The principle of ESR (Erythrocyte Sedimentation Rate) is that during inflammation, acute-phase proteins such as fibrinogen cause red cells to lose their negative surface charge and stick together (rouleaux). Rouleaux are heavier, so they settle faster in a vertical tube. 👉 ESR is non-specific but useful as a broad marker of inflammation, especially in autoimmune and chronic disease.

📖 About ESR

Measured as the rate (mm/hr) at which erythrocytes fall in a vertical tube.
Heavily influenced by plasma fibrinogen & immunoglobulins.
Altered red cell charge promotes rouleaux formation.

📊 Normal Values

👨 Males: <15 mm/hr (rises with age)
👩 Females: <20 mm/hr (rises with age)

🚩 Causes of Markedly High ESR (>100 mm/hr)

Cause	Typical Clinical Features	Key Investigations	Management
🦠 Infections (TB, Endocarditis)	Fever, weight loss, sweats, murmur (endocarditis)	Blood cultures, sputum, echo, CXR, CRP	Antibiotics / anti-TB Rx, surgery if needed
🤲 Autoimmune Disease (RA, SLE)	Joint pain, rashes, fatigue, photosensitivity	ANA, RF, anti-CCP, renal tests, imaging	DMARDs, steroids, biologics
🎗️ Malignancy (Myeloma, Lymphoma)	Bone pain, lymphadenopathy, weight loss	SPEP, bone marrow, imaging, CBC	Chemo, radiotherapy, SCT (myeloma)
🧠 Vasculitis (GCA, ANCA-vasculitis)	Headache, jaw claudication, vision loss	ESR, CRP, temporal artery biopsy, ANCA	High-dose steroids, immunosuppressants
💩 IBD (Crohn’s, UC)	Abdominal pain, diarrhoea, extra-GI features	Colonoscopy, biopsy, stool studies	5-ASA, steroids, biologics, surgery
🩸 CKD	Anaemia, uraemia, hypertension	U&Es, eGFR, renal US	BP control, EPO, dialysis, transplant
🧴 Collagen Vascular Disease (Scleroderma)	Skin thickening, Raynaud’s, pulmonary fibrosis	ANA, anti-Scl-70, HRCT, echo	Immunosuppression, organ support
🔥 Adult Still’s Disease	Spiking fevers, salmon rash, arthritis	Ferritin ↑↑, CBC, LFTs, ESR/CRP	NSAIDs, steroids, DMARDs, biologics

⬇️ Causes of Low ESR

Polycythaemia (↑ RBC mass = slow settling)
Sickle cell disease & spherocytosis (abnormal RBC shape prevents rouleaux)
Extreme leukocytosis (white cell “crowding” slows ESR)
Acanthocytosis (spiky cells disrupt rouleaux)
Hypofibrinogenaemia (less acute-phase protein)

⚠️ Limitations & Interpretation

ESR is non-specific - high in infection, cancer, inflammation.
Rises with age, pregnancy, anaemia, ↑ immunoglobulins (e.g., myeloma).
Changes more slowly than CRP → better for chronic rather than acute monitoring.

📊 ESR vs CRP

Feature	ESR	CRP
Mechanism	RBC settling influenced by fibrinogen & Igs	Hepatic acute-phase protein
Rise & fall	Slow (days to weeks)	Rapid (hours), short half-life
Best for	Chronic inflammation, autoimmune disease	Acute infection, post-surgery monitoring
Affected by	Anaemia, pregnancy, age, myeloma	Few external factors
Limitations	Very non-specific	Unreliable in SLE, UC, scleroderma, leukaemia

💡 Clinical Pearls

ESR >100 mm/hr almost always pathological - think infection, myeloma, vasculitis, or cancer.
In Giant Cell Arteritis, an ESR >50 is typical - but treat on suspicion, don’t wait.
Normal ESR does not exclude significant inflammation if fibrinogen is low (e.g., DIC).
ESR + CRP together: ESR (chronic disease), CRP (acute flare).

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Causes of a high Erythrocyte Sedimentation rate (ESR)