Management of Vitamin C Deficiency
For symptomatic vitamin C deficiency (scurvy), initiate oral vitamin C 100 mg three times daily (300-500 mg/day total) for at least one month, and do not delay treatment while awaiting laboratory confirmation if clinical features are present. 1, 2
Diagnostic Approach
Clinical diagnosis takes priority over laboratory testing. The characteristic features that should prompt immediate treatment include: 2, 3
- Mucocutaneous bleeding (petechiae, ecchymoses, bleeding gums, gingival swelling)
- Perifollicular hemorrhages (pathognomonic finding) 3, 4
- "Corkscrew" or kinky hair appearance 5, 3
- Poor wound healing and easy bruising 5, 6
- Bone pain and joint contractures 3, 6
- Generalized weakness and fatigue 3, 4
Laboratory testing is not necessary to confirm scurvy as plasma levels reflect recent dietary intake rather than tissue stores, and treatment should begin based on clinical suspicion alone. 1, 3 If testing is pursued, plasma vitamin C measurement is the preferred method, but results are unreliable during inflammation (CRP >10 mg/L makes interpretation difficult; normal values are not detected if CRP >40 mg/L). 7, 2
Standard Treatment Protocol
Initial Repletion Phase
Oral administration is the standard route for uncomplicated deficiency: 1, 2
- Primary regimen: 100 mg three times daily (300-500 mg/day total) for 1 month 1, 2
- Alternative regimen: 250 mg twice daily for 3 weeks 1
- Single-dose option: 500 mg once daily for 1 month 1
All three regimens are effective; the choice depends on patient adherence preferences. The ESPEN guideline supports doses of 200-500 mg/day for repletion in patients with chronic malabsorption or oxidative stress. 7
When to Use Parenteral Administration
Switch to IM, IV, or subcutaneous routes when malabsorption is suspected (e.g., inflammatory bowel disease, post-bariatric surgery, severe malnutrition). 7, 2 For IV injection, dilute vitamin C with normal saline or glucose to minimize adverse reactions. 7, 8
A case report illustrates this principle: a 26-year-old woman with Crohn's colitis continued to have bleeding symptoms despite 2000 mg daily oral supplementation and ultimately required routine IV vitamin C in the home setting for symptom resolution. 9 This demonstrates that oral absorption can be inadequate even at high doses in malabsorptive conditions.
High-Risk Populations Requiring Screening
Actively screen for vitamin C deficiency in: 2
- Chronic dialysis patients
- Post-bariatric surgery patients
- Critically ill patients and those undergoing major surgery
- Alcoholics and tobacco smokers 3, 4
- Elderly with poor dietary intake 3, 6
- Patients with severe psychiatric illness 3
- Low socioeconomic status and food insecurity 3, 6
The required daily intake is only ~60 mg, achievable with one medium-sized orange, making deficiency preventable but still encountered in vulnerable populations. 3
Maintenance Therapy After Repletion
Continue treatment until clinical symptoms resolve and adequate dietary intake is established. 1 Post-repletion maintenance requirements vary by population: 1, 2
- Healthy adults: 75-90 mg/day (achievable through diet alone) 1, 2
- High-risk populations (post-bariatric surgery, chronic oxidative stress conditions including diabetes, heart failure, smoking, alcoholism, severe COPD, chronic dialysis): 200-500 mg/day indefinitely 7, 1, 2
Special Clinical Scenarios Requiring Higher Doses
Critical Illness and Acute Inflammation
During the acute phase of critical illness, administer 2-3 g/day IV (Grade B recommendation, 84% consensus). 7, 1, 8 This applies to: 7, 8
- Sepsis and severe sepsis (some protocols use up to 200 mg/kg/day for 4 days) 7
- Acute respiratory failure
- Patients on continuous renal replacement therapy (CRRT)
IV administration is crucial in critical illness because enteral absorption is unpredictable due to limited intestinal transporter capacity and impaired gut function. 8 Dilute 1-3 g doses in 50-100 mL normal saline or dextrose and infuse over 30-60 minutes; for doses >3 g, dilute in 250 mL and infuse over 1-2 hours to reduce adverse effects. 8
Perioperative Cardiac Surgery
Administer 1-2 g/day IV for 5-7 days perioperatively in cardiac surgery patients (Grade 1+ recommendation). 7, 1, 8
Pediatric Dosing
For infants up to 12 months: 15-25 mg/kg/day 2
For older children: 80 mg/day 2
Critical Safety Considerations
Contraindications to high-dose vitamin C (>1 g/day) include: 1, 2
- Hemochromatosis
- G6PD deficiency (especially when treating methemoglobinemia) 8
- Active oxalate kidney stones
- Severe renal dysfunction
The tolerable upper limit is 2000 mg/day based on gastrointestinal upset; doses above this level may cause severe diarrhea and increase oxalate absorption and renal risk. 1 Monitor blood pressure during IV infusion as rapid administration can cause transient hypotension. 8
Common Pitfalls to Avoid
Do not measure vitamin C levels in acutely ill or inflamed patients as results will be falsely low and misleading. 1, 2 Testing is only recommended for suspected scurvy or chronic low intake in stable patients. 1, 2
Do not delay treatment while awaiting laboratory confirmation if clinical symptoms suggest scurvy. 1, 2, 3 Rapid clinical improvement with vitamin C confirms the diagnosis retrospectively. 3
Do not use vitamin C as routine pharmacotherapy for sepsis as current evidence does not support this practice outside of specific research protocols. 2
Do not assume oral supplementation is always adequate. Even high-dose oral vitamin C (2000 mg/day) may fail in malabsorptive conditions, necessitating parenteral administration. 9
Expected Clinical Response
Remarkable improvement occurs within 2 weeks of appropriate treatment. 3 Skin lesions resolve, joint contractures improve, bleeding stops, and energy returns. 3 This rapid response confirms the diagnosis and distinguishes scurvy from other causes of bleeding or anemia. 3, 6