What are the symptoms and treatment of vitamin D deficiency?

Symptoms and Treatment of Vitamin D Deficiency

Vitamin D deficiency commonly manifests as symmetric low back pain, proximal muscle weakness, muscle aches, and throbbing bone pain that can be elicited with pressure over the sternum or tibia. 1 When deficiency is severe, patients may experience osteomalacia, which presents with bone pain, muscle weakness, and stiffness, distinguishing it from asymptomatic osteoporosis. 2

Definition and Diagnosis

Vitamin D status is categorized based on serum 25-hydroxyvitamin D [25(OH)D] levels:

• Deficiency: <20 ng/mL (<50 nmol/L)
• Insufficiency: 20-30 ng/mL (50-75 nmol/L)
• Optimal: 30-100 ng/mL (75-250 nmol/L) 3

Common Symptoms

1. Musculoskeletal manifestations:

   • Bone pain (particularly in sternum, tibia, and lower back)
   • Proximal muscle weakness
   • Muscle aches and throbbing bone pain
   • Increased risk of falls and fractures 1, 4

2. Laboratory abnormalities in severe deficiency:

   • Low calcium and phosphorus levels
   • Elevated alkaline phosphatase
   • Elevated parathyroid hormone (PTH) levels 2

3. Other potential manifestations:

   • Fatigue
   • Increased susceptibility to infections
   • Height loss (due to vertebral fractures) 2

High-Risk Populations

Testing should focus on individuals at high risk for vitamin D deficiency:

• People with malabsorption syndromes
• Homebound or institutionalized persons
• Those with limited sun exposure
• Persons with darker skin pigmentation in northern latitudes
• Individuals with bone, endocrine, or autoimmune diseases 3

Treatment Approach

For Vitamin D Deficiency (<20 ng/mL)

1. Initial treatment:

   • Oral ergocalciferol (vitamin D2) at 50,000 IU per week for eight weeks 1
   • Alternatively, a cumulative dose of at least 600,000 IU administered over several weeks 5
   • Avoid single large doses of 300,000-500,000 IU 5

2. Maintenance therapy:

   • After normalization, cholecalciferol (vitamin D3) at 800-1,000 IU per day from dietary and supplemental sources 1
   • For recurrent deficiency, 4,000-5,000 IU daily for 2 months to achieve blood levels between 40-60 ng/mL 3

3. Monitoring:

   • Recheck vitamin D levels 3-6 months after initiating therapy 3

For Vitamin D Insufficiency (20-30 ng/mL)

• Daily supplementation with 800-1,000 IU of vitamin D3 3, 1

Prevention

• American Academy of Pediatrics recommends at least 400 IU per day for infants and children 1
• For adults, 600 IU/day for ages 19-70 years and 800 IU/day for adults older than 70 years 3
• Evidence shows that vitamin D supplementation of at least 700-800 IU per day reduces fracture and fall rates in adults 1, 6

Important Considerations

1. Ensure adequate calcium intake alongside vitamin D supplementation for optimal response 3

2. Be aware of testing limitations:

   • Significant variability exists between testing methods and laboratories
   • The gold standard method is LC-MS/MS (liquid chromatography-tandem mass spectrometry) 3

3. Special populations may require higher doses:

   • Patients with malabsorption syndromes, inflammatory bowel disease, obesity, bariatric surgery, chronic liver disease 3
   • Critically ill patients with very low vitamin D (<12.5 ng/mL) may benefit from higher doses 3

4. Safety considerations:

   • Upper daily limit is generally 4,000 IU, though up to 10,000 IU may be safe for high-risk patients 3
   • Vitamin D toxicity is rare but can occur with excessive doses, leading to hypercalcemia, hyperphosphatemia, and hypercalciuria 3
   • Toxicity typically occurs when 25(OH)D levels exceed 150 ng/mL 6

By addressing vitamin D deficiency promptly and appropriately, clinicians can help alleviate symptoms, improve musculoskeletal health, and reduce the risk of falls and fractures in affected individuals.