Histological type of carcinoma lung most commonly associated with hypercalcemia is:
|B||Large cell anaplastic carcinoma|
|C||Small cell carcinoma|
|D||Squamous cell carcinoma|
a. Humoral hypercalcemia of malignancy (HHM) occurs in up to 20% of patients with cancer.
b. HHM is most common in cancers of the lung ( SQUAMOUS) , head and neck, skin, esophagus, breast, genitourinary tract, and in multiple myeloma and lymphomas.
c. Several distinct humoral causes of HHM occur, most commonly overproduction of PTHrP.
d. In addition to acting as a circulating humoral factor, bone metastases (e.g., breast, multiple myeloma) may produce PTHrP, leading to local osteolysis and hypercalcemia
e. Another relatively common cause of HHM is excess production of 1,25-dihydroxyvitamin D.
f. The management of HHM begins with removal of excess calcium in the diet, medications, or IV solutions.
g. Oral phosphorus (e.g., 250 mg Neutra-Phos 3–4 times daily) should be given until serum phosphorus is >1.0 mmol/L (>3 mg/dL).
h. Saline rehydration is used to dilute serum calcium and promote calciuresis.
i. Forced diuresis with furosemide or other loop diuretics can enhance calcium excretion but provides relatively little value except in life-threatening hypercalcemia. When used, loop diuretics should be administered only after complete rehydration and with careful monitoring of fluid balance.
j. Bisphosphonates such as pamidronate (30–90 mg IV), zolendronate (4–8 mg IV), or etidronate (7.5 mg/kg per day PO for 3–7 consecutive days) can reduce serum calcium within 1–2 days and suppress calcium release for several weeks.