What is Parathyroid Disease?
Parathyroid disease refers to disorders affecting the parathyroid glands—small endocrine glands located behind the thyroid. These glands regulate calcium homeostasis through the secretion of parathyroid hormone (PTH). When this balance is disturbed, it leads to either hypercalcemia (high calcium) or hypocalcemia (low calcium), manifesting in systemic complications.
Understanding Calcium Metabolism
Calcium levels are regulated through a tight interplay of:
- Parathyroid Hormone (PTH)
- Vitamin D3
- Calcitonin
Functions:
PTH increases blood calcium by:
- Promoting calcium reabsorption in kidneys
- Stimulating calcium release from bones
- Activating Vitamin D (which increases intestinal calcium absorption)
Disturbance in this balance leads to hyperparathyroidism or hypoparathyroidism.
Hyperparathyroidism: Overview & Symptoms
Hyperparathyroidism results in elevated PTH and hypercalcemia.
Causes:
- 75% due to parathyroid adenoma
- 20% due to parathyroid hyperplasia
- 1% due to carcinoma
Types:
- Primary: Autonomous PTH secretion
- Secondary: Reaction to chronic hypocalcemia (e.g. renal failure)
- Tertiary: Persistent autonomous PTH secretion after long-standing secondary cause
Symptoms: "Bones, Stones, Groans, and Psychiatric Overtones"
- Bones: Pain, fractures, osteitis fibrosa cystica
- Stones: Renal calculi, polyuria
- Groans: Peptic ulcers, pancreatitis, abdominal pain
- Psychiatric: Depression, confusion, psychosis
Key Points:
- Common in women >40 years
- Asymptomatic hypercalcemia is often the only sign
- May present with vague symptoms, often misdiagnosed
Hypoparathyroidism: Causes & Signs
Hypoparathyroidism is defined by low PTH levels resulting in hypocalcemia.
Causes:
- Surgical injury (thyroidectomy or parathyroidectomy)
- Autoimmune destruction
- Congenital absence or genetic syndromes
- Pseudohypoparathyroidism (end-organ resistance to PTH)
Symptoms:
- Neuromuscular excitability due to low calcium
- Chvostek’s sign: Facial nerve twitch on tapping
- Trousseau’s sign: Carpopedal spasm with BP cuff inflation
- Perioral paresthesia
- Tetany, muscle cramps
- ECG: Prolonged QT, raised T wave
Causes of Parathyroid Disorders
| Condition | Primary Cause |
|---|---|
| Hyperparathyroidism | Adenoma, hyperplasia, carcinoma |
| Hypoparathyroidism | Post-surgery, autoimmune, congenital |
| Secondary hyperparathyroidism | CKD, malabsorption, Vitamin D deficiency |
| Tertiary hyperparathyroidism | Autonomous PTH post-CKD or transplant |
Diagnostic Tools and Imaging
Laboratory Tests:
- Serum Calcium: High in hyperparathyroidism, low in hypo
- PTH levels: Elevated in primary/secondary, low in hypo
- Phosphorus levels: Often inverse to calcium
- Vitamin D and Magnesium levels
Imaging:
- Ultrasound
- 99mTc Sestamibi scan
- DXA Scan: To check bone density loss
- CT/MRI & Digital Subtraction Angiography for gland localization
Intraoperative:
- PTH blood sampling to guide completeness of gland removal
Treatment & Management Guidelines
Hyperparathyroidism
Surgical:
- Parathyroidectomy is the treatment of choice
- Removal of adenoma or 3.5 glands in hyperplasia
Medical (if unfit for surgery):
- Bisphosphonates (bone resorption inhibition)
- Cinacalcet (calcimimetic)
- Estrogen-progestin in postmenopausal women
- Adequate hydration and Vitamin D maintenance
Hypoparathyroidism
- Calcium and Vitamin D supplements
- Intravenous calcium gluconate for severe tetany
- Monitor magnesium levels
- Chronic cases may need recombinant PTH therapy
Complications & Prognosis
Hyperparathyroidism:
- Complications: Nephrolithiasis, osteoporosis, fractures, pancreatitis
- Post-op hypoparathyroidism: Often transient
Hypoparathyroidism:
- Complications: Seizures, laryngospasm, heart arrhythmias, cataracts
- Prognosis: Good with calcium & Vitamin D compliance
FAQs on Parathyroid Disease
Q1. Can parathyroid disease be asymptomatic?
Yes, particularly primary hyperparathyroidism is often discovered incidentally through high calcium levels.
Q2. How is parathyroid disease different from thyroid disease?
They are distinct glands with different hormones and functions. Parathyroid regulates calcium, while the thyroid regulates metabolism.
Q3. Can you live without parathyroid glands?
Yes, but lifelong calcium and vitamin D supplementation is essential.
Q4. What is pseudohypoparathyroidism?
It is a rare condition where target organs are resistant to PTH, leading to low calcium despite high PTH levels.
Conclusion
Parathyroid diseases are often underdiagnosed, yet they profoundly impact calcium metabolism and systemic health. From bone pain and renal stones in hyperparathyroidism to tetany and seizures in hypoparathyroidism, early detection and management are key. With advancements in surgical localization, intraoperative PTH monitoring, and medical therapies, outcomes have improved significantly for patients with these disorders.
