1 / 16

Calcium / Vitamin D

Calcium / Vitamin D. Calcium metabolism. Serum calcium drops.. PTH released.. In kidney, PTH turns vitamin D into its active form 1,25hydroxycholecalciferol ( calcitriol )... It also increases kidney’s reabsorption of calcium from urine

lara
Télécharger la présentation

Calcium / Vitamin D

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Calcium / Vitamin D

  2. Calcium metabolism • Serum calcium drops.. PTH released.. • In kidney, PTH turns vitamin D into its active form 1,25hydroxycholecalciferol (calcitriol)... It also increases kidney’s reabsorption of calcium from urine • Calcitriol acts to aid absorption of calcium from small intestine

  3. Calcium metabolism • Dietary sources - • Dairy (semi skimmed milk greater content than full fat), sardines, bread, baked beans, cabbage • PTH causes release of calcium from bone into bloodstream. • Absorption of calcium from blood into bone matrix, stimulated by calcitriol

  4. Vitamin D metabolism • Vitamin D is produced by the skin in sunlight (cholecalciferol - D3) • Diet adequate in vitamin D is needed to maintain supplies in Winter (D2 and D3) • Dietary sources: • Eggs, dairy products, oily fish, fortified cereals • Skin and dietary sources of vitamin D are metabolised by liver and then kidney, into active form 1,25hydroxycholecalciferol (calcitriol)

  5. Vitamin D deficiency • Inadequate mineralisation of bone matrix • Leads to low calcium and phosphate, and secondary hyperparathyroidism • In children: Rickets • Bone pain; skeletal deformity e.g bow legs, pigeon chest; pathological #; poor growth; muscle weakness; dental deformities • In adults: Osteomalacia • Bone pain – especially hip and low back pain; muscle weakness; fatigue; pathological #; hypocalcaemia – perioral and extremity numbness; hand/foot spasms; arrhythmias

  6. Risk factors • Dark skin especially in Northern climes • Children and elderly • Pregnancy • Routine covering of face and body, e.g. wearing a veil. • An infant who has prolonged breast-feeding without vitamin D supplementation, especially if the mother is vitamin D-deficient – neonatal seizures • Housebound or institutionalised • Poverty. • Vegetarianism. • Alcoholism • Malabsorption, renal, liver and pancreatic disease.

  7. Causes / treatment • Dietary deficiency • Age related – metabolism deteriorates with age • Secondary osteomalacia - Malabsorption, renal, liver and pancreatic disease • Vitamin D dependent Rickets – rare genetic condition affecting vit D metabolism • Vitamin D resistant Rickets – genetic trait causing reduced phosphate absorption from kidney

  8. Investigations • Children – paediatrics • Renal and liver function (raised alkphos) • Calcium, phosphate (may be low) • Serum vitamin D and PTH – unless high risk and diagnosis clear clinically • Normal vitamin D level: above 50 nmol/L • Vitamin D insufficient: 25-50 nmol/L • Vitamin D deficient: below 25 nmol/L • Consider radiology but may not be necessary if diagnosis clear

  9. Referral • All children with rickets should be referred to a paediatrician.10 It is advisable to refer an adult with vitamin D deficiency to a relevant specialist if:2 • There is no obvious cause. • There is unexplained weight loss or anaemia or any other suggestion of coeliac disease or fat malabsorption. • If medication (e.g. antiepileptic drugs, rifampicin) might be the cause. • If the patient has hepatic or renal disease. • If there is any illness associated with undue sensitivity to vitamin D and so an increased risk of toxicity with treatment (e.g. sarcoidosis, tuberculosis, lymphoma, primary hyperparathyroidism). • Symptomatic patients who have taken supplements as directed for about 2 months with no improvement clinically or in vitamin D status.

  10. Dietary deficiency Vitamin D - treatment • Advice about diet and sun exposure • Prevention: 10mcg / 400 units per day (for those at high risk) • Treatment: 20mcg / 800 units per day • No plain vitamin D tablet available to treat simple dietary deficiency – available either combined with calcium, or as combination vitamin tablets • Calcium and Cholecalciferol – vitamin D3 • e.gAdcal D3, Calceos – 10mcg / 400 units per tablet • Calcium and Ergocalciferol - vitamin D2 • 10mcg / 400 units per tablet • Takes at least a year for bone to normalise. Higher doses may be needed. • Lack of response – is there an underlying cause e.gmalabsorption or renal failure?

  11. Pregnancy / breast feeding / infants • Vitamin D supplements recommended for all pregnant and breast-feeding women and breast-fed babies: • Pregnancy and breast-feeding: 10 micrograms (400 units) of ergocalciferol daily (20 micrograms daily for those with limited sun exposure and those whose diet is deficient in vitamin D). • Babies: all breast-fed babies should receive vitamin drops (e.gAbidec). ?after 6 months only • Infants who are breast-fed and children and adolescents who consume less than 1 L of vitamin D-fortified milk per day will likely need supplementation to reach 400 IU of vitamin D per day.

  12. Calcium and vitamin D in the elderly • A review commentary stated that "..calcium plus vitamin D remains the cornerstone of prevention of fractures in elderly people and patients with osteoporosis". • The doses of calcium and vitamin D were suggested as calcium >= 500mg per day and vitamin D >= 800 IU per day. • Consider giving 800iu/d vitamin D to all >80 years. • Groups that have been recommended to have combined calcium and vitamin D supplementation • Over 70s in residential care • History of recurrent falls • History of a fragility fracture • Older patients with significant oral steroid use e.g. prednisolone 5mg or higher daily for three months • On bisphosphonates • in the major trials where efficacy of bisphosphonates has been demonstrated also gave calcium, and in all studies patients were vitamin D replete

  13. Treatment of other causes • Malabsorption or chronic liver disease • Ergocalciferol - vitamin D2 - in pharmacological doses • Ergocalciferol - Up to 1mg / 40 000 units per day • Serum calcium levels being monitored to avoid toxicity • Alternatively treat with Calcitriol • Alfacalcidol and Calcitriol.. For severe renal failure (the other forms require hydroxylation by kidney)

  14. Monitoring • Serum calcium concentrations should be checked regularly for a few weeks after starting treatment for vitamin D deficiency and then vitamin D, parathyroid hormone (PTH) and calcium concentrations should be checked after 3-4 months of treatment to assess efficacy and adherence to therapy. Vitamin D and calcium concentrations should be checked every 6-12 months • Patients at risk of deficiency e.g elderly on long term prevention, up to 20mcg / 800 units per day – no monitoring needed. • But consider checking calcium prior to treatment, and check calcium if nausea and vomiting • Care with co-prescribing thiazide diuretic – increased calcium.

  15. References • Oxford Handbook of General Practice 3rded • Patient.co.uk • GP notebook • BNF • NHS choices

More Related