Neurogenic laryngeal paralysis in the dog

Idiopathic laryngeal paralysis in dogs is now a frequently recognised disorder, particularly in certain breeds such as the Labrador retriever, Afghan hound and Irish setter. Since it occurs in the older animal, distinguishing the clinical signs and their significance from lower respiratory tract or cardiac disease can be challenging. At present little is known about its aetiology and therefore the treatment is directed at relieving the clinical signs. Recent work indicates that arytenoid cartilage lateralisation achieves the best results as a method of surgically correcting the laryngeal obstruction. However, it should be remembered that the potential benefits of surgery should be assessed for each individual, taking into account the presence of concurrent disease and lifestyle of the dog.     

Innervation of the equine intrinsic laryngeal muscles

The nerve supply to the intrinsic laryngeal muscles of the horse was studied by gross dissection and by electromyography which was carried out before, during and after section of various intralaryngeal nerve branches. The anatomical relationships and passage of the laryngeal nerves throughout the larynx were defined. Unlike the dog and man there was no evidence of the passage of motor nerve fibres from one side of the larynx to the other.     

Neurological laryngeal paralysis in the dog

Abstract

Extract

It is always satisfying to attempt to explain the clinical signs of a disease from the altered physiology that occurs. In the article Neurogenic laryngeal paralysis in the dog(1 Burbidge, H, Goulden, BE and Jones, BR. 1991. Neurogenic laryngeal paralysis in the dog. New Zealand Veterinary Journal, 39: 83–87. [Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]) the clinical signs of laryngeal stridor, increased respiratory rate and exercise intolerance could be explained as follows:     

Bilateral asymmetry of equine laryngeal muscles

One problem in the diagnosis of subclinical roarers is that abnormal auditory signals occur only during a fast gait, and these fade quickly. This paper offers a novel technique to assist this problem. Sound recordings were obtained from five horses following exercise; two roarers, two non-roarers, and one suspected roarer. These signals were converted into spectrograms by Rayspan processing. All frequencies in the 0 to 2.25 kHz range during both inspiration and expiration, as well as occasional noises in the 2–4 kHz band, characterised roarers. Signals from non-roarers consisted of frequencies in the 0 to 2 kHz range with long quiet periods, especially during expiration. An explanation for these phenomena is offered, and supported by diagrammatic cross-sections of equine upper-respiratory tracts. It is suggested that the present technique could assist in the diagnosis of sub- clinical roarers, estimated to be between 20 and 40% of the competitive horse population.     

Extramedullary laryngeal plasmacytoma in a dog

Abstract

CASE HISTORY:?An 8-year-old, female, spayed Border Collie presented with a 3-week history of coughing, choking and haemoptysis.

CLINICAL FINDINGS:?Inspiratory stridor was evident on clinical examination. Cervical radiographs revealed a round soft-tissue mass on the dorsal aspect of the epiglottis. A laryngeal mass was evident on examination under anaesthesia, and an incisional biopsy was obtained. Histopathology revealed a dense proliferation of neoplastic round cells morphologically consistent with plasma cell origin. Immunohistochemisty results were negative for CD3 (T cell marker) and positive for CD79a (B cell marker), resulting in a diagnosis of extramedullary plasmacytoma. The patient was treated with melphalan and prednisolone; clinical signs resolved within 1 week and the mass was no longer evident on laryngoscopy after 1 month of treatment. After 6 months of chemotherapy, the laryngeal mass recurred and euthanasia was requested. There was no evidence of systemic spread on post-mortem examination.

DIAGNOSIS:?Solitary extramedullary plasmacytoma of the canine larynx.

CLINICAL RELEVANCE:?Respiratory extramedullary plasmacytomas are extremely rare with only one laryngeal and two tracheal cases previously reported. This is the first published report of a laryngeal plasmacytoma that recurred despite combination chemotherapy with melphalan and prednisolone.     

Bilateral laryngeal paralysis in a dog secondary to laryngeal osseous metaplasia

A 7-year-old spayed female Lurcher was evaluated for a chronic history of increased upper respiratory noise. Advanced imaging including digital radiography and pre- and post-contrast computed tomography (CT) scan confirmed the presence of an ill-defined soft tissue mineralized mass of the ventral larynx. Histopathology demonstrated pleocellular myositis and fasciitis with osseous metaplasia.     

Juvenile acinar atrophy of the pancreas of a dog.

A dog with juvenile acinar atrophy of the pancreas had degranulation and loss of the acinar cells. Transitional features from normal to degranulation were seen. Electron microscopically, the atrophic pancreas mainly consisted of epithelial cells of duct system, islet cells and multivesicular cells.     

Electrophoretic comparison of myosins from masticatory muscles and selected limb muscles in the dog

Myosins from canine limb muscles (triceps brachii [medial and long heads], anconeus, and extensor carpi radialis) were compared biochemically with myosins from canine masticatory muscles (temporalis and masseter). Compared with the limb muscles, the temporalis and masseter muscles had: a unique myosin isoform pattern as determined by nondenaturing pyrophosphate gel electrophoresis; unique light chains as determined by 1-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis, 2-dimensional gel electrophoresis, and peptide mapping; and a unique heavy chain as determined by peptide mapping.     

An unusual case of retinal atrophy in the Beagle dog

A case of retinal atrophy is described.
Résumé. On décrit un cas d'atrophie de la rétine.
Zusammenfassung. Ein Fall von Netzhautatrophie wird beschrieben.     

Trypanosomiasis and laryngeal paralysis in a dog

Laryngeal paralysis and trypanosomiasis were diagnosed in a 12-year-old Labrador Retriever. Bilateral vocal fold resection and partial excision of the left aryepiglottic fold resolved the dog's respiratory difficulty. Trypomastigotes resembling Trypanosoma cruzi were seen in blood smears during hospitalization. In spite of treatment with nifurtimox and dexamethasone, the dog died. Histologic examination of tissues did not reveal amastigotes of T cruzi or granulomatous myositis previously described in canine trypanosomiasis reported from North America. The lack of granulomatous myositis and amastigotes in muscle is unusual and suggests a strain variation in the behavior of T cruzi.