The parathyroid glands are small endocrine glands in the neck that play a crucial role in calcium homeostasis, which is essential for various bodily functions including bone health, muscle function, and nerve signaling.
Humans typically have four parathyroid glands, though the number can vary, located on the back of the thyroid gland in the neck.
Structure
I. Location and Number:
The parathyroid glands are usually four in number, two on each side, positioned behind the thyroid gland's two lobes.
However, the exact number and location can vary among individuals.
II. Size and Shape:
Each gland is small, about the size of a grain of rice (3-4 mm in length), and has a reddish-brown color.
Function
The primary function of the parathyroid glands is to regulate the body’s calcium and phosphate levels. They do this by secreting parathyroid hormone (PTH).
Parathyroid Hormone (PTH): PTH increases calcium levels in the blood by:
Stimulating the release of calcium from bones.
Increasing the absorption of calcium in the intestines, indirectly, by promoting the activation of vitamin D.
Increasing the reabsorption of calcium in the kidneys, reducing the amount lost in urine.
PTH also regulates phosphate metabolism by reducing its reabsorption in the kidneys, which leads to an increase in phosphate excretion.
Disorders
Disorders of the parathyroid glands typically involve abnormalities in PTH levels, leading to disturbances in calcium homeostasis.
1. Hyperparathyroidism:
This condition is characterized by the overproduction of PTH, leading to high levels of calcium in the blood (hypercalcemia).
Primary hyperparathyroidism is often caused by a benign tumor (adenoma) in one of the parathyroid glands.
Symptoms may include weakened bones (osteoporosis), kidney stones, fatigue, and depression.
2. Hypoparathyroidism:
This condition occurs when the parathyroid glands produce too little PTH, resulting in low calcium levels in the blood (hypocalcemia).
Causes include surgical removal or accidental damage to the parathyroid glands during thyroid surgery, autoimmune disease, or genetic factors.
Symptoms can include muscle cramps or spasms, tingling in the fingertips, toes, and lips, and in severe cases, seizures.
3. Secondary Hyperparathyroidism:
This is a response to low calcium levels in the blood, often due to chronic kidney disease, vitamin D deficiency, or dietary issues, leading to increased PTH production.
The condition aims to normalize calcium levels but can lead to bone disease if prolonged.
Treatment
Treatment for parathyroid disorders depends on the type, cause, and severity of the condition. It may include:
Surgery: Often recommended for primary hyperparathyroidism, to remove the overactive gland(s).
Medication: Drugs may be used to manage symptoms or the underlying cause, such as vitamin D analogs, calcium supplements, or drugs that mimic calcium to inhibit PTH secretion in cases of hypoparathyroidism.
Monitoring: In cases where immediate treatment isn't necessary, regular monitoring of blood calcium levels and bone density may be advised.
Correctly diagnosing and managing parathyroid disorders is crucial for maintaining calcium balance and preventing complications associated with abnormal calcium levels.
