Hypercalcemia Explained: Causes, Symptoms, and When It Becomes an Emergency

Hypercalcemia refers to an abnormally high level of calcium in the bloodstream, specifically when the concentration of ionized calcium exceeds 2.75 millimoles per liter (mmol/L) of serum. This condition disrupts normal physiological processes and can lead to a range of health complications if left untreated. Calcium plays a vital role in bone health, muscle function, nerve signaling, and blood clotting—so maintaining its balance is crucial for overall well-being.

What Defines Severe Hypercalcemia?

When serum calcium levels rise above 4.5 mmol/L, patients may experience a life-threatening condition known as hypercalcemic crisis. This acute state requires immediate medical intervention due to the risk of severe symptoms such as high fever, dehydration, cardiac arrhythmias, confusion, or even loss of consciousness. Early recognition of these signs can be lifesaving and often necessitates hospitalization for aggressive treatment.

Common Causes Behind Elevated Calcium Levels

Several underlying conditions can trigger hypercalcemia. The most frequent causes include malignancies—particularly cancers like multiple myeloma or those that metastasize to the bones—overactivity of the parathyroid glands (hyperparathyroidism), and excessive intake of vitamin D or calcium supplements. Less commonly, certain medications, prolonged immobilization, or endocrine disorders such as hyperthyroidism may also contribute to elevated calcium levels.

Recognizing the Warning Signs

Many individuals with mild hypercalcemia may not exhibit obvious symptoms initially. However, as calcium levels increase, they might begin to notice persistent headaches, difficulty sleeping, nausea, increased thirst, and frequent urination. These early indicators are often mistaken for stress or common illnesses, which can delay diagnosis.

Physical and Systemic Effects on the Body

Over time, untreated hypercalcemia can lead to more pronounced physical effects, including muscle weakness, fatigue, and unintentional weight loss. Cognitive changes such as brain fog or impaired concentration may also develop. In severe cases, kidney stones, bone pain, and cardiovascular issues—including irregular heartbeats—can occur, emphasizing the importance of timely evaluation and management.

Diagnosis and Treatment Approaches

Diagnosing hypercalcemia typically involves blood tests to measure serum calcium, parathyroid hormone (PTH), vitamin D levels, and kidney function. Imaging studies may be used if cancer or parathyroid adenomas are suspected. Treatment depends on the severity and cause but may include intravenous fluids, diuretics, bisphosphonates, or surgical removal of overactive parathyroid tissue.

While calcium is essential for health, too much of it in the bloodstream can have serious consequences. Awareness of the symptoms, understanding risk factors, and seeking prompt medical care are critical steps in managing hypercalcemia effectively and preventing long-term complications.