Thread by @ebtapper

Introducing the “The Hepatologist’s CBC”

A #cirrhosis #tweetorial all about the platelet

Aims:
- Identify cirrhosis based on blood tests-
- Understand why platelets are low in #cirrhosis
- Describe the plt’s role in the #cirrhotic #coagulopathy

#livertwitter

The hepatologist's dream:
identify patients with cirrhosis before complications like HCC and variceal bleeding.

Enter the platelet count
Shout out to JAMA's Rational Clin Exam Series & Udell et al's big beautiful systematic review ncbi.nlm.nih.gov/pubmed/22357834

Platelets are low in #cirrhosis.
We can use this to our advantage - even sparing biopsies.

Easy to do. E.g. Google: FIB-4
(ref aasldpubs.onlinelibrary.wiley.com/doi/abs/10.100…)

There are many platelet-based scores to help ID cirrhosis.
(review: ncbi.nlm.nih.gov/pubmed/2883446

Be like Britain:
Even in their guidelines for the evaluation of elevated ALT, the brits make a plea for looking at platelet-based scores the minute you realize ALT abnormal (ncbi.nlm.nih.gov/pmc/articles/P…)

Act 2:
So why are platelets low in #cirrhosis?

At least 3 reasons:
- Splenic pooling
- Increased destruction
- Low production

1: "The spleen is a platelet hotel"
- Sir William Osler (personal correspondence)

Portal hypertension ▶️splenomegaly ▶️platelet pooling

onlinelibrary.wiley.com/doi/full/10.10…
(Osler was one of the first to link cirrhosis and low plts)

You can shake the platelets loose from a spleen

Temporarily: super cool 1966 study from Aster (Fig 1)
-Radiolabel platelets
-inject epi(!)
-radiotracer shifts spleen to blood
ncbi.nlm.nih.gov/pmc/articles/P…

Permanently: Splenic Embolization (Fig 2)
aasldpubs.onlinelibrary.wiley.com/doi/abs/10.100…

2. Cirrhosis is a pro-inflammatory state which is bad for platelets

Endotoxin from the gut circulates, stimulating immune responses.
As total IgG 🔼, so does anti-platelet antibodies (Fig1)
Reduced spleen volume 🔽 anti-plt IgG (Fig2)
Reduced endotoxin may 🔼plts (Fig3)
Wild?

3. The hormone for platelet growth - thrombopoetin (TPO) - comes from, you guessed it, the liver

Fig 1: replace the liver, 🔼TPO, 🔼platelets
Fig 2: TPO levels and plts by stage of fibrosis
Fig 3: 🔼TPO activity, raise plts

Act 3:
So what does this have to do with the cirrhotic coagulopathy?

Platelets rule!
The platelet is the MVP of the first phase of hemostasis:
Need it to stick, aggregrate, and activate on the vessel wall.
It even catalyzes the coag cascade!(Fig 1)
In cirrhosis, thrombin generation is preserved, independent of INR, until plts are superlow(Fig2)

Platelets are quantitatively AND qualitatively defective in cirrhosis

1. Cirrhosis 🔽 platelet adhesion (fig 1)
2. Cirrhosis 🔽 platelet aggregation in response to stimulus (fig 2-3)
3. Cirrhosis platelets 🔽activation (they are metabolically "exhausted")(Fig4)

The platelet's role in the cirrhotic coagulopathy summarized in this snapshot @JHepatology
journal-of-hepatology.eu/article/S0168-…

Well I hope you enjoyed this platelet rich tweetorial. And I hope it helps you identify #cirrhosis.
Despite all this coagulopathy talk, some parting words.
None of this should stop you from:
Fig1: Doing that para
Fig2: Banding that varix
Fig3: Placing that central line