Hyperparathyroidism

Over activity of the Parathyroid Gland – Too Much Parathyroid Hormone Production

The most common disease of the parathyroid glands is over activity, too much parathyroid hormone is produced, which is called Primary Hyperparathyroidism and may occur in as many as 1% of the population. Under this condition of hyperparathyroidism, one or more of the parathyroid glands makes excessive hormone regardless of the level of calcium in the blood. In other words, the parathyroid glands continue to make large amounts of parathyroid hormone, even when the calcium level is normal or elevated. Over-production of parathyroid hormone by overactive parathyroid glands (hyperparathyroidism) can cause bone fractures or osteoporosis, make you feel run down and tired, cause kidney stones, and many other serious problems. Fortunately, hyperparathyroidism can be fixed with new minimally invasive surgical techniques in most people. In cases when surgery cannot be performed, medications may be very helpful but do not cure the underlying problem. Other causes of hyperparathyroidism (Secondary Hyperparathyroidism) include vitamin D deficiency and chronic kidney disease.

Primary Hyperparathyroidism

The symptoms of Primary Hyperparathyroidism have become known as “moans, groan, stones and bones.” Although most people with Primary Hyperparathyroidism claim to feel well when the diagnosis is made, the majority will actually say they feel better after the problem has been cured. Commonly, patients who thought they were asymptomatic pre-operatively will find post-operatively to sleep better at night, be less irritable, and find that they remember things much easier than they could when their calcium levels were high. “Moans” (feeling depressed, unwell or emotional) and “groans” (unexplained gastrointestinal pain) typically resolve. In some studies, as many as 92% of patients claimed to feel better after removal of a diseased parathyroid gland, even when only 75% claim they felt "bad" before the operation. High levels of calcium in the blood can be dangerous to a number of cells, including the lining of the stomach and the pancreas, causing both of these organs to become inflamed and painful (ulcers and acute pancreatitis).

Another common presentation for persistently elevated calcium levels is the development of kidney “stones”. Since the major function of the kidney is to filter and clean the blood, they will be constantly exposed to high levels of calcium in patients with hyperparathyroidism. The constant filtering of large amounts of calcium will cause high concentration of calcium in the urine, which leads to kidney stones. In extreme cases, the entire kidney can become calcified and destroy the kidneys because of deposition of so much calcium within the tissues. Not only is this painful because of the presence of kidney stones, but in severe cases, it can cause kidney failure.

In severe and chronic hyperparathyroidism, the “bones” can give up so much of their calcium that the bones become brittle (osteoporosis and osteopenia) and break (fractures). This problem is even more of a concern in older patients who already have bone loss. Bones can also have small hemorrhages within their center that will cause bone pain.

The incidence of these problems depends primarily on the duration of the disease and its severity. Everybody will lose some bone density, which is progressive. Fortunately, bone mass usually improves after surgical cure, typically within two years. Pancreatitis and ulcers are rarer. Remember, the typical patient with Primary Hyperparathyroidism has had this disease for several years before it is ever found because its symptoms are so silent. The good news is that it can be cured with a routine operation that carries a success rate of about 95% and a complication rate of around 1% or less. Some centers are even performing minimally invasive surgery for this disease, which can be accomplished under local anesthesia and hospitalization is typically only one day or less. Sometimes patients cannot undergo surgery and some medications can decrease PTH secretion (Sensipar) or reduce it long-term effects on bone (Bisphosphonates).

The most common cause of excess hormone production is the development of a benign (non-cancerous) tumor in one of the parathyroid glands, called a parathyroid adenoma, and it accounts for 85% of all patients with primary hyperparathyroidism. The other 3 glands are small and are responding appropriately to the high calcium by becoming dormant. This adenoma is rarely ever cancerous (less than one in 2,500); however, it slowly causes damage to the body because it induces an abnormally high level of calcium in the blood, which can slowly destroy a number of tissues. Parathyroid adenomas typically are much bigger than a normal pea-sized parathyroid and will frequently be seen by an ultrasound of the neck or a special nuclear medicine scan called a parathyroid scan.

In about 10% of patients, two or multiple glands are overproducing PTH. In less than 1% of patients, all 4 parathyroid glands, a term called parathyroid hyperplasia, occurs. In this instance, all of the parathyroid glands become enlarged and produce too much parathyroid hormone. This is a much less common scenario and usually requires additional endocrine testing and lifelong follow up. The only way to know is to remove only one gland while leaving the others untouched and then following these patients for a number of years.

Secondary Hyperparathyroidism

Other causes of hyperparathyroidism are determined only after the diagnosis of Primary Hyperparathyroidism is excluded by laboratory testing. That is why every patient who is referred for consultation will undergo testing to rule out other potential causes. A vitamin D level and kidney assessment are helpful to identify those patients who have a vitamin D deficiency. Vitamin D is required to absorb calcium from the intestines. When vitamin D levels are low and too little calcium is absorbed from the diet, PTH levels rise so that calcium from the bones can maintain normal blood levels. Low vitamin D is very common and may also be present in those patients who have chronic kidney failure. Other forms of kidney disease can waste calcium from the urine and this is identified by a 24 hour urine calcium assessment.

Diagnosis of Hyperparathyroidism

The diagnosis of hyperparathyroidism is made by the test of parathyroid hormone level in the blood. Tests which help to differentiate the causes of hyperparathyroidism include; serum calcium, kidney function tests, 24 hour urine calcium/creatinine, vitamin D and bone density tests. Once the diagnosis is made, additional imaging tests such as a neck ultrasound, CT and/or parathyroid scan can help localize abnormal parathyroid glands. Even more specialized testing is needed in some.