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Secondary Hyperparathyroidism

Courtesy Wikipedia.com
Parathyroid Glands in the Neck. Courtesy Wikipedia.com

What Is Secondary Hyperparathyroidism?

[dropcap]S[/dropcap]econdary hyperparathyroidism is a parathyroid disorder resulting from hypocalcemia (low blood calcium level) that is characterized by excessive production of parathyroid hormone in the attempt to normalize the low blood calcium by releasing calcium from bone.

Parathyroid hormone is produced by the four pea sized parathyroid glands that are located on the thyroid gland in the front of the neck. In part, because the thyroid and parathyroid glands share the same anatomic place in the body and because they have similar names, they are often confused although they have completely different actions.

Parathyroid hormone regulates calcium and the opposing mineral phosphorus in the blood. In secondary hyperparathyroidism, calcium blood levels are low to normal while phosphorus levels are increased which stimulates the outpouring of parathyroid hormone.

Q: How does secondary hyperparathyroidism differ from primary hyperparathyroidism?

A: In primary hyperparathyroidism blood calcium is high and phosphorus is low, which is the opposite of secondary hyperparathyroidism.

The most common cause of secondary hyperparathyroidism is kidney disease causing failure to reabsorb calcium followed by vitamin D deficiency and malabsorption.

What Is Secondary Hyperparathyroidism In Celiac Disease and/or Gluten Sensitivity?

Hypoparathyroidism, Idiopathic

Parathyroid gland anatomyWhat Is Idiopathic Hypoparathyroidism?

[dropcap]I[/dropcap]diopathic hypoparathyroidism is a metabolic condition that results from reduced secretion or impaired action of parathyroid hormone (PTH) which results in a combination of low calcium and elevated phosphorus levels in the body.

Calcium and phosphorus are minerals that act in opposition to each other in the body. Idiopathic means the cause is not known.

Parathyroid hormone is produced by the four pea sized parathyroid glands that are located on the thyroid gland in the front of the neck. Partly because the thyroid and parathyroid glands share the same anatomic place in the body and partly because they have similar names, they are often confused although they have completely different actions.

Q: What does parathyroid hormone do in the body?

A: This vital hormone maintains a correct balance of calcium and phosphorous in the bloodstream and ultimately has an effect on all organs because of the complexity of intracellular calcium physiology.1 

Parathyroid hormone is required to sustain life, therefore undetected or misdiagnosed hypoparathyroidism may pose a significant threat to health outcomes, as its presence may increase disease and mortality in affected individuals.

The clinical consequences of parathyroid hormone deficiency or impaired receptor action involve many body functions. In some patients, however, its manifestation may be non-specific, and in these cases the correct diagnosis may be easily missed.

Digestive manifestations of hypoparathyroidism are few and consist mainly of steatorrhea due to insufficient meal-stimulated cholecystokinin secretion by the duodenal mucosa.2

Laboratory measurements show hypocalcemia (low blood calcium level), hyperphosphatemia (high blood phosphate level), and inappropriately low or undetectable parathyroid hormone levels. Treatment consists of oral calcium supplementation and vitamin D derivatives.3

Idiopathic hypoparathyroidism is rare, although there is a growing incidence of the autoimmune form of hypoparathyroidism, which may occur in combination with other autoimmune diseases such as celiac disease.

What Is Idiopathic Hypoparathyroidism In Celiac Disease and/or Gluten Sensitivity?

Sources:
  1. Abboud B, Daher R, Boujaoude J. Digestive manifestations of parathyroid disorders. World J Gastroenterol. 2011 Sep 28;17(36):4063-6. doi: 10.3748/wjg.v17.i36.4063. [↩]
  2. Abboud B, Daher R, Boujaoude J. Digestive manifestations of parathyroid disorders. World J Gastroenterol. 2011 Sep 28;17(36):4063-6. doi: 10.3748/wjg.v17.i36.4063. [↩]
  3. Krysiak R, Handzlik-Orlik G, Kedzia A, Machnik G, Okopień B. Hypoparathyroidism: the present state of art. Wiad Lek. 2013;66(1):18-29. [↩]

Cancer, Parathyroid

CT Scan of Parathyroid Carcinoma Displacing the Trachea. Courtesy Orphanet Journal of Rare Diseases
CT Scan of Parathyroid Carcinoma Displacing the Trachea by Doina Piciu. Courtesy Orphanet Journal of Rare Diseases

What Is Parathyroid Carcinoma?

[dropcap]P[/dropcap]arathyroid carcinoma is a slow growing rare malignancy involving overactive parathyroid glands and is characterized by profound hypercalcemia (elevated blood calcium level), parathyroid hormone levels of more than 3 times upper normal limits, and palpable neck mass.1

Parathyroid carcinoma is a cause of severe hyperparathyroidism. Hyperparathyroidism results from overproduction of parathyroid hormone by the parathyroid glands.

Research comparing patients with carcinoma to patients with primary hyperparathyroidism showed that patients with parathyroid carcinoma had significantly higher serum parathyroid hormone and calcium levels compared with patients with primary hyperparathyroidism.2

Q: Why is the blood calcium level elevated?

A: Blood calcium level is elevated due to overproduction of parathyroid hormone by the diseased gland(s).

The function of parathyroid hormone (PTH) is to keep calcium blood levels normal, which it does by drawing calcium out of bones as needed. The problem of too much PTH is that bone is constantly robbed of calcium and this depletion causes bone demineralization, resulting in osteopenia progressing to osteoporosis. Of course, weakened bones are subject to breakage with light trauma.

On the other hand, too much calcium in the blood can cause kidney stone formation because urine production is the way the body excretes excess calcium. That is, highly concentrated calcium precipitates out of the urine solution to form stones.

With an estimated incidence of 0.015 per 100,000 population and an estimated prevalence of .005% in the United States, parathyroid cancer is one of the rarest of all human cancers according to the National Cancer Institute.

What Is Parathyroid Carcinoma In Celiac Disease and/or Gluten Sensitivity?

Sources:
  1. Schaapveld M, Jorna FH, Aben KK, Haak HR, Plukker JT, Links TP. Incidence and prognosis of parathyroid gland carcinoma: a population-based study in The Netherlandsestimating the preoperative diagnosis. Am J Surg. 2011 Nov;202(5):590-7. doi: 10.1016/j.amjsurg.2010.09.025. Epub 2011 Aug 20. [↩]
  2. Schaapveld M, Jorna FH, Aben KK, Haak HR, Plukker JT, Links TP. Incidence and prognosis of parathyroid gland carcinoma: a population-based study in The Netherlandsestimating the preoperative diagnosis. Am J Surg. 2011 Nov;202(5):590-7. doi: 10.1016/j.amjsurg.2010.09.025. Epub 2011 Aug 20. [↩]