Parathyroid gland disorders encompass a spectrum of conditions affecting the four small glands located behind the thyroid gland in the neck.

These glands play a critical role in maintaining calcium and phosphorus balance through secretion of parathyroid hormone (PTH), which regulates metabolism, kidney function, and intestinal calcium absorption.

Types and Pathophysiology

The two most common parathyroid disorders are hyperparathyroidism, characterized by overproduction of PTH, and hypoparathyroidism, reflecting insufficient PTH secretion.

- Hyperparathyroidism results in elevated blood calcium levels, or hypercalcemia, owing to increased resorption, enhanced renal calcium reabsorption, and intestinal absorption. Primary hyperparathyroidism frequently arises from benign adenomas in one or more parathyroid glands but may also result from hyperplasia or, rarely, malignant tumors.

Secondary hyperparathyroidism typically develops in response to chronic kidney disease or vitamin D deficiency, leading to compensatory PTH elevation.

Hypoparathyroidism involves deficient PTH secretion, causing hypocalcemia and hyperphosphatemia. The commonest etiology is inadvertent parathyroid gland injury or removal during thyroid or neck surgeries.

Autoimmune destruction, genetic mutations, magnesium deficiency, or infiltrative diseases comprise other causes. The resultant low calcium impairs neuromuscular excitability, inciting symptoms ranging from mild paresthesia to debilitating muscle cramps and seizures.

Clinical Manifestations

Parathyroid disorders often present with multisystemic symptoms, predominantly related to calcium imbalance.

- Hyperparathyroidism symptoms may be insidious or absent initially but commonly include joint pain, muscle weakness, fatigue, neurocognitive disturbances such as depression or memory problems, increased thirst, frequent urination, gastrointestinal discomfort, and kidney stones. Severe hypercalcemia can precipitate cardiac arrhythmias, pancreatitis, and osteoporosis.

- Hypoparathyroid patients experience tingling or numbness in extremities or perioral region, muscle cramps, spasms, seizures, and in chronic states, brittle nails, coarse skin, and dental abnormalities. Cognitive difficulties and mood alterations are also frequently reported.

Diagnostic Evaluation

Diagnosis integrates biochemical tests measuring serum calcium, phosphorus, magnesium, and parathyroid hormone levels. Elevated calcium with inappropriately high PTH suggests primary hyperparathyroidism; low calcium with reduced PTH points to hypoparathyroidism. Additional tests include 24-hour urinary calcium excretion and vitamin D levels to elucidate cause.

Management Approaches

Treatment depends on the disorder type, symptom severity, and complications.

- Primary hyperparathyroidism often requires surgical parathyroidectomy, which is curative in over 95% of cases. Indications for surgery include symptomatic hypercalcemia, osteoporosis, kidney stones, significant hypercalcemia, or patient preference. Monitoring and conservative management with hydration, activity modification, and medications like bisphosphonates may suit mild or asymptomatic cases.

- Secondary hyperparathyroidism treatment targets underlying causes such as correcting vitamin D deficiency or managing chronic kidney disease. Calcimimetics, phosphate binders, and vitamin D analogs modulate PTH levels.

- Hypoparathyroidism management focuses on maintaining serum calcium within a low normal range using calcium supplements and active vitamin D analogues. Severe hypocalcemia necessitates intravenous calcium. Emerging therapies include recombinant PTH analogues improving biochemical control and quality of life.

Dr. Gregory Randolph is a highly credible expert in the field of parathyroid and thyroid disorders, "The parathyroid glands are small, but they have a big impact on your health. They regulate calcium levels, which affect your bones, kidneys, and heart."

Parathyroid gland disorders, often underrecognized, exert profound effects through disruptions in calcium homeostasis. Their broad clinical spectrum mandates thorough evaluation and personalized treatment strategies to mitigate complications and enhance life quality. Continuous research into diagnostic innovations and novel therapeutics holds promise for more effective management of these endocrinopathies.