Difference between revisions of "Gastric Dilatation and Volvulus"

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{{review}}
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Also known as: '''''GDV
+
 
 +
{{dog}}
 +
 
 +
==Signalment==
 +
*Large deep chested breeds including:
 +
<gallery>
 +
Image:Akita.jpg|Akitas
 +
Image:Bloodhound.jpg|Bloodhounds
 +
Image:Smooth Collie.jpg|Collies
 +
Image:Greatdane.jpg|Great Danes
 +
Image:Irish Setter.jpg|Irish Setters
 +
Image:Irish Wolfhound.jpg|Wolfhounds
 +
Image:Newfoundland.jpg|Newfoundlands
 +
Image:Rottweiler.jpg|Rottweilers
 +
Image:Stbernard.jpg|Saint Bernards
 +
Image:Standard poodle.jpg|Standard Poodles
 +
Image:Weimaraner.jpg|Weirmaraners
 +
</gallery>
 +
 +
==Description==
 +
Gastric dilatation (GD) and Gastric dilatation and volvulus (GDV) are caused by the stomach distending with air. In GDV the stomach twists around its axis mainly in a clockwise direction with both conditions leading to compression of the caudal vena cava. GDV can lead to [[Shock - Pathology#Hypovolaemic shock|hypovolaemic shock]], splenic torsion, gastric wall ischaemia, abdominal viscera congestion, [[Shock - Pathology#Endotoxic shock|endotoxic shock]] and [[Disseminated Intravascular Coagulation - Pathology|disseminated intravascular coagulation (DIC)]]. The exact pathogenesis is unclear but risk factors for GDV include age, fast eating, once- daily feeding, aerophagia, raised feeding bowl and a close relative with GDV.
 +
 
 +
==Diagnosis==
 +
===History and Clinical signs===
 +
*Abdominal distension
 +
*Non-productive retching
 +
*Weakness
 +
*Collapse
 +
*Salivation
 +
*Abdominal tympany
 +
*Tachycardia
 +
*Pallor
 +
*Hypothermia
 +
*[[Altered Impulse Formations - WikiClinical|Cardiac arrythmias]] (present in 40-50% of patients) ([[Altered Impulse Formations - WikiClinical#2. Ventricular Premature Complexes (VPCs)|ventricular premature beats]], [[Altered Impulse Formations - WikiClinical#1. Ventricular Tachycardia|ventricular tachycardia]])
  
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==Introduction==  
+
===Haematology===
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Gastric Dilatation and Volvulus (GDV) is an '''acute, life-threatening emergency''' affecting large and giant breed dogs. The condition is characterised by '''accumulation of gas in the stomach, malpositioning of the stomach, increased intragastric pressure and shock'''. Successful management relies on prompt diagnosis and appropriate emergency treatment as the disease will rapidly progress to death if untreated.
+
*Increased haematocrit
 +
*DIC (thrombocytopaenia, increased firbin degradation products, prolonged patial thromboplastin time and reduced antithrombin III.)
  
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Commonly affected breeds include German Shepherds, Great Danes, Irish Wolfhounds, St Bernards and Doberman Pinschers. GDV has also been reported to occur in cats, primates and rarely small breed dogs such as Dachshunds and Miniature Poodles.
+
===Biochemistry===
 +
Most commonly find hypokalaemia and metabolic acidosis. The acidosis is caused hypoperfusion and anaerobic metabolism leading to lactic acid accumulation. Respiratory acidosis and alkalosis may also be present due to hypo- and hyperventilation.
  
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==Risk Factors==
+
===Diagnostic imaging===
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The exact aetiology of the condition is unknown but a number of risk factors have been identified. Studies have shown that dogs with a '''reduced thoracic width to depth ratio''' are at an increased risk of developing GDV. Female dogs are also more likely to develop GDV than males and stressed, anxious dogs are more likely to develop GDV than calm dogs. Other risk factors include obesity, feeding a dry food diet and exercise after feeding.  
+
Best performed after [[Principles of Fluid Therapy|fluid therapy]] and gastric decompression. It allows distinction between GD and GDV:
 +
*Gastric dilatation: gas distension, on right lateral shows air in the fundus.
 +
*Gastric dilatation and volvulus: pylorus moves dorsally and left with a compartmentalized stomach. (GDV x-ray from WikiCommons[[http://commons.wikimedia.org/wiki/File:GDV_x-ray.JPG]])
 +
A right lateral view will show a large fundus ventrally, with a smaller gas filled pylorus located dorsally to that. These are seperated by a soft tissue strip. The contrast of the abdomen may be lost indicating peritonitis or [[Haemoabdomen - WikiClinical|haemoabdomen]]. Gastric rupture would show as pneumoperitoneum and increased contrast.
 +
 
 +
==Treatment==
 +
The most important first line treatments are [[Principles of Fluid Therapy|fluid therapy]] and gastric decompression.
  
−
==Pathogenesis==
+
===Fluid therapy===
−
An obstruction to gastric emptying due to fluid or gas leads to '''gastric distention''' and a rapid increase in intra-gastric pressure. As the stomach dilates, the '''pylorus shifts through an angle of between 180 and 360<sup>o</sup>C''' from its normal position to a dorsal, cranial and leftward location. More than 90% of all gastric volvuli rotate in a '''clockwise direction''' when viewed from the surgeon's perspective with the dog in dorsal recumbency.
+
Should be individualised to the patient due to the varying nature of the [[Essential Ion and Compound Balance and Homeostasis - Anatomy & Physiology#Acid / Base|acid-base]] disturbances. Large bore (16 or 18 gauge) catheters should be placed into cephalic or jugular veins (ideally two into both cephalic veins). Shock doses of Compound Sodium Lactate (Lactated Ringer's Solution) (60-90ml/kg/h). Hypertonic saline can also be used. Monitoring of the situation should be done by regular blood pressure measurements, heart rates, PCV and total solids and urine output. Potassium can be supplemented to bags in the form of KCl after the initial shock doses.
  
−
The most immediate effect is impairment of the gastric blood supply, leading to severe congestion of the gastric wall and infarction and ulceration of the gastric mucosa. Venous return to heart is reduced due to mechanical compression of the caudal vena cava by the distended stomach, leading to decreased cardiac output and hypovolaemic [[shock]]. Gastric distension also causes a mechanical impediment to movement of the diaphragm resulting in reduced tidal volume, hypoxia and hypercapnia.
+
===Gastric decompression===
 +
Performed by introduction of a lubricated premeasured (from nostril to last rib) stomach tube or by trocharizing the most tympanic area caudal to the ribs with a 14 to 16 gauge catheter. Sedation may be required to allow the passage of the stomach tube. Suitable drugs for this include [[Opioids#Butorphanol|butorphanol]], [[Opioids#Fentanyl|fentanyl]] or oxymorphone and [[Benzodiazepines#Diazepam|diazepam]].
  
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In addition to the above systemic effects, displacement of the stomach may lead to avulsion of the short gastric branches of the splenic artery and of the left epiploic artery along the greater curvature of the stomach. Significant haemorrhage may occur as a result and this may lead to the development of ischaemia-induced gastric necrosis.  
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===Other treatment===
 +
*For shock: [[Steroids|Prednisolone sodium succinate]] or [[Steroids|dexamethasone sodium phosphate]].
 +
*For bacterial translocation and endotoxaemia: Broad spectrum antibiotics (e.g. [[Cephalosporins|cephalosporin]] and a [[Fluoroquinolones|fluoroquinolone]]) should also be given at surgical induction through to the postoperative period.
 +
*For cardiac arrythmias: indicated if weakness, syncope, tachycardia runs with R on T complexes, ventricular tachycardia at rates >150bpm. Treated by correcting [[Essential Ion and Compound Balance and Homeostasis - Anatomy & Physiology#Acid / Base|acid-base]], [[Essential Ion and Compound Balance and Homeostasis - Anatomy & Physiology|electrolyte]] and [[Haemostasis - Pathology|haemostatic]] disturbances. The treatment is [[Local Anaesthetics#Lidocaine|lidocaine]] by bolus or continuous rate infusion or procainamide if they persist.
 +
*For analgesia: Pure [[Opioids|opioid]] of [[Opioids#Morphine|morphine]], [[Opioids#Methadone|methadone]] or [[Opioids#Fentanyl|fentanyl]].
 +
*General: Oxygen supplementation if possible
  
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==History and Clinical Signs==
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===Anaesthesia===
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The clinical signs of GDV are usually '''acute in onset''' and may follow a period of exercise and/or feeding of a large meal. Affected dogs typically display '''non-productive vomiting and abdominal distension'''. Acute onset restlessness, abdominal pain, hypersalivation and abdominal tympany are other common features of GDV. On physical examination, the dog may be collapsed or reluctant to stand. Signs of cardiovascular '''shock''' may be present including tachycardia, pale mucous membranes, prolonged capillary refill time and poor peripheral pulses. An irregular heart rate combined with pulse deficits indicates the presence of [[:Category:Arrhythmia|cardiac arrhythmias]].
+
Anaesthesia must be carried out with care even after the patient has been stabilised. There are limited protocols but included [[Opioids#Fentanyl|fentanyl]] and [[Benzodiazepines#Diazepam|diazepam]] bolus or titrated [[Propofol|propofol]]. Maintenance can be achieved with the use of [[Isoflurane|isoflurane]] and [[Sevoflurane|sevoflurane]] in oxygen however [[Nitrous Oxide|nitrous oxide]] should be avoided due to third spacing. Regular routine monitoring of urine production, blood pressure, [[Blood Pressure#Central Venous Pressure|central venous pressure]], PCV, total solids, blood gas and serum electrolytes. High rates of fluids should be used to maintain tissue perfusion and arterial [[Blood Pressure|blood pressure]].
  
−
==Diagnosis and Management==
+
===Surgery===
−
Diagnosis is usually based on the '''patient's signalment and a history of unproductive vomiting and abdominal distension'''.
+
Surgical aims include:
 +
*Gastric decompression and repositioning
 +
*Assessing the organ viability
 +
*Removing necrotic tissue
 +
*Gastropexy (can perform incisional, tube, belt-loop and circumcostal techniques) to prevent recurrence
  
−
===[[:Category:Fluid Therapy|Fluid Therapy]]===
+
If gastric necrosis (happens in 10-37% of patients) is present (discoloured dark purple or grey/green, don't bleed when incised or feel paper thin) then a parital gastrectomy is required. Damage to the spleen via avulsion or torsion may need partial or complete splenectomy.
−
Initial emergency treatment should be aimed at managing the dog's '''hypovolaemic shock'''. It may be beneficial to provide oxygen supplementation whilst the dog is being stabilised.
 
−
Large bore (16 or 18 gauge) catheters should be placed into the cephalic or jugular veins and a proportion of the '''shock dose of Compound Sodium Lactate''' (90ml/kg/h) should be administered intravenously based on the severity of the dog's clinical signs. Hypertonic saline or colloid fluids may be indicated in very large dogs or those who have not responded to a bolus dose of crystalloid fluids.  
 
  
−
===Gastric Decompression===
+
===Post-operative complications===
−
Following a period of aggressive fluid therapy, '''gastric decompression''' should be performed. A lubricated large-bore stomach tube is premeasured (from nostril to last rib) and marked. A roll of 2 inch adhesive tape should be inserted behind the canine teeth and the dog's mouth should be held closed around the bandage. The stomach tube can then be introduced through the bandage into the oesophagus. It is important to minimise stress when this procedure is carried out. Sedation is not usually required but suitable drugs for this include Butorphanol, Fentanyl or Diazepam. If the animal is resistant to orogastric intubation or becomes stressed, '''trocharization''' of the most tympanic area caudal to the ribs with a 14 to 16 gauge catheter may be performed. This may allow subsequent completion of orogastric intubation for further decompression. Temporary '''gastrostomy''' may also be considered.
+
These are wide and varied and include:
 +
*Hypoperfusion
 +
*Hypotension
 +
*Cardiac arrythmias
 +
*[[Lungs Inflammatory - Pathology#Aspiration pneumonia|Aspiration pneumonia]]
 +
*[[Gastric Motility Disorders - WikiClinical|Abnormal gastric motility]]
 +
*Gastric necrosis
 +
*[[Disseminated Intravascular Coagulation - Pathology|DIC]]
 +
*Systemic Inflammatory Response Syndrome (SIRS)
  
−
===Radiography===
+
==Prognosis==
−
'''Abdominal radiography''' may be beneficial in confirming a diagnosis of GDV and distinguishing between GDV and gastric dilatation. Radiography should not be carried out until gastric decompression has been performed and intravenous fluids have been started. A radiograph performed in right lateral recumbency shows a dorso-cranially positioned pylorus to the left of the midline. The stomach will appear compartmentalised (the classic ''''double bubble'''' pattern) with a soft tissue strip separating the two compartments. The oesophagus may appear dilated with air or fluid. Evidence of air in the abdomen indicates that perforation has occurred and requires an exploratory surgical procedure. Loss of contrast in the abdomen may indicate [[peritonitis]] or haemoabdomen.
+
Simple GDV mortality rates are around 15%. Patients suffering from gastric necrosis, gastric resection or splenectomy have a higher mortality rate at over 30%. Gastric necorsis can be predicted by measuring plasma lactate. Values >6mmol/l indicates necrosis (Specificity 88%, Sensitivity 66%)
  
−
===Other Diagnostic Tools===
+
==References==
−
Plasma '''lactate''' concentration has been reported to have a strong link with the patient's prognosis due to its association with gastric necrosis and systemic hypovolaemia. A plasma lactate greater than 6 mmol/L is associated with a poor prognosis.
 
  
−
'''Electrocardiography''' (ECG) is essential as cardiac arrhythmias may occur in up to 40% of dogs with GDV. Most arrhythmias are ventricular in origin and occur within 36 hours of admission. [[Ventricular Tachycardia|Ventricular tachycardia]] is the most common rhythm disturbance displayed but many other arrhythmias may occur.
+
Hall, E.J, Simpson, J.W. and Williams, D.A. (2005) '''BSAVA Manual of Canine and Feline Gastroenterology (2nd Edition)''' ''BSAVA''
  
−
==Treatment==
+
King, L. and Hammond, R. (1999) '''BSAVA Manual of Canine and Feline Emergency and Critical Care''' ''BSAVA''
−
Once the patient has been stabilised, the volvulus should be surgically reduced via a cranioventral midline laparotomy. The aims of surgery include '''gastric decompression and repositioning, assessment of the abdominal organ viability, removal of necrotic tissue and gastropexy''' (to prevent recurrence).
 
  
−
Stomach contents should be removed using a large stomach tube or through a gastrotomy incision (taking care not to spill gastric contents into the abdomen) prior to any resection of devitalised tissue. Partial gastrectomy is ideally performed using a '''stapler''' as it is easy to use and considerably reduces the operation time.
+
Tivers, M. and Brockman, D. (2009) '''[[http://inpractice.bvapublications.com/cgi/reprint/31/2/66?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&author1=brockman&searchid=1&FIRSTINDEX=0&sortspec=relevance&resourcetype=HWCIT|Gastric dilation–volvulus syndrome in dogs 1. Pathophysiology, diagnosis and stabilisation]]''' 31(2):66 ''In Practice''
  
−
It is important to evaluate the '''viability of the stomach''' carefully (tissue thickness and colour should be assessed and vessels palpated for pulsations - in questionable areas a stab incision should be made and observed for signs of bleeding). If necrotic tissue is not properly identified and then incorporated into the closure wound, this may subsequently breakdown - resulting in peritoneal contamination.
+
Tivers, M. and Brockman, D. (2009) '''[[http://inpractice.bvapublications.com/cgi/reprint/31/3/114?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&author1=brockman&andorexactfulltext=and&searchid=1&FIRSTINDEX=0&sortspec=relevance&resourcetype=HWCIT|Gastric dilation–volvulus syndromein dogs 2. Surgical and postoperative management]]''' 31(3):114 ''In Practice''
  
−
'''Splenic damage''' due to avulsion or torsion may require partial or complete splenectomy. If complete torsion has occurred it is important perform a complete splenectomy '''before''' derotating the spleen. Failure to do so will result in the release of ischemic toxins and thrombi into the circulation on de-rotation. If avulsion or torsion is incomplete (and no thrombi are present) the organ should be re-positioned and then allowed to settle before assessing for viability. Lack of viability may appear as dark areas indicating ischaemia or infarction. Again splenectomy is easier to perform with stapling equipment. Splenectomy may also be indicated if any masses are present on the spleen or if haemorrhage cannot be controlled.
+
==From pathology section==
  
−
Many types of gastropexy have been described including the belt-loop, tube and circumcostal techniques. However the most commonly used in GDV surgery is the '''incisional gastroplexy''' as it is simple to perform and has low levels of complications. This technique involves making a partial thickness incision in both the pyloric antral region and adjacent right abdominal wall and suturing the two incisions together. The use of tube gastrostomy is associated with a higher morbidity rate due to alteration of gastric motility and development of cellulitis around the tube. The circumcostal technique produces reliable adhesions but is technically difficult to perform and can result in [[Pneumothorax|pneumothorax]]. Midline abdominal closure gastropexy should be avoided as this means that any future abdominal incision may penetrate directly into the stomach if the surgeon is not warned.
+
* Is a consequence of '''gastric dilation'''.
 +
** Gastric dilation occurs in dogs, cats, horses, rabbits and primates.
 +
** Cause unclear but may be associated with overeating.
 +
** Gastric dilation is most studied in dog, since it can lead to displacement of the [[Forestomach - Anatomy & Physiology|stomach]] within the abdomen.
  
−
The abdomen should be '''lavaged''' prior to closure.
+
===Clinical===
  
−
==Post-operative Complications and Care==
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* Mainly affects large, deep-chested dogs - Great Dane, St. Bernard's and occasionally German Shepherd dogs.
−
The most common complications following GDV surgery include '''cardiac arrhythmias, shock, [[hypokalaemia]] and surgical complications such as dehiscence'''. Ventricular tachycardia is the most common abnormal rhythm and continuous ECG monitoring is recommended for the 24-48 hours following surgery. Intravenous fluid therapy should be continued and the haemodynamic, acid-base and electrolyte balance should also be closely monitored. If vomiting occurs the patient should be evaluated for possible peritonitis and if gastric rupture.  
+
** A similar condition also occurs in the pig.
 +
* Animal collapses suddenly and must be operated on rapidly.
  
−
==Prognosis==
+
===Pathogenesis===
−
Simple GDV mortality rates are around 15%. Patients suffering from gastric necrosis or requiring gastric resection or splenectomy have a higher mortality rate at over 30%.  
+
 
 +
* Usually occurs around 30 minutes after a meal, or following aerophagia.
 +
** [[Forestomach - Anatomy & Physiology|Stomach]] is distended (gastric dilation).
 +
** Animal excercises, and the [[Forestomach - Anatomy & Physiology|stomach]] twists 180 degrees clockwise on its mesentery.
 +
* Torsion impairs the blood supply- the arterial supply is maintained BUT venous drainage is blocked.
 +
** [[Forestomach - Anatomy & Physiology|Stomach]] wall becomes severely congested and infarction of gastric mucosa may occur.
 +
* [[Forestomach - Anatomy & Physiology|Stomach]] blows up with gas and fluid.
 +
** Block venous return to heart.
 +
** Compresses diaphragm and interferes with respiration.
  
−
{{Learning
+
* '''The actual cause of the problem and the reason for accumulation of gas is unclear.'''
−
|Vetstream = [https://www.vetstream.com/canis/Content/Technique/teq00659.asp, Gastric dilation and volvulus]<br>[https://www.vetstream.com/canis/Content/Illustration/ill00376.asp, Gastric torsion - radiograph]<br>[https://www.vetstream.com/canis/Content/Technique/teq00694.asp, Gastropexy]
+
** It is better to feed big dogs small amounts more frequently.
−
|flashcards = [[Small Animal Soft Tissue Surgery Q&A 02]]<br>[[Small Animal Emergency and Critical Care Medicine Q&A 09]]
 
−
|literature search = [http://www.cabdirect.org/search.html?q=((title:(GDV)+AND+od:(dogs)))+OR+((title:(gastric)+AND+title:(dilat*)+AND+title:(volvulus)))  Gastric Dilatation and Volvulus publications]
 
−
}}
 
  
−
==References==
+
===Pathology===
−
*Gilson, SD (1998) '''Self-Assessment Colour Review Small Animal Soft Tissue Surgery''' '' Manson''
 
−
*Hall, E.J, Simpson, J.W. and Williams, D.A. (2005) '''BSAVA Manual of Canine and Feline Gastroenterology (2nd Edition)''' ''BSAVA''
 
−
*King, L. and Hammond, R. (1999) '''BSAVA Manual of Canine and Feline Emergency and Critical Care''' ''BSAVA''
 
−
*Tilley, L. P., and Tilley, L. P. (2008) '''Manual of canine and feline cardiology''' ''Elsevier Health Sciences''
 
−
*Tivers, M. and Brockman, D. (2009) '''Gastric dilation–volvulus syndrome in dogs 1. Pathophysiology, diagnosis and stabilisation''' 31(2):66 ''In Practice''
 
−
*Tivers, M. and Brockman, D. (2009) '''Gastric dilation–volvulus syndrome in dogs 2. Surgical and postoperative management''' 31(3):114 ''In Practice''
 
−
*Wingfield, W. E. (2001) '''Veterinary Emergency Medicine Secrets''' ''Elsevier Health Sciences''
 
  
 +
====Gross====
  
−
{{review}}
+
* Following the pathogenesis above the [[Forestomach - Anatomy & Physiology|stomach]] contents appear dark red/black and bloody, and the organ may rupture.
 +
* The [[Spleen - Anatomy & Physiology|spleen]] is also affected by venous occlusion.
 +
** Becomes very congested and moves from left to right side of abdomen.
  
−
{{OpenPages}}
+
====Histological====
  
−
[[Category:Stomach_and_Abomasum_-_Pathology]][[Category:Gastric Diseases - Dog]]
+
* Venous obstruction gives rise to congestion, oedema and necrosis of gastric mucosa.[[Category:Stomach_and_Abomasum_-_Pathology]][[Category:Dog]]
−
[[Category:Expert_Review - Small Animal]]
+
[[Category:To_Do_-_Clinical]]

Revision as of 11:48, 28 June 2010

 This article has been peer reviewed but is awaiting expert review. If you would like to help with this, please see more information about expert reviewing.


Category:WikiClinical CanineCow

Signalment

  • Large deep chested breeds including:

  • Akitas

  • Bloodhounds

  • Collies

  • Great Danes

  • Irish Setters

  • Wolfhounds

  • Newfoundlands

  • Rottweilers

  • Saint Bernards

  • Standard Poodles

  • Weirmaraners

Description

Gastric dilatation (GD) and Gastric dilatation and volvulus (GDV) are caused by the stomach distending with air. In GDV the stomach twists around its axis mainly in a clockwise direction with both conditions leading to compression of the caudal vena cava. GDV can lead to hypovolaemic shock, splenic torsion, gastric wall ischaemia, abdominal viscera congestion, endotoxic shock and disseminated intravascular coagulation (DIC). The exact pathogenesis is unclear but risk factors for GDV include age, fast eating, once- daily feeding, aerophagia, raised feeding bowl and a close relative with GDV.

Diagnosis

History and Clinical signs

Haematology

  • Increased haematocrit
  • DIC (thrombocytopaenia, increased firbin degradation products, prolonged patial thromboplastin time and reduced antithrombin III.)

Biochemistry

Most commonly find hypokalaemia and metabolic acidosis. The acidosis is caused hypoperfusion and anaerobic metabolism leading to lactic acid accumulation. Respiratory acidosis and alkalosis may also be present due to hypo- and hyperventilation.

Diagnostic imaging

Best performed after fluid therapy and gastric decompression. It allows distinction between GD and GDV:

  • Gastric dilatation: gas distension, on right lateral shows air in the fundus.
  • Gastric dilatation and volvulus: pylorus moves dorsally and left with a compartmentalized stomach. (GDV x-ray from WikiCommons[[1]])

A right lateral view will show a large fundus ventrally, with a smaller gas filled pylorus located dorsally to that. These are seperated by a soft tissue strip. The contrast of the abdomen may be lost indicating peritonitis or haemoabdomen. Gastric rupture would show as pneumoperitoneum and increased contrast.

Treatment

The most important first line treatments are fluid therapy and gastric decompression.

Fluid therapy

Should be individualised to the patient due to the varying nature of the acid-base disturbances. Large bore (16 or 18 gauge) catheters should be placed into cephalic or jugular veins (ideally two into both cephalic veins). Shock doses of Compound Sodium Lactate (Lactated Ringer's Solution) (60-90ml/kg/h). Hypertonic saline can also be used. Monitoring of the situation should be done by regular blood pressure measurements, heart rates, PCV and total solids and urine output. Potassium can be supplemented to bags in the form of KCl after the initial shock doses.

Gastric decompression

Performed by introduction of a lubricated premeasured (from nostril to last rib) stomach tube or by trocharizing the most tympanic area caudal to the ribs with a 14 to 16 gauge catheter. Sedation may be required to allow the passage of the stomach tube. Suitable drugs for this include butorphanol, fentanyl or oxymorphone and diazepam.

Other treatment

Anaesthesia

Anaesthesia must be carried out with care even after the patient has been stabilised. There are limited protocols but included fentanyl and diazepam bolus or titrated propofol. Maintenance can be achieved with the use of isoflurane and sevoflurane in oxygen however nitrous oxide should be avoided due to third spacing. Regular routine monitoring of urine production, blood pressure, central venous pressure, PCV, total solids, blood gas and serum electrolytes. High rates of fluids should be used to maintain tissue perfusion and arterial blood pressure.

Surgery

Surgical aims include:

  • Gastric decompression and repositioning
  • Assessing the organ viability
  • Removing necrotic tissue
  • Gastropexy (can perform incisional, tube, belt-loop and circumcostal techniques) to prevent recurrence

If gastric necrosis (happens in 10-37% of patients) is present (discoloured dark purple or grey/green, don't bleed when incised or feel paper thin) then a parital gastrectomy is required. Damage to the spleen via avulsion or torsion may need partial or complete splenectomy.

Post-operative complications

These are wide and varied and include:

Prognosis

Simple GDV mortality rates are around 15%. Patients suffering from gastric necrosis, gastric resection or splenectomy have a higher mortality rate at over 30%. Gastric necorsis can be predicted by measuring plasma lactate. Values >6mmol/l indicates necrosis (Specificity 88%, Sensitivity 66%)

References

Hall, E.J, Simpson, J.W. and Williams, D.A. (2005) BSAVA Manual of Canine and Feline Gastroenterology (2nd Edition) BSAVA

King, L. and Hammond, R. (1999) BSAVA Manual of Canine and Feline Emergency and Critical Care BSAVA

Tivers, M. and Brockman, D. (2009) [dilation–volvulus syndrome in dogs 1. Pathophysiology, diagnosis and stabilisation] 31(2):66 In Practice

Tivers, M. and Brockman, D. (2009) [dilation–volvulus syndromein dogs 2. Surgical and postoperative management] 31(3):114 In Practice

From pathology section

  • Is a consequence of gastric dilation.
    • Gastric dilation occurs in dogs, cats, horses, rabbits and primates.
    • Cause unclear but may be associated with overeating.
    • Gastric dilation is most studied in dog, since it can lead to displacement of the stomach within the abdomen.

Clinical

  • Mainly affects large, deep-chested dogs - Great Dane, St. Bernard's and occasionally German Shepherd dogs.
    • A similar condition also occurs in the pig.
  • Animal collapses suddenly and must be operated on rapidly.

Pathogenesis

  • Usually occurs around 30 minutes after a meal, or following aerophagia.
    • Stomach is distended (gastric dilation).
    • Animal excercises, and the stomach twists 180 degrees clockwise on its mesentery.
  • Torsion impairs the blood supply- the arterial supply is maintained BUT venous drainage is blocked.
    • Stomach wall becomes severely congested and infarction of gastric mucosa may occur.
  • Stomach blows up with gas and fluid.
    • Block venous return to heart.
    • Compresses diaphragm and interferes with respiration.
  • The actual cause of the problem and the reason for accumulation of gas is unclear.
    • It is better to feed big dogs small amounts more frequently.

Pathology

Gross

  • Following the pathogenesis above the stomach contents appear dark red/black and bloody, and the organ may rupture.
  • The spleen is also affected by venous occlusion.
    • Becomes very congested and moves from left to right side of abdomen.

Histological

  • Venous obstruction gives rise to congestion, oedema and necrosis of gastric mucosa.
Retrieved from "https://en.wikivet.net/index.php?title=Gastric_Dilatation_and_Volvulus&oldid=68148"