Hi, my name is Tara Bellis. I'm a critical care specialist working predominantly in the eastern part of the United States, and I'm excited to talk to you today about approach to gastrointestinal emergencies. So the learning objectives that we'll cover throughout this talk are listed here and by the end of this presentation, my hope is that you're able to recognise gastrointestinal emergencies in dogs and cats, prioritise stabilisation and feel comfortable triaging them and to review evidence based diagnostics with you that will help you to implement treatment strategies.
There are certain things that an owner may reveal that will provide you with a little bit of an indication as to what might be going on with the patient and certainly signalment will provide certain clues like for example, younger patients are going to be more predisposed to trauma or toxicities and then older patients of course more likely to have metabolic diseases or potentially neoplasia. And then certain breeds will be more predisposed to having certain disease processes that we'll cover a little bit later on in this. Talk.
So when we ask the owners questions, we need to determine, is there any history of potentially having eaten foreign material? Are the pets indiscriminate eaters or could they potentially have had any food that they don't normally have. Certainly exposure to toxins is relevant and it's also important to determine are they vomiting or is this regurgitation, and so that can be ascertained with the questions that you ask.
Are they actively vomiting versus passively regurgitating? Is there any diarrhoea? Is that large bowel, small bowel?
Is there any straining? And are they eating? Are they bright and alert, or are they, lethargic?
When you're examining the pet, first and foremost from a triage perspective, you're always going to want to get your vital signs and check your airway, breathing, circulation and mentation. Obtaining your vitals includes obviously your temperature, pulse rate and respiratory rate, and then do keep in mind the SERS criteria that would indicate an inflammatory disease process in dogs or cats. Then it's really important to be able to assess your perfusion parameters comfortably to rule in or out shock and very commonly we will see hypovolemia in our dehydrated patients.
And so we're gonna cover a little bit about that in the next slide. Other specific things to consider for a physical exam when it comes to GI emergencies is abdominal palpation, of course. So if you hold the front legs up in large breed dogs that can help you to palpate the stomach because obviously it's quite tucked up under the ribs.
And it's important as well that you feel the entire length of the small intestines for any potential masses or foreign material. Obviously if the pet is painful or guarding the abdomen, do exercise caution. In cats, of course, the abdomen is a little bit more malleable to palpation, and so in those circumstances you might feel some firm stool, especially if they're dehydrated.
And maybe they have abdominal distention that could indicate a fusion, in which case you might appreciate a fluid wave or thrill. And then of course there are certain disease conditions, specifically gastric dilatation and volvulus or bloat that will cause a tympanic feel, and you can percuss the stomach and appreciate tympani in those cases. Do be careful with referred back pain because those patients that have discomfort along the thracalumbar or lumbar region.
May exhibit as if they have abdominal pain. Certainly they may be tensing when you come to palpate their abdomen. So with these patients that present for really anything on emergency, you're always going to want to do a more complete neurologic exam after your primary assessment.
So do take care to feel for any potential back pain and assess cranial nerves and proprioception as well. Please don't forget to perform a rectal examination. It's such a crucial part of our physical exam.
There have been studies that have shown how many things get missed when you don't perform a rectal examination, but definitely an important part, especially if a pet has been having vomiting or diarrhoea. So I'd be remiss as a criticalist not to go into a little bit more detail about shock because it is such an important component of managing a patient that comes in through emergency, whatever the reason. And I just highlighted here for you the hemodynamic types of shock that we see most commonly that will affect perfusion.
So that's hypothalemia, distributive, cardiogenic and obstructive shock. As a reminder, all of those with the exception of cardiogenic are going to be addressed primarily with intravenous. Fluids and then our subset of shock, hypoxic, anaemic, and metabolic are just listed there for your reference, less likely to be involved in our gastrointestinal emergencies, but certainly could be part of the whole picture, so something worth knowing about.
But coming back to the perfusion aspect, these patients, when they have vomiting and diarrhoea, they can have hypovolemia pretty commonly, and it will be the most prevalent type of shock that we see, but there are certain conditions that will lead to distributive or obstructive shock that affects the gastrointestinal system. It is absolutely crucial that you feel comfortable assessing the core perfusion parameters, so they're listed here for your reference. Please remember that heart rate will commonly be low in cats in shock, they can be tricky, so.
If a cat has bradycardia and no suggestion of congestive heart failure, I would always be concerned that that cat is in shock until proven otherwise. And then don't forget about breed differences, so we have this table over here that categorises our hypovolemic, mild, moderate and severe types of. Responses, but it is important to remember that a large breed dog is going to have a different resting heart rate to a small breed dog.
And so if a Great Dane comes in with a heart rate of 100, that is concerning and considered to be tachycardia versus a Yorkshire Terrier comes in with a heart rate of 100, much less concerning. So something to keep in mind. And then we have some supplemental diagnostics ancillary tests if you will, that will help us to determine shock in our patients.
There's a shock index we can calculate, which is heart rate over blood pressure and serum lactate or plasma lactate will also give us a lot more information which I'm going to cover in a second. Blood pressure, systolic blood pressure via a Doppler is going to be your most accurate means of blood pressure if there's high or low blood pressure, but obviously a noninvasive oscillometric blood pressure can be utilised as well. So with that, we'll dive a little bit more into the diagnostic approach for our gastrointestinal emergencies.
So typically when an emergency presents and you're assessing it, getting vitals, doing your primary and secondary assessment, you'll be placing an IV catheter, excuse me, to provide . Fluid therapy and pain relief, but also you're gonna get a lot of information from your minimum database. So this picture here just shows the little amount of blood that is retrieved from an IV catheter hub that has so much useful information in it.
So with this I would always check a PCV total protein or total solids, a blood glucose and a lactate, and obviously we have these handheld. Monitors now available throughout most veterinary practises. Point of care allows us to get bedside values on glucose and lactate, and that can be really helpful for our initial stabilisation.
Please don't forget to interpret PCV with total solids because the two together are going to give you a lot of information. And then obviously as we expand our diagnostic profile, most of these cases we are going to recommend doing a complete blood count or haematology and a full biochemistry. Electrolytes are absolutely a crucial part of an evaluation of a GI emergency, and blood gas or acid-based analysis, if you have the capability, is also very helpful.
Certainly metabolic acidosis is going to be the most common acid-based arrangement that we see in our small animal emergency patients, but. When we have an upper GI obstruction, we'll commonly see a hypochloremic, hypokalemic, metabolic alkalosis, and so that can also be helpful to guide our diagnosis. And then of course we've got additional testing that we can expand to depending on where our diagnostics are leading us and depending on obviously what our assessment is suspicious or indicative of.
So here's a slide providing a little bit more detail about lactate, and specifically in the context of GDV because that is one of the gastrointestinal disorders that we have studied it the most in. Just a reminder, type A hyperlactatemia is related to global hypoperfusion, so we get high lactate when a patient is in shock because they have a reduction in oxygen delivery to the tissues and as a consequence, the body is utilising energy in an anaerobic way and lactate is a byproduct of that. So as the lactate is going up in the blood, it's indicating to us the severity of hypoperfusion and hypovolemia.
There's also type B hyperlactatemia, which we'll see in sepsis and septic shock and inflammatory states. So some of the literature that you might be familiar with surrounding lactate and GDV is just listed here, dating back from the late 90s. There was a pretty fundamental paper that concluded that high lactate over six was associated with gastric necrosis and therefore mortality in dogs with GDV.
But subsequent to that, as we're learning more and understanding more about lactate, there was a little bit more emphasis on lactate clearance, so There was another study in 2014 that evaluated how quickly lactate was reduced, irrespective of the initial number, how quickly was it normalised, and they found that a decrease over 40% after fluid resuscitation was associated with a better survival. So that kind of prompted us to pay a little bit more attention to what was the initial lactate, but also what is the lactate doing after fluid resuscitation. Because sort of you can infer that as you fluid resuscitate a patient, you're able to restore perfusion to the tissues, you convert them to an aerobic metabolic state and lactate starts to decrease.
And so that would indicate that you're successfully treating the hypovolemia and the shock. If the lactate remains sustained at a high level, then that tells us that there's ongoing systemic inflammation. And other things need to be utilised to help treat that patient, and so in this particular study they did find a worse outcome with an initial increase in lactate in the face of fluid resuscitation.
And then more recently in 2020, there was another study that looked at both initial lactate and lactate clearance as it pertained to outcome in GDVs and found actually no association between the initial lactate or lactate clearance. And that may be in part due to our fluid resuscitation strategies and now has set out how they have resolved over the years in addition to our stabilisation practises and incorporation of vasopressors and things like that. But it's important to remember.
That when we're thinking about prognostic factors and indicators, we have to really use caution in our conversations with the owners because obviously these are averages and a lot of our studies do include humane euthanasia which will infer a bias. So the most important takeaway for me to convey to you with regards to lactate and GDV or any gastrointestinal issue or any emergency is that a high lactate at presentation indicates severe hyperperfusion. Plus minus inflammatory, processes, and the quicker that you can normalise the lactate, the better for the patient.
So after we've obtained our minimum database and our bedside sort of vital parameters, we're going to move into doing more diagnostics. Now, commonly these days practises are equipped with ultrasounds that we can use at the bedside. So a lot of our emergency patients will have a point of care ultrasound prior to moving forward to radiographs.
And I'm gonna cover that in the next couple of slides in a little bit more detail. But there's still of course a place for radiographs when it comes to gastrointestinal emergencies, and certainly if we're expecting to see air or an obstruction or a foreign body, radiographs are going to have a great clinical utility. If a patient is sick, we really don't want to manipulate them too much for radiographs, which is why point of care ultrasound really became so useful at the bedside, because we can fluid resuscitate.
Our patients and stabilise them while also gaining, you know, imaging information. But if we're able to get x-rays on our patients, always remember to take orthogonal views. A lot of radiographs now are going to be evaluated by a radiologist.
And please, if a patient is hemodynamically compromised but you are getting radiographs, don't put them on their back. That will compromise venous return. Make sure that you're performing the radiographs in a DV position.
And then there are some indications as to what to look for on radiographs, what patterns we look for that might indicate small intestinal obstructive diseases. So for example, the bowel being distended over 1.6 times the height of L5 is something that we'll consistently evaluate for.
And then of course we might see poor contrast if the patient has ascites or a fusion in the abdomen, but hopefully using our point of care ultrasound we've already determined that. Don't forget when you're asking questions to the clients about the history for the patient, if they have any regurgitation of your. Suspicious for regurgitation, to incorporate chest x-rays, but also in a lot of these GI cases, you know, aspiration is a risk, and if they've been vomiting, it's always a risk.
So considering doing thoracic radiographs as well as part of your diagnostic profile would be very reasonable in most of these cases. So here's a slide just with some pictures on different types of patterns that we'll see radiographically that can be diagnostic. So anything with air is going to be diagnostic on a radiograph more so than on an ultrasound.
GDV here's our classic, but on this it's worth noting that a little bit of the chest is visible on this abdominal right lateral radiograph and a megaesophagus or oesophageal dilation is evident, as is a lobar sign and some. Consolidation there in the lung. Obviously we can't interpret that fully because it's not a thoracic radiograph, but please remember in our GDV specifically, they do have a high incidence of aspiration pneumonia and so performing chest x-rays is crucial before you go into surgery.
The picture on the right there, the upper right, has a pneumoperitoneum, so that is a little bit of gas there between the diaphragm and the abdomen, and that's evident as a potential perforation or rupture. And then on the bottom left we've got food bloat, so really, really distended stomach full of food, in that case, that patient probably got into a food bag. And then over on the bottom left there some obstructive pattern where we see two loops or distinct loops of intestine that are dilated and they are quite largely dilated and so that would be indicative of an obstruction.
Now obviously these X-rays are just for the purposes of this presentation are all lateral X-rays. The only time we're really going to get a good diagnosis on a lateral is with a GDV which would be a right lateral. Otherwise, as I said before, orthogonal views are always going to be indicated.
So here's a slide on point of care ultrasound and there's a lot of information that can be obtained with this technique. I put this picture here because this pet is standing and I think it's important to note that as ultrasound has evolved at the bedside, certainly in. Emergency practise, we are now pretty confident and competent at performing this diagnostic technique with the patient in either sternal or in a standing position.
Remember, fluid will always fall dependently, so it's often easier to obtain if there's a small amount of fluid if the pet's standing. But also a lot of these patients that come in through emergency are going to be sick, hypothalemic, hemodynamically compromised, and so restraining them in lateral is often contraindicated. And certainly that's why point of care ultrasound really has come to the forefront with our diagnostics over radiographs to get very quick, life saving information.
Please remember to not apply too much pressure because if there's a small amount of fluid, you can actually displace it and then you won't be able to see it. And then also, do remember to rescan after fluid resuscitation, so much like when you fluid resuscitate a patient, you're reassessing your perfusion parameters, it is super important to be able to reassess them ultrasonographically as well, because when a patient is really volume deplete, they may not have any effusion, and once you volume resuscitate them, they will start to effuse if they have septic peritonitis or a perforation and. So that is a key time to reevaluate.
And then I did put a reference up here for abdominal fluid scoring, which is described in the literature and that's something that if the fluid is worsening would be an indication for obviously obtaining a sample but then ultimately potentially for surgery as well. So that can be quite helpful to perform an abdominal fluid score on a serial basis if you're trying to make treatment decisions. There's been a lot of interest recently or in recent years around expanding our use of point of care ultrasound, and an area of focus has been using it to assess volume responsiveness.
So as I mentioned, fluid resuscitation is very common part of emergency practise, and certainly our gastrointestinal emergencies often will require fluid. And fluid resuscitation. So we can use ultrasound to help guide that.
So the picture to the left there is actually a collapsed left ventricle. So the, the lumen of the left ventricle, I put a reference picture just next to it. The lumen of the left ventricle is completely empty and you'll see that the left ventricular walls are actually the The inner walls are touching each other and that is a patient, a real life patient, a Yorkshire Terrier that had acute hemorrhagic diarrhoea syndrome and was very, very, very hypovolemic, and you can see a great visual there that he had such a poor cardiac output and so required a significant amount of volume resuscitation to re-establish preload.
And then over to the right, I've got a picture there that I pulled from another resource that is evaluating or demonstrating how to measure caudal vena cava distensibility or collapsibility, and so that's an area that there's a few more recent publications in looking at the. To predict fluid responsiveness in patients that are hypovolemic and it's another tool that we have to help guide our determination on whether a patient needs more fluid as part of their resuscitation strategies or whether they might need to move on to vasopressors and so on. If you do see abdominal effusion, always, always, always take a sample, it can just be a small sample, but this is going to be diagnostic for septic peritonitis, if you see bacteria, intracellular bacteria.
You can also just evaluate, of course, the slide for degenerate neutrophils. Near plastic cells, but the sample of fluids that you take should also be looked at with the refractometer and just by knowing what the total protein is, you can classify your fluid type into a transudate, a modified transudate or an exudate. There are described techniques on how to perform diagnostic peritoneal lavage if you can't see any obvious fluid pocket, or you can perform a four quadrant technique.
But often, like I said, after fluid resuscitation, if you can identify a small pocket of fluid, please do get a sample because that will help you to make a diagnosis. And then with that sample of fluid you can do more of a fluid analysis, so I just listed here for your reference those categories that I mentioned that you can establish with your total protein looking at it on the refractometer. But if you're able to also evaluate nucleated cell count, that can help you to further categorise and that's gonna help you to narrow down your causes of effusion.
So there are some other fun things that we can do on peritoneal effusion, specifically as it pertains to making a diagnosis of septic peritonitis. We can look at the glucose and the lactate on the fluid and compare it to that minimum database that we obtained on presentation. So generally speaking, if the glucose is lower in the fluid and the lactate is higher than it is in peripheral blood, that is supportive of a diagnosis of.
Septic peritonitis in dogs and cats, there's a slight variation on sensitivity and specificity, and ultimately your diagnosis should be more definitive with a cytology evaluation that confirms the presence of intracellular bacteria. But these two tests can also be supportive because of course if you have septic peritonitis, it is crucial that you make the decision to go to surgery on the sooner side. So now we've got some diagnostics underway, let's talk about stabilising and treating the patient.
As you've assessed your patient's perfusion parameters, you'll make a determination as to whether or not they are hypovolemic, and certainly if they are restoring volume via a fluid bolus is really important. If they are dehydrated, then obviously we can give fluid back to the interstitial space, they can get. Subcutaneous fluids or potentially maintenance IV fluids if they have ongoing losses, but in the immediate sense it's always vital to determine does the patient need restoration of volume, in which case a fluid bolus is going to be most appropriate.
Isotonic crystalloids that are balanced are always going to be our first best choice. There has been some historic interest in lactated ringers, the fact that it contains lactate, could that potentially make hyperlactatemia worse. The summary or the summation of the investigation.
Has been no, it's not going to do that. In fact, using lactated ringers, which is a buffered solution, is going to correct the metabolic acidosis more rapidly and therefore decrease the lactate probably more quickly. So the little amount of lactate that it contains as a buffer is not going to do any harm.
And so giving fluids that are balanced, that are going to treat the metabolic acidosis that's occurring as a result of the hypothalemia is really crucial. The total shock dose that you'll see reported in the literature really refers to the blood volume in both dogs and cats, so that's 60 to 90 mL per kilo in dogs and 40 to 60 mL per kilo in cats. And so we're not going to intend to replace the entire blood volume immediately, what we do is we give a bolus.
And in increments, we give small amounts and then we reassess perfusion parameters to determine whether or not we need to repeat those boluss. And so for dogs we typically will give a 10 or 20 or even maybe a 15 in the middle there, mL per kg bolus over about 10 to 20 minutes. And in cats, I tend to go lower and err on the side of caution.
Cats, as you guys probably know, are very prone to fluid overload and may have underlying cardiomyopathy. So we'll go a little bit more cautiously on cats, we can always give more, we're reassessing our fluid responsiveness with our perfusion parameters, repeat blood pressure, repeat lactate, and so on. And then just remember that in large dogs, based on the drip pumps and the rapidity with which they can give fluids, often you're going to need a pressure bag to deliver that bolus over that recommended period of time.
Otherwise, if you set, a fluid machine to 999 mLs an hour, it is literally going to provide the pet with a litre over 1 hour, and you may want to get a litre into that patient in a quicker period of time. If they are a large dog and they're profoundly hypovolemic, so something to keep in mind. Then we're always re-evaluating our perfusion parameters, as I mentioned, and using our other ancillary diagnostics to help.
0.9% saline may be helpful in certain situations, but please remember that it is acidifying, so there's been a lot of literature in human medicine talking about how it worsens metabolic acidosis. Specifically, it will contribute to hyperchloremia, which can then cause kidney injury.
And so we. Avoid 0.9% saline as our initial fluid resuscitation.
But where it can be helpful is if we do have those hypochloremic patients, specifically with upper GI obstructions. And so in those, it would be very reasonable to give a balance, or a mixture. So have a balanced isotonic crystalloid running as your fluid resuscitation, but also have a a 0.9% saline solution going alongside to help address the hypochloremia until the obstruction can be resolved.
Artificial colloids, so your vet starch, head to starch, and so on, are generally universally not indicated. Certainly in human medicine for a long time now they have been contraindicated. They do run the risk of causing acute kidney injury and certainly in our patients we do have a lot of evidence to support a dose dependent coagulopathy and and delayed platelet closure time and so in our emergency patients, I tend to shy away from artificial colloids and certainly.
A lot of our hypovolemic patients are already at risk for AKI and so that would be another reason for me to avoid them. We don't have any real strong indications that they're going to do good, so as we weigh up risk benefit I would encourage you to think on you know, what might you need them for and is there an alternative that you could give considering that there is some risk associated. So pain relief, obviously a crucial tenet of what we do as veterinarians, you know, alleviate discomfort, and so opiates are always going to be our first choice.
They're always recommended as the first choice for unknown or unexplained pain. And certainly with gastrointestinal pain and abdominal pain, opiates are a very viable first choice. The pure agonists are always going to be preferred because they're reversible and they're cardiovascularly safe.
But we do have other options, so obviously a partial agonist being buprenorphine, and then our antagonist. Combo butorphanol, very good for sedation, so to obtain radiographs and other indications in our emergency patients, but not very good for pain relief. So please keep that in mind if the pet is uncomfortable on abdominal palpation, they're going to need something stronger than Torb.
And then side effects of opiates in general, bradycardia, nausea, ileus. Cats of course can be very sensitive to their temperatures changing and sometimes we'll see panting with certain pure Agnes more than others. And so often when we give opiates, we'll give a centrally acting anti-emetic as well to counter any potential nausea because obviously if the patient is already vomiting, we don't want to exacerbate that.
So even though our opiates are mainstay for analgesia, please do remember, you know, we often will practise multimodal analgesia, and so I've listed a few other considerations here. Lidocaine can be incorporated certainly for patients being hospitalised as a. CRI for prokinesis and additional pain relief, it's not always just indicated for VPCs, but a lot of our dogs that come in with severe GI disease do have a propensity for ventricular arrhythmias, and so lidocaine could address that as well.
Ketamine is great for windup pain, for anticipatory pain, it's an NMDA antagonist and it's also really great for visceral pain relief. And so incorporating that into your pain control strategies, especially if the patient's hospitalised, can be really helpful. It's great for pancreatitis.
In the UK and Europe, I know paracetamol is used a lot less so over in the States, but for dogs, plus minus codeine and obviously has the added benefit of being antipyretic. And then gabapentin is being used certainly where I practise a lot these days but it's important to remember that it's really, there's evidence, the evidence is lacking in terms of its efficacy as a pain control and certainly we should be using it as an adjunct rather than as sole use. So post-operative GI surgeries and things like that, probably gabapentin alone is not going to quite cut it.
But in the acute setting, when these patients come in with GI upset, we're always going to want to avoid non-steroidals, and so just keep that in mind. Non-steroidals are going to irritate the GI tract. The pet's already got hypoperfusion, they're going to potentially exacerbate acute kidney injury, and obviously they have added side effects with the liver and so.
We'll always avoid NSAIDs in the acute GI setting, certainly if the pet goes to surgery and requires NSAIDs as part of post-operative care, that's a different conversation, but in the acute setting, our opiates plus minus some of these other things are always going to be preferred. There's been a lot of conversation about the pros and cons of different types of antacids, so H2 blockers versus proton pump inhibitors. I just listed a reference here that back in 2018 concluded proton pump inhibitors are preferable to manage sustained acid suppression and that H2 blockers they, patients can develop a tolerance of.
It's really important to remember that you know these drugs are indicated when we do have a suspicion for gastric ulcers or increased acid production and so they shouldn't be used, you know, without indication. And then obviously we've got some great centrally acting anti-emetics which can be very helpful. Especially because if a patient's symptomatic for nausea, we really want to limit the likelihood of them vomiting because every time they vomit, they do have risk of aspiration and our brachycephalics that are just, you know, blown up in popularity over the last few years, they are high, high risk, as you know for aspiration.
So sooner we can get antiemetics into them, the better. And then obviously we have Carafate that will bind to any potential ulceration. And so that's something that could be incorporated into your treatment plan, do remember just to give it staged from any other medications.
Now if part of the patient's clinical picture is ileus and you have ruled out an obstruction, then they may benefit from some prokinesis. So metoclopramide would be one that we use the most commonly. I've put a couple of tables in the next slide just comparing the different mechanisms of action of different prokinetics.
And I do like to refer to this er gastrointestinal dysmotility review from JVC quite a few years ago now that just lists them out. Don't forget about the value of moving the patient. So when we hospitalise our GI patients or any patients, we do need to remember that, you know, they're confined within a kennel and that's gonna contribute to ileus, and so getting them up and having it as a treatment order to include a motility walk very frequently can be really helpful for Ilias.
And then remember we can also place nasogastric tubes, so if there are a lot of gastric residuals and there's gastric ileus specifically, that's gonna contribute to the likelihood of the patient vomiting or regurgitating. And so placing a nasogastric tube in those patients as part of your hospitalisation strategy can be important. Just a side note.
Sometimes with NG tubes, they can cause irritation to the lower esophageal sphincter, so if you don't have any need to aspirate residuals and if the stomach itself isn't dilated, but you still want to provide enteral nutrition, a nasal esophageal tube may be preferable because of that potential side effect. So I put a table here just comparing some of the prokinetics that you may or may not have available. Don't forget about low dose erythromycin, that can be quite helpful.
Sisapride we commonly will incorporate into our cats with a megacolon for its enhanced capabilities in the large bowel. Ranitidine is obviously something that is incorporated, that can have some upper GI prokinesis, as well as acid suppression. And then there's some suggestion that mirtazapine may have some weak indirect prokinetic effects as well.
Are antibiotics indicated, and that really depends on what the condition is that you're treating. So without a doubt, there's a lot of evidence to support early use of antibiotics in patients that are septic or have septic peritonitis. That is really crucial.
We're all trying to adhere to antimicrobial stewardship guidelines and the one area that we really should be very proactive in administering broad spectrum antibiotics is in patients. With suspected septic peritonitis because they will have an increased likelihood of mortality if we don't get that infection under control. So always to the best of your ability, try to rule out septic peritonitis in your GI cases because that would be something that as soon as you diagnose that you do need to get antibiotics started on the sooner side, and that does have a direct impact on mortal mortality.
And then for other causes, generally with again, kind of adhering to our guidelines, there's little indication for administering antibiotics unless you have a likely or a a strong suspicion of or a confirmed bacterial infection. So most cases of outpatient vomiting, diarrhoea, dietary indiscretion, and so on are not going to require antibiotic therapy. But the suspect septic patients will, and the patients that have a low white cell count or even the patients that have a low normal white cell count, I would be very suspicious, especially if they have a fever.
That there may be a bacterial component to their illness, and so in that case I would consider it very reasonable to have them on broad spectrum antibiotics. Certainly if they're being hospitalised, intravenous is going to be best, and for the most part, a potentiated amoxicillin with fluoroquinolone, complementing it is going to give you the broadest spectrum of cover for the particular types of bacteria that we see, from the GI tract. And so it is important just to consider, you know, an appropriate use of antibiotics.
Certainly if you're able to get cultures, de-escalating is recommended. And then your other big question as you're stabilising these patients, as you're gathering information diagnostically and you're starting treatments, is to determine does this patient need to go to surgery or not. And so I just listed out some of the surgical conditions versus some of the non-surgical conditions to be aware of when we are managing patients with gastrointestinal upset.
So I'm now going to spend the remainder of the presentation talking to you in a little bit more detail about some of those specific conditions. So GDV or gastric dilatation and volvulus, one of those very emergent, scary conditions that we see. Here is our right lateral radiograph again, that is demonstrating that double bubble sign that is pathognomonic for a er torsion.
The signalment in these patients, as you guys know, it typically is gonna be large breed deep chested dogs. Smaller breed dogs can get a GDV but it's more common in these large dogs and often but not always, the owner will describe a history of gagging or wretching, they may have vomited or it may be more likely to be unproductive wretching. And on physical exam, these patients are in severe shock, so.
Because of what is happening where the stomach twists, it compromises venous return to the heart, and these patients are hypovolemic, they're also in a distributive and an obstructive type of shock. Sometimes you'll appreciate the abdomen is distended and tympanic, but do remember that these are very deep chested dogs and so as you can see by that X-ray, a lot of the gas is actually under the rib cage. And so sometimes percussing with a stethoscope and listening for a tympani can be helpful, but you may not appreciate distention on your physical exam.
Often these patients are going to be really painful, so they'll be restless and agitated and panting, and that can be another indicator for a gastric torsion. So diagnosis is gonna be via a right lateral radiograph and that's what is depicted there. It's again very pathic mnemonic, very easy diagnosis most of the time.
This is because the pyloris, when it rotates, it sits up above and it's mal positioned from where it should be. And you may also have a malpositioned spleen, so something to keep in mind when you're performing an ultrasound point of care at the bedside, that the spleen may be in an abnormal position. You may also not see anything on ultrasound because of the gas that's in the stomach.
I already mentioned lactate as part of your diagnostic workup and kind of how to utilise that. It's really important with these dogs as well that we take chest x-rays once they're stabilised because a lot of them do have aspiration pneumonia, so that would be an indication obviously for antibiotics. And then a lot of them will commonly have ventricular arrhythmias, so ventricular premature complexes, accelerated in your ventricular rhythms or ventricular tachycardia, and that would require lidocaine.
Intervention, there was actually a paper that looked at using lidocaine preemptively to mitigate those arrhythmias in GDV patients, and generally it's recommended to give lidocaine to Mig Pig as part of your stabilisation and obviously if patient does then have ventricular tachycardia, placing them on a lidocaine CRI would be. Indicated and then of course ultimately going for surgery is what is necessary. As you're preparing the patient for surgery and you're stabilising them, give them really strong pain medication and the sooner you can decompress the stomach, whether that be with gastrocentesis, trochoization or stomach tube placement, the better.
And each of those techniques is going to come with its own risk benefit. But it is important to try to decompress the stomach because that is going to take pressure off the vena cava and help you to treat your shock. But aggressive fluid resuscitation is always necessary.
We talk about placing two cephalic large bore catheters in these patients. To get fluids into them ASAP, it wouldn't be appropriate to place back leg catheters in these dogs because again of that compromise to venous return, so getting fluid as quickly to the heart as you can is a crucial part of stabilisation. Moving on to small intestinal obstructive foreign bodies, also commonly seen in our small animal patients, both dogs and cats.
Cats tend to be more likely to get linear foreign bodies, they eat things like hair ties or dental floss, and then, dogs, as you guys know, can eat absolutely anything. So sometimes there's a history of having scavenged or got into the bins, and other times there's no history of that at all. Do bear in mind with older pets that masses can cause obstructions as well.
Typically with a GI obstruction or an intestinal obstruction, the patient is going to have persistent or refractory vomiting because the stomach is going to continue to fill with fluid, they're gonna continue to feel nauseous with everything proximal to the obstruction. On presentation, they'll be dehydrated, hypovolemic, commonly, metabolic acidosis, have some abdominal pain. You may be able to palpate the foreign body, especially in the smaller patients or cats that have the the the softer abdomen on palpation, but not always.
And then with cats, please don't forget to look under the tongue to make sure that they don't have a string, a foreign body anchored there. Diagnosis is usually done either with a radiograph or ultrasound, depending on what the capabilities are in the hospital that you're in. But as I mentioned earlier in the presentation, using radiographs to look for two populations, two distinct populations of bowel, and also confirming that there's dilation of the smallest.
Intestine is really helpful. Commonly with ultrasound you'll see a portion of bowel that is distended and then potentially an obstruction and then a portion of bowel that is not distended. And with an obstruction ultrasonographically you should see shadowing, which is depicted in this middle right picture here.
You may have free fluid which can be present just for severe inflammation from enteritis. Or maybe the pet has concurrent pancreatitis and that can cause a fusion. But at the same time you want to always rule out of course septic peritonitis because again that is going to be an indication to start antibiotics sooner and get these patients into surgery ASAP.
So if you do have a small sample of fluid that you can obtain for diagnostic purposes, that would be something very important to do as well. So hopefully you're noticing a pattern of treatment approaches that we're always going to be treating the hypovolemia, we're giving these patients fluids, we're giving them pain relief, probably opiates, they're getting gastro protectants, anti-nausea medications. And then of course if we see an obstruction, the recommendation is surgical.
Intervention for an exploratory laparotomy, removal of the obstruction, whether that be via an enterotomy or a gastronomy or a resection and anastomosis. Of course if you see something upper GI that is in the stomach or the proximal duodenum, then endoscopy may be indicated. Antibiotics would not typically be needed unless we have any of the indications that I mentioned before.
So if there is leakage of fluid and we're concerned about perforation, they should be on antibiotics. If they're neutropenic or leukopenic, they should be on antibiotics, because that could be an indication of bacterial translocation through a distended gastrointestinal tract. And if they have evidence of aspiration, of course, so again, getting radiographs of the chest in these patients before they go into surgery as a baseline would be very helpful.
I thought it was worth mentioning interception because this is a type of small intestinal obstruction that will affect our younger dogs, not always, but most commonly younger dogs, because it's usually associated with parasitic infections or other concurrent viruses or bacterial infections. Sometimes there'll be intestinal foreign bodies that will precipitate a intersusception or maybe there's a history of a recent diet change. But ultrasonographically and radiographically, radiographically you'll see similarly signs of obstruction, but you may see a mass-like effect.
And on ultrasound they have a very pathicnomonic appearance of this sort of double walled intestine, both longitudinally and transversely. And commonly these pets will have some bloody stool as well as vomiting. They do present also dehydrated and hypovolemic with abdominal pain, and you may be able to palpate the interception as a mass.
So radiographically, as I mentioned, small intestinal obstructive pattern and on ultrasound, as you see here in this picture, treatment is fluids and gastrict protectants, anti-nausea, same pattern as before, pain relief and then surgery obviously is indicated for these guys as well. So septic peritonitis, one of my favourite conditions to treat as a critical care specialist, certainly in humans there's a lot of interest around, recognising sepsis, and if it's of interest to you, I would encourage you to review the surviving sepsis guidelines, which are published every 4 years. And so we did just have a recent publication there in the human literature.
It is, they're typically published in the New England Journal of Medicine, but. We typically extrapolate our treatment and diagnostic protocols from those, especially for sepsis, because there's such an interest in evaluating, you know, factors that might influence mortality and and how we can reduce mortality, especially in people because it still is a leading cause. So in patients that we see, dogs and cats, they could really present as with any background.
Sometimes you will know that they have had a foreign body ingestion or a previous foreign body surgery that could have dehisced, or they could have a rupture from a mass, or they could potentially have a ruptured gastric ulcer. Always ask with these GI patients as well if they've been on any non-steroidal medications that can be helpful. These guys will present in hypovolemic and distributive shock, and so that's important to remember because as we stabilise them we're going to need to incorporate vasopressors to maintain our blood pressure.
And please remember that these patients can commonly be hypoglycemic, so they may present with a very altered mentation or very dull, and so that is important to rule out and you'll be doing your minimum database at the bedside when you're placing an IV catheter and you're gathering diagnostic information and you're doing your triage. So in that instance you'll know pretty quickly if a patient is hypoglycemic or not and if they are, it should . Alert you to the possibility of sepsis.
So on radiographs you might see a small intestinal obstructive pattern, you may see loss of detail if there's abdominal effusion. Certainly on point of care ultrasound you will hopefully start to see free fluid as you volume resuscitate your patient and as soon as you do, please get a sample. Looking at a cytology in-house is exactly the same as any other cytology that we look at in-house, so everybody is, you know, more than capable of identifying intracellular bacteria, and if you do have that diagnosis.
Stenosis, then immediately this patient must be prepared for surgery while it's being stabilised. Like I said before, you can perform paired glucose and lactate on the fluid, that can help increase your index of suspicion, but if you see bacteria intracellularly, that patient has to go to surgery. Treatment includes much of the same, like we've mentioned for all our other conditions, so you're gonna give fluids, analgesia, gastroprotectants, anti-nausea, and then of course because they're hypoglycemic commonly, they'll need dextrose supplementation.
I mentioned before vasopress is for hypotension, that is because of the inflammatory state that these patients are in, they have circulating cytokines causing massive dysregulation to their pro and counter-inflammatory cascades, and so getting them on vasopressors sooner rather than later to improve hypotension is key as you continue to fluid resuscitate them. Antibiotics early, I've already mentioned a couple of times now, so hopefully that's a takeaway from this presentation. It's really important with septic peritonitis to increase the likelihood of them going home and then obviously getting them set for abdominal exploratory surgery is the next step.
So mesenteric torsion and volvulus, this is not very common, but it is definitely something that is er worth recognising. Once you've seen one you will not forget it. Typically will occur in er small sorry, in younger dogs, but er German Shepherds are very, very much overrepresented.
So if you have a young German Shepherd that comes in with vomiting or bloody stool, this should be on your radar. Often they will have some diarrhoea, they may not have been vomiting as much as an upper GI obstruction, but, they typically, as you fluid, they, they present in severe shock. So with a mesenteric torsion, that is where the intestines have twisted at the root of the mesentery, and so blood supply to the intestines has been immediately and severely compromised.
These patients are hypovolemic, but they're also in a type of distributive and obstructive shock, and they're in often severe pain. And as you fluid resuscitate them to treat the hypovolemia, you won't see much improvement in their perfusion parameters. You might see a little, but you're not treating the obstruction because it needs to be untwisted to restore blood supply.
So typically these dogs are very hard to stabilise and getting a diagnosis sooner rather than later is really important because surgical intervention rapidly is absolutely key. Many of these cases unfortunately do die even in spite. Of early surgical intervention, so the sooner you can get to it the better.
Radiographically, there's often diffuse gas dilation of the intestines throughout the abdomen, and you can see some pictures here. On ultrasound again you may see what looks like generalised ileas, very diffusely dilated intestines. You may see some free fluid from so much inflammation.
They'll be translocating bacteria, of course, they've got areas of. That are now ischemic and so getting these guys on antibiotics earlier is also really crucial, treating them like a septic abdomen. And then unfortunately you then have to contend with ischemia reperfusion injury which is you know a contributing factor to mortality with these patients.
But the sooner that you can recognise this condition, the better for intervention and you know hopefully a more positive outcome. So I did mention that checking for NZ ingestion is an important part of your history taking. Also steroids, of course, has the pet been on any steroids?
A lot of times people don't know, you know, if the pet's on steroids, but they do know that they're on a daily pill for allergies and such. Sometimes there will be a gastric foreign body that could create some gastric ulceration. I had a patient once that ingested gorilla glue that created bleeding in the stomach.
And so there's just a picture here to remind you that gastric foreign bodies could do it. But NSAIDs remain probably our leading cause. Mast cell tumours can also cause gastric ulceration from histamine release, and sometimes you'll also see with these patients, not just a history of vomiting or abdominal pain but a history of melana indicating that upper GI bleeding from the gastric ulceration.
So radiographs may yield more information, ultrasound you know might also provide more information. Ultimately to determine gastric ulceration, performing endoscopy is indicated. That being said, if you have a high suspicion of gastric ulceration, treating empirically and supportively is obviously very valuable.
And then. Some of these patients, they will be anaemic, you'll see a drop in total solids as well as a drop in PCV and they may require either pack cells or whole blood transfusions, as part of their treatment protocol, certainly if they're anaemic. And I would still recommend doing imaging diagnostics to better understand is there something that needs either surgical intervention because some gastric ulcers can rupture, and that's what this picture at the bottom here shows you a little bit of free gas that's consistent with a pneumoproteinium.
Obviously that's a surgical intervention that's recommended, but other. Disease processes may need to be addressed as well. Pancreatitis is something that we'll commonly see in emergency medicine and it has a spectrum of presenting signs.
So some patients will come in super sick, multiple organ dysfunction from such severe inflammation in the pancreas. Other patients will come in with a more insidious clinical history, and then you'll have some patients that will have had a very obviously high fat meal preceding an episode of vomiting and potentially diarrhoea, and now they have abdominal pain. Some patients.
Genetically predisposed, so no matter what they eat or they may eat nothing unusual, they're still going to get a flare up or a bout of pancreatitis, and our schnauzers fit that category. So on presentation, they're typically dehydrated. They may or may not be hypovolemic depending on the severity of illness, and they may have pretty severe abdominal pain, even if they've just vomited a couple of times.
And so that would be an important differential for a patient presenting with GI signs and abdominal pain. To diagnose pancreatitis, there are specific pancreatic enzyme analysis available. Commonly it can also be a diagnosis of exclusion.
Ultrasonographically we can often see pancreatitis. Sometimes you'll see free fluid on ultrasound that's consistent with a sterile exudate or inflammatory cytology. And then a lot of these patients can have.
Pleural effusion as well, so don't be too panicked if you see a scant amount of pleural effusion. It's because of the severity of inflammation, and if they're not clinical for it, as you treat them, they will ultimately resolve the pleural effusion, but it can become more of a clinical problem. And then we do need to monitor these patients closely for signs of multiple organ dysfunction syndrome.
Sometimes they can be hyperglycemic if they're concurrently diabetic or develop diabetes, and other times they can be hypoglycemic if the inflammation is really severe. Sometimes we can see pancreatic abscesses develop as well, and it is pretty common to see acute kidney injury from that pre-renal azotemia, specifically associated with pancreatitis, just because of the, distant sort of the cytokines that are released from an inflammatory perspective can impact the kidneys as well. So I mentioned these patients are usually in some degree of pain and strong pain medication, multimodal ideally is preferable.
I mentioned incorporating lidocaine and ketamine into hospitalisation protocols alongside opiates, and that's really appropriate for pancreatitis patients. That they get fed the better as we now know nutrition is key, enteral nutrition is preferred, and so we can use our gastro protectants, anti-nausea medications, and appetite stimulants, but if we're hospitalising these patients, getting enteral nutrition in via a nasogastric or a nasoesophageal tube is really important. It's important to counsel the owners that you know, these patients, once they have one bout of pancreatitis, will usually have more.
And other treatments when they're really severe and inflammatory states would be to consider corticosteroids. There has been a recent review in 2021 suggesting a possible benefit to dogs, less so perhaps in cats. However, a lot of cats will also concurrently have inflammatory bowel disease or a triaditis type of picture, and so perhaps they might have an indication for anti-inflammatory corticosteroids as well for another reason.
So plus minus on the steroids, no strong supporting evidence. Certainly would avoid NSAIDs because these patients commonly have AKI and antibiotics are not indicated since it's usually a sterile inflammation, unless of course you're concerned about a pancreatic abscess. And then ultimately down the road these patients need to stay on a very bland diet indefinitely, and owners need to be counselled on avoiding feeding them human food.
So acute hemorrhagic diarrhoea syndrome or hemorrhagic gastroenteritis is something that commonly will affect smaller breeds but can affect absolutely any breed. They may have had some dietary indiscretion. Often they'll have hemorrhagic diarrhoea and vomiting.
They may have some abdominal pain as well. And sometimes they can become hypoglycemic from just really severe inflammation in the GI tract, so they may have altered mentation. You may see a generalised ileus on ultrasounds, so not suggestive of a obstructive foreign body, but a generalised diffuse dilation of the GI tract.
They may be, as I mentioned before, hypoglycemic, they certainly might be hypotensive, they may have a pre-renal azotemia. And hemo concentration is the cardinal sign for this condition, along with a low. Than expected total solids, given the degree of dehydration and commonly as you fluid resuscitate these patients, the total solids will drop further and so it is important to consider oncotic support in these patients, and I mentioned at the beginning with fluid resuscitation that you know avoiding artificial colloids is preferable in these patients, you might, there might be other ways that we could administer .
Oncotic support, so enteral nutrition would be a big one, as soon as we can get food into them, whether that be via a nasogastric or nasoesophageal tube, that is going to help to bring up their protein levels. We can also give canine plasma in certain clinics. It may or may not be available to you.
And then fresh frozen plasma will, in our smaller breed dogs, increase the protein or provide some oncotic support to some degree. In our large breed dogs, it's less useful because you need such large volumes to make an appreciable change to albumin. And then we just have to remember that fresh frozen plasma is a a little bit pro-inflammatory as well, so something to consider.
And of course it's a a transfusion and another intervention. So for me, the sooner I feed these guys, the better, the total solids tend to come up on their own, but they do require large volumes of crystalloid fluid resuscitation. So that picture that I showed you of the empty left ventricle when we were talking.
Talking about point of care ultrasound, that was from a Yorkshire Terrier with severe AHDS and so that is worth noting that these guys need really to stand by them and constantly fluid resuscitate them and to maintain volume and maintain blood pressure. If you are concerned about bacterial translocations, if they're hypoglycemic or leukopenic or low normal white blood cell count, then it would be reasonable to give them empiric antibiotics, but if that is not the case, there is not an indication to give antibiotics to these patients, and certainly we no longer recommend giving metronidazole to these patients, but if we did need to give any type of antibiotic, the choice would be broad spectrum Unicin or potentiated amoxicillin. So just to wrap up, I'll provide a slide to talk about some of the take home messages from this talk.
So I've really enjoyed being able to review gastrointestinal emergencies with you. Hopefully there's been some useful information provided. Some of the things to remember are, you know, making an early diagnosis, using your diagnostic tools to gather rapid information, as with any emergency really can help you to go in.
Different directions, you know, for treatments and diagnostics. And so please use your minimum database, please use your point of care ultrasound, make sure you get an adequate history to help you to determine which treatments and diagnostics you want to recommend. And then, and just a point to make.
In terms of being up to date on the veterinary literature and the evidence base that's out there, because some things do change, you know, as we evolve and as we learn more in the profession and so staying on top of new recommendations is also really important. There's been a lot of interest lately, I didn't cover diarrhoea specifically but. You know, using certain probiotics, we now have a lot more literature to support the use of probiotics for diarrhoea and there's a lot of interest around diet and nutrition and things like that, which is all outside the scope of this lecture, but just something to be mindful of.
So thanks very much for having me, really appreciated talking to you today.
