Counterclockwise gastric dilatation and volvulus in a dog

Abstract

A 6-year-old neutered male golden retriever mix dog was presented for investigation of acute restlessness, increased respiratory effort, non-productive retching, and anorexia. Initial abdominal radiography revealed marked gastric dilation with a normal gastric shape and position, along with mineralized granular material in the pyloric region, consistent with a pyloric outflow obstruction secondary to suspected sand impaction. The dog was stabilized with gastric trocharization and medical management with intravenous fluids, antiemetics, polyethylene glycol via a nasogastric tube, and analgesia was initiated. The dog developed aspiration pneumonia during hospitalization and became oxygen-dependent. There was no significant improvement of clinical status despite 72 h of medical management, and surgical intervention was subsequently recommended. Exploratory laparotomy revealed a counterclockwise gastric dilatation and volvulus. The stomach was repositioned into normal anatomic position and an incisional gastropexy was performed. The dog was maintained in the intensive care unit for 4 d postoperatively. Currently, 3 mo postoperatively, the dog is healthy without recurrence of clinical signs.

Key clinical message:

Counterclockwise gastric dilatation and volvulus is a rare condition in veterinary medicine; however, it should be considered in a patient with acute gastric distension and signs of pyloric outflow obstruction when characteristic radiological signs of clockwise gastric dilatation and volvulus are absent, and there is radiological evidence of persistent gastric foreign material despite medical management. Misdiagnosis of counterclockwise gastric dilatation and volvulus can delay definitive surgical intervention and lead to higher morbidity and mortality.

Case description

A 6-year-old neutered male golden retriever mix dog was presented for investigation of acute restlessness, increased respiratory effort, non-productive retching, and anorexia. The dog had no prior medical history and was up-to-date on all vaccinations and parasite control. The dog became acutely restless during a 3 h drive home after spending 1 wk at a cottage on a sandy beach. Clinical signs then progressed to frequent nonproductive retching and eventually increased respiratory effort. On presentation the dog was bright and alert but noted to be very anxious and was retching and producing a thick white foam. The dog was tachycardic, tachypneic, and hypertensive (systolic blood pressure: 160 to 185 mmHg). The abdomen was soft with no abdominal distention; however, the dog was reactive to deep palpation of the cranial abdomen. Thoracic auscultation was within normal limits, and the remainder of the physical examination was generally unremarkable. Venous blood gas analysis revealed hypokalemia (3.4 mmol/L), hyperlactatemia (5.7 mmol/L), base deficit (−5.4 mEq/L), and elevated anion gap (19.7).

The dog was stabilized with an intravenous fluid bolus (Plasmalyte A 10 mL/kg; Baxter, Alliston, Ontario) and was sedated with butorphanol (Torbugesic 10 mg/mL; Zoetis, London, Ontario), 0.2 mg/kg, IV. Thoracic and abdominal radiographs (APR-VET Digital Radiography; Toshiba Rotanode, Japan) were acquired and sent for radiologist’s interpretation (VetCT Teleradiology, Cambridge, United Kingdom). Abdominal radiographs revealed marked gastric dilation with a normal gastric shape and position, along with mineralized granular material in the antrum, consistent with a pyloric outflow obstruction secondary to sand impaction. There was additional granular material visualized in some of the small intestinal loops in the mid-abdomen, with no small intestinal dilation (Figure 1). Thoracic radiographs revealed an unremarkable thorax. Supportive therapy with serial abdominal imaging was recommended to reassess gastric size and movement of gastrointestinal granular material.

Figure 1.

Initial abdominal radiography. Marked gastric dilation with a normal gastric shape and position. Mineralized granular material in the antral area of the stomach, consistent with a pyloric outflow obstruction secondary to sand impaction. Additional granular material visualized in some small intestinal loops in the mid-abdomen with no small intestinal dilation. A — Right lateral views. B — Ventral-dorsal views.

The dog was sedated with dexmedetomidine, 2 μg/kg, IV and propofol, 0.75 mg/kg, IV titrated to effect. Gastric trocharization was performed using a 16-gauge catheter (Sur-Vet Surflo IV catheter), and a nasogastric tube (Argyle feeding tube 5Fr 91cm; Covidien, Brampton, Ontario) was placed. Gastric emptying produced a total of 300 mL granular gastric fluid and 87 mL air. The dog was clinically stable following the procedure, and previous tachycardia, tachypnea, and hypertension had all resolved. The dog was maintained in hospital on twice-maintenance intravenous fluids (Plasmalyte A 120 mL/kg per hour), maropitant citrate, 1 mg/kg, IV, q24h, and methadone, 0.2 mg/kg, IV, q4 to 6h, as needed.

The dog continued to retch overnight which progressed to productive regurgitation. Gastric emptying yielded a total of 550 mL of granular gastric fluid over 12 h. Throughout the day, the dog became tachypneic with an increased respiratory effort. He was sedated with dexmedetomidine (2 μg/kg, IV) to facilitate repeat thoracic radiography, which revealed an increased alveolar pattern in the right and left caudal lung fields, consistent with aspiration pneumonia. An abdominal ultrasound (Philips HD15 Ultrasound System; Royal Philips Electronics, Amsterdam, The Netherlands) was performed which revealed gastric distention with fluid and gas, with gravity-dependent material settling within the fluid. The pylorus could not be visualized due to gas shadowing (Figure 2). The small intestines were normal in size and appearance. Medical management for sand impaction was continued, and metoclopramide (Metoclopramide Hydrochloride Injection 5 mg/mL; Sandoz, Toronto, Ontario), 0.5 mg/kg, IV every 8 h, famotidine (Famotidine 10 mg/mL; Omega, Montreal, Quebec), 0.5 mg/kg, IV, q12h, and ampicillin, 22 mg/kg, IV, q8h, were added to the treatment regimen. The dog became oxygen dependent; a nasal oxygen line was placed, and oxygen therapy (5 L/min) was initiated.

Figure 2.

Abdominal ultrasound. Gastric distention with fluid and gas, with gravity-dependent material settling within the fluid. The pylorus could not be visualized due to gas shadowing. The small intestines were normal in size and appearance.

The following day, 2 d after initial presentation, repeat abdominal radiographs were obtained without sedation, which revealed a decrease in gastric size and improvement in the previously described sand impaction (Figure 3). Despite radiographic improvement, the dog’s clinical status remained static with persistent regurgitation and retching. Famotidine was discontinued, and pantoprazole (Pantoprazole 4 mg/mL; Sandoz), 1 mg/kg, IV, q12h was added to the treatment regimen, along with a polyethylene glycol (PEG; Restoralax Polyethylene Glycol 3350 powder; Bayer, Mississauga, Ontario) constant rate infusion (CRI) at 100 mL/h via the previously placed nasogastric tube. After 7 h of PEG administration, the dog regurgitated a large volume of fluid, and PEG therapy was discontinued.

Figure 3.

Abdominal radiography after 2 d of medical management. Decrease in gastric size and improvement in the previously described sand impaction. Nasogastric tube in place. A — Right lateral view. B — Ventral-dorsal view.

Due to the lack of clinical improvement with medical management, an exploratory laparotomy was performed 3 d after initial presentation to attempt to manually remove the remaining sand. The abdomen was entered routinely via a ventral midline celiotomy. Immediately upon entry into the abdomen, the stomach was identified and markedly distended with no omentum covering it. The stomach was rotated 90° counterclockwise, and the pylorus of the stomach was abnormally located along the dorsal-left side of the abdomen. The stomach was repositioned into normal anatomic position. No foreign material was palpable within the stomach. A right-sided incisional gastropexy was performed between the pyloric antrum and just caudal to the last rib using 0 PDS (Polydioxane violet monofilament; Ethicon, Sommerville, New Jersey, USA). The remainder of the abdominal organs were assessed and were within normal limits, and there were no signs of peritonitis or contamination. The abdomen was closed routinely. The procedure was performed without complication, and the dog recovered from anesthesia uneventfully. He was maintained in the intensive care unit on maintenance intravenous fluids (Plasmalyte A 60 mL/kg per day), fentanyl CRI 3 μg/kg per hour, dexmedetomidine CRI 1 μg/kg per hour, metoclopramide CRI 2 mg/kg per day, maropitant citrate 1 mg/kg, q24h, pantoprazole 1 mg/kg, q12h, ampicillin 22 mg/kg, q8h, enrofloxacin, 10 mg/kg, q24h, and high-flow nasal oxygen (Airvo2 Nasal High Flow/HFNC System; Fisher & Paykel, Auckland, New Zealand) at 1 L/kg per minute. Enteral feeding (Gastrointestinal Low Fat liquid diet 0.9 kcal/mL) at 1/3 of the resting energy requirement (RER) via the nasogastric tube was initiated 12 h postoperatively and was well-tolerated by the dog.

No additional retching or regurgitation was noted after surgery. The dog’s clinical status began to improve, and enteral feeding was consistently increased to full RER over 72 h. Oxygen therapy was weaned over 48 h and discontinued. The dog began eating on his own 3 d after surgery, with no further gastrointestinal signs. The dog was discharged from the hospital on oral antibiotics and analgesics 4 d after surgery. Currently, 3 mo postoperatively, the dog is healthy without recurrence of clinical signs.

Discussion

Gastric dilatation and volvulus (GDV) syndrome is an acute, life-threatening condition of large and giant breed dogs that requires immediate medical and surgical treatment. The pathogenesis of GDV is complex and not completely understood. The order in which gastric distension and mispositioning occurs is unclear, with supporting data for each hypothesis (1–3). Several risk factors predispose dogs to development of GDV, including purebred large or giant breed, increased thoracic depth-to-width ratio, history of GDV in a first-degree relative, increasing age, increasing hepatogastric ligament length and laxity, aggressive, anxious, or fearful temperament, rapid eating, feeding fewer, larger meals per day, and exercise or stress after a meal (4,5). Other risk factors for development of GDV have been proposed, although a consensus within the literature has not been reached. Dogs with previous gastric foreign bodies have been documented to have a higher incidence of GDV; however, a causal relationship has not been demonstrated (6). There is also conflicting evidence as to whether a previous splenectomy is a significant risk factor for development of GDV (7–10).

When gastric dilatation and volvulus occurs, the stomach becomes filled with gas and twists on its longitudinal axis. The most common type of torsion is a 180° clockwise torsion; however, 90° clockwise torsion and 270° and 360° clockwise volvulus have also been documented in the literature (1,11). In a typical 180° torsion, the pylorus and proximal duodenum first move ventrally then cranial to the body of the stomach. The pylorus continues to migrate from right to left past midline due to stretching of the hepatoduodenal ligament, creating a fold in the stomach. The pylorus is then located dorsal to the esophagus and gastric fundus on the left side of the abdominal cavity (1). This malposition creates compartmentalization of the stomach, leading to the characteristic “double bubble” appearance on right lateral abdominal radiography (1,12). Rotation of the stomach in a clockwise direction greater than 180° obstructs both the esophagus and the pylorus. Placement of an orogastric tube is recommended to achieve gastric decompression prior to gastric repositioning; however, occlusion of the distal esophagus in clockwise GDV can make passage of the tube into the stomach difficult. It is important to note, however, that clockwise torsion does not always preclude successful orogastric intubation. Percutaneous needle gastric decompression can be performed rather than orogastric intubation based on clinician preference. However, if orogastric tube placement is unsuccessful, gastrocentesis is indicated to achieve gastric decompression (1,13).

Counterclockwise volvulus is a rare presentation of GDV syndrome and is uncommonly reported in veterinary literature (11). The pylorus is unable to move dorsally within the abdomen a full 180° due to the relatively fixed position of the adjoining duodenum. When the stomach rotates counterclockwise, torsion is limited to 90° around the gastric axis (14). The result is compression of the pylorus and a subsequent pyloric outflow tract obstruction. The esophagus remains patent, making orogastric intubation more straightforward in this presentation. In addition, compartmentalization of the stomach does not occur, and the diagnostic radiographic appearance of a clockwise GDV is not seen on abdominal radiographs. Instead, diagnostic imaging is generally consistent with uncomplicated gastric distension, as the torsion component is not evident on abdominal radiographs (11,14).

Both medical and surgical management of gastrointestinal sand impaction has been described in the literature. Recommended medical therapy includes fluid and electrolyte therapy, analgesia, antiemetics, laxative therapy, and gastrointestinal prokinetics (15). It is important to note that the use of antiemetics and prokinetics should be reserved for patients with symptomatic partial bowel obstruction and is contraindicated in patients with radiographic or ultrasonographic evidence of complete bowel obstruction (16). Surgical removal of impacted sand from the gastrointestinal tract can be difficult, and risks particulate contamination of the abdomen. It is therefore recommended that medical management is attempted first, with serial abdominal imaging to monitor for effectiveness of treatment. Surgery should be reserved for patients that do not respond to medical therapy (15). Due to the radiographic appearance of uncomplicated gastric distension with no evidence of intestinal obstruction, medical therapy was initially favored in this case, and was continued for 72 h based on radiographic improvement of sand impaction. However, due to the lack of significant improvement of the dog’s clinical status, surgical abdominal exploration was eventually elected to assess for concurrent conditions precluding successful passage of the sand impaction.

To the authors’ knowledge, this is the first reported case of a counterclockwise GDV with a clinical presentation and radiographic findings consistent with a sand impaction. Although uncommon, is important for veterinarians to be familiar with a counterclockwise presentation of GDV and consider it a differential diagnosis for pyloric outflow tract obstruction, especially when other causes of pyloric obstruction are not evident and there is a lack of clinical improvement with typical medical management. In this case, misdiagnosis of counterclockwise GDV delayed definitive surgical intervention and lead to higher morbidity as the dog developed aspiration pneumonia prior to surgery. Although this case yielded a positive result, delayed surgical intervention of known GDV should not be considered in the future. CVJ