13 Parathyroid Disease

Parathyroid Disease

The parathyroid glands, located behind the thyroid gland, produce parathyroid hormone (PTH), which regulates calcium levels in the blood. Disorders of the parathyroid glands can lead to significant metabolic imbalances.

1. Hyperparathyroidism
   • Pathophysiology: Hyperparathyroidism is characterized by the overproduction of PTH, leading to elevated calcium levels in the blood (hypercalcemia). This condition can be primary (due to a parathyroid adenoma or hyperplasia) or secondary (as a response to chronic hypocalcemia, often seen in chronic kidney disease).
   • Clinical Manifestations:
     • Hypercalcemia: Elevated calcium levels can cause symptoms such as muscle weakness, fatigue, constipation, and polyuria.
     • Bone Pain and Fractures: Excess PTH causes bone resorption, leading to osteoporosis and an increased risk of fractures.
     • Kidney Stones: High calcium levels can lead to the formation of kidney stones.
     • Psychiatric Symptoms: Patients may experience depression, confusion, or memory problems.
   • Diagnosis: Elevated serum calcium and PTH levels confirm the diagnosis. Bone density tests and imaging studies may be used to assess the extent of bone involvement.
   • Management:
     • Surgical Removal: Parathyroidectomy is the definitive treatment for primary hyperparathyroidism.
     • Medications: Calcimimetics and bisphosphonates may be used to manage hypercalcemia and protect bone density.
     • Monitoring: Regular monitoring of calcium and PTH levels is essential, along with bone density assessments.
2. Hypoparathyroidism
   • Pathophysiology: Hypoparathyroidism is characterized by insufficient production of PTH, leading to low calcium levels in the blood (hypocalcemia). It can occur after thyroid or parathyroid surgery or be idiopathic.
   • Clinical Manifestations:
     • Hypocalcemia: Symptoms include muscle cramps, tetany (muscle spasms), numbness, and tingling in the fingers and toes.
     • Chvostek’s and Trousseau’s Signs: Positive Chvostek’s sign (twitching of facial muscles when tapped) and Trousseau’s sign (carpal spasm with blood pressure cuff inflation) indicate hypocalcemia.
     • Seizures: Severe hypocalcemia can lead to seizures.
   • Diagnosis: Low serum calcium and PTH levels confirm the diagnosis. Phosphate levels may be elevated due to the lack of PTH.
   • Management:
     • Calcium and Vitamin D Supplements: These are the mainstays of treatment to maintain normal calcium levels.
     • PTH Replacement: In some cases, synthetic PTH (teriparatide) may be used to manage chronic hypoparathyroidism.
     • Monitoring: Regular monitoring of calcium levels is necessary to prevent complications of hypocalcemia.