Primary Hyperparathyroidism Flashcards
what is the definition of PHPT?
Primary hyperparathyroidism (PHPT) is an endocrine disorder in which autonomous overproduction of parathyroid hormone (PTH) results in derangement of calcium metabolism.
what is the epidemiology of PHPT?
Common
Affects females more than males
Uncommon in first 2 decades of life
Women of around 50-60 yrs most commonly affected
what is the aetiology of PHPT?
Parathyroid adenomas are the most common aetiology. Around 80% are a single, benign adenoma, which in most cases is sporadic. Multiple adenomas and hypertrophy of all 4 glands are less common.
Inherited forms, affecting 5% to 10% of patients, lead to hyperfunctioning parathyroid glands. A history of family members with PHPT should prompt suspicion of multi-gland disease. These disorders include multiple endocrine neoplasia (MEN) 1, MEN 2, and MEN 4; HPT-jaw tumour syndrome; and familial isolated hyperparathyroidism.
<1% due to parathyroid malignancies
what are the risk factors for PHPT?
Female >50yrs Family history MEN 1, 2A or 4 Current or historical lithium treatment Hyperparathyroidism-jaw tumour syndrome Head and neck irradiation
what are the pathophysiology of PHPT?
Low serum calcium ordinarily stimulates parathyroid hormone (PTH) secretion, whereas high calcium levels suppress PTH secretion. In primary hyperparathyroidism, PTH secretion is not suppressed (as would typically be expected) by high calcium levels. Excessive PTH leads to over-stimulation of bone resorption, with cortical bone affected more than cancellous bone. PTH also stimulates the kidneys to reabsorb calcium and to convert 25-hydroxyvitamin D3 to its more active form of 1,25-dihydroxyvitamin D3. This active vitamin D is responsible for the gastrointestinal absorption of calcium.
Over-stimulation of PTH receptors, specifically type-2 PTH receptors, is thought to play a role in the subjective neurocognitive and affective symptoms. Hypercalciuria may also lead to nephrolithiasis.
what are the key presentations of PHPT?
Incidental finding on biochemical testing
History of osteoporosis or osteopenia
Family history of hyperparathyroidism, nephrolithiasis
what are the signs of PHPT?
Incidental finding on biochemical testing History of osteoporosis or osteopenia Family history of hyperparathyroidism nephrolithiasis Hard and dense neck mass
what are the symptoms of PHPT?
Poor sleep Fatigue Myalgia Anxiety Depression Memory loss
what are the first line and gold standard investigations of PHPT?
Serum calcium - raised
Serum intact PTH with immunoradiometric or immunochemical assay - elevated
what are the differential diagnoses for PHPT?
FHH, humoural hypercalcaemia of malignancy, multiple myeloma
how is PHPT managed?
Surgical indications:
Parathyroidectomy, vit D supplementation, monitoring, bisphosphate, cinacalcet
No surgical indications:
Monitoring, vit D supplementation, (parathyroidectomy)
how is PHPT monitored?
After surgical intervention, clinicians should monitor for the development of a cervical haematoma, observe wound healing, check voice quality, and perform laboratory evaluation as necessary. Postoperative management involves determining surgical success and monitoring for complications.
what are the complications of PHPT?
Head and neck haematoma following surgery
Recurrent and superior laryngeal nerve injury
Hypocalcaemia
Pneumothorax
Osteoporosis
what is the prognosis of PHPT?
For asymptomatic patients who do not meet the criteria for surgical intervention, 75% have stable disease for up to 10 years. Twenty-five percent of patients progress to meeting criteria for parathyroidectomy.
