Parathyroid Hormone and Kidney Disease

parathyroid-hormone-and-kidney-disease

How well do you know about your kidneys? Did you know, other than just kidney stones one might suffer from, you might get problems ensued by parathyroid hormone too? Read this article now to find out more about PTH:

What is PTH?

PTH is the acronym for parathyroid hormone, which is a hormone produced by parathyroids, the four tiny glands that are located in the neck, that control the body’s calcium levels. Each gland is about the size of a grain of rice that weighs approximately 30 milligrams and is 3-4 millimetres in diameter. PTH raises the blood calcium level by breaking down the bone and causing calcium release, increasing the body’s ability to absorb calcium from food after consumption.

The key purpose of these parathyroid glands is to keep the calcium and phosphorus levels in your blood at a constant and normal level. For example, if the blood calcium level becomes low, the parathyroid gland will respond by secreting more PTH. Once the calcium level is increased with the extra PTH, binding of calcium to the calcium-sensing receptor reduces the production and secretion of PTH, returning these levels to normal. This give-and-take response works well until kidney failure begins to occur.

What happens to PTH when the kidney fails

There are several reasons why an increase in PTH is common with kidney failure. This happens “about three times more common in women than men and patients are usually older, with an average age at presentation of 65 years (most cases are over 45 years),” according to The American Association of Endocrine Surgeons.

As blood phosphorus levels rise, so do PTH levels. With the PTH levels risen, the diseased kidney cannot activate vitamin D. Without activated vitamin D, calcium cannot be absorbed from your intestines into your blood. When the blood calcium level drops, the parathyroids respond by producing more PTH. This is when hyperparathyroidism often develops. Hyperparathyroidism is the enlargement of the parathyroid glands. Then, more PTH is produced to counter-attack the low blood calcium level.

Signs and symptoms of hyperparathyroidism

Hyperparathyroidism is enlarged, overactive parathyroids which will produce more PTH than needed, which PTH levels become high. PTH raises the serum calcium level partly by increasing osteoclast-mediated bone resorption. With prolonged elevation, they weaken. This may cause bone pain and increased fracture risk. The calcification of tissues and organs is another symptom that can occur throughout the body. The lungs, heart, blood vessels, joints and skin may be affected.

Prevention

This can be avoided by keeping your phosphorus below 5.5 to decrease problems. Both diet and phosphate binders can help. Phosphate binders are medications used to reduce the absorption of dietary phosphate, in high amounts in protein foods such as milk, milk products, meat, beans, lentils and nuts.

Another way is to consume medications with vitamin D. Zemplar®, Hectorol®, and calcitriol are medications that are often used. A medication called Sensipar® is also available. It decreases levels of PTH, calcium and phosphorus in the body. Side effects are rare but include nausea, vomiting and occasionally, hypocalcemia (low calcium levels).

Result of low PTH levels

A normal PTH level is 10-65 pg/ml. As the kidney function deteriorates, the PTH level gradually increases. If a person is on dialysis and their intact PTH level is less than 100 pg/ml, this is known as dynamic bone disease, also known as low bone turnover. This may occur if the parathyroid glands become overly suppressed with vitamin D medication such as Zemplar or Hectorol.

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Kidney Stones and Chronic Kidney Disease