Peripheral nerve disease in the dog and cat

Motor nerve conduction and repetitive nerve stimulation in captive ring-tailed coati (Nasua nasua)

There are few electrophysiologic studies in wild animals. The aim of this study was to determine normal data for motor nerve conduction studies and repetitive stimulation in sciatic-tibial and ulnar nerves in clinically normal captive coati. Eight adult ring-tailed coatis (Nasua nasua), two females and six males weighing 6-8 kg, were used. Average nerve conduction velocity was 70.81 m/sec (standard deviation [SD] = 3.98) and 56.93 m/ sec (SD = 4.31) for the sciatic-tibial and ulnar nerves, respectively. Repetitive stimulation responses demonstrated minimal variations of the area of the compound muscle action potentials at low (3 Hz) and high (20 Hz) frequencies. The maximal obtained decremental area response was 8%. These normal data of conduction studies may be used in assessing abnormalities for clinical diagnosis. In addition, the obtained normal repetitive stimulation data were similar to dogs and humans and may be used for post- and presynaptic disturbances of the neuromuscular transmission in coatis.

Canine inherited motor and sensory neuropathies: an updated classification in 22 breeds and comparison to Charcot-Marie-Tooth disease

Canine inherited neuropathies form a group of degenerative diseases affecting motor and/or sensory and autonomic peripheral nerves. There is now a large number of inherited motor and sensory neuropathies (IMSN) reported in the veterinary literature, for which clinical, electrophysiological, histopathological and mode of inheritance data are available. Their resemblance with Charcot-Marie-Tooth disease in humans is suggested, although direct comparison is difficult due to the small number of cases described in each breed and the lack of genetic knowledge in dogs. Charcot-Marie-Tooth disease forms a wide group of hereditary neuropathies for which a genetic mutation is recognised in more than 70% of patients. In dogs, no genetic mutation has so far been identified and the knowledge available for human hereditary neuropathies may be useful to identify genetic mutations in dogs. This review provides an update on data available on inherited neuropathy in Leonberger dogs and three new degenerative neuropathies are briefly described in two Russian Black terriers, two Cocker Spaniels and a Podhale Shepherd dog.

Electromyographical, Ultrasonographical and Morphological Modifications in Semitendinous Muscle after Transposition as Ventral Perineal Muscle Flap

The aim of this study was to evaluate modifications occurring in semitendinous muscle after transposition as a ventral perineal muscle flap using electromyography, ultrasonography, and morphological studies. Ten male crossbreed dogs of 3-4 year old were used. The left semitendinous muscle was cut close to the popliteus lymph node, rotated and sutured at the perineal region. The contralateral muscle was considered as control. Motor nerve conduction studies of both sciatic-tibial nerves, and electromyographic and ultrasonographic examinations of both semitendinous muscles were performed before surgery and 15, 30, 60, and 90 days postoperatively. Semitendinous muscle samples were collected for morphological analysis 90 days after surgery. No alterations were observed in clinical gait examinations, or in goniometrical and electroneuromyographical studies in pelvic limbs after surgery. Electromyography demonstrated that the transposed muscle was able to contract, but atrophy was detected by ultrasonography and morphological analysis.

Sensory neuropathy in two Border collie puppies

A peripheral sensory neuropathy was diagnosed in two Border collie puppies. Neurological, electrophysiological and histopathological examinations suggested a purely sensory neuropathy with mainly distal involvement. Urinary incontinence was observed in one of the puppies and histological examination of the vagus nerve revealed degenerative changes. An inherited disorder was suspected.

Functional assessment of sciatic nerve recovery: biodegradable poly (DLLA-epsilon-CL) nerve guide filled with fresh skeletal muscle

The aim of this study was to compare functional peripheral nerve recovery in the rat sciatic nerve model after reconstruction of a 10-mm gap with a biodegradable poly (DLLA-epsilon-CL) nerve guide, as filled with either fresh skeletal muscle or phosphate-buffered saline (PBS). During 24 weeks of recovery, motor and sensory functional evaluation was tested by extensor postural thrust (EPT) and withdrawal reflex latency (WRL), respectively. At the end of the experiment, anesthetized animals were prepared for motor nerve conduction velocity (MNCV) studies, followed by gastrocnemius and soleus muscle weight measurement. Motor functional recovery was greater in the muscle-grafted group, and reached a significant difference from weeks 8-12 (P < 0.05). The results of this investigation suggest that filling a nerve guide with fresh skeletal muscle induces faster maturation of regenerated nerve fibers in comparison with traditional tubular repair.

Acquired canine peripheral neuropathies

Accurate diagnosis of the many causes of acute and chronic peripheral neuropathy in the dog presents a challenging prospect for any clinician. Being able to accurately localize the observed neurologic signs to the peripheral nervous system is the first challenge. Once this is accomplished, a logical series of diagnostic steps should be pursued so as to have the best chance of reaching a final etiologic diagnosis. Specific therapy can then be instituted to attempt to halt or, in some cases, reverse the peripheral nerve dysfunction.

Polyneuropathies of cats

Polyneuropathies of cats have a variety of clinical presentations. Areflexic flaccid quadriparesis, or quadriplegia, progressing over a 24- to 48-hour period, may be associated with polyneuropathies, as can chronic insidiously progressive tremors and muscle weakness that wax and wane or progress slowly over weeks or months, and which can go undiagnosed for years. In addition, these neurological signs may be due to spinal cord, neuromuscular junction or muscle disorders, so the diagnosis of polyneuropathy can be a challenge even for the most astute of clinicians. Polyneuropathies may have congenital, inherited, inflammatory, metabolic and toxic causes. Sometimes the underlying aetiology is not found and a diagnosis of idiopathic polyneuropathy is made. Since the treatment and prognosis of polyneuropathies in cats vary, the purpose of this review is to assist the veterinary practitioner to recognise, appropriately manage and provide an accurate prognosis for these challenging cases.

Determinação da velocidade de condução nervosa motora dos nervos radial e ulnar de cães clinicamente sadios

O presente trabalho teve como objetivo a padronização dos valores de referência de velocidade de condução nervosa motora dos nervos radial e ulnar em cães clinicamente sadios. Para tanto, foram utilizados 30 cães, 11 machos e 19 fêmeas, sem raça definida, com idade entre dois e seis anos. Os valores médios das medidas do potencial muscular produzidos por meio de estimulação proximal e distal do nervo radial foram, respectivamente: latência inicial, 2,46+0,72ms e 1,58+0,62ms, amplitude de pico a pico, 8,79+2,26mV e 9,52+2,42mV e duração, 2,85+0,76ms e 2,71+0,75ms. Os respectivos valores do nervo ulnar foram: latência inicial, 4,17+0,53ms e 2,67+0,38ms; amplitude de pico a pico, 10,72+2,60mV e 11,72+2,81mV e duração, 2,23+0,38ms e 2,04+0,35ms. Os valores médios das medidas de velocidade de condução nervosa motora dos nervos radial e ulnar foram, respectivamente, 66,18+7,26m/s e 60,50+7,86m/s.

Horner's syndrome following intrathoracic tube placement

Two dogs developed unilateral Horner's syndrome attributable to the placement of a thoracic drainage tube. Signs resolved following removal of the chest drains.

Horner's syndrome following cervical spinal surgery in the dog

Two dobermanns exhibited Horner's syndrome following the surgical treatment of cervical spondylopathy. Denervation hypersensitivity testing demonstrated a 2nd order lesion in both. Spontaneous resolution occurred within one month.

Neospora caninum infection in English Springer Spaniel littermates. Diagnostic evaluation and organism isolation

Progressive paraparesis developed in four male English Springer Spaniel pups from a litter of five during the first 10 weeks of life. Two of the pups, which had the earliest onset of neurologic signs, were euthanatized without further workup. However, a detailed investigation was completed on the remaining two littermates at 12 weeks of age. Both pups had progressive paraparesis for 3 to 4 weeks before presentation, with one dog developing subsequent asymmetric pelvic limb extensor rigidity. Based on results from neurologic examination, cerebrospinal fluid (CSF) analysis, electrophysiology, and muscle/nerve biopsy, a presumptive diagnosis of protozoal polyradiculitis and polymyositis was made. Necropsy of the most severely affected pup confirmed the clinical diagnosis of inflammatory nerve root and muscle disease but no organisms were found. To increase the potential yield of organisms, the second pup was placed on immunosuppressive doses of corticosteroids and euthanatized 2 weeks later. Numerous organisms were found in lesions in muscle and the central nervous system. Organisms grew in tissue culture and were isolated from the peritoneal fluid of gerbils inoculated with infected tissue. Organisms were not isolated from inoculated mice, guinea pigs, rabbits, and hamsters. No parasites were seen in feces or tissues of three cats fed infected dog tissues. Serologic testing demonstrated a strong positive titer to Neospora caninum in both pups, and electron microscopy showed the characteristic morphology of this parasite.

The pathogenesis of equine laryngeal hemiplegia — a review

Recent research on the muscular and nervous changes which occur in idiopathic equine laryngeal hemiplegia has indicated that many of the traditional concepts of the aetiology of this disease are erroneous. In light of the new knowledge gained, the various predispositions and possible causes of laryngeal hemiplegia are discussed, and it is suggested that the underlying mechanism of axonal damage in this neuropathy of horses may be related to abnormal energy metabolism in the axon.

Congenital and acquired neuromuscular disease of young dogs and cats

Neuromuscular disorders in small animals include a diverse group of congenital and acquired diseases. The prognosis will vary according to the disorder and the portion of the motor unit affected. A number of diseases might be satisfactorily treated (for example, myasthenia gravis, congenital myotonia), whereas others may be self-limiting (for example, hereditary myopathy of Labrador Retrievers). Accurate diagnosis is necessary for establishing a prognosis and treatment plan suitable to the patient and client. Specific diagnosis in the absence of specialized tests is difficult, although not always impossible (for example, congenital myotonia in the Chow Chow). A knowledge of the neuromuscular diseases that might affect small animals, a detailed history, and a thorough physical examination will help in the presumptive diagnosis. Specialized laboratory examinations may need to be applied (for example, antiacetylcholine receptor antibody titer for acquired myasthenia gravis). Referral may be necessary for more detailed diagnostic workup (for example, electromyographic examination, nerve or muscle biopsy examination). In the case of inherited neuromuscular disorders, a knowledge of inheritance patterns will allow genetic counseling to avoid future problem breedings.

Insulinoma and subclinical peripheral neuropathy in two dogs

Two dogs with diffuse, subclinical polyneuropathy associated with insulinoma are reported. Seizures were the dominant sign of central nervous system disease. One dog had clinical signs of facial nerve paralysis. Lesions in selected appendicular and cranial nerves included a mixture of demyelination, remyelination, and axonal degeneration. The incidence (range: 18-47%) of these changes far exceeded that of comparable nerves from six control dogs (range 0-11%). Myopathic and electrodiagnostic findings were compatible with the nerve changes.

Coonhound paralysis. Further clinical studies and electron microscopic observations

Prior study of coonhound paralysis (CHP) revealed an acute polyradiculoneuritis in raccoon-hunting dogs with clinical and pathologic features resembling those of Guillain-Barré syndrome (GBS). In the present series of five cases, the clinical features were investigated with emphasis on electrodiagnostic and CSF findings, and pathologic changes were evaluated with both the light and electron microscope. The demonstration of motor nerve conduction delay and CSF albuminocytologic dissociation in affected dogs further supported the clinical similarity of CHP and GBS. As in GBS, affected roots and nerves contained mononuclear cell infiltrates, segmental myelin changes and axon degeneration. Despite these general pathologic similarities, the present study suggested that axon damage was a more consistent finding in CHP than in GBS. In contrast to ultrastructural findings in GBS, the demyelinating process in CHP did not appear dependent upon macrophages for its initiation. Swelling, separation and vesiculation of myelin occurred around axons of reduced diameter often in the absence of proximate macrophages. Macrophages, rather than initiating demyelination, appeared to be superimposed on existing damage. In this regard, the observed changes resembled those reported in galactocerebroside-induced EAN and sera-mediated in vivo demyelination.