Management of Secondary and Tertiary Hyperparathyroidism- Joint Hospital Grandround 20.12.2003

Henry JoengDepartment of SurgeryUnited Christian Hospital, HKSAR

Overview

Pathophysiology Medical treatment Surgical treatment

Indication Pre-op localization study Different types of parathyroidectomies Rapid PTH assay

Experience in UCH

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

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

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

Complications of 2o/3o HyperPTH

Pruritus

Other Myopathy Peptic ulcer disease Neuropathy Cardiotoxicity

Biochemical changes Elevated “intact” PTH key

feature Elevated phosphate Elevated ALP Normal serum calcium level.

Elevated in 3o hyperPTH

Radiological changes Plain X ray

Subperiosteal bone resorption “Pepper pot” appearance of skull

Bone density Progressive decline

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

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

PTX - Optimization Correct biochemical disturbance due

to underlying renal disease

Hemodialysis before operation

Aggressive pre-op calcium replacement

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

PTX - Localization Different from 1o HyperPTH Multi-gland disease Bilateral neck exploration Locate ectopic or supernumerary PTH

glands Sestamibi scan, USG

Types of parathyroidectomies

Subtotal parathyoidectomy

Total parathyroidectomy with autotransplantation

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

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

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

Choice of operation Controversy

Persistant/ recurrent hyperPTH Symptom improvement HypoPTH/ Hypocalcemia

Literature search Database: Medline, EBM review, EMBase Keywords: 2o/ 3o hyperparathyroidism,

parathyroidectomy, compar$

Evidence … 1 RCT comparing subtotal PTX vs

Total PTX with autotransplantation Rothmund. Word J Surg 1991

Rothmund, 1991SPTX PTX+AT

No. of patient 20 20

Persistent hyperPTH 4/20 0/20 p<0.03

Symptom improvement

Bone pain 61% 87%

Radiological sign of renal osteodystrophy

33% 69% p<0.05

Muscle weakness 20% 83% p<0.04

Pruritus 45% 100% p<0.005

Hypocalcemia 1/20 1/20

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

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

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

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

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