This patient is an 80-year-old female with a history of multiple myeloma. She was recently discharged from the hospital. Her daughter said that she has been more confused and lethargic over the last few days. The patient herself is not aware that she has any confusion but her exam clearly is not reliable. She was previously doing well after discharge from her recent hospital admission.
Physical exam is notable only for disorientation and mild lethargy. She has a nonfocal neurologic exam. The remainder of her exam is normal.
Notable lab finding is a calcium of 16.
The diagnosis is hypercalcemia.
From article published by the National Cancer Institute
Normal serum calcium levels are maintained within narrow and constant limits, approximately 9.0 to 10.3 mg/dL (= 4.5–5.2 mEq/L or 2.25–2.57 mmol/L) for men and 8.9 to 10.2 mg/dL (= 4.4–5.1 mEq/L or 2.22–2.54 mmol/L) for women. Symptoms of hypocalcemia or hypercalcemia are caused by abnormalities in the ionized fraction of the plasma calcium concentration; however, ionized calcium levels are rarely checked routinely in clinical laboratories. The total plasma calcium is used to infer the ionized calcium fraction and is usually accurate, except in the setting of hypoalbuminemia. Because hypoalbuminemia is not uncommon among patients with cancer, it is necessary to correct the total plasma calcium concentration for the percent of calcium that would have been measured if the albumin level were within normal range. The calculation is as follows:
total serum calcium corrected for albumin level: [(normal albumin – patient’s albumin) × 0.8] + patient’s measured total calcium
This calculated value is fairly accurate, except in the presence of elevated serum paraproteins, such as in multiple myeloma. In this case, laboratory measurement of the actual ionized calcium concentration may be necessary.
1. The classic presentation of hypercalcemia includes: Stones, bones, abdominal groans, bladder moans, psychiatric overtones. Hypercalciuria increases the risk of kidney stones. Patient’s also have bone pain and can sometimes have bony destruction. Abdominal pain often times is associated with constipation. Bladder moans implies that the patient has frequent urination as they’re trying to rid the body of calcium. Mental status changes are common in patients who have hypercalcemia.
2. Always consider hypercalcemia, in addition to the usual things, in a cancer patient altered mental status and a nonfocal exam.
3. The cancers that are most likely to produce hypercalcemia include: Multiple myeloma, certain t-cell lymphomas (HTLV1-related), breast cancer, lung cancer, renal cancer. Another cancer that goes to the bone his prostate cancer although hypercalcemia is not as common with this although it is possible.
4. The mechanism by how hypercalcemia is created in cancers his complex and is often due to an interaction between
parathormone and activation of osteoclasts. It is not simply by bony invasion and displacement of calcium.
5. All of these treatments can be started at the same time!
Saline: The patient can get 2 L of normal saline upfront. They will get a lot more over the next 24 hours. The effect is not very long-lived.
Forced diuresis with Lasix: Is no longer indicated. The only use of Lasix is to make sure that the person doesn’t develop congestive heart failure or volume overload when they’re getting saline. Lasix does not increase calcium loss via the kidney.
Calcitonin: CalciTONIN TONES up the bones! Inhibits bone resorption. It is quick in onset (~4 hours) however it doesn’t have a very big effect. 4 units per kilogram. Calcitonin loses effectiveness in a couple of days.
Bisphosphonates: Zoledronic Acid (Zometa). This drug is slower in onset (24-48 h) but much more effective in lowering calcium.