Southern Derbyshire Shared Care Pathology Guidelines. Vitamin D

Transcription

1 Southern Derbyshire Shared Care Pathology Guidelines Vitamin D Purpose of guideline Provide clear advice on when to measure vitamin D and identify patients with insufficiency and deficiency. To provide information on treatment and monitoring. When to measure vitamin D levels? Vitamin D deficiency is very common in the UK with an estimated % of the population being insufficient.. Population screening by measuring Vitamin D levels is unnecessary, even in high risk populations High risk populations (see table 1) without symptoms should not have Vitamin D levels measured, but should be offered lifestyle advice in order to avoid vitamin D deficiency. Over the counter (OTC) supplements may also be suggested. Measure Vitamin D levels only in patients with symptoms of rickets or osteomalacia (see table 2). Who is most at risk of Vitamin D deficiency? Table 1: Age/Groups Poor exposure to UVB light Dietary intake/ absorption Metabolic risk 75years <5 years Pregnancy Breastfeeding Pigmented skin Occlusive garments Housebound Use of sun blocking creams Vegetarian/ fish-free diet Malabsorption (including bariatric surgery) Cholestatic liver disease Breast fed infants Elderly (reduced synthesis) Liver disease (reduced stores) Renal disease (reduced activation) Obese people (excess storage in fat) Drugs: Rifampicin, Antiretroviral drugs, anticonvulsants, cholestyramine, glucocorticoids. Authorised by Julia Forsyth Page 1 of 5

2 Symptoms of deficiency n specific aches and pains are the commonest features. As such, vitamin D deficiency can be easily overlooked. Consider a diagnosis of Vitamin D deficiency in patients with risk factors presenting with musculoskelatal pain. The symptoms outlined in the table below are more commonly observed in patients with severe deficiency leading to Rickets in children or Osteomalacia in adults. Table 2: Clinical features of Vitamin D deficiency Children Poor growth, delayed fontanelle closure Delayed walking or waddling gait Bone pain or tenderness Tender or swollen joints Muscle spasms, seizures or irritability due to hypocalcaemia requiring urgent treatment Breathing difficulties Late teething Adults Proximal muscle weakness Gradual onset and persistent musculoskeletal pain (often in back or lower limbs) Waddling gait Fragility fracture Carpopedal spasm, tetany, seizures or irritability due to hypocalcaemia Laboratory Investigations Serum 25-hydroxy vitamin D (25-OH Vit D) levels are the most reliable marker of overall Vitamin D status. Measurement of other vitamin D metabolites or subfractions is not recommended. 1. In patients with symptoms, measure U&E, LFT, calcium, phosphate and 25-OH Vit D. 2. Severe vitamin D deficiency can result in hypocalcaemia. Measure 25-OH Vit D in any hypocalcaemic patient. If deficient, treatment with vitamin D alone should correct the hypocalcaemia. 3. PTH is commonly raised in vitamin D deficiency (secondary hyperparathyroidism). Measure 25-OH Vit D in any patient with unexplained raised PTH. A high PTH is common in renal disease - there is no indication for measuring vitamin D levels in CKD patients, unless the patient is at risk of deficiency. Authorised by Julia Forsyth Page 2 of 5

3 Diagnosis and Management of Vitamin D Deficiency in Primary Care Symptoms of rickets or osteomalacia? (see table 2) Investigations U&E, LFT, Calcium, Phosphate 25-OH Vitamin D Risk factors for Vitamin D deficiency? Vit D <30 nmol/l Prescription 1 Referral to Specialist Indicated? 2 Refer GP to Prescribe Vit D nmol/l Lifestyle advice & OTC supplements 1 Further Action investigation required Offer lifestyle advice Suggest OTC supplements te 1 Cut off for high dose vitamin D prescription Symptomatic deficiency is unlikely when 25-OH VitD is >30 nmol/l but there is no clear threshold. If symptoms are strongly suspected to be vitamin D related it is reasonable to offer high dose treatment when levels are between 30 and 35 nmol/l. te 2 Reasons for Secondary Care Referral Referral should be to Osteoporosis & Metabolic Bone Clinic unless otherwise stated CKD 4&5 Renal Referral Malabsorption Gastro Referral Atypical biochemistry (includes hypercalcaemia) Failure to respond to treatment after 3 months Short stature / skeletal deformity Focal bone pain Unexplained severe deficiency Authorised by Julia Forsyth Page 3 of 5

4 Management of Vitamin D deficiency < 30 nmol/l Deficiency High dose treatment, long term maintenance nmol/l Insufficiency Lifestyle advice and OTC supplements > 50 nmol/l Adequate rmal no indication for supplementation Please refer to the Derbyshire Joint Area Prescribing Committee (JAPC) guidance on the management of Vitamin D deficiency in primary care. Follow the link y_by_bnf_chapter_prescribing_guidelines/bnf_chapter_9/vitamin%20d%20deficiency %20in%20primary%20care%20(review%20Oct%202015).pdf Monitoring Vitamin D Insufficiency Over-the-counter supplementation should be continued long term in most patients unless there is reason to believe that a change in lifestyle has altered requirements. The majority of these patients do not need biochemical monitoring. Vitamin D Deficiency 2 months following the commencement of the high dose phase, re-check calcium, phosphate and ALP. Routine repeat of vitamin D levels is not needed if symptoms of vitamin D deficiency resolve. If symptoms do not resolve despite adequate vitamin D repletion then the symptoms are not due to vitamin D deficiency Sun exposure: Sun exposure is the main source of vitamin D and should be exploited! However, this should be balanced with the risks of excessive exposure. Diet: Dietary sources of Vitamin D include: Oily fish, cod liver oil/ fish oils, red meat, egg yolks Fortified breakfast cereals, soya products, fortified margarines, low fat spreads The average daily intake from a normal diet is just 2-4 µg/day, and it is difficult to obtain enough vitamin D from usual diet alone. Where supplementation is indicated a dose of units is advised. Authorised by Julia Forsyth Page 4 of 5

5 Contacts Duty Biochemist (8am to 7pm, Mon - Fri) On Call Consultant Biochemist Via RDH switchboard, (24/7) Renal Registrar 9am to 9pm, via RDH switchboard bleep 8121 Osteoporosis and Metabolic Bone Clinic References Vitamin D and Bone Health: A practical Clinical Guideline for Patient Management. National Osteoporosis Society. April 2013 Diagnosis and Management of vitamin D deficiency. Pearce SHS & Cheetham TD. BMJ 2010; 340: b5664 Primary Vitamin D deficiency in adults. Drug & Therapeutics Bulletin. 2006; 44(4): Authors: Dr Vicky Thurston, Dr Penny Blackwell, Dr Roger Stanworth, Dr Rustam Rea; Dr Greg Summers, February 2012 Reviewed by: Date: Expiry date: Dr P Blackwell, Dr R Stanworth, Dr G Summers, Mrs H Seddon June th Jun 2016 Authorised by Julia Forsyth Page 5 of 5