By Doug Brum, DVM
Acute vomiting is one of the most common presenting complaints recorded for urgent appointments in veterinary medicine. The work up and treatment for vomiting can be very simple or require extensive diagnostics and supportive care. As our profession has grown, veterinarians have become more dependent on more advanced diagnostics. In house laboratories, remote radiologists and abdominal ultrasounds are now readily available in many practices, but as an example, just because we can do an abdominal ultrasound, does not mean that all vomiting dogs need one. Diagnostic approaches should vary based on the signalment, history and clinical condition of the patient.
The first thing to consider in the acute vomiting pet is the signalment. Is the dog young or older? Young dogs are more likely to have gastrointestinal (GI) parasites, dietary indiscretion, GI foreign bodies or intussusceptions. Vomiting is usually not related to metabolic problems (with the exception of Addison’s disease) in younger animals. In older dogs, systemic illness is generally more of a concern.
The history is vital in determining your work up. How much vomiting, what the dog has been eating that may be unusual, potential toxins or drug exposure should all be considered. Sometimes an acutely vomiting dog has a history of historical chronic vomiting. It is critical to ask the questions, and not just rely on what the client is telling you. As veterinarians, we can judge what in the history is significant. Clients may not know that what they have given their pet is toxic for dogs. Ask questions such as: have they given any new medications; has the dog eaten anything he usually does not get; have they recently changed brands of food ‑ these are critical things to know, and may be the cause of the dog’s clinical signs. A good example is the client whose dog was lame several days prior to the vomiting episode and might have given the dog a couple of days of ibuprofen prior to presentation. Knowing this prior to doing the work up can save the client hundreds of dollars and allow for more accurate treatment.
Additionally, in today’s practice it is routine for a technician to get the history from a client first before a veterinarian comes in for the exam portion. It is very reasonable for the veterinarian to again review the history with the client, as many times the owner will remember things the second time around after being prompted initially by the technician’s questions. I am amazed at the number of times that a client tells me something totally different from what they tell the technician, or they omit a critical part of the history. Other important questions include: how soon after eating does vomiting occur; is the vomitus food-like, digested, or liquid; and is the patient actually vomiting or regurgitating (regurgitation being a more passive, less forceful movement of ingested material, usually before it even reaches the stomach). The diagnostic work-up between vomiting and regurgitation may be much different.
As our profession has advanced, there is less emphasis on the physical exam because of the quick access to more advanced diagnostics (STAT blood work, aFAST, full abdominal ultrasounds). A complete physical exam is critical in guiding how aggressive one should be in designing the diagnostic and treatment plans. Hydration status and perfusion should be assessed. Skin turgor, and mucus membrane moisture should be assessed together. Tacky mucous membranes generally correlate to 5% dehydration, decreased skin turgor generally 7%, and dry mucus membranes with tented skin correlate to about 10%. Take into account the age of the animal when assessing hydration as geriatric animals often (normally) have decreased skin turgor. Cardiovascular status can also help guide your decisions. Animals that are tachycardic with poor pulses are treated very differently from those with normal cardiovascular parameters. If the vomiting is severe, serious consequences may result including dehydration, acid-base and electrolyte disturbance, esophagitis, or aspiration pneumonia.
Abdominal palpation is also very important in your assessment. Is there a palpable mass; is there significant abdominal discomfort? The finding of abdominal pain and/or dehydration almost always requires more aggressive treatments; however it is reasonable to take a more conservative approach in more stable patients. Most vomiting animals will not need an abdominal ultrasound, but all should have a good physical exam. An abdominal ultrasound is not a replacement for a thorough abdominal palpation.
The diagnostic work-up for a dog presenting with acute vomiting should correlate with the signalment, history, and physical exam findings. If an animal is well hydrated and has no abdominal discomfort then conservative management may be fine. A diagnosis does not have to be made each time, as the exact cause of acute vomiting is often never discovered. Many times conservative management (withholding food and water, prescribing a bland diet, possibly administering anti-emetics and/or SQ fluids) on an outpatient basis is all that is needed. It is reasonable to draw basic blood work to rule out potential toxic insults if the historical cause of the vomiting is not known. In a young dog with a history of eating inappropriate items, performing radiographs to rule out a potential foreign body is always a prudent diagnostic step.
As long as the patient is well hydrated and clinically stable, taking a step-wise approach is reasonable. If the dog is improving, continuing the diagnostics is not needed. But if the dog is not getting better, further diagnostics (radiographs, abdominal ultrasound, and basic blood work) will be needed. The decision to hospitalize a dog should be based on the history, clinical assessment, and the client’s financial abilities. As always, thorough and frequent client communication can help facilitate this step-wise plan.
One of the areas up for debate in our hospital is the use of anti-emetics, more specifically, Maropitant, in the acute vomiting animal. Maropitant is a neurokinin-1 receptor antagonist that inhibits substance P binding to NK-1 receptors in the emetic center, chemoreceptor trigger zone and the enteric plexus of the gut. It is an excellent anti-emetic and commonly used in the acute vomiting patient; however it should be used cautiously in animals suspected of having a GI obstruction. When given to an animal with a GI obstruction it may cause the vomiting to stop (at least for a while) and may make it seem as if the animal is improving. It could delay the decision to pursue more advanced diagnostics and thus delay surgical intervention. Dogs with GI obstructions not given Maropitant will continue to vomit, pushing the clinician to find a cause. Even a 6 hour surgical intervention delay in a dog with a GI obstruction could lead to an intestinal perforation. The use of anti-emetics in dogs suspected of having a GI obstruction should be considered carefully if advanced imaging is not planned.
On the other hand, if the cause of the vomiting is known or advanced imaging is pending, then there is no reason not to give it if indicated.
The treatment of acute vomiting in dogs can vary from a quick outpatient visit (or even a phone call), to hospitalization with aggressive supportive care and emergency surgery. Not every animal needs a full work-up to determine the cause of vomiting. Diagnostic work-ups and treatments depend on the signalment, getting a good history, performing a thorough physical exam, and the clinical condition of the patient. Taking the time to accurately assess each animal is vital to providing appropriate care, preventing the accrual of inappropriate costs and aiming for improved client satisfaction.