What is the diagnostic approach for scurvy?

Diagnosis of Scurvy

The diagnosis of scurvy is primarily clinical, based on characteristic physical findings and dietary history, with confirmation through plasma vitamin C measurement and/or rapid response to vitamin C supplementation. 1

Clinical Manifestations

Key Diagnostic Features

• Pathognomonic signs:

  • Hemorrhagic manifestations: perifollicular purpura (petechiae around hair follicles) 1, 2
  • Corkscrew or contorted hairs 2, 3
  • Follicular hyperkeratosis, particularly affecting the legs 2

• Mucocutaneous findings:

  • Gingival bleeding and periodontal disease 1, 2
  • Spontaneous ecchymosis (bruising) 2, 3
  • Poor wound healing 2
  • Perifollicular petechiae 4

• Musculoskeletal manifestations (present in 80% of cases):

  • Joint contractures due to periosteal and intra-articular hemorrhages 1
  • Arthralgia, myalgia, hemarthrosis, and muscular hematomas 5
  • Subperiosteal hemorrhage causing pain and pseudoparalysis 2, 6
  • Lower limb pain and swelling, especially in children 4, 6

• Constitutional symptoms:

  • Fatigue, malaise, depression, and irritability 2, 4
  • Loss of appetite 4

Radiological Findings

• Characteristic changes include:
  • Osteopenia
  • Sclerosis of provisional calcification zones
  • Dense epiphyseal rings 1
  • Subperiosteal hemorrhage 6
  • Trabecular and cortical osteoporosis 5

Diagnostic Algorithm

1. Identify high-risk populations:

   • Children fed exclusively cow's milk without supplementation 1
   • Individuals with restrictive or selective dietary habits 4
   • People with developmental delays, autism spectrum disorder 4
   • Elderly with inadequate nutrition 1
   • Individuals with alcohol abuse 3
   • Displaced populations or refugees 1

2. Obtain detailed dietary history:

   • Focus on intake of vitamin C-rich foods (fresh fruits and vegetables)
   • Duration of restricted diet
   • Assess for malabsorption issues

3. Physical examination:

   • Look for pathognomonic skin findings (perifollicular purpura, corkscrew hairs)
   • Examine gums for bleeding and disease
   • Assess for musculoskeletal manifestations
   • Check for peripheral edema and bruising

4. Laboratory testing:

   • Plasma vitamin C measurement (gold standard) 2
     • Levels <0.2 mg/dL indicate deficiency 3
     • Strict sample collection procedures required (immediate separation, protection from light, storage at -70 to -80°C) 7
   • Complete blood count (anemia is common) 4, 5
   • Inflammatory markers may be elevated 4

5. Imaging studies:

   • Plain radiographs to identify characteristic bone changes
   • Consider MRI in cases with significant musculoskeletal symptoms

6. Confirmatory approaches:

   • Skin biopsy (if needed): may show follicular hyperkeratosis and extravasated perifollicular red blood cells 4
   • Therapeutic trial: rapid response to vitamin C supplementation is diagnostic 1, 6

Common Pitfalls and Caveats

• Misdiagnosis is common due to:

  • Rarity of the condition in modern society 6
  • Non-specific early symptoms (fatigue, irritability) 2
  • Confusion with other conditions like osteomyelitis, vasculitis, or bone tumors 4, 6

• Laboratory considerations:

  • Plasma vitamin C analysis requires specific pre-analytical precautions 7
  • Serum determination should be avoided; plasma is preferred 7
  • Inflammation affects vitamin C levels (levels decrease with CRP >10 mg/L) 7

• Differential diagnosis to consider:

  • IgA vasculitis 4
  • Osteomyelitis 6
  • Bone tumors 6
  • Bleeding disorders

Treatment Approach

Once diagnosed, treatment is straightforward:

• American Academy of Pediatrics recommends 250 mg of vitamin C orally twice daily for 3 weeks 1
• Alternative dosing: 1 g/day for at least one week in severe cases 1, 3
• Clinical improvement typically occurs within 1-2 weeks of supplementation 1, 6

Remember that subclinical vitamin C deficiency is more common than overt scurvy, particularly in low-income populations (25% of men and 16% of women), with smoking being a strong predictor 2.