Two Cases of Pneumothorax During Mechanical Ventilation in Vietnamese Potbellied Pigs

This case report describes pneumothorax associated with positive pressure ventilation in two Vietnamese potbellied pigs while under general anesthesia. A discussion of possible causes and barotrauma/volutrauma follows. The cause of pneumothorax in both cases was probably an interaction of intermittent positive pressure ventilation with some factor unique to these two pigs.     

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.     

COMPARATIVE MAGNETIC RESONANCE IMAGING FINDINGS BETWEEN GLIOMAS AND PRESUMED CEREBROVASCULAR ACCIDENTS IN DOGS

Cerebrovascular accidents, or strokes, and gliomas are common intraaxial brain lesions in dogs. An accurate differentiation of these two lesions is necessary for prognosis and treatment decisions. The magnetic resonance (MR) imaging characteristics of 21 dogs with a presumed cerebrovascular accident and 17 with a glioma were compared. MR imaging findings were reviewed retrospectively by three observers unaware of the final diagnosis. Statistically significant differences between the appearance of gliomas and cerebrovascular accidents were identified based on lesion location, size, mass effect, perilesional edema, and appearance of the apparent diffusion coefficient map. Gliomas were predominantly located in the cerebrum (76%) compared with presumed cerebrovascular accidents that were located mainly in the cerebellum, thalamus, caudate nucleus, midbrain, and brainstem (76%). Gliomas were significantly larger compared with presumed cerebrovascular accidents and more commonly associated with mass effect and perilesional edema. Wedge‐shaped lesions were seen only in 19% of presumed cerebrovascular accidents. Between the three observers, 10–47% of the presumed cerebrovascular accidents were misdiagnosed as gliomas, and 0–12% of the gliomas were misdiagnosed as cerebrovascular accidents. Diffusion weighted imaging increased the accuracy of the diagnosis for both lesions. Agreement between observers was moderate (κ=0.48, P<0.01).     

Hemolysis in identifying Eaton's pleuro-pneumonia-like organism

A method for readily demonstrating hemolysis of mammalian erythrocytes by Eaton's pleuropneumonia-like organism is described. This reaction may be useful in preliminary identification of this organism, since other strains from human sources are not known to have this property.     

Histopathology of bullminnows, Fundulus grandis Baird & Girard, infected with a non-haemolytic group B Streptococcus sp.

Abstract. Histopathological changes in bullminnows, Fundulus grandis Baird and Girard, experimentally infected with a non-haemolytic group B Streptococcus sp. were studied. Following experimental exposure to the Streptococcus sp. approximately 40% of the fish developed exophthalmia, dropsy or petechial haemorrhage along the abdomen. The exophthalmic eye showed haemorrhage with neutrophil infiltration. The liver was oedematous and hepatocytes were atrophied, accompanied by a decrease in glycogen and increases in vacuolization, hyaline droplet degeneration and necrosis. The spleen was congested and cells of the sheathed artery were necrotized.     

MAGNETIC RESONANCE IMAGING APPEARANCE OF THE CISTERNA CHYLI

Thoracolumbar spinal magnetic resonance imaging (MRI) examinations in dogs frequently include the region of the cisterna chyli within the field of view. It is important to be aware of the appearance and location of this structure to avoid confusing it for a pathologic periaortic lesion. MRI examinations of the thoracolumbar spine were reviewed in 30 dogs. The cisterna chyli was identified in 26 dogs and was most commonly located caudal to the diaphragmatic crura at the level of L4; afferent and efferent lymphatics were seen in all dogs. Transverse T2-weighted images were the most useful to locate the cisterna chyli. It was isointense to fluid on T2-weighted images and isointense to muscle on T1-weighted images. Mild contrast enhancement was seen in three dogs. The cisterna always wrapped around the aorta, but varied in shape, with the most common being the wide right dorsolateral ellipse. The thoracic duct was also visible in 30 dogs. MRI may have potential for noninvasive evaluation of the abdominal and thoracic lymphatic ducts in dogs.     

IMAGING DIAGNOSIS—DEGENERATIVE INTRASPINAL CYST ASSOCIATED WITH AN INTERVERTEBRAL DISC

A 6-year-old neutered male Rottweiler had chronic episodic signs of thoracolumbar pain and inability to stand that did not improve after rest and nonsteroidal antiinflammatory medication. In magnetic resonance images, an extradural mass was identified between the spinal cord and the T13/L1 intervertebral disc; the mass was compressing the cord in a dorsoventral direction. The lesion had a low signal intensity rim that enhanced slightly after gadolinium administration, and contents with similar signal intensity to cerebrospinal fluid. The lesion was removed surgically by severing its attachments to the annulus fibrosus. The histologic diagnosis was degenerative intraspinal cyst. The origin of such cysts, and their relationship to synovial and ganglion cysts is discussed.