Hypercalcemia

last authored: April 2012, David LaPierre
last reviewed:

 

 

 

Introduction

Hypercalcemia, or elevated blood calcium, is above the normal range of 2.2-2.6 mmol/L (9-10.5 mg/dL). Symptoms begin appearing above 3 mmol/L, while hypercalcemia above 3.75 mmol/L (15-16 mg/dL) is considered a medical emergency. Ionized calcium should be less than 1.23.

Severe hypercalcemia is often related to malignancy.

 

 

The Case of Bob R.

Bob R is a 67 year-old man who presents to the emergency department with increasing abdominal pain and vomiting. His wife says he has been more confused over the past few days. Amongst other blood tests, his calcium returns at 3.2 mmol/L.

• What symptoms could Bob also be experiencing as a result of his elevated calcium?
• What could be causing this condition?
• What investigations do you consider?
• What treatments do you begin?

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Causes and Risk Factors

Hypercalcemia can result from a number of processes:

• increased osteoclastic bone resorption or decreased bone mineralization
• excess GI absorption or impaired renal excretion

 

Causes include

malignancy: lung, breast, prostate, renal, thyroid, GI, melanoma, sarcoma, multiple myeloma, lymphoma, leukemia   hyperparathyroidism adenoma, hyperplasia, carcinoma immobilization acute or chronic renal failure hypophosphatemia

granulomatous conditions sarcoid can increase vitamin D infections such as TB histoplasmosis coccidoidomycosis endocrine Addison's, hypothyroidism, acromegaly  familial AIDS drug induced  calcium, vitamin A, thiazides, lithium, tamoxifen

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Pathophysiology

Malignancy can increase calcium levels through a number of mechanisms:

• ectopic production of PTHrP, which results in bone resorption by osteoclasts
• osteolytic cytokines (lymphotoxin, TNF, IL-1a and b, TGFa): solid tumour metastasis or myltiple myeloma
• calcitriol production by lymphomas

Vomiting and renal losses can lead to profound dehydration, which is responsible for many of the signs and symptoms.

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Signs and Symptoms

Clinical features depend on duration and severity, and include:

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Investigations

 

 

 

Treatments

The underlying cause should be identified and treated as calcium levels are controlled.

 

Avoid bedrest or immobilization as much as possible.

 

Fluids are very important to correct dehydration and flush calcium from the body. Normal saline is frequently used.

 

Loop dieuretics may be used once hydration has been provided, in order to increase renal excretion.

 

Calcitonin may be used to inhibit calcium reabsorption in the distal tubule. It also requires adequate hydration.

 

Phosphate should be replaced PO or by NG tube.

 

Decreased bone resorption can be mediated by

• bisphosphonates such as zolendronic acid, pamidronate (caution with impaired renal function)
• calcitonin: onset 4-6 hours, shorter

Glucocorticoids can also assist renal excretion.

 

Dialysis can be used if calcium levels are not dropping, if patient is in congetive heart failure.

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Consequences and Course

The consequences of hypercalcemia can include:

• cardiac: arrhythmias, QT shortening
• gastrointestial: pancreatitis, peptic ulcers
• musculoskeletal: osteopenia/osteoporosis, fractures
• renal: nephrolithiasis (1e hyperparathyroidism), nephrocalcinosis

Hypercalcemia related to malignancy has a very poor prognosis.

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Resources and References

 

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Topic Development

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