Hypercalcemia A diagnostic and treatment approach UCI Internal Medicine – Mini Lecture

Hypercalcemia objectives Identify true hypercalcemia Understand basic calcium regulation Understand the most common etiologies Have a clear diagnostic and workup plan Understand acute management

Initial evaluation A 68 year-old female with no PMH or home meds is brought to the ER by family with altered mental status, nausea, and diffuse bony pain.

Initial Evaluation VS unremarkable. A&Ox1, tries to get out of bed and is distracted. Rest of exam normal. Labs are normal except below: Corrected Calcium = (0.8 * (Normal Albumin - Pt's Albumin)) + Serum Ca What is patient’s corrected calcium? Albumin= 1.0

Calcium regulation: PTH= increases calcium – Release of bone Ca stores – Increase renal tubular Ca resorption – Increase production of activated Vit D by increased kidney hydroxylase Vitamin D= increases calcium – Needs to be activated to active form (calcitriol) – Increases calcium absorption in gut Calcitonin= decreases calcium – Slows down osteoclasts, decreases bone resorption – Increase renal calcium clearance

Common causes of hypercalcemica PTH mediated – Primary hyperparathyroidism Non-PTH mediated – PTHrp, vitamin D intoxication, granulomatous disorders, osteolytic bone metastases, malignancy Medications – Thiazide diuretics, lithium Misc – Hyperthyroid, immobilization, Milk-alkali, etc…

Treatment: Mild and Moderate Mild (<12): No acute tx necessary – Avoid thiazides and lithium, volume depletion – Low calcium diet Moderate (12-14): May or may not require tx – If mildly symptomatic (constipation), no immediate therapy needed – Treat if severely symptomatic (ie mental status changes)

Treatment: Severe Hypercalcemia (>14) Normal Saline (200cc/hr, adjust for UOP cc/hr) Calcitonin 4 IU/kg q6-12 hrs (if Ca>14) Bisphosphonates (Reclast 4mg IV over 15 mins) Especially for excessive bone resorption/malignancy Dialysis if above measures fail Monitor with Q8 serum calcium levels

Treat Underlying Cause Multiple Myeloma Squamous Cell Cancer Gynecologic Cancer Sarcoidosis Tuberculosis Thyrotoxicosis Pituitary Adenoma Multiple Endocrine Neoplasia

Back to the case Admitted to medicine PTH 77 (normal 11-55) Tc99m-sestamibi demonstrated a single parathyroid adenoma Referred to surgery for parathyroidectomy

Hypercalcemia objectives Identify true hypercalcemia Understand basic calcium regulation Understand the most common etiologies Have a clear diagnostic and workup plan Understand acute management

Take home points Remember to correct calcium based on albumin levels Calcium regulation based on multiple factors including PTH, Vitamin D, Calcitonin Primary hyperparathyroidism and malignancy are the most common causes

Take home points Check PTH first, if elevated likely primary hyperparathyroidism If PTH not elevated, check vitamin D (both 25- OH and 1,25-OH) Treat all symptomatic patients with IVF – Calcitonin, bisphosphonates if warranted