In this lecture, we’ll be speaking about gastroenteritis,
and vomiting and diarrhea in children.
Let’s first talk about vomiting.
Vomiting is obviously a forceful, coordinated expulsion of stomach contents.
If you see a patient with vomiting,
you need to take a very good history and a complete history.
You need to do a focused physical exam.
You need to do some lab work.
And you may need to do some imaging studies.
Let’s talk about what exactly we do under what circumstances.
So, in terms of the history,
it’s key to figure out if the child is dehydrated.
In a child with vomiting,
dehydration can happen relatively quickly.
And typically, in children, they can look very, very well
and then suddenly get much sicker.
So, a good history about whether the child was drinking
and whether the child has good urine output is important.
It’s important to assess what the color of the vomit is, especially in babies.
Bloody emesis may be indicative of something in the esophagus
like Mallory-Weiss tears, or problems in the stomach like gastritis.
But in particular, in babies, green emesis may indicate bilious emesis.
And while in adults, we think of bilious emesis as just
the end result of a prolonged period of vomiting.
In infants, this may be indicative of a malrotation of the intestines,
which may be a surgical emergency.
You should ask about associated symptoms.
It’s perhaps this vomiting that’s from something other than the GI tract.
Couple examples:
For example, if a patient has hydrocephalus or increased intracranial pressure,
vomiting may occur, and it’s the vomiting you’re noticing
and not the fact that the child is having some
problems with the pressure inside their head.
The renal tract also can cause vomiting,
either through stones or urinary tract infection.
It’s important to ask about the duration of symptoms,
and we’ll discuss chronic versus acute episodes of gastroenteritis.
But understanding how long this has been going on for
may give you clues as to the etiology.
Typically, viral illness is reasonably short, only a few days.
Other illnesses can last a much longer time.
Timing in relation to feeds is important because it
may give you a clue as to what organ is involved.
A few examples:
If a baby has a problem with their esophagus,
they’ll often spit up immediately after the feed.
If the problem is in the stomach, there may be a slight delay.
If the problem is in the pancreas,
a patient may not feel pain for up to an hour after eating.
Social history is always important
and may give you some clues as to what’s actually going on with this patient.
I have, in the last months, seen a patient who had vomiting
and it turned out the cause was in fact child abuse and blunt head trauma.
So let’s shift the gear and look towards physical exam findings,
and there are some key physical exam findings
that are important in any child with vomiting.
Signs of dehydration, as in addition to the history, can be found on physical exam;
dry mucous membranes, a delayed capillary refill,
things along that nature.
If a patient has peritonitis or an acute abdomen,
you know this is going to be a very different problem
than just acute viral illness.
A patient with an appendicitis can have pain with palpation
or a rebound or guarding over the abdomen.
And remember, diseases like appendicitis can
be very tricky to pick up in small children.
In fact, a sizable percentage are missed until they perforate.
A complete physical exam is important to understand
all the extra abdominal etiologies of vomiting.
So, understanding, for example,
their pupillary reflex is important if you’re worried about increased ICP.
So if you’re seeing a child who’s vomiting and you’re curious what labs you might get,
let’s go through them a little bit at a time.
First,
the Chem-7 is generally a reasonable lab to get in a child who’s vomiting
and you’re not sure what’s going on.
A high BUN to creatinine ratio is going to be indicative of dehydration.
If the patient has a very high creatinine but not a very high BUN,
you might think about renal causes of emesis as opposed to just dehydration.
Generally, in patients with significant dehydration, there will be some acidosis.
Some practitioners like to use a cut-off of say about 14 for the bicarb in a Chem-7
in terms of where you would worry about a child
in terms of their ability to continue hydration.
Others feel that it’s simply a matter of giving the child a drink
and seeing how they do and using their clinical appearance
to determine whether these children need to be
hospitalized or whether they can be sent home.
Excessive vomiting may cause an alkalosis.
The classic example would be an infant with pyloric stenosis,
and we’ll talk about pyloric stenosis in another talk.
But an infant with pyloric stenosis will have
excessive vomiting and loss of acid out of their vomit,
and that will present as an alkalosis on the Chem-7.
A urinalysis is commonly performed because infants, especially,
can’t tell you when they have symptoms of urinary tract infections,
and urinary tract infections are more common in infants.
A lumbar puncture is absolutely indicated if meningitis is concerned.
However,
remember the clinical context because we wouldn’t want to do a lumbar puncture
in someone with acutely raised ICP
unless you knew exactly what was going on.
LFTs and a lipase are useful.
I know on your slide it says amylase, and that probably may be on a test,
but we’ve actually stopped getting amylase as much as a test for pancreatitis.
It’s much more the lipase because the amylase is nonspecific
and may be from the salivary gland.
Don’t always forget, adolescents can get pregnant,
and a pregnancy test is almost always indicated in an adolescent female
who presents with vomiting of unclear etiology.
So let’s talk about imaging studies you might get in a vomiting child.
Well, first, the abdominal X-ray.
Generally, we’ll get an upright picture in an older child
because that will allow us to see things like free air under the diaphragm.
And as you can see on the slide here, you might see air fluid levels.
This patient with multiple air fluid levels probably has a gastroenteritis.
You can see that fluid contents will layer out with nice lines,
and that gives us a sense that the issue here is that
the intraintestinal compartment is containing liquid as opposed to solid material.
We will get an upper GI in some circumstances
where we suspect intraabdominal pathology.
Remember that the regular upper GI does follow through the ligament of Treitz.
That means that if you have that bilious emesis in an infant
where you’re worried about malrotation, a regular upper GI is all that you need.
An upper GI will also show you something like pyloric stenosis.
A small bowel follow through is really only used
where you’re concerned about small bowel disease.
We don’t need to get that for a patient with concern for malrotation.
We might get that test for someone, for example, with inflammatory bowel disease
where you’re worried there might be some small intestine abnormalities.
However, we’re really moving more towards intestinal MRI
as opposed to small bowel follow through for those patients.
Ultrasound is a mainstay for many diseases in children.
We’ll use an ultrasound for things like pyloric stenosis and intussusception.
And actually, some practitioners are getting much better at it
and we can even evaluate for things like malrotation.
The abdominal CAT scan is a very useful test
for patients where we’re worried about intraabdominal pathology.
But remember, there’s quite a bit of risk for radiation in children.
Children, who are young, have more mitosis
and are greater risk for developing cancer down the line.
As a result, most centers are moving gradually away from the abdominal CAT scan
and more towards ultrasound.
Abdominal MRI is an evolving tool,
and we’re getting better at using it in certain circumstances.
Certainly, we use it for inflammatory bowel disease
as a way of assessing the small bowel in children.