Pearls:

Most cases (90%) of hypercalcemia are caused by hyperparathyroidism or malignancy. The first step is to order a parathyroid hormone level (PTH). Anything that is inappropriately elevated or normal in the setting of hypercalcemia is hyperparathyroidism or familial hypocalciuric hypercalcemia. If it is low, you should be thinking about malignancy, granulomatous disease, hyperthyroidism, hypervitaminosis D, prolonged immobilization and meds (thiazides, lithium).

Symptoms of hypercalcemia are diffuse but can be characterized by “stones (kidney), moans (bone pain), groans (constipation) and psychiatric overtones (confusion, cognitive deficits).” They will vary in severity based on the level of hypercalcemia.

Hypercalcemia should be first corrected for albumin levels and confirmed with a repeat test.

Case: 53-year-old patient that you saw last week for a routine check up, and for some reason or other that escapes you as you're going through her lab tests, you felt compelled to order a calcium. It is high at 12.1 mg/dL (3.02 mmol/L, normal range: 8.5 to 10.2 mg/dL or 2.13 to 2.5 mmol/L). What do we do with that value?

Pearl from Malcolm: We can say to our patients, "See how thorough I was? See how healthy you are? But, unfortunately what happens is sometimes things come back out of the normal range.”

Step 1: Remember ionized calcium is what counts not total calcium because much of it that is bound to albumin.

Anything that drives up albumin will also drive up total calcium such as dehydration or those people who just naturally have higher albumin levels. A high protein diet can also drive up albumin.

Corrected Ca = [0.8 x (normal albumin - patient's albumin)] + serum Ca level

Normal albumin level is 4 mg/dL Standard Units or 40 g/L if using SI Units

Step 2: Repeat the level within the next few days. You don’t have to wait weeks or months to do it. If it is normal, you can be done with it.

Step 3: If it is elevated again, you can explore symptoms though they are somewhat vague and will can become more severe with increasing level of hypercalcemia or if there are acute changes. As with most other electrolyte disorders, the body can adapt to slower changes in time but not to acute changes.

Constitutional: fatigue

Cardiac: short QT interval associated with slight increased risk of supraventricular and ventricular tachyarrhythmias

GI: constipation

Renal: polyuria, polydipsia, renal stones (especially at higher levels over 14)

Neuro: Confusion, cognitive deficits (especially at higher levels over 14)

Step 4: You’ve confirmed it is real, you may initiate a work-up regardless of symptoms. They have smoldering hyperparathyroidism which can lead to bone problems later down the line like osteoporosis or osteitis fibrosis cystica.