Vitamin D deficiency and Chronic muscle pain

Introduction:

Chronic widespread muscle pain is very prevalent in general population. Many studies have been done to identify its reason and hypovitaminosis d is one of the major cause of chronic muscle pain. Deficiency of vitamin d causes not only muscle pain but also ricktets in children, osteomalacia.

It is a fat soluble vitamin which helps in absorption and metabolism of calcium and phosphorus.It is biologically inert and its  active form is called Calcitriol (1,25-Dihydroxycholecalciferol). Body synthesizes it from cholesterol when sun exposure is adequate. Hence  it is also known as the “sunshine vitamin“.It  can also be ingested as cholecalciferol (vitamin D3) or ergocalciferol (vitamin D2) .

 

Sources:

  • Adequate sunlight exposure
  • flesh of fatty fish (such as salmon, tuna, and mackerel) and fish liver oils are among the best sources
  •  beef liver, cheese, egg yolks, mushroom, fortified milk

 

Synthesis:

 

vit d metabolism

Recommended Daily Allowance:

Infants 0-6 months 400 IU*

Infants 7-12 months 400 IU*

Children 1-3 years 600 IU

Children 4-8 years 600 IU

Children/Adults 9-70 years 600 IU

Adults more than 70 years 800 IU

Pregnancy & Lactation 600 IU

 

Hypervitaminosis D

Regular intake of more than 1250 micrograms/day (50,000 IU) can produce overt toxicity after several months. Vitamin D overdose causes hypercalcemia, anorexia, nausea, vomiting,weakness, insomnia, pruritus and sometimes renal failure. Treatment of hypervitaminosis D is discontinuation if intake of vitamin d and calcium supplements.  But exposure to sunlight for extended periods of time does not normally cause vitamin D toxicity.

Symptoms of Hypovitaminosis D:

Chronic muscle pain lasting for more than 3 months

Easy fatigability

Muscle weakness

Low bone mineral density

Pathological fracture

 

Our research on 2000 Nepalese patients with muscle pains showed deficient vitamin D levels in 90 percent of them. This shows that this is prevalent even in our country.

Diagnosis:

–       Symptoms

–       Serum 25 OH cholecalciferol level

 

Categories:

Sufficient: 30-100 ng/ml

Insufficiency: 20-29 ng/ml

Mild Deficiency: <20 ng/ml

Severe: <10 ng/dl

 

Who should be tested for hypovitaminosis D?

Patients with inadequate sun light exposure or intake

History of chronic muscle pain

Elderly

Malabsorption

Chronic kidney disease

 

Treatment:

Patients with 25OHD level < 30 ng/dl should be treated with oral supplementation of cholecalciferol to be taken 6 lakh IU once a week for 8 weeks and then maintenance dose of once a month for 6 – 8 months.Calcium supplementation can also be added while taking vitamin d supplements. Vitamin D level can be repeated after 6 months of treatment. If the level is corrected (>30 ng/dl), cholecalciferol supplementation can be taken once a month for years, whereas if the level is not corrected even after taking supplementation for 6 months, parenteral vitamin d should be administered ( 6 lakh IU IM once a year). If the patients don’t respond to parenteral vitamin d too, other causes of chronic muscle pain like fibromyalgia should be considered and managed accordingly.

 

Authors:
Dr Binit Vaidya,
MD(AIIMS), FACR
Alka Hospital
Jiwanta Swasthya Sewa Sadan (01-4303010)

 

Dr Shweta Nakarmi,
MBBS, MD Resident

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