Management of Secondary and Tertiary Hyperparathyroidism - Joint Hospital Grandround 20.12.2003

1. Management of Secondary and Tertiary Hyperparathyroidism- Joint Hospital Grandround 20.12.2003 Henry Joeng Department of Surgery United Christian Hospital, HKSAR

2. Overview • Pathophysiology • Medical treatment • Surgical treatment • Indication • Pre-op localization study • Different types of parathyroidectomies • Rapid PTH assay • Experience in UCH

3. Secondary Hyperparathyroidism • Chronic extrinsic overstimulation of otherwise normal parathyroid gland • Diffuse hyperplasia of all 4 PTH glands • A negative calcium balance is the key stimulus • Chronic renal insufficiency is the commonest cause

4. Tertiary hyperparathyroidism • Autonomous hypersecretion of PTH in long lasting secondary hyperPTH despite correction of the underlying cause • Commonly seen in post-renal transplantion patient with long history of dialysis beforehand

5. Complications of 2o/3o HyperPTH • Skeletal • Progressive bone demineralization • Osteitis fibrosa cystitca • Bone pain, pathological fracture • Soft tissue calcification • Involve different organs or tissues • Calciphylaxis

6. Complications of 2o/3o HyperPTH • Pruritus • Other • Myopathy • Peptic ulcer disease • Neuropathy • Cardiotoxicity

7. Biochemical changes • Elevated “intact” PTH key feature • Elevated phosphate • Elevated ALP • Normal serum calcium level. Elevated in 3o hyperPTH

8. Radiological changes • Plain X ray • Subperiosteal bone resorption • “Pepper pot” appearance of skull • Bone density • Progressive decline

9. Medical treatment • Oral calcium supplement • Oral 1,25 – D3 supplement • Oral phosphate binder

10. Surgical treatment • 5-10 % patients on long term dialysis need parathyroidectomy • Indication • When complications of 2o/3o hyperPTH arise. E.g. skeletal cx • Medical treatments fail • Biochemical parameter • E.g. [Ca][PO4] product > 70

11. PTX - Optimization • Correct biochemical disturbance due to underlying renal disease • Hemodialysis before operation • Aggressive pre-op calcium replacement

12. Anatomy of parathyroid gland • Upper glands position more constant • 77% around the intersection of RLN and inferior thyroid artery • Lower glands more variable • Lower pole of thyroid, thyrothymic ligament • 9% in thymus gland • Supernumerary gland in up to 8% cases • Butterworth. J R Coll Surg Edinburg 1998

13. PTX - Localization • Different from 1o HyperPTH • Multi-gland disease • Bilateral neck exploration • Locate ectopic or supernumerary PTH glands • Sestamibi scan, USG

14. Types of parathyroidectomies • Subtotal parathyoidectomy • Total parathyroidectomy with autotransplantation

15. Subtotal parathyroidectomy • Stanbury, 1960 • 3 ½ PTH glands resected • 50 mg of one viable gland left behind • Advantage • Less post-op hypoparathyroidism • Disadvantage • Second neck exploration if persistent or recurrent hyperparathyroidism

16. Total parathyroidectomy with autotransplantation • Wells, 1975 • Remove all 4 PTH glands • Autotransplant one PTH gland, usu into brachioradialis muscle • 20 pieces of 1 mm size fragment • Separate pockets and marked with non-absorbale suture

17. Total parathyroidiectomy with autotransplantation • Advantage • Easier to differentiate between hyperfunctioning graft or residual gland in neck • Easier to remove hyperfunctioning graft • Disadvantage • Higher risk of post-op hypoparathyroidism

18. Choice of operation • Controversy • Persistant/ recurrent hyperPTH • Symptom improvement • HypoPTH/ Hypocalcemia • Literature search • Database: Medline, EBM review, EMBase • Keywords: 2o/ 3o hyperparathyroidism, parathyroidectomy, compar$

19. Evidence … • 1 RCT comparing subtotal PTX vs Total PTX with autotransplantation • Rothmund. Word J Surg 1991

20. Rothmund, 1991

21. Total parathyroidectomy alone • Remove all 4 PTH glands • Not widely practiced, due to post-op hypoparathyroidism and risk of adynamic bone disease • Recent case series and non-randomized comparative studies  feasible method

22. Role of rapid PTH assay • Short ½ life of intact PTH • Immunochemiluminometric assay • Confirm adequate resection and alert the possibility of supernumerary gland • At 10min after resection, decrease iPTH of >60% is predictive of cure • Chou. Archives of Surgery. 2002 Mar

23. UCH experience • From 5.2002 till 12.2003 • 15 patients with renal failure and 2o/3o hyperPTH • Total PTX + AT in all patients • Transcervical thymectomy in 4 patients • Hemithyroidectomies in 3 patients

24. UCH experience • Mean FU 7.7 months (0.5 – 20) • Mean Duration of dialysis 7.3 yrs (2 – 17) • Persistent/ recurrent hyperPTH 4/15 (26.7%) • iPTH > 7.7 pmol/l • Asymptomatic • No need of re-exploration • Improvement in bone pain 7/7 (100%) • 2/15 patients had undetectable iPTH

25. Summary • 5-10% patients on dialysis need parathyroidectomy due to development of complication • Total PTX + autotransplantation and subtotal PTX are the common surgical options • Rapid PTH assay may be a useful adjunct