Vale

However, even if we correct these values, the leukocyte values, we still get way over the PMN cutoff to consider bacterial peritonitis.

But then, why is it so hemorrhagic?

Is it possible that being on anticoagulants plus the platelet dysfunction, part of his myeloprotiferative neoplasm, could account for this?

However, we wouldn't want to miss a malignancy.

The lack of imaging that suggests a tumour on the liver or infiltration to the peritoneum and the negative tumour markers makes this a little less likely.

Cytology on this acidic fluid would be ideal to have more clarity on this point.

The other pitfall when interpreting this fluid is that we should take into account the serum cell counts of this patient because his normal range is higher than our usual lab ranges.

Still, I would probably continue antibiotics because of the morbidity and mortality of not treating an infection.

An important distinction I would be eager to solve if we have an infectious hypothesis is, is this a spontaneous or a secondary source of bacterial peritonitis?

As their name suggests, spontaneous peritoneitis means that without a clear source, the peritoneum has been contaminated, versus secondary peritoneitis, which means that there is a source and it is often surgical.

Some red flags we can look for to suspect there is a secondary source include abdominal tenderness that is more exquisite, but this point is only empiric evidence.

Then we can look for more specific and sensitive evidence, such as finding free air on ultrasound, which can clue us to perforation.

as well as multiple organisms found on gram stain of the acidic fluid.

Finally, we can also use the test of time.

As I said, secondary causes of bacterial peritonitis often need surgery, which means that antibiotics are not enough.

We can increase our sensitivity if we sum our red flags with the Runyon criteria.

which requires two of the following three on acidic fluid to suspect secondary peritonitis.

First, greater than one gram per deciliter of total protein, then a glucose less than 50 milligrams per deciliter, and finally an LDH higher than the serum value.

The algorithm published by Runyon also includes the fluid bilirubin as a clue,

A bilirubin greater than 6 or a fluid to serum bilirubin ratio greater than 1 is suggestive of biliary perforation.