Background
Pathogenesis: The function of the Parathyroid Hormone. 2) Vitamin D Action.
-What is Vitamin D?
-How is vitamin D made?
-Undiagnosed vitamin D deficiency is common.
-Test: 25-hydroxyvitamin D is the barometer for vitamin D status.
Most experts define vitamin D deficiency as a 25-hydroxyvitamin D level <20 ng/mL (50 nmol/L).
-Vitamin D is linked with Depression, ADHD. Many psychiatrists recommend it in ADHD patients and in patients with depression and anxiety.
-Deficiency causes muscle pain.
-Need Vitamin D for healthy bones throughout life.
-You get it from the sun. However, many people don’t get enough of it.
-Foods that have vitamin D include fortified milk and fatty fishes.
-For many people, a Vitamin D supplement is a good idea. Talk with your doctor about it.
People who need supplementation
“Patients with chronic renal disease or those taking antiepileptic drugs are at risk for severe vitamin D deficiency and may require large maintenance doses of vitamin D (i.e., up to 50,000 IU one to three times weekly) (SOR C). Levels of 25-hydroxyvitamin D should be maintained above 32 ng/mL (80 nmol/L) to maximize bone health (SOR C).” ABFM
“The AAP recommends a minimum daily intake of 400 IU of vitamin D for all infants and children, including adolescents, beginning within the first few days of life. Because breast milk has been found to contain insufficient levels of vitamin D, starting supplementation in the newborn period for infants who are solely breastfed is strongly recommended (SOR C).” ABFM
“Breast cancer survivors taking bisphosphonates are at risk for developing vitamin D deficiency, and guidelines recommend routine vitamin D supplementation for all women with metastatic breast cancer (SOR C).” ABFM
USPSTF recommendations for vitamin D supplementation.
Vitamin D Supplementation in Children.
Replacement:
Cholecalciferol (Vit D3) will be used instead of Vit D2 because it may be more effective in preventing nonvertebral fractions. (AFP. 2013 Feb 15;87(4):online.)
Vitamin D deficiency (low 25-Hydroxy Vit D) may be associated with elevated Alkaline Phosphatase
“A comprehensive metabolic panel prior to the visit revealed the following: Serum calcium…………9.2 mg/dL (N 8.5–10.2) Albumin…………4.0 g/dL (N 3.5–5.4) Creatinine…………0.6 mg/dL (N 0.6–1.1) 25-hydroxyvitamin D…………9 ng/mL (N >20) Alkaline phosphatase…………151 U/L (N 47–147) Which one of the following is true, based on these findings?
This patient has slight elevations of her alkaline phosphatase along with a deficiency of vitamin D and normal calcium levels. This constellation of findings is most consistent with secondary hyperparathyroidism related to vitamin D deficiency. Vitamin D storage is best reflected by the serum 25-hydroxyvitamin D level. While there is some disagreement regarding normal levels, a level <10 ng/mL is clearly deficient. This would put the patient at risk for osteomalacia but not rickets, which is a clinical diagnosis based on the effects of insufficient bone mineralization secondary to low vitamin D activity before the closure of growth plates. Supplementation with activated vitamin D (calcitriol) is generally only necessary in patients with renal failure or other conditions associated with inadequate activation of the storage forms of vitamin D. Supplementation with vitamin D should decrease PTH activity and thus bone turnover in this patient, which would likely normalize the alkaline phosphatase.” ABFM
“Absorption and metabolism of vitamin D is known to be affected by interaction with other medications. Isoniazid and thiazide diuretics can lead to increased blood levels or activity of vitamin D. Estrogen replacement therapy can also increase levels of vitamin D in the blood, although this potential benefit seems to diminish when progesterone is added.
Vitamin D absorption through the gut can be reduced by mineral oil, cholestyramine, and certain antacid preparations, leading to lower blood levels. The metabolism of vitamin D is accelerated by anticonvulsant drugs such as phenobarbital and phenytoin, which can also result in lower than desired levels of vitamin D. Statins are not reported to have any known effect on vitamin D levels.” ABFM
Resources:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3166406/
http://www.webmd.com/diet/guide/vitamin-d-deficiency (Check the accompanying video)
http://www.medscape.com/viewarticle/876941?src=wnl_tp10f_170420_mscpedit&uac=117880MG&impID=1331690
https://www.uptodate.com/contents/overview-of-vitamin-d
https://www.uptodate.com/contents/vitamin-d-deficiency-in-adults-definition-clinical-manifestations-and-treatment
://www.uptodate.com/contents/vitamin-d-deficiency-in-adults-definition-clinical-manifestations-and-treatment