NSAID Induced Gastric Ulcers in Dogs

Fig 1: Perforating gastric ulcer of the pyloric antrum (arrow)

Non-steroidal antinflammatory drugs (NSAIDs) that are labeled for dogs have markedly improved management of chronic pain. However NSAIDs make the stomach more prone to ulceration by several mechanisms including mucosal irritation, reduction in prostaglandin production, decreasing gastric blood flow, and interfering with repair of superficial injury to the mucosa. This is a well-established phenomenon in humans and animals. A clinical study in dogs many years ago found that the most common causes of non-neoplastic ulcers in dogs were NSAIDS and hepatic disease.¹  In the past few years, most likely due to widespread and chronic use of NSAIDS in dogs, we have seen an alarming number of dogs with perforating gastric ulcers. Ulcers have been associated with multiple drugs and in some cases due to more than one type of NSAID being used concurrently or a NSAID used with a corticosteroid drug.

Fig 2: The forceps is demonstrating the full thickness ulcer

Diagnosis

The dogs with perforating gastric ulcers present with variable signs that include vomiting, anorexia, lethargy, and abdominal pain. Abdominal radiographs frequently show pneumo-peritoneum and loss of serosal detail. (Fig. 3) Emergency abdominal exploratory is indicated.

Fig 3:Right lateral abdominal radiograph of a dog with
pneumoperitoneum. Note the intraabdominal air visible under the
crura of the diaphragm. (arrows) Radiograph courtesy of Dr. David Biller
Kansas State University College of Veterinary Medicine

Surgery

The perforating ulcers tend to be located at the lesser curvature of the pyloric antrum very close to the pylorus. (Fig. 1-2) Inflammation and omental and serosal adhesions are commonly found on the affected area.  Generalized peritonitis is usually present with serosal inflammation and peritoneal effusion.

After performing a complete surgical exploratory attention is focused on the ulcer. Adhesions are removed and the edges of the ulcer are debrided. The edges of the ulcer tend to be very thickened and friable. This resected tissue is saved and submitted for histopathology to rule out malignancy. Samples of peritoneal fluid are submitted for culture and sensitivity.

Fig 4: Closure of gastric ulcer using a local full thickness flap.

To close the ulcer I have found it helpful to develop a full thickness local advancement flap of pyloric antrum and move it to the site of the defect. (Fig. 4) Closure is with 3-0 or 4-0 PDS in a simple interrupted pattern.  A Jackson-Pratt (closed suction) drain is placed in the abdomen to remove fluid and is left in place for several days.  Postoperative intensive care is required for management of the peritonitis including fluid therapy, nutritional therapy, antibiotics, and gastric antacids and protectants.

Prevention

Prevention of this potentially life threatening complication of NSAID administration should be considered for all dogs and cats receiving these drugs.

Recommendations to prevent gastric ulcers secondary to NSAIDS:

• Allow a “wash-out” period of 3-5 days when changing from 1 NSAID to another;
• Never prescribe more than 1 NSAID at a time;
• Never administer a NSAID and a corticosteroid at the same time ²;
• Avoid using NSAIDs in dogs with gastrointestinal disease or after gastrointestinal surgery of any kind;
• Avoid using NSAIDs in dogs with mast cell tumors (histamine release by the tumor can cause gastrointestinal irritation);
• Avoid administering NSAIDs to animals that are anorexic.

 References

Stanton ME, Bright RM. Gastroduodenal ulceration in dogs. Retrospective study of 43 cases and literature review. J Vet Intern Med. 1989 Oct-Dec;3(4):238-44.

Boston SE, Moens NM, Kruth SA, Southorn EP. Endoscopic evaluation of the gastroduodenal mucosa to determine the safety of short-term concurrent administration of meloxicam and dexamethasone in healthy dogs. Am J Vet Res. 2003 Nov;64(11):1369-75.

The Story of Crystal, The Chicken That Ate Metal

Crystal
(This really is Crystal, not some random picture from the internet.)

I guess you could say she was into “heavy metal”, but not the musical kind. She was a pet Rhode Island Red chicken (above). The fact that she had a name was a clue that she was not just your run of the mill member of a flock. She presented to the Veterinary Hospital at Ohio State many years ago for treatment of suspected gastrointestinal foreign bodies. Our avian veterinarian, Dr. Barb Oglesbee, admitted Crystal and did a diagnostic evaluation. After determining that foreign material was present in her GI tract, she performed endoscopy under general anesthesia and removed multiple metallic foreign bodies from the crop and proventriculus.

Metallic foreign bodies removed from Crystal's crop and proventriculus
by endoscopy. The nickel is shown for sizing purposes only.

However, one piece of metal remained that could not be removed by endoscopy. Dr. Oglesbee came to me for a surgical consult. My first reaction was: “Really? You want me to do an abdominal exploratory on a chicken?” I had done surgery on birds before but never on a chicken. All veterinarians know that sometimes you have to go outside of your comfort zone and do what needs to be done.

Crystal was still under anesthesia from the endoscopy so she was transported to the surgical area and her abdomen plucked and prepped for surgery. I ran to my office to do a quick avian abdominal anatomy review, developed an impromptu plan and returned to the surgical prep area to get the surgical team ready.

Basic anatomy of the chicken. 
www.poultryhub.org

We positioned Crystal in dorsal recumbency and did a ventral abdominal midline approach. A nail was immediately found protruding from the gizzard, and black caseous debris was present around the gizzard in the peritoneal cavity. 

Nail protruding through the gizzard (arrows). Black caseous
debris is due to leakage from the gizzard.

We performed a “gizzard-otomy” to remove the nail and closed the gizzard with simple interrupted absorbable sutures. Inverting suture patterns would have been impossible on this very muscular organ.  We then flushed the peritoneal cavity and did a routine closure of the abdomen. I did not place a drain in the abdomen since bandaging the abdomen would have been difficult and removal of the drain by the patient seemed like a good possibility.

The nail and other metallic debris removed from Crystal's gizzard.
The dime is for sizing purposes only.
(Crystal did not eat money.)
(Well considering the bill for surgery maybe she did!)

One of the interesting things that occurred during the surgery on Crystal was related to the hemostasis. As is done routinely in surgery we used electrocautery to control bleeding. When we used it on Crystal, particularly in the muscle, we became aware of something. The smell of cautery on the muscle was like fried chicken! I guess that's because it was . . . fried chicken! I can honestly say it was the first time that operating on a patient stimulated my appetitie!

Amazingly, Crystal made a full recovery with no complications. This was incredible considering she had a perforated gizzard and septic peritonitis. She returned home and probably started searching for more metal. 

For so many reasons, I will never forget this patient.

Gastric Invagination for GDV Induced Necrosis: Safe and effective, or risky and ill advised?

 

Gastric necrosis along the fundus and body of an Irish Setter with GDV.
Note the abnormal color and sharp demarcation between normal and devitalized tissue.

The gastric invagination technique was first described in a series of experimental dogs in 1986.¹ The necrotic area of stomach, instead of being removed by partial gastrectomy, was pushed into the stomach lumen and over sewn with inverting suture patterns. The devitalized tissue was left to be digested by the stomach enzymes allowing the healthy tissue to heal. Some of the dogs in the study had melena for several days and healing of the gastric wall took more than 2 weeks.

The technique seems to fly in the face of conventional surgical wisdom. Necrotic tissue is supposed to be removed.  Allowing the dead tissue to remain and then slough out in the stomach lumen would potentially result in a serious gastric ulcer and possible delayed healing of the stomach wall. In fact, a case report described that very scenario.² A German Shepherd, 3 weeks after surgical treatment for GDV and gastric invagination, presented with a bleeding ulcer that required partial gastrectomy. The dog had also developed a splenic torsion.

Although anecdotal, many surgeons have reported performing gastric invagination on dogs with good success and minimal complications. Dr. John Williams, a respected and experienced surgeon in the United Kingdom, wrote in a book chapter: “Gastric invagination is a quick, safe, and effective technique.”³ Personally, I have performed the technique on only a few dogs over the years but they have done well and did not develop bleeding ulcers.

As with most controversial issues common sense probably lies somewhere in the middle ground. The accepted technique for treating necrotic stomach is partial gastrectomy. Stay sutures are placed around the necrotic area, the tissue removed and the stomach closed with a double layer inverting suture pattern (Cushing followed by Lembert patterns).

However, invagination could be considered in these situations:

• The surgeon’s skills and facilities do not allow for a properly performed partial gastrectomy,
• The dog is not stable under anesthesia and the surgery needs to progress quickly,
• The necrotic area is relatively small and well demarcated,
• PDS or similar suture is available for the closure,
• Appropriate postoperative monitoring and care can be administered.

The invagination is begun by placing a continuous inverting suture
(Cushing pattern) with 2-0 PDS grabbing healthy tissue at the dotted lines.

This is the same dog as above after completing the invagination
with a second layer of inverting suture (Lembert pattern)

Here are a few other considerations. If invagination is performed, monitor the dog postoperatively for evidence of bleeding ulcer or other issues such as peritonitis. Also, treat the dog with gastric protectants like Sucralfate and antacids such as famotidine. These drugs should be continued for at least 1 month postoperatively.

Additional observations: If the the short gastric vessels have been ruptured or thrombosed as a result of the GDV, the spleen may also be infarcted and may have to be removed. Also, I have not had good success with stomach stapling for partial gastrectomy. Problems with delayed healing and leakage have been my experience and that of others.  The stomach tissue tends to be quite thick and I think the staples may not always properly engage and appose the tissues, particularly in dogs with GDV.

1. MacCoy DM, Kneller SK, Sundberg JP, Harari J. Partial invagination of the canine stomach for treatment of infarction of the gastric wall. Vet Surg 1986, 15:3, 237-245.

2. Parton AT, Volk SW, Weisse C. Gastric ulceration subsequent to partial invagination of the stomach in a dog with gastric dilatation-volvulus. J Am Vet Med Assoc. 2006 Jun 15;228(12):1895-900.

3. Williams JM. Gastric dilatation and volvulus. In: Williams and Niles, editors BSAVA Manual of Canine and Feline Abdominal Surgery. British Small Animal Veterinary Association, 2005, pg. 80.

VKP Goes International, and What's In Store for Next Week?

Page visits from all over the world!

We have been up and running for 2 weeks and below is a list of which countries have been the source of our page views, and how many for each country:

United States 4899
Greece 229
Canada 93
Japan 87
United Kingdom 24
Cyprus 10
France 9
Australia 7
Germany 7
Oman 5

Almost 5500 hits in total! Amazing that veterinarians from all over the world are learning the Halsted Chant and what to say when you make a mistake in surgery. It would be wonderful to know how to say "There" in all the languages represented by these countries! Anyone want to help with that?

It is very gratifying to know that this many veterinarians and others in the profession and the general public have been interested in the blog. Again thanks to all of you who have written kind words either on facebook or in the comments section of the blog. Your enthusiasm is the fuel that drives the engine of VKP so keep the comments coming. Also, constructive criticism is welcome and ideas for future topics would be excellent. I have many ideas but I would love to know what you want.

What's in store for next week?

We will do one more session on GDV; a simplified method for handling gastric necrosis associated with GDV. Then we will talk about NSAID induced perforating gastric ulcers in dogs. They have increased in frequency in my experience and they can be life threatening. So tune in for both of these in the days to come.

One more very important update:

The animated GDV stomach video (previous blog) now has musical accompaniment! Check it out!

Incisional Gastropexy: Detailed description and video!

Fig. 1: The letters and arrow indicate where the gastric incision
is made for incisional gastropexy

A critical part of the operative treatment for GDV is to perform a gastropexy. Creating a permanent adhesion between the pyloric antrum and the right side of the abdominal cavity prevents recurrence of rotation of the stomach. Many options for gastropexy are available, including tube gastrostomy, circumcostal gastropexy, belt loop gastropexy, or incisional gastropexy. Because of its simplicity, incisional gastropexy has gained popularity among surgeons in recent years. Creating a seromuscular incision in the pyloric antrum and a similar incision in the interior abdominal wall starts the incisional gastropexy. These two incisions are sutured to each other to create the permanent adhesion. Incisional gastropexy is a straightforward technique and studies have shown it to be very effective at preventing gastric volvulus in dogs.

            
In addition to performing the procedure for dogs that have already developed GDV prophylactic gastropexy is also indicated in dogs that may develop GDV sometime in their life. (see previous blog on risk factors for GDV)

Towel clamps are placed on the edge of the right body wall and held by an assistant to increase exposure. A simple interrupted suture of 2-0 PDS (taper needle) is placed at the lesser curvature of the pyloric antrum ("a" in Fig. 1) and sutured to the interior of the abdominal wall just caudal to the last rib. A second suture is placed at the greater curvature of the antrum ("b" in Fig. 1) and then sutured to the interior of the abdominal wall at a point approximately 4-6 cm caudal to the first suture depending on the size of the animal. (Fig. 2) The needles are left on these initial sutures since they will be used to suture the stomach to the abdominal muscle after incisions are made.

Fig. 2 The pyloric antrum has been tacked to the interior of the
body wall on the right side.
(R: right, L: left, Cr: cranial, Ca: caudal)         

A seromuscular incision is made in the pyloric antrum being careful not to enter the stomach lumen. The incision is perpendicular to the long axis of the stomach. (arrow in Fig. 1) To start this incision, the stomach wall can be pinched between the thumb and first finger. Allow the gastric mucosal layer to slip through the fingers and thus not be included in the incision. Metzenbaum scissors or scalpel are used to incise the tissue being held by the fingers which amounts to a seromuscular incision. This incision is then lengthened by using the Metzenbaum scissors to undermine the seromuscular layer and separate it from the mucosal layer. The scissors are then used to incise the seromuscular tissue to complete the stomach incision. A corresponding incision is then made in the interior abdominal musculature the exact same length as the stomach incision. (Fig. 3)

Fig. 3 Incisions have been made in both the stomach and body wall.

Use the previously placed PDS sutures to appose the stomach incision to the abdominal incision. Suture the lateral aspect of the stomach incision to the dorsal aspect of the abdominal incision with one suture line. (Fig. 4) 

Fig. 4 The lateral aspect of the stomach incision has been sutured
to the dorsal aspect of the body wall incision.

Then suture the medial aspect of the stomach incision to the ventral aspect of the abdominal incision with the other suture line. (Fig. 5)

Fig. 5 the medial aspect of the stomach incision has been sutured
to the ventral aspect of the body wall incision.

Video:

Acknowledgement: Thank you to my good friend and colleague Dr. Gary Ellison for his help in developing this incisional gastropexy technique.

Decompression of the massively distended GDV stomach: Needle or stomach tube?

The dog presents in distress, pale mucous membranes, shock, and a has huge gas distended stomach. The owner says he has been trying to vomit for several hours but has only brought up some foamy fluid. Radiographs reveal a very large stomach filled with air and a Smurf hat appearance on the lateral view (see previous blog on diagnosis). The distended stomach is compressing the vena cava causing hypovolemia and inhibition of normal respiration by putting pressure on the diaphragm.

First step?

From: www.studyblue.com

The two most importance initial actions in GDV are to begin intravenous fluid therapy at shock doses (90ml/kg/hr), and to decompress the stomach. Decompression can be via gastrocentesis with a needle or over-the-needle catheter or with a stomach tube. I have used both, but in a severely affected dog my first step would be to do a quick clip and prep of the lateral abdomen over the area of greatest distention and insert a large bore over the needle catheter percutaneously into the stomach to evacuate the air. In a large dog a 14 gauge, 6 inch catheter (horse jugular vein catheter) works very well.

Large bore over the needle catheter is being placed into the stomach percutaneously

Massage the abdomen to allow additional air to escape. This is a quick and effective way to initially empty the stomach and allow improvement of venous return and cardiac output.

I would then attempt to pass a stomach tube. It is not necessary to use a large stomach tube; a medium or even smaller sized tube is all that is necessary. Measure the tube from the tip of the nose to the 13th rib and place a piece of tape in that spot to serve as orientation and let you know when you are at the cardia of the stomach. Lubricate the end of the tube with KY jelly and gently pass it into the stomach. Do not try to force the tube into the stomach if you feel resistance. The gastric fundus and cardia may be compromised so gently pushing the tube in this area is important. Sometimes a slight twisting motion will help get the tube past the cardia. Try putting the dog in different positions if the tube will not pass initially. A stomach tube is more likely to remove fluid and solid debris from the stomach than gastrocentesis.

If there is an anticipated delay between initial treatment and the surgery to correct the GDV, an option to maintain decompression is to pass a nasogastric tube. Although this will be a small bore tube (a 14 Fr size tube would be ideal) it can be used to remove excessive gas from the stomach and keep the animal stable during the interim period between emergency treatment and surgery.

From: Crisp MS. Critical care techniques in Saunders Manual of Small Animal Practice.  1st edition,  Birchard and Sherding, editors, W.B. Saunders, 1994, pg 22.

Acknowledgement: Thank you to my wife Dr. Becky Ball for her help with this blog.

Next blog: Incisional gastropexy to prevent recurrence of GDV.

Blog Site Updates

I added a couple of features to the Veterinary Key Points site. In the upper right column, you'll see a box entitled "Search This Blog". You can type in key words to quickly find content that you are interested in.

The other feature is just below the search box and is entitled "Follow By Email". If you want to be notified by email when a new post is added to the blog, type your email address in this box and it will automatically send you an email whenever new content is posted.

I recently read an article that said that posting something on facebook only reaches 16% of your friends! That is very surprising and is the reason I added the email notification feature to the blog. I want to make sure everyone who is interested is getting the word whenever something is hot off the presses.

One other thing: the features that I added can only be seen on the web version of the blog. If you are viewing the blog from your smartphone, scroll down to below all the blogs and click on "View Web Version" which is just below the "Home" button. Then you will see the boxes I mentioned above.

Thanks for your interest and stayed tuned! We're just getting started!