All Pets Veterinary Clinic
VOMITING IN ANIMALS
Vomiting is one of the most common reasons that animals are presented to a veterinary clinic
for examination. Unfortunately, vomiting is not a specific sign for any one problem. In
fact, vomiting can be the result of many very different things including dietary indiscretion,
metabolic diseases, motility disorders, obstructive diseases, inflammatory processes,
neoplasia/cancer, food allergies, and parasites, among others. Thus, a thorough history
and physical examination are necessary to gain important clues as to the cause of the
vomiting and to determine what tests are necessary for an accurate diagnosis.
The first part of this article will discuss some of the most common causes of vomiting.
The second part will look at the different diagnostic testing options needed to diagnose
CAUSES OF VOMITING
Dietary Indiscretion and Overindulgence are probably the most common reasons for
acute vomiting. Pets that have gotten into the trash or have been given table scraps or
human foods commonly experience temporary vomiting. For some animals, any change from
the normal diet can result in vomiting while other animals can handle foods outside of
their normal regimen.
Hairballs are more common in cats due to their frequent grooming behavior.
However, they can occur in dogs. Animals with hairballs may cough or retch with or
without producing the offending hairball. If the hairball causes an obstruction, the
vomiting will often worsen and the animal will become sick.
Physaloptera or the stomach worm is a frequent, yet under diagnosed, cause
of chronic vomiting in dogs and cats. It is obtained when animals eat bugs, grubs, or
beetles or frogs, birds, or rodents that are carrying the parasite. Animals with this
parasite may have severe vomiting episodes despite otherwise normal behavior.
Constipation, if severe enough, can result in vomiting. Many animals will
stop eating prior to the onset of vomiting from constipation but some will continue to try
to eat despite the fact that their GI tract is essentially full.
Feline Hyperthyroidism can result in vomiting that is associated with a
voracious appetite and weight loss. If it is left untreated, hypertension, blindness,
liver damage, and heart disease can result.
Foreign Bodies are non-food items that become ingested and can lodge within
the GI tract. Some examples of commonly ingested foreign bodies include toys, rocks,
strings, and clothing items. They can be partially obstructive or fully obstructive.
Animals with fully obstructive foreign bodies are typically much sicker than animals with
Stomach or Esophageal Ulcers or Erosions can result from certain medications
or chronic vomiting. Sometimes ulcers can result from unknown causes. An erosion is a
superficial ulcer. Either can cause vomiting.
Helicobacter is a spiral shaped bacteria that can be found in the stomachs
of normal and vomiting animals. In humans, this bacteria has been associated with stomach
ulcer formation. This association has not been proven in animals at this time. However,
animals with clinical signs and the presence of Helicobacter will often improve if the
bacteria are eliminated.
Food allergy, food intolerance, and food aversion can all result in persistent
or intermittent vomiting. Because there are no reliable tests for these problems, diagnosis
can often be difficult.
Pancreatitis or inflammation of the pancreas can result from the ingestion of
greasy meals, trash, or certain medications. It is often accompanied by diarrhea and can
be acute or chronic.
Chronic Kidney Failure is a common cause of vomiting in older animals.
Affected animals may or may not have a decreased appetite, weight loss, and increased
thirst in addition to the vomiting. Chronic renal failure is often the result of years
of repeated small amounts of damage to the kidneys but it may be associated with heart
disease as well.
Acute Renal Failure is a common cause of vomiting typically in younger animals.
Certain toxins, drugs, and infectious agents can cause acute renal failure.
Liver Diseases can cause vomiting in some individuals but not in others.
There are many different liver diseases including but not limited to hepatic lipidosis,
chronic active hepatitis, cholangiohepatitis, and cirrhosis.
Idiopathic or Geriatric Vestibular Disease causes severe incoordination,
dizziness, falling, head tilting, and nystagmus (rapid side to side eye twitching) in
addition to nausea/vomiting.
Addison’s disease or Hypoadrenocorticism is an uncommon, life threatening
condition in which vomiting can be one of several signs. It is usually diagnosed in young
animals and can be successfully treated if diagnosed properly.
Morning Sickness in the earliest stages of pregnancy is uncommon but can
cause vomiting in some animals.
Inflammatory Bowel Disease is a collection of conditions that can result
in chronic vomiting. More often, animals with inflammatory bowel disease have diarrhea.
Cancer or Neoplasia of the liver, kidneys, pancreas, intestine, or brain can
result in vomiting. Intestinal obstruction by a mass or tumor can also result in vomiting.
Megaesophagus or an enlarged flaccid esophagus results in regurgitation of
undigested food. Regurgitation is technically different from vomiting in that regurgitation
vomiting, especially if it does not happen right after eating.
While this is a fairly large list of common causes of vomiting in animals, it is not a
complete list. There are other causes. Because vomiting has so many different causes,
there is not a single diagnostic test that will yield a firm diagnosis in all cases.
It is quite likely, especially in chronic or complicated cases, that several diagnostic
tests will be necessary to identify the source of the vomiting. Different diagnostic
tests give different types of information. Thus, knowing the pros and cons to each
diagnostic test as well as when a test can be useful is essential. Next we will look at
the tests used to sort out these various causes.
History. A detailed history is an important first step to diagnosing the
cause of vomiting. Information on the duration of vomiting, the relationship of vomiting
to eating, and the overall condition of the patient can all give important clues and point
towards the cause. In some instances, a history alone can be highly diagnostic. For example,
if the owner saw their dog eat a pair of shorts two days earlier and the dog has been
vomiting ever since, the diagnosis is likely a GI obstruction with a foreign body. If the
history is not diagnostic, it can help determine which tests should be conducted.
Physical Examination. Like a complete history, a thorough physical examination
can give important clues that lead to a diagnosis. For example, a vomiting cat that has a
palpable nodule in its neck and a heart murmur is likely to be diagnosed with hyperthyroidism.
The physical examination will also help determine what tests should be conducted.
Bloodwork. Two general panels of bloodwork are often used to rule out several
different metabolic causes of vomiting as well as provide important clues about the overall
health status of the animal. A CBC, or complete blood count, looks at the cells. This panel
will count the red cells, white cells, and platelets. A chemistry panel will look at several
different organs, such as the liver, kidneys, pancreas, and thyroid glands, as well as
provide information on electrolytes, protein levels, and blood sugar.
Routine bloodwork is inexpensive and minimally invasive and can rule out many
of the different causes of vomiting so it is often run early in the diagnostic process.
Bloodwork is good for diagnosing kidney, liver, pancreas, and thyroid abnormalities. It
can also given an indication of inflammatory or infectious conditions.
Plain Radiographs/X-rays. Radiographs allow us to see important structures
on the inside of the body. Determination of the relative size and position of the major
organs can provide important information on the vomiting animal. Excessive amounts of gas
within the bowel can provide evidence of decreased motility and possibly point to an
obstructive cause. Dense foreign objects, such as metal or dense plastics, can often be
seen within the GI tract on plain radiographs.
Radiographs are inexpensive, non-invasive, and easy to take so they are often
done early in the diagnostic process. Plain radiographs are good for diagnosing some masses
and foreign bodies.
Barium Series. Barium is a liquid contrast media that appears solid white on
radiographs. Barium is given alone or with food and can increase the diagnostic accuracy of
radiographs by outlining objects and structures that do not show up on plain radiographs.
In addition, taking a sequential series of radiographs can allow the determination of
decreased GI motility.
A barium series is easy to do but takes at least 4-6 hours. If the animal
has frequent and/or severe vomiting that will not allow for the retention of the barium,
it may not be a helpful test. Barium is good for diagnosing megaesophagus, foreign bodies,
and decreased motility.
Treatment Trial. Treatment trials for certain suspected disorders or in
patients that only have minor clinical signs can serve as a means of diagnosis. For
example, a persistent hair ball problem in a cat can cause intermittent vomiting. A
treatment trial with a hairball medication can eliminate clinical signs and result in a
presumptive diagnosis. Broad spectrum deworming for parasites, such as physaloptera,
the stomach worm, can eliminate clinical signs in affected patients as well.
For some conditions, such as food allergy, food aversion, and food intolerance, there are no
reliable diagnostic tests. The only way to diagnose these problems is to feed a novel diet
for 2-3 months. If the vomiting resolves during this time frame, the original food is then
restarted. If the vomiting reoccurs, the animal most likely has a food issue.
Treatment trials are often inexpensive and may or may not be easy to complete. In some
instances they can be 100% successful and can result in the cessation of vomiting. In
other instances, treatment trials may not work resulting in a delay of clinical diagnosis.
Ultrasound. Ultrasound alone is not often diagnostic for many of the causes
of vomiting. It is often used in conjunction with many of the other tests listed here.
Ultrasound is good to look within certain solid structures, such as the liver. It is also
good to verify the origin of suspicious masses. In some instances, a needle biopsy can be
taken with ultrasound guidance.
Ultrasound is easy and non-invasive but requires the use of expensive, specialized
Endoscopy. An endoscope is a long tube with a light source and a camera. It
can be inserted into the mouth and passed into the stomach and small intestine allowing for
the direct examination of the esophagus, stomach, and small bowel. Foreign bodies can often
be removed without traditional surgery with the endoscope. If the cause of vomiting is not
readily apparent with direct examination, multiple small biopsies of these areas can be
obtained via the endoscope.
Endoscopy allows for a lot of information to be obtained and is minimally invasive. There
is minimal recovery time. Animals that have endoscopic procedures can often go home and
resume their normal life the same day as the procedure. There are only two real
disadvantages to endoscopy. First, the entire length of the GI tract cannot be examined
with the scope. The upper GI tract can be examined via the mouth and the lower GI tract
can be examined via the rectum but the middle portion will be unable to be reached.
Second, areas outside of the bowel cannot be visualized with the scope. Endoscopy can
diagnose GI ulcers and erosions, physaloptera, foreign bodies, stomach or intestinal
cancers, Helicobacter infections, and inflammatory bowel disease.
Exploratory Laparoscopy. A laparoscope is also a tube with a light source
and a camera. Instead of being placed inside of the GI tract, it is placed through the
abdominal wall and into the abdominal cavity. It can allow direct visualization of all
the abdominal organs. In addition, full thickness biopsies of liver, pancreas, spleen,
stomach, and intestine can be done with the laparoscope.
Laparoscopy allows for the full evaluation of the abdominal cavity with two to three
very small incisions. Recovery time is minimal and most animals go home the same day.
The main disadvantage is that it is more expensive than some of the other diagnostic
methods. Many different conditions can be diagnosed and even treated with exploratory
Exploratory Surgery. Exploratory surgery allows for the full examination of
the entire abdomen through a large incision. Removal of foreign bodies, relief of GI
obstructions, biopsies, etc. can all be done during exploratory surgery.
Exploratory surgery is expensive and invasive. Animals will often need several days
to recover from surgery. For animals that have become dehabilitated from chronic vomiting,
recovery can be long and hard. Many different conditions can be diagnosed and treated
with exploratory surgery.
***The information provided here is for educational purposes only. It is not intended to
take the place of an examination and diagnosis by a licensed veterinarian. As always, if
you have questions or concerns regarding the health of your pet, please consult with a
The information provided is for educational purposes only and is not
intended to take the place of your regular veterinarian. Please do not hesitate
to contact your regular veterinarian if you have questions regarding your pet.
Karen Blakeley, DVM, MPH
7 June 2005