Gastric Dilatation Organoaxial Volvulus in a Dog.

A 9 yr old castrated male mixed-breed dog was presented for acute vomiting. Abdominal radiographs appeared to show a normal positioned stomach with marked gas dilation, which persisted despite frequent suctioning with a nasogastric tube. An abdominal ultrasound showed splenomegaly, malpositioning of the spleen, and the pyloroduodenal junction. A ventral midline celiotomy revealed an organoaxial gastric volvulus, rotating on the gastroesophageal, and pyloroduodenal junctions. The omentum was not overlying the stomach, typically seen in mesenteroaxial gastric volvulus. The body of the stomach was derotated with no evidence of gastric necrosis noted. The spleen was in the right cranial abdomen and returned to its normal anatomic position after derotation of the stomach. The patient recovered uneventfully and was discharged the next day. To the authors' knowledge, organoaxial gastric volvulus has not been reported in dogs. This is rare in humans but occurs most commonly in children <5 yr of age associated with hernias. The recommended treatment is surgical in majority of cases. As a result of the unusual orientation of the stomach, the diagnosis of gastric dilatation-volvulus was challenging. Organoaxial gastric volvulus demonstrates the need for further imaging and evaluation in cases of persistent gas dilation.

Transient methemoglobinemia suspected secondary to ingestion of Brassica species in a dog.

This case report describes methemoglobinemia in a dog suspected to be the result of consumption of a large volume of fermented bok choy. The patient presented with clinical signs and co-oximetry consistent with methemoglobinemia without ingestion of a known toxin. A large volume of fermented bok choy had been ingested earlier that day and decontamination procedures were performed as a result. Supportive care led to resolution of clinical signs and appropriate clearance of methemoglobin. While erythrocyte oxidant damage is a consequence of ingestion of plants in the genus Brassica (such as bok choy) in ruminant species due to rumen microbiota producing sulfur-containing compounds, specifically dimethyl disulfide, there are potential pathways that can lead to similar effects in monogastric animals. The methemoglobin formation in this patient may have resulted from the large volume consumed with the natural fermentation releasing dimethyl disulfide and leading to oxidant damage analogous with that in ruminants. This case report provides additional mechanisms for methemoglobin formation in dogs and to direct the clinician toward methemoglobinemia in patients with compatible clinical signs with ingestion of specific plant species.

Severe lamotrigine toxicosis in a dog.

OBJECTIVE: The objective of this study was to describe a case of severe lamotrigine toxicosis in a dog, which was successfully treated using minimal medical interventions. CASE SUMMARY: A 7-month-old male, intact, Labrador mix was evaluated because of acute onset of vomiting, rigidity, and dull mentation after ingesting lamotrigine tablets. The estimated oral dose that had been ingested was 278 mg/kg (611.6 mg/lb). Physical examination was unremarkable other than abnormalities noted in the cardiovascular and neurological systems. Neurological examination revealed dull mentation, vertical nystagmus, four-legged extensor limb rigidity, and alligator rolling. Cardiovascular examination revealed pale pink mucous membranes and multifocal ventricular tachycardia. Intravenous (IV) fluids were started at three times maintenance (180 mL/kg/day). Methocarbamol (100 mg/kg [220 mg/lb], rectally) and lidocaine (2 mg/kg [4.4 mg/lb, IV]) were administered. Twenty-four and seventy-two hours after presentation, the dog was clinically normal with no ventricular tachycardia being noted. CONCLUSION: Lamotrigine (6-[2,3-dichlorophenyl]-1,2,4-triazine-3,5-diamine) is an anticonvulsant medication used in humans, which inhibits voltage-gated sodium channels. The clinical success of this case suggests that administration of only methocarbamol for the neurologic effects and lidocaine for the arrhythmias, as well as supportive IV fluid therapy, could be a successful treatment strategy for dogs, even with severe lamotrigine toxicosis.

Bicavitary effusion secondary to liver lobe torsion in a dog.

We described the diagnosis and successful treatment of pleural and peritoneal effusion secondary to liver lobe torsion in a dog. A 12-year-old female spayed Borzoi dog was referred for heart failure. Emergency room thoracic and abdominal ultrasound showed a large volume of pleural effusion with mild peritoneal effusion and an abdominal mass. Pleural fluid analysis classified the effusion as exudative. A complete ultrasound revealed mild peritoneal effusion and decreased blood flow to the right liver lobe. Other causes of bicavitary effusion were ruled out based on blood work, ultrasound, echocardiogram, and computed tomography. The patient was taken to surgery and diagnosed with caudate liver lobe torsion and had a liver lobectomy. At the 2-week postoperative recheck, the patient was doing well and there was complete resolution of the pleural effusion. Liver lobe torsion is a rare occurrence in dogs and can be difficult to diagnose. Clinical signs are nonspecific for liver lobe torsion and patients may present in respiratory distress with significant pleural fluid accumulation. When assessing patients with pleural and peritoneal effusion, liver lobe torsion should be considered as a differential diagnosis.