosis at its initial presentation. This report provides the first description in the veterinary literature of the MRI appearance of a cerebral cryptococcoma and emphasises the importance of performing cryptococcal antigen determination in cats with signs of intracranial disease.