Parathyroid Hormone

Dental radiographs help hygienists spot signs of elevated PTH, which may point to kidney disease.

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by Cheryl A. Thomas, RDH

Dental radiographs help hygienists spot signs of elevated PTH, which may point to kidney disease.

Parathyroid hormone (PTH) is excreted from the parathyroid glands. Each gland usually comes in a pair located at either side of the thyroid. Although these are relatively small glands, they play a large role in bone metabolism. The role of PTH in the endocrine system is to regulate blood calcium levels by regulating bone turnover. PTH draws calcium into the blood from the bones, intestines, and kidneys.1 It also plays an important role in removing phosphorus from the blood to the kidneys, where it is excreted in urine. While this is interesting, what does it have to do with dental hygiene? When you interpret dental radiographs, are you looking for signs of elevated PTH?

Elevated PTH, or hyperparathyroidism (HPT), can occur as a primary disease, which is a malfunction of the parathyroid gland alone (fairly rare), or a domino effect of another condition, usually kidney disease (fairly common). Many people are not familiar with the prevalence of renal disease in the United States, much less that secondary hyperparathyroidism (elevated intact PTH) is a silent, often undiagnosed condition of people with kidney disease, or that medical and dental professionals could be instrumental in screening for this condition.

Prevalence of kidney disease

The statistics for kidney disease are remarkable, yet many dental health-care providers are unaware of its prevalence. According to the National Kidney Foundation, 20 million Americans (one in nine adults) have chronic kidney disease (CKD).2 In addition, another 20 million are at increased risk for CKD.2 Those at highest risk are African Americans, Hispanics, Pacific Islanders, Native Americans, and senior citizens.2 Like periodontal disease, CKD can be asymptomatic for many years, so treatment is often not sought until there is extreme damage to renal function. Reports indicate that the average patient lives with CKD for 10 years before seeking medical treatment. More importantly, there are only 5,000 full-time nephrologists in the United States.3

With these statistics and a dramatically increasing senior citizen population, it’s only natural to assume that overburdened health-care professionals would have a difficult time detecting a silent disease such as HPT. Because secondary hyperparathyroidism causes a disruption in bone metabolism, dental health-care professionals can take the opportunity to collaborate with medical health-care providers to facilitate early intervention of CKD.

The most popular and radiographically obvious manifestation of elevated PTH is a brown tumor, a radiolucent lesion where calcium has been extracted from the bone. In the head and neck region, the most common location for a brown tumor is the mandible. Brown tumors are considered rare in the United States, where most people in end-stage renal failure can obtain lifesaving dialysis treatment.

PTH calcium deposits

What many dental health-care providers do not know is that during HPT there are excessive amounts of calcium in the bloodstream, and calcium salts are deposited into soft tissues throughout the body. Without medical intervention, these can be deposited into the heart, lungs, liver, etc., which can result in calcinosis. Without medical intervention, calcinosis can be lethal.

More subtle calcium deposits can also be detected in other soft tissues, such as the pulp of a tooth. This is where radiographic interpretation and medical referral can assist in the early intervention of CKD and secondary hyperparathyroidism. It is likely that calcification of the dental pulp in patients with secondary hyperparathyroidism would not appear as classic pulp stones, but rather a more subtle narrowing of the pulp chamber. Left untreated, the complete pulp chamber could become calcified. See Table 1 for additional symptoms of secondary hyperparathyroidism.

Early detection of CKD can provide critical medical intervention and prevent or delay end-stage renal disease. Furthermore, when dental health-care providers screen for secondary hyperparathyroidism in patients who have or are at risk for CKD and refer them to their primary health-care provider, it can help medical providers obtain homeostasis in patients with elevated PTH and avoid catastrophic conditions such as calcinosis.

Radiographic interpretation is a service that dental hygienists perform on a daily basis. Although a calcified dental pulp alone is not a definitive diagnosis for secondary hyperparathyroidism, it might be linked to a systemic disease in patients who are at high risk for kidney disease. When we strive to understand disease processes such as CKD in our medically complex patients, we open a door to collaborative care that benefits both our patients and our profession. RDH

References

1 Fluids & Electrolytes. 2002. Second edition. Judith A. Schilling McCann, RN, MSN - Springhouse.

2 National Kidney Foundation. 2006. Available online www.kidney.org. Accessed Nov. 15, 2006.

3 U.S. Department of Health and Human Services. National Institute of Diabetes and Digestive and Kidney Diseases. 2003. Available at http://nkdep.nih.gov/resources/nkdep_ckd_presentation. ppt#285,1,Chronic Kidney Disease in the United States. Accessed Nov. 15, 2006.


Table 1

Additional symptoms of secondary hyperparathyroidism

  • Fatigue
  • Back pain
  • Joint pain
  • Fractures of long bones
  • Increased urine output
  • Increased thirst
  • Upper abdominal pain
  • Loss of appetite
  • Nausea
  • Muscular weakness
  • Muscle pain
  • Depression
  • Personality changes
  • Itching of the skin
  • Blurred vision
  • Chronic bone pain or tenderness

Medline Plus. Oct. 2006. Available at http://www.nlm.nih.gov/medlineplus/ency/article/001215.htm.

Cheryl A. Thomas, RDH, currently resides in Galveston, Texas. She can be contacted at catblue@aol.com, or visit her Web site at dentalinspirations.org.

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