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Bone Health Clinic
Bone Health Clinic


Di George (Q22 deletion syndrome) and other Hypoparathyroid Disorders


Functionally we categorized patients as having either partial or complete hypoparathyroidism. Normal ranges of PTH may vary depending on the assay and the laboratory. To refer a patient to the Calcium Clinic at SickKids see below.

Complete Hypoparathyroidism

Defined as PTH level below the lower end of the normal range associated with a total Calcium < or equal to  1.8mmol/L and /or ionized  calcium < or equal to 0.8 mmol/L


  1. Treatment
    • IV calcium infusion (see SickKids Handbook) is often required
    • Calcitriol 0.1 mcg/kg/day by mouth until calcium returns to normal range then reduce to 0.04mcg/kg/day
    • Calcium requirement by mouth based on age
  2. Investigations
    • Blood: serum calcium (total and ionized), phosphate, alkaline phosphatase, creatinine, 25 (OH) Vitamin D, 1, 25 (OH)2 Vitamin D, PTH
    • Urine: spot; calcium/creatinine ratio
    • X L hand
  3. Consultation
    • Contact endocrine doctor on call to review treatment and investigations
    • Fax referral to Calcium Bone Clinic with copies of results

Partial Hypoparathyroidism

Total Calcium > 1.8 and < 2.2mmol/L and PTH < 30 (SickKids normal range 10-65 ng/L) or ionized Calcium > 0.8  and < 1.1 and PTH <30 (SickKids normal range 10-65 ng/L)


  1. Treatment
    • Calcitriol 0.02 - 0.04mcg/kg/day by mouth to be started if total calcium is <2 or just above 2.0 with an ionized calcium <1.0.  Note:  Calcitriol may not be needed for children with serum calcium levels between 2.0 -2.2
    • Calcium requirement( need link) for age through dietary sources and supplement (if needed) to make up the deficit.
    • Vitamin D 800 IU by mouth.
  2. Investigations
    • As for Complete Hypoparathyroidism.
  3. Consultation
    • If patient is on calcitriol, fax referral to Calcium Clinic with copies of results

To refer a patient to the Calcium Clinic at SickKids

    1. Children with severe hypoparathyroidism
    2. Children with partial hypoarathyroidism if on calcitriol

Monitoring of children with Hypoparathyroidism

    1. Partial Hypoarathyroidism not on Calcitriol: Blood monitoring every 2- 4 months and with significant illness (by family doctor or pediatrician)
    2. When using Calcitriol, serum calcium, phosphate and creatinine and random urine calcium/creatinine ratio (aim to keep this below 0.5) 2-4 times a year.
    3. On discharge from hospital, with a new diagnosis of DiGeorge/other forms of hypoparathyroidism, family doctors and paediatricians are requested to check serum total calcium 2-4 weekly until stable.
For more information, please contact:

Etienne Sochett
Phone: 416-813-7041 ext. 206218

Anne Murphy
Nurse Coordinator
Phone: 416-813-7654  ext. 201768
Fax: 416-813-8770
email: anne.murphy@sickkids.ca