Updated: 12/9/2021

Hyperparathyroidism

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  • Snapshot
    • A 55-year-old woman presents to the clinic for an annual well-exam. She has no major complaints besides some constipation over the past week that she attributes to her change in diet. She denies any chest pain, fever, weight changes, abdominal pain, or palpitations. A routine laboratory exam demonstrates hypercalcemia.
  • Introduction
    • Clinical definition
      • disorder characterized by the over secretion of parathyroid hormone (PTH) by 1 or more of the parathyroid glands
      • can be of primary, secondary, or tertiary causes
    • Associated conditions
      • multiple endocrine neoplasia (MEN) 1 and 2A (primary hyperparathyroidism)
      • chronic renal disease (secondary and tertiary hyperparathyroidism)
      • renal osteodystrophy (secondary or tertiary hyperparathyroidism)

    • Serum Ca2+Serum PhosphasteSerum PTH
      Primary
      Secondary
      • Normal/↓
      Tertiary
  • Epidemiology
    • Demographics
      • occurs in 0.1% of the population and 90% of cases result from a single adenoma
    • Risk factors
      • severe, prolonged calcium or vitamin D deficiency
      • menopause
      • neck radiation
      • lithium use
  • ETIOLOGY
    • Pathogenesis
      • PTH leads to
        • activation of osteoclasts leading to increased Ca2+ and phosphate reabsorption at the bone
        • increased reabsorption of Ca2+ in the distal convoluted tubule at the kidney
        • stimulation of kidney 1α-hydroxylase in the proximal convoluted tubule to increase calcitriol production
      • primary hyperparathyroidism
        • most commonly results from parathyroid adenoma or hyperplasia
        • associated with osteitis fibrosa cystica
          • high osteoclast activity at bone resulting in cystic bone spaces with brown fibrous tissue
          • commonly occurs at the jaw
      • secondary hyperparathyroidism
        • secondary parathyroid hyperplasia as a result of low Ca2+ absorption and/or high phosphate levels
        • often in association with chronic renal disease (e.g., hyperphosphatemia and hypovitaminosis D leading to hypocalcemia)
        • other conditions include severe calcium or vitamin D deficiency
      • tertiary hyperparathyroidism
        • dysregulation of parathyroid glands following chronic renal disease
          • will secrete PTH regardless of Ca2+ levels
  • Presentation
    • Symptoms
      • asymptomatic (most common)
      • weakness
      • kidney stones (“stones”)
      • bone pain (“bones”)
      • constipation (“groans”)
      • abdominal/flank pain
      • depression (“psychiatric overtones”)
      • uncommon cause of secondary hypertension
    • Physical exam
  • imaging
    • Bone mineral density test
      • dual energy X-ray absorptiometry (DEXA) is the most common test to measure bone mineral density
      • allows for measurement skeletal involvement and guides management
    • Computed tomography (CT)
      • abdominal CT may be indicated to determine if kidney stones or other abnormalities are present
    • Radiograph
      • cystic bone spaces (“salt and pepper”) most common at the skull
      • loss of phalange bone mass with increased concavity
    • Sestamibi parathyroid scan
      • allows for visualization of the parathyroid glands
      • indicated if surgery is expected
  • Studies
    • Diagnostic testing
      • diagnostic approach
        • patients often present asymptomatically and the disease is often discovered through either routine blood tests or tests order for another condition
      • studies
        • serum calcium test
          • best initial test
          • primary hyperparathyroidism
            • hypercalcemia
          • secondary/tertiary hyperparathyroidism
            • hypocalcemia/normocalcemia
        • serum PTH
          • best initial test
          • levels will be elevated in all forms of hyperparathyroidism
        • 24-hour urinary calcium
          • routinely measured in patients to assess risk of renal complications
          • hypercalciuria/normocalciuria
        • serum 25-hydroxyvitamin D
          • helps in differentiating from FHH
          • guides management
        • genetic testing
          • may be indicated in patients suspected of MEN 1 or MEN 2A
  • Differential
    • Paraneoplastic syndrome (e.g., squamous cell cancer of the lung)
      • distinguishing factors
        • serum PTH levels will be low due to negative feedback
    • Familial hypocalciuric hypercalcemia (FHH)
      • distinguishing factors
        • urine calcium will be low
  • Treatment
    • Acute hypercalcemia
      • IV fluids
      • loop diuretics
    • Asymptomatic patients
      • first-line
        • observation with follow-up
      • second-line
        • surgical intervention indicated in select patients with abnormal studies indicating skeletal and renal damage
    • Symptomatic patients (e.g., nephrolithiasis)
      • first-line
        • parathyroid surgery is the only definitive therapy
          • complications include post-operative hypocalcemia (e.g., numbness, tingling, and muscle cramps)
          • treat with IV calcium gluconate
      • second-line
        • cinacalcet indicated in patients who are unable to have surgery
          • decreases PTH levels by sensitizing Ca2+ sening receptors at the parathyroid gland
  • Complications
    • Peptic ulcer disease
      • ↑ gastrin production stimulated by ↑ Ca2+
    • Acute pancreatitis
      • ↑ lipase activity stimulated by ↑ Ca2+
    • CNS dysfunction
      • anxiety, confusion, and coma
      • result of metastatic calcification of the brain

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(M3.EC.12.9) A 45-year-old man undergoes a parathyroidectomy given recurrent episodes of dehydration and kidney stones caused by hypercalcemia secondary to an elevated PTH level. He is recovering on the surgical floor on day 3. His temperature is 97.6°F (36.4°C), blood pressure is 122/81 mmHg, pulse is 84/min, respirations are 12/min, and oxygen saturation is 98% on room air. The patient is complaining of perioral numbness currently. What is the most appropriate management of this patient?

QID: 103032

Calcium gluconate

83%

(5/6)

Observation

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(0/6)

Potassium

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TSH level

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Vitamin D

17%

(1/6)

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