Hyperparathyroidism, Primary

• • Due to excess secretion of parathyroid hormone (PTH)

  • "Stones, bones, abdominal groans, psychic moans, and fatigue overtones"

  • Some patients are asymptomatic

  • Most common cause of hypercalcemia in the ambulatory patient

  • Nonparathyroid cancer is the most common cause of hypercalcemia in the hospitalized patient

Epidemiology

• • 0.1-0.3% of the general population

  • 83% from single parathyroid adenoma, 6% from multiple adenomas, 10% from 4-gland hyperplasia, 1% from parathyroid carcinoma

  • Uncommon before puberty

  • Peak incidence is between third and fifth decade

  • 2-3 times more common in women than men

Symptoms and Signs

• • Fatigue, weakness, arthralgias, nausea, vomiting, dyspepsia, constipation, polydipsia, polyuria, nocturia, psychiatric disturbances, renal colic, bone and joint pain

  • Nephrolithiasis and nephrocalcinosis, osteopenia, osteitis fibrosa cystica, peptic ulcer disease, gout, chondrocalcinosis, pancreatitis

  • Hypertension, band keratopathy

  • Neck mass (rare)

Laboratory Findings

• • Elevated serum calcium

  • Elevated intact PTH level (although can be inappropriately high normal)

  • Elevated chloride; low or normal phosphate

  • Serum chloride to phosphate ratio of greater than 33

  • Uric acid and alkaline phosphatase sometimes elevated

  • Urine calcium increased or normal

  • Urine phosphate increased

  • Tubular reabsorption of phosphate decreased

  • Urine osteocalcin and deoxypyridinoline crosslinks increased

  •Hydrocortisone suppression test: Reduces serum calcium in most cases of sarcoidosis and vitamin D intoxication but not primary hyperparathyroidism

Imaging Findings

• • Subperiosteal resorption of radial side of phalanges

  • Demineralization of skeleton (osteopenia or osteoporosis)

  • Bone cysts

  • Nephrocalcinosis or nephrolithiasis

  • Neck sestamibi scan may localize adenomatous parathyroid gland

  • Neck US may localize an abnormally large parathyroid gland

  • Bone densitometry can document level of bone demineralization

• • Primary hyperparathyroidism also is part of the multiple endocrine neoplasia syndromes, type I and IIa

  • Other causes of hypercalcemia include:

  • -Hyperthyroidism

    -Addison disease

    -Pheochromocytoma

    -Hypothyroidism

    -VIPoma

    -Milk-alkali syndrome

    -Vitamin D or A overdose

    -Thiazides

    -Lithium

    -Aluminum

    -Granulomatous disease

    -Familial hypocalciuric hypercalcemia

    -Paget disease

    -Immobilization

    -Idiopathic hypercalcemia of infancy

    -Dysproteinemias

    -Rhabdomyolysis

  • Nonparathyroid tumors that secrete pure PTH are extremely rare

  • In patients with previous neck explorations, and negative preoperative localization studies (sestamibi/US), selective venous catheterization with PTH assay is recommended and helps localize tumors in about 80% of patients

Rule Out

• • Parathyroid carcinoma (usually intraoperative discovery)

  • Ectopic hyperparathyroidism or nonparathyroid cancer

• • Complete history and physical exam

  • Serum calcium, PTH, phosphate, chloride, alkaline phosphatase, creatinine, blood urea nitrogen, urinary calcium

  • Cervical localization study (sestamibi with or without US)

When to Admit

• • Hypercalcemic crisis:

  • -Patients need to be hydrated and have hypokalemia and hyponatremia corrected

    -Furosemide can increase calcium excretion in rehydrated patients

    -Glucocorticoids are effective in sarcoid, vitamin D intoxication, and cancer

    -Etidronate, plicamycin, and calcitonin are effective ...