summary Hyperparathyroidism is the increase in serum parathyroid hormone (PTH) production that may be of primary, secondary or tertiary causes. Diagnosis is made based on evaluation of serum labs and clinical evaluation. Treatment can be medical management or tumor resection depending on underlying cause of disease. Epidemiology Incidence occurs in 0.1% of the population 90% result form a single adenoma remaining 10% from parathyroid hyperplasia Demographics more common in women hyperparathyroidism and malignancy make up the majority of patients with hypercalcemia Etiology Pathophysiology PTH indirectly stimulates osteoclasts by binding to its receptor on osteoblasts, inducing RANK-L and M-CSF synthesis Excessive PTH leads to over-stimulation of bone resorption cortical bone affected more than cancellous Associated conditions Brown tumor resembles a giant cell tumor of bone relating to focal demineralization of bone in the setting of hyperparathyroidism. Classification Primary typically the result of hypersecretion of PTH by a parathyroid adenoma/hyperplasia may result in osteitis fibrosa cystica breakdown of bone, predominently subperiosteal bone commonly involves the jaw Secondary secondary parathyroid hyperplasia as compensation from hypocalcemia or hyperphosphatemia ↓ gut Ca2+ absorption ↑ phosphorous associated conditions chronic renal disease renal disease causes hypovitaminosis D leads to ↓ Ca2+ absorption renal osteodystrophy bone leisons due to secondary hyperparathyroidism Tertiary parathyroid glands become dysregulated after secondary hyperparathyroidism secrete PTH regardless of Ca2+ level Primary, Secondary and Tertiary hyperparathyroidism Serum Ca Serum Phos Serum PTH Primary Increased Decreased Increased Secondary Normal or decreased Increased Increased Tertiary Increased Increased Increased Presentation Symptoms often asymptomatic weakness kidney stones ("stones") bone pain ("bones") constipations ("groans") uncommon cause of secondary hypertension Evaluation Serology primary hypercalcemia ↑ PTH secondary hypocalcemia/normocalcemia ↑ PTH malignancy ↓ PTH ↑ alkaline phosphatase normal anion gap metabolic acidosis ↓ renal reclamation of bicarbonate Urinalysis primary hypercalciuria (renal stones) ↑ cAMP Radiograph cystic bone spaces ("salt and pepper") often in the skull loss of phalange bone mass ↑ concavity (see key image of this topic) EKG shortened QT Treatment Acute hypercalcemia IV fluids Loop diuretics Symptomatic hypercalcemia is treated surgically treat with parathyroidectoy complications include post-op hypocalcemia manifests as numbness, tingling, and muscle cramps should be treated with IV calcium gluconate Complications Peptic ulcer disease ↑ gastrin production stimulated by ↑ Ca2+ Acute pancreatitis ↑ lipase activity stimulated by ↑ Ca2+ CNS dysfunction anxiety, confusion, coma result of metastatic calcification of the brain Osteoporosis bone loss occurs as result of bone resorption due to excess PTH orthopedic surgeons should recognize lab abnormalities as patients may present with fragility fractures