High blood calcium, medically known as hypercalcemia, occurs when the calcium level in the blood rises above the normal range. Calcium plays a crucial role in many bodily functions, including nerve signaling, muscle contraction, blood clotting, and maintaining strong bones. While calcium is essential for health, an excess can disrupt these processes and lead to various health problems.
Recognizing the Signs
The manifestations of elevated blood calcium vary, with some individuals experiencing no noticeable indications, especially in mild cases. When symptoms do occur, they often involve multiple body systems.
Digestive issues may include nausea, vomiting, reduced appetite, and constipation. Individuals might also experience increased thirst and more frequent urination.
Neurological effects can present as fatigue, confusion, difficulty concentrating, or depression. Muscle weakness and bone pain are also common. The severity of signs doesn’t always correlate with calcium levels, highlighting the need for medical evaluation for persistent or concerning changes.
Understanding the Causes
The most frequent reason for elevated blood calcium is an overactive parathyroid gland, known as primary hyperparathyroidism. These four small glands, located in the neck, produce parathyroid hormone (PTH), which regulates calcium levels. When one or more glands enlarge or develop a non-cancerous growth, they produce too much PTH, leading to increased blood calcium.
Certain cancers can also lead to hypercalcemia, particularly advanced stages of lung, breast, kidney, and multiple myeloma. This can occur if cancer interferes with calcium regulation, spreads to bones causing calcium release, or produces substances like parathyroid hormone-related protein (PTHrP) that mimic PTH.
Other less common causes include excessive vitamin D supplements, which enhance calcium absorption. Certain medications, such as lithium and thiazide diuretics, can also contribute to higher calcium levels by affecting hormone production or reducing calcium excretion. Prolonged immobility, chronic kidney disease, and some granulomatous diseases like sarcoidosis or tuberculosis can also elevate blood calcium.
How High Calcium Affects the Body
Sustained high calcium levels can affect several organ systems. Bones can become weakened as excess calcium is leached into the bloodstream, potentially leading to osteoporosis and an increased risk of fractures.
The kidneys are also significantly impacted, working harder to filter the extra calcium, which can result in painful kidney stones. Over time, chronic hypercalcemia can impair kidney function, potentially progressing to kidney failure.
The cardiovascular system can also be affected, with elevated calcium levels sometimes leading to high blood pressure. In rare instances, severe hypercalcemia can disrupt the heart’s electrical signals, causing irregular heart rhythms. The central nervous system can also experience consequences such as impaired cognitive function, including confusion, drowsiness, and fatigue.
Diagnosis and Management
Identifying elevated blood calcium typically begins with blood tests measuring total calcium. If high, further tests like ionized calcium, parathyroid hormone (PTH), and vitamin D levels help determine the underlying cause.
Imaging studies, including ultrasound or specialized scans of the parathyroid glands, may be performed if an overactive gland is suspected. For potential cancer causes, imaging like CT scans or mammograms can identify the primary source or spread.
Management depends on the cause and severity. Mild cases might only require increased fluid intake to help kidneys excrete more calcium. For significant elevations, medical interventions may include bisphosphonates, which reduce calcium release from bones, or calcitonin, which temporarily lowers calcium levels.
If an overactive parathyroid gland is the cause, surgical removal can often resolve hypercalcemia. In cancer-linked cases, treatment focuses on managing the underlying malignancy. A healthcare provider can recommend the most appropriate course of action.