Hi Antoine,
Screening - In all VLBW infants <1500 g - Check - Serum P, Alkaline phosphatase & PTH. Start at four weeks of age with subsequent biweekly testing. In infants <2000 g screening only if risk factors
Diagnosis - Biochemical features : – Low P <1.3mmo/l, ALP>1000, Normal Ca (rare for low Calcium), Elevated PTH.
If Alk Phos⬆︎ & Phosphate⬇︎ - Measure 25OHD & PTH
PTH⬆︎ - -Likely Ca+ and/or Vit.D def. - Start Ca suppl. Optimise 25OHD. Stop P supplements if prescribed. Ensure enteral (milk + supplements) Ca:P ratio 1.6:1 to 1.8:1
Optimise Ca in PN if prescribed (Ca:P ratio ~1.7 :1)
PTH - Normal - -Likely Phosphate def. - Consider P supplements.Ensure enteral (milk + supplements)Ca:P ratio >1.6:1 – add Ca supplements if needed to ensure balance.
Repeat bone profile &PTH in 2 weeks
If 25OHD <50 nmol/L (vitamin D deficiency – 25OHD <30 nmol/L; vitamin D insufficiency – 25OHD 30-50 nmol/L) • Ensure on regular multivitamins (containing 400 IU/day cholecalciferol)
Regards
Sunny