Primary hyperparathyroidism

From Ganfyd

Introduction

A relatively common and treatable cause of hypercalcaemia often picked up by chance on biochemical screening.

Background

• The commonest cause of hypercalcaemia.
• Seen in 3-4/1,000 of population
• Commoner with age
• Women > Men

Rarely can be seen as part of the multiple endocrine neoplasia syndromes.

Aetiology

1. Solitary adenoma 80-85%
2. Diffuse Hyperplasia 15 %
3. Multiple adenoma 2%
4. Carcinoma < 1%

• Increased production of parathyroid hormone leads increased bone turnover.
• Loss of cortical bone more than trabecular

Clinical features

• Asymptomatic
• Picked up on blood test

When more advanced disese was seen the classical complaints were Stones Bones Groans Abdominal Moans

• Symptoms of Hypercalcaemia
• Neuropsychiatric manifestations (Groans)
• Nephrocalcinosis
• Nephrolithiasis
• Pancreatitis
• Peptic ulcer disease
• Osteopaenia
• Osteoporosis
• Osteitis fibrosa cystica
• Hypertension
• Left ventricular hypertrophy
• Myocardial and valvular calcifications
• Proximal muscle weakness
• Gout
• Pseudogout

Treatment

Medical

Surgery is less costly than the medical treatment of PHPT when the time interval required for medical treatment exceeded 5.5 year and the cost of annual treatment medically was about £200 ($221 USA 2005).

• Bisphosphonates reduce bone turnover, but unclear if reduces fracture risk
• HRT is now out of favour
• Cinacalcet is an option for those in whom surgery is truly contraindicated. Its high cost limits its use.

Surgical

• Parathyroidectomy - Adenoma localisation and unilateral neck exploration with minimally invasive parathyroidectomy becoming the operation of choice.

Indications for surgery

NIH Consensus Conference on primary hyperparathyroidism defined criteria for surgical intervention in 1990 and updated in 2002 Symptomatic patients with elevated serum calcium If asymptomatic Markedly elevated serum calcium (ie &gt 0.25 mmol/l (1.0 mg/dl) increment over normal) Creatinine clearance reduced by more that 30% on age matched norm 24hour urine calcium > 0.1 mmol/kg (400mg/d) Fractures Nephrolithiasis

Surgery for Asymptomatic Primary Hyperparathyroidism: Proceedings of the Third International Workshop Criteria 2009[1] Virtually all patients with symptomatic biochemically confirmed PHPT Asymptomatic patients with biochemically confirmed PHPT should be referred for consideration of surgery if: Neuropsychiatric symptoms of fatigue, lassitude, mood swings, irritability, anxiety, depression, difficulty concentrating, memory loss, and increased sleep requirements Osteoporosis Nephrolithiasis High risk of cardiovascular disease, including as determined by left ventricular hypertrophy, cardiac calcific deposits in the myocardium, and/or aortic and mitral valve calcification

Although historic criteria exist^[2], they have been recently replaced^[3] particularly as they were based on age^[4] and other criteria might better predict quality of life improvement after surgery^[5] This will lead to some confusion, as will the fact that surgery can be very safe in expert hands. There is probably universal agreement on the below:

• Hypercalcaemia ≥3 mmol/l
• Renal impairment - stone disease
• Acute pancreatitis
• Bone disease
  • Osteitis fibrosa cystica
• Neuropsychiatric symptoms of:
  • Proximal myopathy
  • Muscle atrophy
  • Hyperreflexia
  • Gait disturbance
• Age < 50
• Bone mass meets criteria for osteoporosis (T-score at or below -2.5)

References