University:
Western Sydney University
Course:
MEDI 2003 | Clinical Sciences 2
Academic year:

2024
Views:

90

Pages:

2
Author:

Mariam A.

Hypercalcemia: Causes and Clinical Manifestations Causes of Hypercalcemia Hypercalcemia is defined as an elevated level of calcium in the blood, typically above 10.5 mg/dL. It can result from various underlying conditions, which can be broadly categorized into increased calcium entry into the extracellular fluid, decreased renal excretion of calcium, and increased bone resorption. Below are the primary causes: 1. Primary Hyperparathyroidism: This is the most common cause of hypercalcemia, accounting for about 90% of cases. It is due to the overproduction of parathyroid hormone (PTH) from one or more hyperactive parathyroid glands, leading to increased calcium release from bones, increased intestinal absorption of calcium, and reduced renal excretion of calcium. 2. Malignancy: Certain cancers, especially those that metastasize to bone (like breast, lung, and multiple myeloma), can cause hypercalcemia. Tumors can produce parathyroid hormone-related protein (PTHrP) or cytokines that stimulate bone resorption. 3. Vitamin D-Related: Excessive intake of vitamin D or its analogs can increase calcium absorption from the gut. Granulomatous diseases like sarcoidosis or tuberculosis can increase the conversion of vitamin D to its active form, also causing hypercalcemia. 4. Medications: Certain drugs such as thiazide diuretics, lithium, and excessive use of calcium-containing antacids can lead to elevated calcium levels. 5. Endocrine Disorders: Conditions like hyperthyroidism and adrenal insufficiency can also contribute to hypercalcemia. 6. Genetic Disorders: Familial hypocalciuric hypercalcemia (FHH) is a rare genetic condition where the body's regulation of calcium is altered, leading to mild, asymptomatic hypercalcemia. Clinical Manifestations of Hypercalcemia The symptoms of hypercalcemia vary depending on the severity and the rate at which calcium levels rise. They can be divided into several categories: 1. Neurological Symptoms: High calcium levels can lead to neuropsychiatric manifestations such as lethargy, confusion, depression, and even psychosis. Severe hypercalcemia can result in stupor and coma. 2. Gastrointestinal Symptoms: Patients may experience nausea, vomiting, anorexia, and constipation. These symptoms are due to the effects of high calcium on the gastrointestinal tract. 3. Renal Symptoms: Hypercalcemia can lead to polyuria and polydipsia due to its effects on the kidneys, including nephrogenic diabetes insipidus. It can also cause nephrolithiasis (kidney stones) and nephrocalcinosis. 4. Cardiovascular Symptoms: Hypercalcemia can affect the heart, causing hypertension, arrhythmias, and in severe cases, shortening of the QT interval on the electrocardiogram, which can lead to ventricular arrhythmias. 5. Musculoskeletal Symptoms: High levels of calcium can cause muscle weakness, bone pain, and in chronic cases, osteoporosis due to increased bone resorption. Conclusion Hypercalcemia is a multifactorial condition with diverse etiologies and clinical manifestations. Prompt diagnosis and treatment are essential to manage symptoms and prevent complications. Understanding the underlying cause is critical for effective management and treatment of hypercalcemia. If hypercalcemia is suspected, further evaluation including laboratory tests, imaging, and possibly referral to a specialist is warranted for a comprehensive approach to care.