🧵 Procalcitonin (PCT) –
Tweet 1:
Procalcitonin- once just a peptide in calcitonin synthesis, now a powerful biomarker in infection & sepsis care. But when should we trust it, and when not? 🧵@IhabFathiSulima @DrAkhilX @CelestinoGutirr #MedTwitter #Rheumatology #ID
Tweet 2 (Basics):
🔹 What is Procalcitonin?
•Precursor of calcitonin, normally produced in thyroid C-cells.
•During bacterial infection, PCT is released from multiple tissues in response to endotoxins & cytokines (IL-1β, TNF-α).
•Viral infections usually suppress PCT.
Tweet 3 (Why important?):
✨ PCT rises early (within 6–12 hrs) in systemic bacterial infection → helps clinicians:
•Differentiate bacterial vs viral infections
•Assess sepsis severity
•Guide antibiotic decisions
Tweet 4 (Interpretation):
📊 Levels & meaning (general guide):
•<0.1 ng/mL → Normal
•0.1–0.25 → Low likelihood of bacterial infection
•0.25–0.5 → Possible bacterial infection
•0.5 → Suggestive of bacterial infection/sepsis
(Higher = more severe infection)
Tweet 5 (Pros):
✅ Advantages of PCT:
•Rises earlier than CRP in sepsis
•Falls rapidly with infection control → good for monitoring
•Useful in ICU, pneumonia, sepsis management
•Helps reduce unnecessary antibiotics
Tweet 6 (Cons & pitfalls):
⚠️ Limitations:
•Can rise in non-infectious inflammation (major surgery, trauma, burns, CKD)
•May not rise in localized infections (e.g., abscess)
•Viral infections may keep it low despite illness
•Should never replace clinical judgment
Tweet 7 (Special note for Rheumatology):
💡 In autoimmune & rheumatic diseases, PCT helps:
•Distinguish flare vs infection in patients on immunosuppressants
•Guide safe antibiotic use
But beware → high-dose steroids & biologics may blunt inflammatory markers.
Tweet 8 (Take-home):
Procalcitonin = 🧪 helpful tool, not a magic bullet.
Best used with clinical exam + other labs (CRP, cultures, imaging).
👉 It guides antibiotics, but doesn’t write the prescription for you.
#MedEd #Procalcitonin #Sepsis
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One of the most debated biomarkers.
Ordered often, misinterpreted even more.
Let’s clear the confusion 👇
#Rheumatology #Sarcoidosis #Biomarkers @IhabFathiSulima @DrAkhilX @CelestinoGutirr
1/ 🔬 Serum ACE is produced by epithelioid cells in granulomas.
Hence, levels may be elevated in granulomatous diseases — especially sarcoidosis.
2/ 📊 When is ACE useful?
•Supporting diagnosis of sarcoidosis (not diagnostic alone)
•Monitoring disease activity (trend > absolute value)
•May fall with treatment response
A lab we all order. A deficiency we often find.
But what does it really mean in autoimmune disease?
Let’s clear the confusion 👇
#Rheumatology #VitaminD
@IhabFathiSulima @DrAkhilX @CelestinoGutirr
1/ 💡 Vitamin D is not just about bones.
It’s an immunomodulator: affects T cells, B cells, and dendritic cells.
Deficiency is linked to ↑ autoimmunity risk (RA, SLE, MS, etc.).
2/ 🔍 Testing:
•Serum 25(OH)D is the correct test (not 1,25(OH)₂D).
•Deficiency: <20 ng/mL
•Insufficiency: 20–30 ng/mL
•Sufficiency: >30 ng/mL
Tweet 1:
Serum uric acid — one of the most over-ordered and misinterpreted tests in medicine.
Here’s how to understand it in rheumatology 👇
@IhabFathiSulima @DrAkhilX @CelestinoGutirr #MedTwitter #Rheumatology
Tweet 2 (Basics):
•Uric acid = end product of purine metabolism
•Normal range: ~3.5–7 mg/dL (varies by lab/sex)
•Excreted mainly by kidneys (~70%) + gut (~30%)
Tweet 3 (Hyperuricemia ≠ Gout):
•Many people with high uric acid never develop gout
•Risk rises as uric acid >9 mg/dL
•Gout diagnosis = clinical + crystals, not just lab value
🧵 Anti-Phospholipid Antibodies (aPL) in Rheumatology:
Tweet 1:
Anti-Phospholipid Antibodies — a small blood test with big consequences.
From clots to pregnancy complications, they guide APS diagnosis and management.
Here’s what every clinician should know 👇@IhabFathiSulima @DrAkhilX @CelestinoGutirr #MedTwitter #Rheumatology
Tweet 2 (What are aPL?):
•Autoantibodies against phospholipid-binding proteins
•Main types tested:
• Lupus anticoagulant (LA)
• Anticardiolipin (aCL) IgG/IgM
• Anti-β2 glycoprotein I (β2GPI) IgG/IgM
Tweet 1:
ANCA — one antibody, many confusions.
From GPA to drug-induced vasculitis, it’s powerful when used right…
and misleading when used wrong.
Here’s a quick guide 👇
@IhabFathiSulima @DrAkhilX @CelestinoGutirr #MedTwitter #Rheumatology
🧵 HLA-B27 in Rheumatology:
Tweet 1:
“HLA-B27 — a genetic marker with a powerful reputation.
From ankylosing spondylitis to reactive arthritis, it shapes how we think about SpA.
But what does a positive result really mean? 👇”
@IhabFathiSulima @DrAkhilX @CelestinoGutirr #MedTwitter #Rheumatology
Tweet 2 (What is HLA-B27?):
•Human Leukocyte Antigen, class I molecule
•Encoded on chromosome 6
•Important in antigen presentation
•Strong association with seronegative spondyloarthritis
Tweet 3 (Prevalence):
•General population: 6–8% (varies by ethnicity)
•AS patients: >90% positive
•But: Most HLA-B27+ people never develop disease