Thread by @rabihmgeha

Teaching Rounds

Diarrhea - Part 1

3 Misleading Mimics
&
2 Key Questions

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Diarrhea = increase in stool water content.

We tend to use the term loosely (Ha! 😉) so your patient may be referring to another change in bowel habits when they say diarrhea.

How do we know?

The Bristol Stool Chart!

bit.ly/2TWeVgS
🙏🙏 @Dietitianbytes

3 Misleading Mimics...

1. Constipation + overflow

2. Stool incontinence

3. Hyperdefecation
This amazing @COREIMpodcast case is a great example - bit.ly/332uDuR

I've been fooled by all 3...multiple times.

2 Key Questions...

If you are confident your patient has diarrhea, 2 pieces of data organize what is an incredibly long DDx.

1. Time course - acute (<2-4 weeks) or chronic (>2-4 wks)

2. Inflammation

How do we determine if there is inflammation?

I am so glad you asked!

Determining "inflammation" in general - bit.ly/2VXeky0

For diarrhea, we usually have these 3 data points readily available.

There are other, more advanced, methods too, like the fecal calprotectin - bit.ly/38DW6UK

So, after we've assessed for the 3 Misleading Mimics
and answered the 2 Key Questions, we end up with a 2x2 table

Let's chat about Acute Diarrhea

Acute Diarrhea...

Notice how we've simplified the mechanism from -

Osmotic, Secretory, Inflammatory

to

Non-inflammatory & Inflammatory.

Why?

The DDx of ACUTE diarrhea is limited enough, that the extra cognitive energy to classify as osmotic versus secretory isn't worth it.

Chronic diarrhea is a whole different equation.
We'll talk about that soon.

Acute Non-Inflammatory Diarrhea

1. Infections
2. Meds
3. Toxins

Y'all see Legionella up there?

Yes!

A reasonable # of extra-intestinal infections result in acute diarrhea
🤯🤯🤯

More here - go.nature.com/2Iz6nXI

Acute Inflammatory Diarrhea

1. Infection
2. Ischemia
3. Radiation

Infections + acute diarrhea

Yup - infections make it on both lists - inflammatory and non-inflammatory acute diarrhea

We don't need a specific microbiologic Dx for most acute infectious diarrhea - a large # is viral - but key your eye out for:

1. C.diff!!

2. Traveler's diarrhea - a large fraction is bacterial
(the majority don't need antibiotics)

Great review from @adamcifu here - bit.ly/2TAtmIp

Alright friends, let's recap

1. Before you deploy a schema for diarrhea, consider the 3 Misleading Mimics.

2. Make the incredibly long DDx of diarrhea simpler by studying the 2 Key Variables - Time Course & Inflammation

3. Infections can lead to both a non-inflammatory and inflammatory acute diarrhea

4. Most patients with acute infectious diarrhea outside C.diff, don't need antibiotics.

Next time - we'll take on a tougher Dx problem - chronic non-inflammatory diarrhea

See ya then!

Other "Teaching Rounds" topics here -

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