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Hyperparathyroidism Investigations


  • Elevated corrected Ca2+.
  • Low PO43-.
  • Normal alkaline phosphatase.
  • Normal or elevated serum PTH.
  • High 24 hr urinary Ca2+.
  • To exclude Familial Hypocalcuirc Hypercalcaemia (FHH), the calcium clearance to creatinine clearance ratio should be > 0.01. This is calculated as follows:

Calcium Clearance

[Urine Calcium (mmol/l) x urine volume (ml)] / [ Plasma Calcium (mmol/l) x 1440]

Creatinine Clearance (This may be calculated already)
[Urine Creatinine (mmol/l) x urine volume (ml)] / [ Plasma Creatinine (mmol/l) x 1440]
Plasma creatinine is normally expressed in umol/l and needs to be converted to mmol/l by dividing by 1000.

However, this ratio can be reduced to

Urine Calcium (mmol/l) x [Plasma Creatinine (umol/l) / 1000]
Plasma Calcium (mmol) x Urine Creatinine (mmol/l)

For example
Urine calcium 1.0 mmol/l Ratio = 1.0 x [130/1000] = 0.0079
Urine creatinine 6.2 mmol/l 2.65 x 6.2
Plasma creatinine 130 umol/l
Plasma calcium 2.65 mmol/l

Primary Hyperparathyroidism
Urine calcium 2.2mmol/l Ratio = 2.2 x [74/1000] = 0.035
Urine creatinine 1.4 mmol/l 3.3 x 1.4
Plasma creatinine 74 umol/l
Plasma calcium 3.3 mmol/l


None of the techniques are reliable and often a combination of methods are used.

  • Ultrasound of neck.
  • Sesta-MIBI scanning.
  • 123I and sesta-MIBI double isotope scan (higher sensitivity, ask nuclear medicine).
  • MRI of neck.
  • CT neck (+ upper mediastinum).
  • Selective venous sampling for PTH is not routinely used and reserved for difficult cases. Patient requires hospital admission, and investigation needs to be booked with Dr Jackson well in advance.


  • Usual pre-operative bloods, including U+E, Ca2+, PO4, alkaline phosphatase, albumin.
  • Maintain adequate hydration.
  • Replace deficit and maintain 3-4 l fluids /day i.v. and then orally if patient able to drink.
  • If above measures do not reduce corrected Ca2+ <2.8 mmol/l give bisphosphonates (e.g. pamidronate 30 mg in 1l 0.9% saline over 4 hrs). This will not start to work for 24hrs, with maximum effect 5-6 days. Plan in advance to avoid severe post-operative hypocalcaemia.


  • Enquire for symptoms of hypocalcaemia (paraesthesiae, cramps etc.).
  • Trousseau's and Chvostek's test daily.
  • Daily U+E and corrected Ca2+.
  • If mild symptoms and corrected Ca2+ >2.0 mmol/l, give effervescent Ca2+ (Sandocal).
  • If severe symptoms and corrected Ca2+ <2.0 mmol/l, give Ca2+ infusion (calcium gluconate 15 mg/kg i.v. in 1l 0.9% saline over 4 hours).
  • If hypocalcaemia persists, introduce alfacalcidol (0.125 ng od).