Magnetic resonance imaging in the diagnosis and treatment of a canine spinal cord injury

A nine-year-old female crossbred dog was presented with tetraplegia following a fall. No vertebral abnormalities were detectable on plain radiographs of the cervical spine. Magnetic resonance imaging scans revealed absence of extraparenchymal compression and an area of oedema within the cervical spinal cord, suggesting a favourable prognosis. Following nursing care and physiotherapy, the dog recovered the ability to walk, although mild neurological deficits persisted in the left limbs.     

The recognition and treatment of the intermediate syndrome of organophosphate poisoning in a dog

Objective: To discuss a new clinical presentation of organophosphate toxicity called the intermediate syndrome in a dog. Case summary: A mixed breed dog presented with generalized weakness, hypoventilation and hypoxemia. The weakness was most marked in the thoracic limbs, cervical and respiratory muscles. The history revealed a likely exposure to an organophosphate compound. The other dog in the household demonstrated mild clinical signs of organophosphate toxicity. A blood cholinesterase level was markedly reduced. Therapy included placement of a tracheostomy tube and mechanical ventilation. The dog gradually improved over the following 8 days but had persistent cervical ventroflexion for a total of 4 weeks. New or unique information provided: Organophosphate toxicity can present as a paralysis following the acute cholinergic crisis. The muscular weakness predominantly affects the thoracic limb and neck muscles but cranial nerve deficits can also occur. Dogs can die from the associated respiratory depression. Oxime therapy is indicated in the treatment of this syndrome.     

Pneumothorax secondary to pulmonary thromboembolism in a dog

Objective – To describe a case of spontaneous pneumothorax secondary to pulmonary thromboembolism possibly associated with pituitary dependent hyperadrenocorticism.
Case Summary – A 7-year-old spayed female Collie weighing 26 kg was referred for evaluation of spontaneous pneumothorax. An exploratory thoracotomy was performed and revealed 2 lung lobes to be diffusely hemorrhagic and they were resected. Histologic examination of multiple sections documented diffuse thromboembolism. A 2–3 cm thrombus was visualized distal to the bifurcation of the pulmonary artery during an echocardiographic examination postoperatively. The dog was discharged to the owner after recovery from surgery. The thrombus had resolved at the 4-week recheck examination. Diagnosis of pituitary dependent hyperadrenocorticism was confirmed based on follow-up endocrine testing.
New or Unique Information Provided – This is the first report of pulmonary thromboembolism causing spontaneous pneumothorax in the dog.     

Spontaneous pneumothorax caused by pulmonary blebs and bullae in 12 dogs

Spontaneous pneumothorax caused by pulmonary blebs and bullae was diagnosed in 12 dogs based on history, clinical examination, thoracic radiographs, surgical findings, and histopathological examination of resected pulmonary lesions. Radiographic evidence of blebs or bullae was seen in only one dog. None of the dogs responded to conservative treatment with thoracocentesis or thoracostomy tube drainage. A median sternotomy approach was used to explore the thorax in all dogs. Pulmonary blebs and bullae were resected with partial or complete lung lobectomy. Ten of the dogs had more than one lesion, and seven of the dogs had bilateral lesions. The cranial lung lobes were most commonly affected. Histopathology results of the blebs and bullae were consistent in all dogs and resembled lesions found in humans with primary spontaneous pneumothorax. None of the dogs developed recurrence of pneumothorax. Median follow-up time was 19 months. The outcome following resection of the pulmonary blebs and bullae was excellent.     

Catheter drainage of pleural fluid collections and pneumothorax

A technique for virtually atraumatic placement of small size chest catheters for suction drainage of pleural effusions and pneumothorax in the dog and cat is described. Thirty-nine dogs and two cats were treated for pyothorax (10 cases), hydrothorax (eight). chylothorax (three), haemothorax (three), haemothorax/pneumothorax (three) and pneumothorax (14). In all 41 cases, thin or viscous fluid and/or air were efficiently drained. The mean period of drainage was four days (range, 0.5 to 18 days). The average amount of fluid removed from each patient in 24 hours was 530 ml in pyothorax cases (range, 140 to 1100 ml) and 1300 ml in the other cases (range, 20 to 5000 ml). In 40 cases there were no complications related to the procedure. One dog with severe pleural adhesions was euthanased because of lung perforation and pneumothorax secondary to misplacement of the catheter.     

Adverse effect of complete thoracic evacuation during chronic pneumothorax in a dog

OBJECTIVE: To describe an unusual response to evacuation of a chronic pneumothorax in a dog. CASE: Resolution of a pneumothorax is usually associated with lung expansion and a marked improvement in pulmonary function. In the case presented here, evacuation of a chronic pneumothorax improved oxygenation, but markedly impaired ventilation. CLINICAL RELEVANCE: This is a previously unreported complication associated with the treatment of pneumothorax in dogs. It suggests that in some cases of chronic pneumothorax, total evacuation of the pleural air pocket may improve oxygenation but ventilation deteriorates and increases PCO2, causing further complications.     

Allogenic blood patch pleurodesis for management of pneumothorax in a Cavalier King Charles Spaniel puppy with multiple pulmonary blebs and bullae

A 9‐week‐old male intact Cavalier King Charles Spaniel was presented for evaluation of acute onset dyspnea caused by left‐sided pneumothorax. Thoracic computed tomography (CT) identified multiple pulmonary bullae and blebs in multiple lung lobes. Rupture of ≥1 pulmonary blebs or bullae, precipitated by low impact trauma, was the suspected cause of pneumothorax. A volume of 7.5 mL/kg of fresh whole blood was collected from a type‐matched donor dog and administered into the left pleural space using a thoracostomy tube. The pneumothorax was successfully resolved and no adverse effects of blood patch pleurodesis were noted. The dog was clinically normal 12 months later.     

Stabilisation with dorsal and ventral fixation of a traumatic cervical instability in a dog

This case study reports the outcome of dorsal and ventral stabilisation of a traumatic cervical instability in a dog. A 2-year-old, male Pointer was admitted following a motor vehicle accident. Clinical examination revealed non-ambulatory tetraparesis, severe neck pain and upper motor neuron changes in all limbs. Deep pain response was present. Subluxation of C2/3 and fractures of the dorsal spinous process and lamina of C2 were observed on radiographs. Ventral stabilisation was performed with screws and bone cement (polymethylmethacrylate). For dorsal fixation of the fractures, screws and cerclage wire were used. The dog stood up independently after 1 month, was able to walk 1.5 months postoperatively and had recovered completely at 1 year following surgery. We conclude that combined stabilisation techniques are effective for this type of cervical fracture in which the dorsal, middle and ventral structures of the vertebra are severely disrupted.     

Clinical and MRI findings of lissencephaly in a mixed breed dog

A 7-year-old castrated male mixed-breed dog was presented with a complaint of acute pain. The dog had suffered from isolated seizures for two years. Magnetic resonance imaging (MRI) of the brain revealed a smooth brain surface due to lack of gyri and sulci formation of the cerebrum and thick cortical grey matter. Additionally, ventriculomegaly and an arachnoid cyst were noted. Multiple spinal cord compressions induced by intervertebral disc protrusion were observed on a cervical MRI. Based on these findings, the dog was diagnosed as having lissencephaly concurrent with intervertebral cervical disease. After therapy for seizure and cervical pain, the clinical signs were completely resolved. To the author's knowledge, this is the case report to diagnose lissencephaly in a mixed-breed dog.     

Subarachnoid abscess as a complication of discospondylitis in a dog

A three-year-old German shepherd dog was presented with a history of acute neck pain. A diagnosis of acute discospondylitis involving two intervertebral disc spaces was made. The dog initially responded to conservative treatment over an eight-week period and then suddenly deteriorated. Spinal cord compression was evident on cervical myelography. At autopsy, a subarachnoid abscess was present at the intervertebral disc space between the sixth and seventh cervical vertebrae.     

Polyostotic lymphoma with vertebral involvement and spinal extradural compression in a dog

A 10-year-old, male, mixed-breed dog that developed cervical pain and neurological deficits was diagnosed with primary lymphoma of the second cervical vertebra. The cervical lesion was not surgically resectable. A dorsal cervical hemilaminectomy was performed to provide temporary decompression. The dog had complete pain relief after surgery but was euthanized 6 weeks later with recurrent clinical signs and evidence of lymphoma in the right femur.     

Cervical injury following a horse kick to the head in two dogs

Two dogs were presented to North Carolina State University Veterinary Teaching Hospital following blunt trauma to the head delivered by a horse kick. On presentation, both dogs had resolving clinical signs directly related to the head trauma, but both also had compromise to their upper airway as a result of indirect injury to the soft tissues of the neck, visible on plain radiographs. One dog made a full recovery following a period of assisted ventilation. The other dog was euthanized at the request of the owner. These injuries illustrate the importance of evaluating the cervical spine and soft tissues of the neck following blunt trauma to the head.     

Invasive thymoma complicated by pneumothorax and haemothorax in a dog

An invasive thymoma associated with pneumothorax and haemothorax is described in a 3^-year-old Labrador Retriever. Diagnosis was based upon radiological and surgical findings and confirmed at autopsy. The case is compared with other thymomas reported in the dog.     

Ectopic cervical thymic carcinoma in a dog

A 10-year-old male German shepherd dog was referred for evaluation of a cranial cervical mass causing progressively worsening respiratory distress. A fine-needle aspirate of the mass was obtained and the cytology results were compatible with a carcinoma. The dog underwent chemotherapy without clinical improvement and was ultimately euthanased because of clinical deterioration. At post-mortem examination, an irregular multi-lobated mass in the cranial cervical region was observed causing ventro-lateral tracheal deviation. Histopathology and immunohistochemistry revealed a mixed population of CD3 lymphocytes and macrophages in an exuberant fibrous stroma, associated with dispersed cytokeratin-positive epithelial cells with marked eosinophilic cytoplasm. Some of the epithelial cells were arranged in concentric clusters that were interpreted as Hassall's corpuscles. Histopathological examination of the thyroid gland revealed several neoplastic emboli composed of epithelial cells similar to those observed in the cervical mass. To the authors' knowledge, this is the first report of an ectopic cervical thymic carcinoma in a dog.     

Surgical correction of primary pneumothorax in a dog

Surgical repair of primary pneumothorax in a dog was performed by a median sternotomy and partial lung lobectomies using an automatic suturing device. A median sternotomy was performed since the location of the lesion was undetermined preoperatively. The automatic suturing device provided a quick, simple, and secure method of performing the partial lobectomies. Ruptured blebs and subpleural emphysema were present in the excised pulmonary tissue. Mechanical pleurodesis was also performed in an attempt to prevent recurrence. Large-gauge orthopedic wire was used to close the sternotomy in order to minimize postoperative complications. On follow-up evaluation 6 months later, the dog was normal.     

Suspected Tension Pneumomediastinum In A Dog: A Case Report

Successful resuscitation of a trauma-induced, suspected tension pneumomediastinum in a dog is presented. The cause was a caudal cervical penetration wound which acted as a one-way valve allowing air to enter, but not exit, the cranial mediastium. Early in the course of hospitalization, respiratory and cardiovascular collapse occurred; an emergent parasternotomy allowed decompression of the mediastinum, and the cradiovascular system immediately responded. The dog made a complete recovery following surgical exploration and removal of contaminated mediastinal tissue. Nine days of intensive care included 24-hour monitoring, oxygen therapy, intravenous crystalloids and colloids, continuous pleural suctioning, nutritional support, antibiotics, and pain control.     

Video-assisted thoracoscopic surgery for pneumothorax induced by migration of a K-wire to the chest

A 2 yr old female English setter dog was admitted for acute dyspnea. The dog underwent treatment of a T9T10 thoracic vertebral fracture subluxation at the authors' institution 15 mo earlier. Upon admission, a chest X-ray revealed a pneumothorax and a metallic foreign body in the left hemithorax. An emergency video-assisted thoracoscopic surgery was successfully performed to remove a 4.6-mm long Kirschner wire that migrated from the thoracic vertebral column to the thoracic cavity. The operating time was 27 min. The dog made an uneventful recovery and was discharged on the third day after surgery. Pneumothorax should be considered in patients that develop acute dyspnea and have a history of wire fixation in the thoracic vertebral column. Video-assisted thoracoscopic surgery is a safe and effective treatment of this condition.     

Esophageal duplication cyst in a dog

A cranial cervical mass was surgically removed from a dog. On histologic examination, the mass was consistent with an esophageal duplication cyst, a condition rare in humans and not reported in the dog.     

OCCIPITAL DYSPLASIA AND ASSOCIATED CRANIAL SPINAL CORD ABNORMALITIES IN TWO DOGS

Occipital dysplasia was found in association with cervical spinal cord abnormalities in two dogs. One dog presented for tetraparesis and cervical hyperesthesia, the other for historical cervical hyperesthesia and mild paraparesis. In dog 1, a midline cervical spinal cord defect consistent with a communicating syrinx was found. In the other dog, a presumptive syringo/hydromyelia of the cervical spinal cord was found on magnetic resonance imaging. While occipital dysplasia alone is not thought to cause any clinical abnormalities, the dogs of this report suggest that intramedullary central nervous system abnormalities may be present concurrently with occipital dysplasia and should be considered as a possible cause of the clinical signs. The relationship between occipital dysplasia and syringo/hydromyelia in these dogs remains unclear, however, similar associated abnormalities are occasionally found in humans with Chiari malformation.