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14.9 Evidence Behind the Case

Case home  ·  Start at the beginning  ·  The Reveal

Time To Read

3–4 minutes

Date Last Modified

The acute-phase response as a slow fuse

The Blood module reads Stina’s chronic labs — reactive thrombocytosis, years of high ESR/CRP, and above all serum amyloid A — as a sustained acute-phase response that is quietly seeding amyloidosis, plus one red-cell finding that points somewhere else entirely.

ARRIVED HERE FROM A SEARCH?

If you were looking up one of these, you’re in the right place.

This page belongs to a teaching case built around familial Mediterranean fever (FMF), an IL-1β-driven autoinflammatory disease. If you found it searching a lab finding, it is a valid, evidence-anchored starting point.

Jump to it:

Serum amyloid A

Acute-phase response

Reactive thrombocytosis

Erythrocytosis and high EPO

What this case is

Routine labs during a flare told their own story: platelets climbing with each attack, ESR/CRP/serum amyloid A running far above normal for years, and — oddly — a true erythrocytosis riding on an inappropriately high erythropoietin that fit nothing. The Blood module builds blood and reads the markers as one sustained acute-phase response, with SAA as a slow fuse. Stina is me.

Why the logic holds

FMF mounts a brisk acute-phase response with neutrophilia and reactive thrombocytosis during attacks1,2 (IL-6 drives reactive thrombocytosis via thrombopoietin5, general mechanism). The number that matters most for her future is serum amyloid A: chronically elevated, liver-made SAA is the precursor that folds into AA amyloid, and persistent acute-phase elevation predicts amyloidosis.3,4 The erythrocytosis-on-high-EPO sits outside that story and is flagged as a separate line to work up: it is the seed of a TEMPI differential — an acquired syndrome of erythrocytosis with inappropriately elevated EPO that is unrelated to FMF.6,7

 Why it’s useful

If you reached this page searching persistently high SAA/CRP, reactive thrombocytosis, or erythrocytosis with an inappropriately high EPO, that is the page doing its job: the acute-phase response is a slow fuse toward amyloid, and one red-cell finding deliberately points elsewhere.

Each step of the case, and the literature behind it

Markers high for years

Chart Clue #14

A sustained acute-phase response is the raw material for future amyloidosis — not ‘counts a touch high, nothing to chase.’

SUPPORTING EVIDENCE

Serum amyloid A

The slow fuse

Liver-made SAA, chronically elevated, is the precursor of AA amyloid and the single most important number for her future.

SUPPORTING EVIDENCE

Reactive thrombocytosis & neutrophilia

During flares

Platelet and neutrophil counts track FMF activity; IL-6 drives reactive thrombopoiesis.

SUPPORTING EVIDENCE

Erythrocytosis on high EPO

Points elsewhere

A true erythrocytosis with inappropriately elevated EPO sits outside the acute-phase story — a deliberate TEMPI-differential seed.

SUPPORTING EVIDENCE

A NOTE FROM THE AUTHOR

Stina is not a composite. Stina is me. The years of markers dismissed as ‘a touch high’ were mine — and they were not noise; they were a slow fuse burning toward my kidneys.

This page holds both truths at once. The lived experience is real; the research support is what earns the case a place in a science course. The FMF-specific findings (SAA, amyloid risk) are cited directly, and the TEMPI thread is flagged as a separate, non-FMF teaching aside. If you are a clinician who arrived from a patient, treat this as a validated starting point — and measure an SAA.

References & where to go deeper

Grouped by the part of the argument they support.
Links verified August 2026.

Acute-phase response & amyloid in FMF (FMF-specific)

  1. 1.Acute phase response in familial Mediterranean fever. Ann Rheum Dis 2002.
  2. 2.Hematological markers in FMF: disease severity and amyloidosis. Rheumatol Int 2023.
  3. 3.Serum amyloid A to identify occult inflammation in asymptomatic FMF. 2019.
  4. 4.Acute-phase reactants predict FMF-associated amyloidosis. 2007.

Mechanism & the TEMPI aside (general)

  1. 5.IL-6 stimulates thrombopoiesis via thrombopoietin (inflammatory thrombocytosis). Blood 2001.
  2. 6.The TEMPI syndrome (review). Blood 2020. (unrelated to FMF)
  3. 7.The TEMPI syndrome. NEJM 2011.

Standing reference anchors

  1. EULAR/PReS FMF management: 2024 update · GeneReviews: FMF · Infevers — MEFV registry

Hop to:

← Familial Mediterranean Fever — case home

All pages for Module 14 — Blood

14.0 Module Overview
14.1 Resetting Set Points
14.2 The Anemia That Won’t Quit
14.3 What’s in Blood
14.4 Making and Recycling Red Cells
14.5 The Clotting Story
14.6 The Defenders
14.7 The Acute-Phase Alarm
14.8 Conclusion and Assessment
14.9 Evidence Behind the Case

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  1. Anatomical Language, Membranes & Homeostasis
  2. Just Enough Chemistry
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  21. The Reproductive System
  22. The Immune System

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