Hyperparathyroidism and High Calcium

Hyperparathyroidism and High Calcium

Hyperparathyroidism is a condition where the parathyroid glands produce excessive parathyroid hormone (PTH), leading to elevated blood calcium levels (hypercalcemia). The parathyroid glands — four small glands behind the thyroid — regulate calcium metabolism. When they become overactive, the consequences can affect bones, kidneys, and multiple organ systems.

What Is Hyperparathyroidism?

PTH regulates calcium by:

• Increasing calcium release from bones
• Increasing calcium absorption from the intestine (via vitamin D activation)
• Reducing calcium excretion by the kidneys

When PTH is excessive, blood calcium rises, causing hypercalcemia. Over time, this leads to bone loss, kidney stones, and other complications.

Hyperparathyroidism affects approximately 1 in 1,000 people, with women being 2-3 times more likely to develop it than men. The prevalence increases with age, peaking between 50-60 years.

Types of Hyperparathyroidism

1. Primary Hyperparathyroidism

Caused by an adenoma (benign tumor) in one parathyroid gland (80-85% of cases) or hyperplasia of all four glands. The gland autonomously overproduces PTH despite high calcium. This is the most common form.

2. Secondary Hyperparathyroidism

The parathyroid glands enlarge in response to low calcium levels (from vitamin D deficiency, chronic kidney disease, or malabsorption). PTH is appropriately elevated but calcium remains low or normal.

3. Tertiary Hyperparathyroidism

Occurs after long-standing secondary hyperparathyroidism, where the glands become autonomous and continue overproducing PTH even after calcium is corrected.

Symptoms of Hyperparathyroidism

Often called "bones, stones, abdominal groans, and psychic moans":

• Bones: Osteoporosis, bone pain, fractures, osteitis fibrosa cystica
• Stones: Kidney stones (nephrolithiasis), nephrocalcinosis
• Abdominal groans: Nausea, vomiting, constipation, peptic ulcers, pancreatitis
• Psychic moans: Depression, anxiety, cognitive impairment, fatigue

Additional symptoms:

• Excessive thirst and urination (polydipsia, polyuria)
• Muscle weakness
• Joint pain
• High blood pressure
• Cardiac arrhythmias (from high calcium)

A 2020 study in The Journal of Clinical Endocrinology & Metabolism found that 80% of patients with primary hyperparathyroidism are asymptomatic at diagnosis, discovered incidentally on routine blood tests.

Diagnosis

• Blood calcium: Elevated (> 10.5 mg/dL)
• PTH: Elevated or inappropriately normal (should be suppressed when calcium is high)
• 25-hydroxyvitamin D: Often low (vitamin D deficiency coexists)
• Phosphorus: Low or normal
• 24-hour urine calcium: To distinguish from familial hypocalciuric hypercalcemia (FHH)
• Bone density scan (DEXA): To assess bone loss
• Kidney imaging: To check for stones
• Sestamibi scan: To localize the abnormal parathyroid gland before surgery

Treatment

1. Surgery (Parathyroidectomy)

The definitive treatment for primary hyperparathyroidism. A single adenoma is removed, or 3.5 glands are removed in hyperplasia. Cure rate exceeds 95% with experienced surgeons.

Surgical indications:

• Symptomatic patients
• Serum calcium > 1 mg/dL above upper normal limit
• Creatinine clearance < 60 mL/min
• Bone density T-score < -2.5
• Age < 50
• Patient preference

2. Medical Management (for non-surgical candidates)

• Cinacalcet: Calcimimetic that reduces PTH secretion. Lowers calcium effectively.
• Bisphosphonates: Protect bone density but don't lower calcium
• Vitamin D supplementation: Correct deficiency (carefully, as it can raise calcium)
• Hydration: Maintain adequate fluid intake to reduce kidney stone risk

3. Monitoring (for asymptomatic patients)

• Annual calcium and PTH levels
• DEXA every 1-2 years
• Kidney imaging as needed

Complications of Untreated Hyperparathyroidism

• Osteoporosis and fractures
• Kidney stones and renal impairment
• Cardiovascular disease (hypertension, arrhythmias)
• Neuropsychiatric symptoms (depression, cognitive decline)
• Pancreatitis
• Peptic ulcer disease

Conclusion

Hyperparathyroidism is a common and treatable cause of elevated blood calcium. While many patients are asymptomatic, untreated disease can lead to bone loss, kidney stones, and cardiovascular complications. Surgery is curative for primary hyperparathyroidism, and medical management is available for those who cannot undergo surgery. Regular monitoring is essential for all patients.

References:

• Bilezikian, J.P., et al. (2014). Guidelines for the management of asymptomatic primary hyperparathyroidism. The Journal of Clinical Endocrinology & Metabolism, 99(10), 3561-3569.
• Silverberg, S.J., et al. (2014). Current issues in the presentation of asymptomatic primary hyperparathyroidism. The Journal of Clinical Endocrinology & Metabolism, 99(10), 3580-3594.
• Khan, A.A., et al. (2017). Primary hyperparathyroidism: review and guidelines. Endocrine Practice, 23(2), 177-201.
• Udelsman, R., et al. (2011). The surgical management of asymptomatic primary hyperparathyroidism. The Journal of Clinical Endocrinology & Metabolism, 96(1), 13-18.
• Peacock, M. (2010). Calcium metabolism in health and disease. Clinical Journal of the American Society of Nephrology, 5(Supplement 1), S23-S30.