A field study of eight ovine vertebral body abscess cases

A vertebral body abscess extending into the epidural space causing spinal cord compression was diagnosed in the cervical spinal cord in four lambs and the thoracic spinal cord in four lambs. The affected lambs were aged between 4 and 10 weeks and clinical signs had been present for 7-21 days before veterinary examination. Treatment with high doses of penicillin did not result in an improvement of the neurological signs and all lambs were destroyed on humane grounds. Collection and analysis of cerebrospinal fluid (CSF) revealed a significant increase in the protein concentration in lumbar compared to cisternal CSF samples. There was a neutrophilic pleocytosis in two lumbar CSF samples. In lambs aged between 4 and 10 weeks with no history of previous locomotor dysfunction, paresis of more than 1 week duration may be suggestive of a vertebral body abscess which has extended into the epidural space causing spinal cord compression. Stagnation of CSF caudal to the lesion results in an increased protein concentration in the lumbar sample.     

SINGLE‐SHOT TURBO SPIN ECHO PULSE SEQUENCE FINDINGS IN DOGS WITH AND WITHOUT PROGRESSIVE MYELOMALACIA

Progressive myelomalacia is an uncommon type of ischemic, hemorrhagic spinal cord infarction. Diagnosis can be difficult, but prompt recognition is important. We hypothesized that cerebrospinal fluid signal attenuation on magnetic resonance (MR) images would be more extensive in dogs that developed progressive myelomalacia vs. control dogs. A retrospective analytic cohort study was designed. Dogs were included if they presented for acute paraplegia and loss of deep pain perception and had undergone MR imaging using both sagittal single‐shot turbo spin echo (SSTSE) and standard sagittal T2‐weighted fast spin echo (T2W) pulse sequences. Dogs were divided into progressive myelomalacia and control groups for comparisons. All MR examinations were evaluated by three reviewers blinded to patient outcome. Length of cerebrospinal fluid attenuation was recorded as a ratio to the length of the L2 vertebral body in SSTSE and T2W sequences (CSF:L2_SSTSE and CSF:L2_T2, respectively). Length of intramedullary spinal cord hyperintensity was recorded as a ratio to the length of the L2 vertebral body in T2W sequences. A total of 21 dogs were included (five in the progressive myelomalacia group and 16 in the control group). The mean CSF:L2_SSTSE attenuation value was significantly higher in dogs that developed progressive myelomalacia (CSF:L2_SSTSE = 10.7) compared to controls (CSF:L2_SSTSE = 5.4; P = 0.015). A cut off ratio of attenuation >7.4 provided optimal differentiation between groups in this study. Findings supported the conclusion that dogs with CSF:L2_SSTSE ≤ 7.4 are unlikely to develop progressive myelomalacia while dogs with CSF:L2_SSTSE > 7.4 are indeterminate for progressive myelomalacia.     

A rostrocaudal gradient for neurotransmitter metabolites and a caudorostral gradient for protein in canine cerebrospinal fluid

Neurotransmitter metabolites (dihydroxyphenylacetic acid [DOPAC], homovanillic acid [HVA], and 5-hydroxyindoleacetic acid [5-HIAA]) in CSF of 10 healthy dogs were evaluated with reverse-phase high-pressure liquid chromatography and electrochemical detection. Neurotransmitter metabolite concentrations determined in CSF collected from the cisterna magna were compared with those values in CSF collected from the lumbar dorsal subarachnoid space. Amounts of DOPAC (P = 0.0444), HVA (P = 0.0001), and 5-HIAA (P = 0.0316) were significantly lower in lumbar spinal fluid compared with those values in the cervical spinal fluid. Metabolite concentrations in cervical and lumbar CSF were: DOPAC = 2.81 +/- 0.73 ng/ml of CSF and 1.28 +/- 0.57 ng/ml; HVA = 98.29 +/- 12.42 ng/ml and 4.68 +/- 1.61 ng/ml; and 5-HIAA = 46.29 +/- 8.17 ng/ml and 36.96 +/- 4.07 ng/ml, respectively. Cytologic evaluations of cervical and lumbar CSF revealed a similar concentration of 3 +/- 1 WBC/microliters in both fluids. A significant (P = 0.0002) difference in protein concentration between the 2 regions was observed, with 16.1 +/- 1.8 mg of protein/dl in the cervical CSF and 27.2 +/- 2.3 mg of protein/dl in the lumbar CSF. Between the cisterna magna and lumbar dorsal subarachnoid space of dogs, a rostrocaudal gradient existed for neurotransmitter metabolites, and a caudorostral gradient existed for protein.     

Analysis of cerebrospinal fluid from the cerebellomedullary and lumbar cisterns of dogs with focal neurologic disease: 145 cases (1985-1987)

Data were obtained from 158 CSF samples from 145 dogs with focal, noninfectious/noninflammatory neurologic disease. The effect of lesion location and the duration and severity of clinical signs were studied. One hundred and twenty-five samples were obtained from the cerebellomedullary cistern (CMC), and 33 were obtained from the lumbar cistern (LC). Intracranial and cervical disease affected the CSF from the CMC more often than did thoracolumbar disease. However, lumbar CSF was more frequently affected by disease anywhere along the neuraxis. For compressive spinal cord disease, the protein concentration at both cisterns was more often high in acute, clinically severe lesions. Intracranial lesions consistently caused abnormalities in CSF from both the CMC (7 of 7; 100%) and LC (2 of 2; 100%). Abnormalities were identified in 16 of 38 (42%) and 5 of 7 (71%) CMC and LC samples, respectively, in dogs with cervical disease. In dogs with thoracolumbar lesions, only 22 of 80 (27.5%) CMC samples were abnormal, compared with 21 of 24 (87.5%) LC samples. These findings suggest that CSF collected cranial to the lesion may be normal or only mildly altered by focal neurologic disease. Fluid obtained caudal to the lesion presumably is more substantially altered because of the predominant caudal flow of CSF. To maximize the yield of diagnostic information from CSF analysis, the fluid should preferably be obtained caudad to the disease site; however, because of problems associated with lumbar puncture, we suggest that CSF from the CMC also be obtained.     

RADIOGRAPHIC DIAGNOSIS: CARTILAGINOUS EXOSTOSES IN A DOG

A 6 month-old dog was examined for progressive paraparesis. On physical examination bony malformations were palpated over the cranial lumbar vertebral bodies and on the left metatarsal bone. Neuroanatomic lesion localization for the paraparesis was a T3-L3 spinal cord lesion. Radiographs confirmed bony masses at L1-L2 and on the left 3rd metatarsal bone. Magnetic resonance imaging was performed from T3-L3. Severe spinal cord compression was identified at L1-L2. Surgical decompression and biopsy confirmed the mass to be cartilaginous exostoses. This paper is an example of cartilaginous exostoses imaged with MR.     

IMAGING DIAGNOSIS—NECROTIZING MENINGOMYELITIS AND POLYARTHRITIS

A vaccinated 2-year-old female neutered Weimaraner had bilateral pelvic limb ataxia that progressed over 12 h. The dog became nonambulatory, with signs of pain on palpation of the lumbar spine. The dog also developed multiple joint effusions. On magnetic resonance (MR) imaging, there was a diffuse, asymmetric T2-hyperintensity in the thoracolumbar spinal cord which was characterized by contrast enhancement. Lumbar cerebrospinal fluid (CSF) analysis had an elevated white blood cell count and protein. On the basis of MR images and CSF analysis, a presumptive diagnosis of diffuse myelitis was made. The dog became paraplegic and was euthanized. Postmortem examination confirmed the presence of myelitis with vasculitis and nonerosive polyarthritis.     

Ehrlichia canis infection in the cerebrospinal fluid of a dog characterized by morulae within monocytes and neutrophils

An 8-year-old neutered female English Pointer was referred to a veterinary referral center (southwest of England) with a 4-5-month history of fecal incontinence and no evidence of urinary incontinence. Blood and free-catch urine samples were collected and sent to an off-site laboratory. Further investigations were postponed until laboratory results were available. Blood results showed a mild leukopenia, mild nonregenerative anemia, moderate to marked thrombocytopenia, and a mild increase in ALT and ALP activities. The primary veterinarian and client did not proceed with any further investigations for thrombocytopenia. Three weeks after the initial presentation, there was considerable clinical deterioration and progression of neurologic signs. Thoracic radiographs and an abdominal ultrasonographic examination were unremarkable. Magnetic resonance imaging (MRI) of the brain and spinal cord revealed an intramedullary lesion at the level of the C7 vertebra, a cystic lesion in the forebrain, and a bilateral lesion in the thalamus. A lumbar cerebrospinal fluid (CSF) was collected. CSF analysis showed a robustly increased protein concentration and marked pleocytosis. The cytologic evaluation revealed a mixed cellular population. Occasional neutrophils and monocytoid cells showed purple spherical intracellular inclusions, resembling Ehrlichia morulae. An aliquot of CSF was used off-label with a dot ELISA test, which showed a strong positive result for antibodies against Ehrlichia canis/Ehrlichia ewingii. PCR identified these morulae to be E canis. To best of the authors’ knowledge, this is the first case of ehrlichial infection in canine CSF where Ehrlichia sub-species morulae present within neutrophils were confirmed to be Ehrlichia canis using PCR.     

Thymic lymphosarcoma with metastases causing spinal cord compression and pelvic limb paresis in a heifer

Neurological examination of a heifer displaying pelvic limb ataxia and paresis progressing to a dog-sit position but with normal thoracic limb function indicated a spinal cord lesion in the low thoracic/high lumbar region. The progressive neurological deterioration despite normal radiological and cerebrospinal fluid findings were suggestive of a non-inflammatory, non-traumatic extradural compressive lesion; this was subsequently shown to be a lymphosarcoma.     

Diagnostic techniques and clinicopathologic findings in ruminant neurologic disease.

In ruminant species, cerebrospinal fluid (CSF) collection and analysis provide rapid (in some situations, instant) information to the veterinary clinician investigating a disease problem in the living animal. CSF analysis is particularly useful with respect to confirming the presence of an inflammatory lesion involving the leptomeninges,such as bacterial meningoencephalitis, and in investigating potential compressive lesions of the spinal cord. When correctly performed under local anesthesia, lumbar CSF collection in ruminants is a safe procedure and there are no harmful sequelae. Familiarity with the technique aids high extradural injection of lidocaine or xylazine, which has many applications in farm practice. There are few indications for cisternal CSF collection in food animals.     

Some factors influencing the level of clinical sedation induced by medetomidine in rabbits

Rabbits (n=23) received intravenous bolus medetomidine at 100 mug/kg. Prior to medetomidine administration, heart and respiratory rates were measured, arterial blood was collected and analysed for plasma cortisol, glucose and albumin concentrations. Fifteen minutes after medetomidine administration, heart and respiratory rates were measured again and sedation was scored. The rabbit was afterwards anaesthetized with 20 mg/kg ketamine administered intravenously to enable spinal tap and heart puncture. Cerebrospinal fluid (CSF) was collected (this occurred 20 min post medetomidine administration) and analysed for medetomidine concentration. Blood was collected by heart puncture immediately after the spinal tap and analysed for serum medetomidine concentration. Cerebrospinal fluid medetomidine concentration correlated negatively with sedation. Serum medetomidine correlated positively with CSF medetomidine concentration. Cerebro-spinal fluid medetomidine was 17 +/- 13% of serum medetomidine concentration. Plasma cortisol and glucose concentrations correlated negatively with serum medetomidine. We conclude that after an intravenous bolus administration of a low sedative dose of medetomidine to rabbits; CSF concentration of the drug correlate negatively with sedation and that this may be because of the fact that only the free and unbound medetomidine may be available for detection in the CSF, the concentration of medetomidine detected in the CSF was much lower than that in blood and a positive correlation exists between CSF and serum medetomidine concentrations. Stress may have some effect on the distribution or metabolism of medetomidine in rabbits.     

RADIOGRAPHIC DIAGNOSIS–PARASPINAL ABSCESS IN A DOG

A two-year-old intact male Brittany Spaniel was admitted for evaluation of progressive spinal pain. Previous treatment had been initiated for suspected lumbosacral intervertebral disk disease, however there was poor response to therapy. On presentation the dog was laterally recumbent and neurological examination revealed hyperesthesia over the lumbar vertebral segments. On survey radiography there was loss of detail in the sublumbar fascial planes and inconclusive lumbar vertebra proliferation. Magnetic resonance (MR) imaging was performed to better evaluate the lumbar spine and surrounding tissues, which revealed extensive paralumbar cellulitis, abscessation and osteomyelitis with extradural compression of the spinal cord. MR imaging allowed delineation of the abscessed area, and distinct visualization of its extension into and involvement of the surrounding tissues including muscle, fat, and retroperitoneal structures. In this case, MR imaging was instrumental in defining the extent of the infection and determining whether medical or surgical management of the diseased tissue was necessary. If available, MR may be the imaging method of choice for evaluation of paraspinal abscesses yielding a better insight to the spinal structures involved and facilitating medical or surgical intervention.     

Motor neuron abiotrophy in a saluki.

A nine-week-old saluki puppy was presented to Tufts University School of Veterinary Medicine for progressive, generalized weakness and bilateral forelimb deformities. Examination suggested a diffuse neuromuscular lesion. Cerebrospinal fluid (CSF) analysis showed normal nucleated cell count and protein level; however, many macrophages had vacuolated cytoplasm. Electromyography (EMG) recordings suggested denervation in paraspinal and appendicular muscles. Tibial motor nerve conduction velocity was normal, but direct evoked muscle potential had reduced amplitude. Histopathology revealed diffuse, symmetrical, degenerative motor neuronopathy of the ventral horn of the spinal cord with associated lesions in nerves and muscles. Histopathology was consistent with an abiotrophy that was likely inherited.     

IMAGING DIAGNOSIS—IMAGING AND HISTOPATHOLOGIC CHARACTERISTICS OF A VERTEBRAL HAMARTOMA IN A CAT

A 9‐month‐old domestic shorthair cat had progressive ambulatory paraparesis, proprioceptive ataxia, and thoracolumbar hyperesthesia. An extradural mass affecting the left pedicle and lamina of the second lumbar vertebra (L2) causing marked spinal cord impingement was identified in magnetic resonance (MR) images. The mass was predominantly calcified in computed tomographic (CT) images. A hemilaminectomy was performed to resect the mass. Clinical signs were greatly improved at 12‐month follow‐up. The histopathologic diagnosis was vascular hamartoma. To our knowledge, this is the first report describing the MR characteristics of a vascular hamartoma associated with the vertebral column.     

Neuroblastoma with neuronal differentiation in the spinal cord in an Aberdeen Angus heifer calf

A 5-month-old, female, Aberdeen Angus heifer presented to the veterinary medical teaching hospital for evaluation of slowly progressive hindlimb ataxia. The calf was clinically normal until 4 months of age, following routine pregnancy and delivery. Neurologic examination revealed marked symmetric spastic hindlimb paraparesis. Thoracolumbar radiographs and cerebrospinal fluid (CSF) analysis were unremarkable. A presumptive diagnosis of T3-L3 myelopathy was made, and neurologic status remained static for 3 months with broad-spectrum antibiotic and nonsteroidal anti-inflammatory therapy. Additional diagnostic tests were refused, and a necropsy was performed following euthanasia. A moderately well delineated, reddish-tan, soft mass 18 mm in diameter replaced 80% of the fourth lumbar spinal cord segment. Histologic examination revealed two distinct features: undifferentiated, primitive, polygonal-to-round cells with typical morphologic characteristics of primitive neuroectoderm; and interspersed areas containing myelinated axons and cells with neuronal differentiation. Immunohistochemical examination confirmed the presence of primitive neuroepithelium and cells with neuronal differentiation.     

Spinal nephroblastoma in a crossbreed dog

A three-year-old, male crossbreed dog presented with progressive hindlimb paresis. Magnetic resonance imaging revealed an intramedullary spinal cord lesion of 1.5 cm diameter at the levels of the first and second lumbar vertebrae. Following surgical excision of the mass, there was resolution of the neurological signs. Twelve months later, hindlimb paresis was again evident. A second surgical procedure restored ambulatory status for a further five months before signs recurred and the dog was euthanased. A diagnosis of spinal nephroblastoma was made on the basis of signalment, lesion location and histopathological analysis of biopsy specimens.     

Spinal cord astrocytoma in a cat

A nine-year-old neutered male domestic shorthaired cat with a history of spinal pain and progressive hindlimb dysfunction was presented to the Norwegian School of Veterinary Science. Following neurological and myelographic examination, an intramedullary mass affecting several lumbar spinal cord segments was diagnosed. A neoplastic lesion was suspected and a poor prognosis was given. On postmortem examination, the spinal cord was found to be dorsally flattened from the 12th thoracic vertebra to the fifth lumbar vertebra and severely thickened with a dorsal cleft from the fifth to the seventh lumbar vertebra. Histologically, the tumour was diagnosed as an anaplastic astrocytoma.     

Clinical characterization of a familial degenerative myelopathy in Pembroke Welsh Corgi dogs

BACKGROUND: Adult dogs with degenerative myelopathy (DM) have progressive ataxia and paresis of the pelvic limbs, leading to paraplegia and euthanasia. Although most commonly reported in German Shepherd dogs, high disease prevalence exists in other breeds. OBJECTIVE: Our aim was the clinical and histopathologic characterization of familial degenerative myelopathy (FDM) in Pembroke Welsh Corgi (PWC) dogs. ANIMALS: Twenty-one PWCs were prospectively studied from initial diagnosis until euthanasia. METHODS: Neurologic examination, blood tests, cerebrospinal fluid (CSF) analysis, electrodiagnostic testing, and spinal imaging were performed. Concentrations of 8-iso-prostaglandin F2alpha (8-isoprostane) were measured in CSF. Routine histochemistry was used for neuropathology. Deoxyribonucleic acid and pedigrees were collected from 110 dogs. RESULTS: Median duration of clinical signs before euthanasia was 19 months. Median age at euthanasia was 13 years. All dogs were nonambulatory paraparetic or paraplegic, and 15 dogs had thoracic limb weakness at euthanasia. Electrodiagnostic testing and spinal imaging were consistent with noncompressive myelopathy. No significant difference was detected in 8-isoprostane concentrations between normal and FDM-affected dogs. Axonal and myelin degeneration of the spinal cord was most severe in the dorsal portion of the lateral funiculus. Pedigree analysis suggested a familial disease. CONCLUSIONS AND CLINICAL IMPORTANCE: Clinical progression of FDM in PWC dogs was similar to that observed in other breeds but characterized by a longer duration. Spinal cord pathology predominates as noninflammatory axonal degeneration. Oxidative stress injury associated with 8-isoprostane production is not involved in the pathogenesis of FDM-affected PWC dogs. A familial disease is suspected.     

Congenital external hydrocephalus in a dog

A 4-year-old female Chihuahua was presented with progressive seizures, blindness and lethargy. Neurolocalisation was consistent with a diffuse brain lesion affecting the forebrain and cerebellum. MRI demonstrated dilation of the subarachnoid space dorsolaterally surrounding the cerebrum, filled with cerebrospinal fluid (CSF). Ventricular system size was normal, but mild cerebral atrophy was suspected. There was pachymeningeal contrast enhancement, but CSF analysis was unremarkable. This lesion was interpreted to be an external hydrocephalus of suspected congenital origin.     

MRI characteristics of suspected acute spinal cord infarction in two cats, and a review of the literature

A 10-year-old neutered male Persian cat and a 4-year-old spayed female domestic shorthair (DSH) cat were evaluated for acute-onset severe lateralising tetraparesis and hemiplegia, respectively. Both cats also had left-sided Horner's syndrome. Neurological examination of the cats localised the lesion to cranial to C5 in the Persian and the left cervical intumescence (C6-T2) in the DSH. Physical examinations were otherwise generally unremarkable. Routine laboratory tests and spinal radiography were normal for the Persian cat and were not performed for the DSH cat. A cerebrospinal fluid (CSF) tap was attempted for the Persian cat but aborted because of gross blood contamination, and was not performed for the DSH cat. Magnetic resonance imaging (MRI) of the Persian cat revealed a lesion within the spinal parenchyma at segments C1 to C3 (slightly more left-sided) which was iso- to hypointense on T1-weighted scans and hyperintense on T2-weighted scans, and which enhanced slightly with gadolinium. MRI of the DSH cat revealed a lesion within the spinal parenchyma at segment C7 (predominantly left-sided) which was hypointense on T1-weighted scans and hyperintense on T2-weighted gradient echo scans. Contrast was not administered. The MRI findings in both cases were highly suggestive of acute spinal cord infarction, based upon comparison to human cases. Both cats made full neurological recoveries with supportive treatment only. This paper describes two cases of suspected acute spinal cord infarction in the cat, demonstrates the potential diagnostic value of MRI, and discusses the clinical syndrome of this condition with a brief review of published cases.     

Diffuse leptomeningeal histiocytic sarcoma in the cerebrospinal fluid of 2 dogs

Two adult male castrated dogs were evaluated for progressive paraparesis and ataxia. Neurologic examination showed severe ataxia, delayed proprioceptive placement in the pelvic limbs, pain upon palpation of the lumbar spine as well as facial paresis in one dog, and decreased withdrawal reflex of the pelvic limbs in the other dog. Magnetic resonance imaging (MRI) in both dogs showed diffuse meningeal and intramedullary lesions. However, no evidence of a mass was found. Biopsies could not be performed safely due to the location of the lesions. Cerebrospinal fluid (CSF) examination revealed an inflammatory pleocytosis associated with increased protein concentration and numerous large atypical round cells, often multinucleated. Nuclear fragmentation, micronuclei, and rare atypical mitoses were observed. Immunocytochemistry revealed CD1⁺ and CD11c⁺ staining, which, in concert with the morphology confirmed the diagnosis of histiocytic sarcoma (HS). Euthanasia was elected due to poor prognosis. Histopathologic examination showed diffuse spinal and meningeal infiltration with CD18⁺ neoplastic cells, without any evidence of mass formation, which completed the diagnosis of diffuse leptomeningeal HS involving the brain and the spinal cord. Canine central nervous system (CNS) HS has been seldom reported in the literature, with only isolated cases identified on CSF cytology. The cases reported here are remarkable in describing a diffuse CNS leptomeningeal HS associated with neoplastic cells in the CSF of dogs without a tumor mass. These cases emphasize the potential critical importance of CSF analysis in providing an antemortem diagnosis of neoplasia in neurologic patients.