Osteomalacia

• What is osteomalacia?

  Softening of bones secondary to low vit D levels (decreased bone mineral content)
• What are the potential causes of osteomalacia?

  Vitamin D deficiency (malabsorption, lack of sunlight, diet)

  CKD

  Drugs (e.g. anticonvulsants)

  Inherited (hypophosphataemic rickets)

  Liver disease (e.g. cirrhosis)

  Coeliac disease
• What are the RFs of osteomalacia?

  Older age (over 65)

  Darker skin pigmentation

  Obesity

  Pts who cover skin for cultural, religious or health reasons

  Housebound pts or pts who live in care homes

  Malabsorption

  End-stage CKD

  Severe liver cirrhosis

  Vegetarian/vegan diets

  Meds (orlistat, carbamazepine, antacids)
• What are the signs & symptoms of osteomalacia?

  Bone pain (lower back, pelvis, shoulders, legs or ribs)

  Muscular weakness & pain

  Difficulty walking

  Malaise

  Persistent fatigue

  Paraesthesia (late sign)

  Waddling gait

  Proximal muscle weakness

  Generalised bone & joint tenderness

  Signs of hypocalcaemia

  Spinal deformities
• What are the Inx for osteomalacia?

  Obs

  Full Hx & examination

  Urinalysis

  Urine calcium

  Bloods (FBC, bone profile, PTH, U&Es, LFTs, ferritin, B12, folate, TFTs)

  XRs

  DEXA scan
• Pathophys - osteomalacia

  Inadequate vitamin D -> low serum calcium & phosphate -> bone mineralisation & osteomalacia -> increased PTH -> promotes calcium reabsorption from bones -> further impairment of bone mineralisation
• What are the DDx of osteomalacia?

  Osteoporosis

  Paget's disease (chronic progressive disorder of bone remodelling)
• What are the possible complications of osteomalacia?

  Insufficiency fractures or pseudofractures

  Secondary hyperparathyroidism

  Hypercalcaemia

  Kidney stones
• What is the management of osteomalacia?

  Colecalciferol (vitamin D3)

  • loading dose (50,000 IU once weekly for 6 wks OR 4000 IU daily for 10 wks)
  • maintenance dose (800-2000 IU per day)

  Increase dietary calcium (or calcium supplements)

  Follow up to check levels normalise & symptoms resolve

  Pts with CKD -> alfacalcidol instead of calciferol