Parathyroid

Done by: Heba AL-smiarat

Definition PRIMARY HYPERPARATHYROIDISMSecondary HyperparathyroidismTertiary Hyperparathyroidism

PARATHYROID ADENOMA: (80% )A benign tumor of the parathyroid gland.

It is the most common cause of primary hyperparathyroidism which is usually a sporadic, single hyperfunctioning gland that has resulted from a clonal mutation.

Treatment is operative removal.

PARATHYROID HYPERPLASIA(15% to 20% ) A condition of diffuse enlargement of all 4 parathyroid glands.

The result is elevated parathyroid hormone and serum calcium

levels. It may occur sporadically or as part of a familial syndrome.

Etiology PRIMARY HYPERPARATHYROIDISM

PARATHYROID CARCINOMA(1%): A rare neuroendocrine tumor of the parathyroid gland.

The usual presentation is that of primary hyperparathyroidism withhigher serum calcium levels or an associated neck mass. Treatment is en bloc removal with the ipsilateral thyroid lobe and adjacent tissue

, in addition to the removal of contiguous lymphnodes (tracheoesophageal, paratracheal, and upper mediastinal

FAMILIAL HYPOCALCIURIC HYPERCALCEMIA: A condition of mild elevations of serum calcium.

Most cases are associated with mutations in the Calcium Sensing Receptor gene. Diagnosis is confirmed with low 24-hour urine calcium levels. FHH is benign and does not require treatment

to 25% 20%

15%subperiosteal bone

resorption

Diagnostic InvestigationsBiochemicalRadiologic Tests

Localization Tests

⚫ Preoperative, noninvasive- Sestamibi-technetium-99m scan -Ultrasound -CT scan -MRI scan⚫ Preoperative, invasive-FNAB-Angiogram-Venous sampling⚫ Intraoperative:-PTH assay

Sestamibi scan in a patient with primary hyperparathyroidismshowing persistent uptake suggesting a left lower hypercellularparathyroid gland.

TreatmentWhen patients have biochemicallydocumented primary hyperparathyroidism and nonlocalized

pathology by preoperative imaging, there is a higher probability parathyroid hyperplasia exists.

These individuals may require more extensive parathyroid explorations, subtotal parathyroidectomy, and have a lower chance of cure

TreatmentPHPT may occur as a component of various inherited syndromes such as MEN1 and MEN2A.Inherited PHPT also can occur as isolated familial HPT (non-MEN) or familial HPT with jaw tumors.Although not absolutely necessary, preoperative sestamibi scan and ultrasound can be obtained in patients with inherited HPT to identify potential ectopic glands. A standard bilateral neck exploration is performed, along with a bilateral cervical thymectomy, regardless of the results of localization studies. Both subtotal parathyroidectomy and total parathyroidectomy with autotransplantation.

A hypercalcemic crisis may occur in 1.6% to 3.2% of patients with primary hyperparathyroidism.

It manifests with marked hypercalcemia, with serum calcium levels

usually > 15 mg/ dL and an altered mental status. Present withnausea, vomiting, dehydration, lethargy, and confusion or frank coma.

Treatment of hypercalcemic crises consists of hydration and forced diuresis with normal saline infusion and furosemide administration.

Persistent and Recurrent Hyperparathyroidismmore frequently in the setting of familialHPT and MEN1, in particular. The most common causes for both these states include: ectopic parathyroids, unrecognized hyperplasia, or

supernumerary glands

Secondary Hyperparathyroidism-occurs in patients with chronic renal failure but also may occur

in those with hypocalcemia secondary to inadequate calcium or vitamin D intake or malabsorption

-Patients generally are hypocalcemic or normocalcemic

-Calciphylaxis

Treatment Medically: with a low-phosphate diet, phosphatebinders, adequate intake of calcium and 1, 25-dihydroxy

vitamin D, and a high-calcium, low-aluminum dialysis bathCalcimimeticsSurgical treatment was traditionally recommended for

patients with bone pain, pruritus, and (a) a calcium-phosphate product =70, (b) calcium >11 mg/dL with markedly elevated PTH, (c) calciphylaxis, (d) progressive renal osteodystrophy, and (e) soft tissue calcification and tumoral calcinosis, despite

maximal medical therapy

Calciphylaxis

Tertiary HyperparathyroidismGenerally, renal transplantation is an excellent method of

treating secondary HPT, but some patients develop autonomous parathyroid gland function and tertiary HPT

pathologic fractures, bone pain and worsenedbone disease, renal stones, peptic ulcer disease, pancreatitis,and mental status changes.⚫ The transplanted kidney is also at risk from tubulointerstitial

calcification⚫ many patients with tertiary HPT are being treated with

cinacalcet

The traditional surgical management of these patients consistedof subtotal or total parathyroidectomy with autotrans

plantationnand an upper thymectomy

A 60-year-old postmenopausal woman with osteoporosis has a serum calcium level of 11.4 mg/ dL, a serum phosphorus level of 2.0 mg/ dL, and a 24-hour urine calcium excretion of 425 mg. Which of the following serum tests is most likely to establish the cause of her hypercalcemia?A. Chloride/ phosphorus ratioB. PTH-related polypeptideC. Urine calcium clearanceD. Intact PTH levelE. A sestimibi scan