Acronym Trick for Scurvy and Collagen (Biochemistry)
When USMLE stems say bleeding gums + perifollicular hemorrhages + corkscrew hairs, your reflex should be: Scurvy = Vitamin C deficiency → defective collagen hydroxylation.
The Mnemonic (Quick, Shareable)
SCURVY = C-UR-VY
Acronym breakdown:
- C = Vitamin C deficiency
- UR = Under-hydroxylated collagen (↓ hydroxylation of proline + lysine)
- VY = Very weak connective tissue (fragile vessels, poor wound healing)
One-liner:
Scurvy is Vitamin C deficiency → ↓ hydroxylation of proline/lysine → unstable collagen triple helix → bleeding + poor wound healing.
The Visual “Sticky Note” Mental Image
Picture collagen as a 3-strand rope that needs “C-clips” to stay tight:
- Vitamin C = the “clips” that help enzymes hydroxylate proline & lysine
- Without clips, the rope frays → tissues that depend on strong collagen fail first
- Gums bleed
- Skin bruises
- Wounds don’t heal
- Hair follicles hemorrhage
If you like a mini visual:
C (ascorbic acid) → enables hydroxylation → stabilizes triple helix
No C → no hydroxylation → weak helix → hemorrhage + poor healing
High-Yield Biochemistry: Collagen Step Where Vitamin C Acts
Where Vitamin C matters:
- Rough ER: Hydroxylation of proline and lysine residues (post-translational modification)
- Enzyme: prolyl hydroxylase / lysyl hydroxylase
- Cofactor: Vitamin C (ascorbic acid) keeps Fe²⁺ in the active state
Why hydroxylation matters:
- Hydroxyproline helps stabilize the collagen triple helix (H-bonding)
- Hydroxylysine contributes to cross-linking and strength (later steps)
USMLE phrasing you’ll see:
- “Defect in hydroxylation”
- “Impaired triple helix stability”
- “Poor wound healing and bleeding”
USMLE Clinical Pattern Recognition (Step 1 → Step 2 Friendly)
Classic scurvy findings:
- Bleeding gums
- Petechiae / purpura, easy bruising
- Perifollicular hemorrhage
- Corkscrew hairs
- Poor wound healing
- Bone pain (impaired osteoid formation; can be tested in kids)
Who gets it?
- Alcohol use disorder
- Elderly with poor diet
- Food insecurity
- Restrictive diets (no fruits/vegetables)
Rapid Differentials (Common Test Trap)
- Scurvy (Vitamin C deficiency): ↓ hydroxylation → unstable triple helix
- Ehlers-Danlos (often AD): abnormal collagen synthesis/structure → hyperextensible skin, hypermobile joints
- Osteogenesis imperfecta (COL1 defect): brittle bones, blue sclerae, hearing loss
Exam-Ready Takeaway
If it bleeds and bruises with weird hairs and bad wound healing, think: “No C → No hydroxylation → No stable collagen.”