Idiopathic facial paralysis in the dog

Facial nerve paralysis of acute onset is reported in seven mature dogs, five of which were cocker spaniels. The clinical signs were characterised by ear drooping, lip commissural paralysis, sialosis, and collection of food on the paralysed side of the mouth. All dogs showed absent menace responses and trigeminofacial/acousticofacial reflexes. Horner's syndrome was not present in any dog. In four dogs, bilateral facial paralysis developed. The facial paralysis was unrelated to otitis media. Electrodiagnostic studies revealed denervation potentials and absent evoked muscle potentials. Facial nerve biopsies from two cases showed nerve fibre degeneration and apparent loss of larger diameter myelinated fibres. The condition has been termed idiopathic facial paralysis since the aetiopathogenesis is presently unknown.     

Ceratohyoidectomy for treatment of equine temporohyoid osteoarthopathy (15 cases)

This study investigated 15 horses diagnosed with temporohyoid osteoarthopathy (THO) and treated by ceratohyoidectomy between 2004 and 2012. The presenting complaint, duration and nature of the clinical signs, additional diagnostic procedures, and complications were reviewed retrospectively. Long-term follow-up on horses was used to determine prognosis. All horses were diagnosed by guttural pouch endoscopy. Follow-up was available for 14 horses that survived to discharge. Eight of 10 horses that were used athletically prior to surgery returned to previous levels of use. Persisting clinical signs included mild facial nerve paralysis (3/14; 21.4%) or head tilt (6/14; 42.8%) but these were not functionally limiting. It was concluded that equine THO affects a wide range of breeds, disciplines, and ages of horses, and has a variety of presenting clinical signs most commonly associated with vestibular and facial nerves. Prognosis following ceratohyoidectomy is good for resolution of ataxia but some cranial nerve deficits may persist.     

Neurological Manifestations of Hypothyroidism: A Retrospective Study of 29 Dogs

Neuromuscular signs in association with hypothyroidism are described in 29 dogs. Eleven dogs had lower motor neuron signs, 9 had peripheral vestibular deficits, 4 had megaesophagus, and 5 had laryngeal paralysis. Primarily older (mean = 9.5 years), large-breed dogs were affected, and there was no sex or breed predisposition. Duration of clinical signs before presentation ranged from 2 to 8 weeks (mean = 5 weeks). The diagnosis was based on (1) results of neurological examination (29 dogs); (2) electromyographic abnormalities (18 dogs), including fibrillation potentials (n = 18), positive sharp waves (n = 15), and complex repetitive discharges (n = 4); (3) high serum cholesterol concentration (10 dogs; mean = 335 mg/dL); (4) low response to thyroid-stimulating hormone (29 dogs; mean T₄ prestimulation concentration = 0.8 μg/dL; mean T₄ poststimulation = 1.2 μg/dL); and (5) good response to thyroxine supplementation (26 dogs). Dogs with vestibular deficits had abnormal brainstem auditory-evoked responses (BAER), including increased latencies of P₁-P₆ and decreased amplitude of P_4,5-N₅. Seven other dogs had similar BAER abnormalities without manifesting clinical signs of vestibular involvement. Three dogs with vestibular signs had fibrillation potentials and positive sharp waves without exhibiting lower motor neuron signs. All dogs were supplemented with levothyroxine (0.02 mg/kg P0 bid). The follow-up period ranged between 6 and 30 months (mean, 14 months). Serum T₄ concentrations were measured at least 3 times for each dog every 2 months (mean T₄ concentration = 2.6 μg/dL). All but 1 dog with lower motor neuron signs and 1 dog with vestibular signs recovered after 2 months (mean, 57 days). Signs of megaesophagus became progressively less severe over 4 months. Dogs with laryngeal paralysis improved partially after 5 months. We suggest that either vestibular or lower motor neuron signs, megaesophagus, or laryngeal paralysis may be the only clinical signs of an underlying, more generalized polyneuropathy associated with hypothyroidism. Electro-diagnostic abnormalities may be detected before clinical disease develops.     

MAGNETIC RESONANCE IMAGING OF THE INTRATEMPORAL FACIAL NERVE IN IDIOPATHIC FACIAL PARALYSIS IN THE DOG

The most common cause of peripheral facial nerve paralysis in dogs, in the absence of otitis media, is thought to be idiopathic. Gadolinium-enhanced (Gd) magnetic resonance (MR) imaging has been used to study peripheral facial weakness in humans with a wide variety of disorders, including Bell's palsy, the clinical equivalent of idiopathic facial nerve paralysis in dogs. Gd-MR imaging may be useful to demonstrate abnormal enhancement of the intratemporal facial nerve. The aim of this study was to define the role of the Gd-MR imaging in dogs with idiopathic facial nerve paralysis, with regard to pattern of enhancement, and to search for prognostic information. Six dogs with peripheral facial nerve paralysis, followed between 2003 and 2005, were studied. Physical and neurologic examinations, as well as clinical tests, were performed, including routine hematology, serum biochemistry, thyroid screening, cerebrospinal fluid analysis, and MR imaging. The time interval between the onset of the clinical signs, the progress of the disease, and the final recovery was noted in each dog. The following four intratemporal segments of the facial nerve were analyzed: internal acoustic meatus, labyrinthine segment/geniculate ganglion, tympanic segment, and mastoid segment. Along its length, contrast enhancement was found in four dogs. In this group, contrast enhancement of the facial nerve was found in all segments of two dogs, in three segments of one dog, and in one segment of the other dog. In the four dogs with enhancement, one recovered completely in 8 weeks and three have not recovered completely. The two dogs without evidence of enhancement recovered completely in an average time of 4 weeks.     

Vestibular syndrome associated with temporohyoid joint fusion and temporal bone fracture in three horses

Acute onset of vestibulocochlear and facial nerve dysfunction due to a stress fracture of the petrous part of the temporal bone was diagnosed in 3 horses. The fracture was secondary to chronic inflammatory changes in the petrous part of the temporal bone and the proximal stylohyoid bone, with fusion of the temporohyoid joint. Bacterial meningoencephalitis was a complicating factor. Treatment resulted in reduction of severity of clinical signs in 2 of the 3 cases, but residual compensated vestibular deficits persisted.     

Otitis media‐interna and secondary meningitis associated with Corynebacterium pseudotuberculosis infection in a horse

A one‐year‐old Thoroughbred colt was evaluated because of facial nerve paralysis, ataxia and fever. Neurological evaluation found the colt to be obtunded and grade 3/5 ataxic in all 4 limbs. Right‐sided facial nerve paralysis was present and a large, deep corneal ulcer noted in the right eye. Signs of vestibular disease were also present, including circling towards the right and horizontal nystagmus. A complete blood count showed mild leucocytosis, neutrophilia and hyperfibrinogenaemia. A computed tomography (CT) examination of the skull was performed under general anaesthesia and a diagnosis of right sided otitis media‐interna was made. Culture of fluid taken from the middle ear and cerebrospinal fluid collected from the atlanto‐occipital site yielded pure growth of Corynebacterium pseudotuberculosis. Initial therapy consisted of antimicrobial treatment with cefotaxime and anti‐inflammatory treatment with flunixin meglumine. Six days after initiating treatment, the colt developed Clostridium difficile associated colitis. The colitis resolved with supportive care and the colt was discharged from the hospital receiving chloramphenicol. Eight months later, the colt continued to be mildly ataxic (grade 1/5), with a slight head tilt and facial nerve paralysis. To the authors' knowledge, this is the first reported case of otitis media‐interna due to C. pseudotuberculosis in the horse.     

Total ear canal ablation in the cat: indications, morbidity and long-term survival

Fifty-two total ear canal ablation (TECA) procedures in 44 cats were reviewed. The indication for surgery was neoplasia in 41 per cent of the cats, 86 per cent of which had ceruminous gland adenocarcinoma. Chronic inflammatory or polypoid disease accounted for 50 per cent of surgical procedures. Postoperative complications included Horner's syndrome (42 per cent) and facial paralysis (56 per cent) and these were permanent in 14 per cent and 28 per cent of cases, respectively, with the rest resolving in the ensuing weeks or months. The higher incidence of Horner's syndrome and facial paralysis in the cat, compared to the dog, was attributed to greater fragility of the feline tympanic plexus and facial nerve. The median survival time of cats with ceruminous gland adenocarcinoma was 50-3 months, and did not differ significantly from that for inflammatory or polypoid disease. A potential prognostic indicator for this tumour was the mitotic index (MI): cases with MI < or = 2 survived significantly longer than those with MI > or = 3.     

Cerebrospinal elaphostrongylosis in sheep in northern Norway.

Pathologic examination of four sheep from northern Norway exhibiting neurologic signs of paresis, paralysis and vestibular system disease revealed nematodes in the central nervous system (CNS). The worms were identified as Elaphostrongylus rangiferi Mitskevich, 1960, the elaphostrongylid nematode of reindeer (Rangifer tarandus tarandus). Microscopic lesions found in the CNS were focal traumatic encephalomyelomalacia caused by migrating worms, eosinophilic meningitis and choroiditis, lymphohistiocytic and nematode granulomas, and perineural infiltrations. The disease occurred in November and December 1990, after the sheep had been on pasture in areas frequented by considerable numbers of reindeer.     

Neurologic evaluation of the ear.

Diseases of the ear often cause signs of neurologic dysfunction because of damage of peripheral nervous system structures associated with the middle and inner ear. Vestibular dysfunction, facial paralysis, Horner's syndrome, and hearing deficits are the most common neurologic deficits that accompany middle and inner ear disease. Differentiating these signs from disease of the central nervous system is crucial for an accurate diagnosis and prognosis but can be difficult. Understanding the normal anatomy of the ear and its association with the brain is crucial to interpretation of the neurologic examination. This article reviews neurologic dysfunction commonly associated with diseases of the ear and differentiating these signs from central disease.     

Paradoxical vestibular disease with trigeminal nerve-sheath tumor in a dog

A thirteen-year old spayed female poodle was referred because of atrophy of temporal and masseter muscles on the left and head tilt and episodical circling to the right side. Additionally, decreased facial sensation, absent menace reaction, palpebral and corneal reflexes on the left side, as well as ipsilateral hemiparesis and tongue palsy were noticed. Generalised vestibular ataxia and hypermetria in the front limbs were present. Based on the clinical signs, the presumptive anatomical localization of the lesion was the cerebellopontine angle including parts of the caudal brainstem with involvement of the trigeminal, facial and hypoglossal nerves. Involvement of either flocculonodular lobe or the caudal cerebellar peduncle on the left side causing paradoxical vestibular disease was suspected. On magnetic resonance imaging a large enhancing lesion in the area of the left cerebellopontine angle involving the trigeminal nerve and compressing cerebellum and brainstem was seen. Because of the poor prognosis the dog was euthanized on the owner's request. This space occupying lesion could be identified as a trigeminal neurofibrosarcoma/schwannoma on post mortem histopathological examination.     

Asymmetrical focal neurological deficits in dogs and cats with naturally occurring tick paralysis (Ixodes holocyclus): 27 cases (1999-2006)

OBJECTIVE: To describe basic epidemiological features, clinical characteristics and outcomes of asymmetrical focal neurological deficits identified in dogs and cats with naturally occurring tick paralysis (Ixodes holocyclus). DESIGN: A retrospective study. PROCEDURE: Computer records were reviewed for all dogs and cats treated for tick paralysis between July 1999 and June 2006 at a suburban veterinary hospital in Newcastle, New South Wales. RESULTS: Neurological deficits were identified in 17/197 dogs and 10/89 cats and included unilateral facial paralysis (14 dogs; 2 cats), anisocoria (4 dogs; 7 cats), unilateral loss of the cutaneous trunci reflex (1 dog; 1 cat) and Horner's syndrome in 2 cats with anisocoria. Occurrence of deficits was not linked to season, severity of tick paralysis, breed, age, sex or body weight. With facial paralysis and anisocoria, the site of tick attachment was invariably on the head or neck and always ipsilateral to the facial paralysis. By contrast, with anisocoria alone, no consistent relationship was noted between any one pupillary dimension and the side of tick attachment. With cutaneous trunci deficits the site of tick attachment was the ipsilateral caudal axilla. Compared with recovery times from generalised signs of tick paralysis, those for facial paralysis were significantly longer (days to weeks; P < 0.001), those for anisocoria showed no significant difference (P = 0.25) and those for cutaneous trunci deficits lagged by 6 and 7 days. CONCLUSIONS: Asymmetrical focal neurological deficits are a consistent finding in a proportion of dogs and cats with naturally occurring tick paralysis due to I. holocylcus.     

Neurologic dysfunction in hypothyroid, hyperlipidemic Labrador Retrievers

BACKGROUND: Hypothyroidism has been associated with a variety of neurologic signs, but the mechanism for this association is not completely understood. Hypothyroidism also is associated with hyperlipidemia that predisposes to atherosclerosis, increased blood viscosity, and thromboembolic events. OBJECTIVE: The objective is to characterize neurologic signs potentially associated with hyperlipidemia and atherosclerosis in canine hypothyroidism. ANIMALS: This study used dogs referred to North Carolina State University Veterinary Teaching Hospital for evaluation of neurologic signs. MATERIALS AND METHODS: A retrospective study was conducted in which medical records of dogs with neurologic signs and a diagnosis of hypothyroidism and hyperlipidemia were reviewed. Details of the history, presenting signs, results of routine blood tests, thyroid tests, cerebrospinal fluid (CSF) analysis and diagnostic imaging, and response to therapy were compiled. RESULTS: Three Labrador Retrievers and one Labrador Retriever cross fit the inclusion criteria. All dogs were hypothyroid and severely hyperlipidemic. Neurologic signs included tetraparesis, central and peripheral vestibular signs, facial paralysis, and paraparesis. Two dogs had an acute history and rapid resolution of signs consistent with an infarct, the presence of which was confirmed in 1 of the dogs by magnetic resonance imaging. Two dogs had chronic histories of cranial neuropathies and paraparesis. One of these dogs had evidence of iliac thrombosis and atherosclerosis on ultrasound examination. All dogs improved with thyroid hormone supplementation. CLINICAL RELEVANCE: Labrador Retrievers may be predisposed to the development of severe hyperlipidemia in association with hypothyroidism. One possible consequence of severe hyperlipidemia is the development of neurologic signs due to atherosclerosis and thromboembolic events.     

A survey of neurological diseases in horses

SUMMARY: Case records of 450 horses with signs of neurological disease are reviewed. One hundred and nineteen horses with neurological disease due to trauma were examined, of which 60 were due to spinal cord trauma, 47 to brain or cranial nerve trauma and 12 to peripheral nerve trauma. Cervical vertebral fractures/trauma were the most common injury. Basisphenold/basloccipital bone fractures were the most common form of cranial trauma and facial nerve paralysis the most common cranial nerve injury. Eighty-nine horses with neurological disease due to malformation were examined. Cervical vertebral malformation occurred in 83 horses and congenital defects in 6 foals. Neurological disease due to inflammation or infection occurred in 30 horses. The most common disease of this type was meningitis, which occurred in 11 horses and foals. Neoplasms in the CNS caused neurological disease in 8 horses. The final category was miscellaneous neurological disease, which was diagnosed in 204 horses. Diseases in this category included neonatal (28 cases), toxic/metabolic (27 cases), idiopathic (133 cases), degenerative (3 cases) and other neurological diseases (13 cases). The most common condition was idiopathic laryngeal hemiplegia (116 cases).
Where possible, diagnosis relied on a thorough neurological examination with use of ancillary tests in selected cases including rhinolaryngoscopy, radiography, myelography, ophthalmoscopy and cerebrospinal fluid analysis when indicated. In many cases necropsy and histopathological confirmation or diagnosis was necessary.     

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.     

Feline vestibular disorders. Part I: anatomy and clinical signs

An understanding of the anatomy of the feline vestibular system is essential for interpretation of the clinical signs associated with vestibular dysfunction, for precise lesion localisation, and for accurate interpretation of results of diagnostic imaging. Appropriate recognition and interpretation of the clinical signs of vestibular disease is also an essential aspect of the precise diagnosis of the cause of vestibular dysfunction in cats. The objectives of this review are to provide an overview of the anatomy of the feline vestibular system, and to review the clinical signs of peripheral and central vestibular dysfunction of cats.     

Hypothyroidism in a boxer dog

A 6-year-old boxer was presented with head tilt and facial nerve paralysis. Hypothyroidism was diagnosed and treated appropriately. Hypothyroidism can have an affect on almost any organ system, so the practitioner must be familiar with all clinical signs in order to select appropriate tests and treatment.     

Spontaneous laryngeal paralysis in four white-coated German shepherd dogs

Four cases of spontaneous laryngeal paralysis in juvenile white-coated German shepherd dogs are described. The presenting signs were typical for laryngeal paralysis, with stridor present in all four cases. Laryngoscopy revealed bilateral laryngeal paralysis in three cases, and unilateral paralysis in one. Concurrent megaoesophagus was also identified in one dog. All dogs underwent surgical treatment for laryngeal paralysis. Euthanasia was performed in one case due to intractable regurgitation and aspiration pneumonia. A possible association with white coat colour is discussed.     

Bilateral recurrent laryngeal neurectomy as a model for the study of idiopathic canine laryngeal paralysis.

The purposes of this study were to develop an experimental model of canine laryngeal paralysis that mimicked the naturally occurring disease and to document the upper airway changes produced, both clinically and with pulmonary function testing. Ten dogs had bilateral recurrent laryngeal neurectomy performed and were recovered from anesthesia. Tidal breathing flow-volume loop analysis and upper airway resistance measurements were taken before and after the development of clinical laryngeal paralysis while dogs breathed room air and after the individual administration of 2 respiratory stimulants. Clinical signs of laryngeal paralysis developed 38 days (median) following denervation. Although some variations were present, tidal breathing flow-volume loop analyses on room air, following denervation, were similar to those reported in naturally occurring cases. Upper airway resistance increased following denervation and was significantly increased with both respiratory stimulants. We concluded that bilateral recurrent laryngeal neurectomy resulted in clinical signs and respiratory changes similar to those of idiopathic canine laryngeal paralysis.     

Passive Drainage Versus Primary Closure After Total Ear Canal Ablation-Lateral Bulla Osteotomy in Dogs: 59 Dogs (1985–1995)

Objective- Compare passive wound drainage to primary closure of total ear canal ablation-lateral bulla osteotomy (TECA-LBO) in dogs.
Study Design- Retrospective analysis of medical records.
Sample Population- Fifty-nine dogs with end-stage otitis externa or neoplasia of the external and middle ear.
Methods- Medical records of dogs with TECA-LBO were reviewed. Dogs were divided into postoperative drain and primary closure groups. Statistical analyses were performed to identify differences in data for signalment, preoperative treatment, duration of hospitalization, immediate complications, and long-term complications between groups.
Results- No significant differences were detected in signalment, diagnosis, and duration of medical management between groups ( P >.05). Duration of hospitalization was greater for dogs in the drain group ( P <.05). Immediate postoperative complications occurred in 26 of 59 dogs and included ipsilateral facial palsy, incision swelling, vestibular signs, premature drain removal, and one dog died of aspiration pneumonia. Long-term (>6 months) complications were identified in 12 of 50 dogs and included dermatitis of the medial aspect of the pinna, chronic fistula formation, and permanent facial paralysis. No association between immediate or long term complications and method of closure was identified.
Conclusions- Primary closure is an acceptable alternative in dogs undergoing TECA-LBO when surgical wound dead space can be managed with meticulous hemostasis, complete debridement of devitalized tissue, and accurate apposition of tissue planes.     

Intracranial metastases from an ovarian dysgerminoma in a 2-year-old dog.

A 2-year-old, intact female rottweiler was presented for signs of lethargy. A mass was ultrasonographically observed, cranial and lateral to the left kidney. Exploratory laparotomy revealed a mass in the left ovary that was diagnosed histopathologically as an ovarian dysgerminoma. Two weeks after surgery, the dog was readmitted with signs of peripheral vestibular disease that progressed to central vestibular disease. Magnetic resonance imaging of the brain revealed the presence of a mass in the caudal fossa. The histopathological diagnosis of the mass was metastases from the ovarian dysgerminoma.