Vitamin D in the Clinic

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Vitamin D in the Clinic

Journal Title: Biomedical Journal of Scientific & Technical Research (BJSTR) - Year 2018, Vol 11, Issue 2

Abstract

The purpose of this short paper is to review clinical questions regarding vitamin D that arise in the course of treating patients with calcium problems or metabolic bone disease. These will include the optimal dosing of the vitamin, potential toxicities and impact on its use in the clinical setting. The information presented here is purely clinical, culled from years of clinical experience. Our patients in the Bronx have little or no exposure of their skin to sun light. This results in vitamin deficiency that sometime may be extreme. The reader will note that I make no reference to the medical literature, which is very extensive and grows daily. The first question is the dose of vitamin D to be used in any individual patient. To understand the reply, one must remember that the primary function of vitamin D is in the gut, facilitating the reabsorption of calcium from the internal recirculation and its absorption from dietary sources. These maintain blood calcium at a normal level. In the absence or insufficiency of vitamin D the blood level of calcium tends to fall. The parathyroid glands discharge some extra hormone, resulting in the resorption of bone and reabsorbing calcium by the kidneys. The sensitivity of the parathyroid glands to fluctuations of calcium blood level is the key to the reply to the question of vitamin D dosing: If PTH (Para Thyroid Hormone blood level) is elevated and blood calcium is normal, one may suspect that vitamin D intake may be deficient. This, indeed, is true if the blood level of the metabolite – 25-hydroxyvitamin D - is below the normal range but also if it is in the normal range. The last statement is very significant: a) The normal range is 30 to 100 ng/ml. if a patient presents with a level of 32 ng/ml, she may well be vitamin D deficient. One may be deficient even with levels of 40 or 60 ng/ml! One’s level is adequate only if PTH is normal. b) Are there any physical signs that will suggest the need to evaluate these levels? There may be none. However, if a patient complains of bone pain and slight percussion of the clavicles elicits pain, the diagnosis of D deficiency is likely. A case in point a woman in her fifties who was referred because she had a thyroid nodule. This was not a clinically significant problem, but the patient was very anxious, because she had bone pain. She had had surgery for breast cancer and was convinced that her disease had spread to her bones in spite of her oncologist reassurance, after extensive evaluation, that she is free of cancer. Her clavicles were extremely tender, her 25-hydroxyvitamin D blood level was below 10 ng/ml and her PTH markedly elevated. This leads me to the dosing of vitamin D deficiency: Patients require as much as 1 million international units for correction of severe deficiency. This woman was treated with 50,000IU biw for twelve weeks. When seen on follow-up she reported that the first two weeks had no clinical effect but on the third week of treatment she began to improve and after the fourth week she became convinced that she did not have metastatic bone disease. For maintenance, some patients require 1000IU daily, some 4000IU daily. This patient was advised to take 2000IU daily, for life, after reevaluation of blood levels of 25-hydroxyvitamin D and PTH.

Authors and Affiliations

Uriel S Barzel

Keywords

Uriel S Barzel Unconscious Nystagmus Vestibular Receptor Dizziness Ampulla Microcalification Meniere Syndrome Labyrinthitis Susac’s Syndrome; Vitamin D; Bone Disease; Deficiency; Parathyroid Glands; 25-hydroxyvitamin D; Hypercalcemia; Sarcoidosis

EP ID EP592356
DOI 10.26717/BJSTR.2018.11.002084
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