Thyroid Disease: Why Do Celiacs Have It?
Patricia Daly, M.D., Endocrinologist, Harvard Medical School
CSA Annual Conference, October 1998, Warwick, RI

 

An endocrinologist is an internist with a subspecialty in glandular disorders and glands that produce hormones. This includes the thyroid, pituitary, pancreas that makes insulin, ovaries, testicles and adrenal glands.

Thyroid disease and abnormal thyroid tests are more common in people with sprue than in the general population. At the same time sprue is more common in individuals who have thyroid disease. This association appears to be based on the tendency for people with autoimmune diseases to be predisposed to other autoimmune diseases. The term autoimmune refers to diseases in which the immune system of the body makes antibodies (normally made to attack foreign substances like viruses). If you have an antibody against part of yourself, that antibody can cause disease, that is, an autoimmune disorder. Celiac disease is an autoimmune condition; likewise a number of thyroid diseases are autoimmune conditions.

Table 1: Thyroid directed antibodies
  1. Antibodies that stimulate the thyroid gland (causing) an overactive thyroid condition, or Graves Disease)
  2. Antibodies that block the effect of the thyroid (causing an underactive thyroid condition, or hypothyroidism)
  3. Antibodies relating to autoimmune destruction of the thyroid, or Hashimoto's thyroid disease. (This condition can result in an underactive thyroid, and also can lead to enlargement of the thyroid or the formation of nodules in the thyroid gland.)

 

Research articles support evidence that there is a connection between sprue and thyroid disease.

  1. JCI 1972, Lancet; 1976 Gut 1983. Graves disease patients have a higher than usual proportion of HLDA DR3 antigens.
  2. 1994, European Journal of Endocrinology--5% of patients with autoimmune thyroid disease had sprue.
  3. 1995, Endocrinology Practice, a case study report of increased dose requirements of thyroid hormone (because of malabsorption) leading to diagnosis of sprue.
  4. 1997, British Journal of Dermatology--4.3% of UK and 6% of sprue patients had autoimmune thyroid disease. Since we now know of the link between sprue and thyroid disease, what can you and your physician look for to determine if you might have thyroid disease in addition to sprue?

The thyroid gland, located at the base of the Adam's apple in your throat, is important in regulating metabolism. This gland affects every system of the body including the brain, heart, liver, kidney, pancreas, reproduction system, etc. When you don't have enough thyroid hormone, everything tends to slow down. When you have an overactive thyroid, things speed up. The heart beats faster, you breathe faster, you lose weight, bowels move faster, etc., but you feel more tired because more energy is being expended.

Table 2: Symptoms of Hypothyroidism (underactive)
  • Thyroid enlargement
  • Constipation
  • Weight gain
  • Brittle nails
  • Bradycardia (slowing of heart rate)
  • Hypertension (increase in blood pressure)
  • Menstrual irregularities
  • Infertility
  • Psychiatric abnormalities, such as depression
  • Cold intolerance
  • Fatigue
  • Coarse hair
  • Dry, scaly skin
  • Elevated cholesterol

 

Hypothyroidism

Hypothyroidism is 4 to 8 times more common in women, more likely with family history of autoimmune disease, affects 10-20% of women over 50 in the general population, is more common in the elderly, and often misattributed to menopause and aging.

Hypothyroidism affects all cells in the body and the symptoms tend to worsen over time.

Thyroid disease can contribute to menstrual disorders, particularly to heavier periods. Infertility is common in untreated hypothyroidism, and pregnancy management is an important issue if one had thyroid disease.

Treatment of hypothyroidism consists of replacement therapy. Treatment choices include desiccated thyroid or Levothyroxine. Desiccated Thyroid is made from desiccated (ground-up) pig thyroids. The amount of thyroid can vary greatly from batch to batch. Levothyroxine (Synthroid, Levoxyl, Levothroid and other brands) is synthesized in the laboratory. It contains a fixed amount of Levothyroxine (T4). This is one of the hormones your thyroid gland makes. Using Levothyroxine tends to be more accurate than with desiccated thyroid.

Side effects of over-treatment (getting too much thyroid hormone) include an increased risk of osteoporosis and an increased risk of irregular heart rhythm, known as atrial fibrillation.

Because absorption can vary from brand to brand, once you start on one brand, it is best to stay with the same brand. Or if you switch, blood tests can be taken to see of levels are still in range (6-8 weeks after change).

Hyperthyroidism

Graves disease is a condition in which the body makes antibodies that "trick" the thyroid into thinking it needs to continue making excessive amounts of thyroid hormone. Graves Disease can sometimes result in hypothyroidism due to thyroid destructive therapies or the natural history of the disease itself.

Common symptoms of Graves Disease are outlined as follows:

Table 3: Symptoms of Graves Disease
  • Heat intolerance, sweaty
  • Weight loss, but with increased appetite
  • Warm, smooth skin
  • Hyperpigmentation (darkening of the skin)
  • Plummer's nail
  • Pretibial myxedemia (rare)
  • Hives
  • Eye signs--deteriorations
  • Enlarged throat (goiter)
  • Emotional instability--irritability and moodiness
  • Shortness of breath with exertion
  • Racing heart beat
  • Contributes to congestive heart failure
  • Increased frequency of bowel movements
  • Changes in periods, fewer, lighter
  • Tremors
  • Myopathy--weakness of proximal muscles (near shoulders and thighs)
  • Osteoporosis
  • Insomnia

 

The best laboratory test to diagnose an overactive thyroid is the TSH (thyroid stimulation hormone). The normal range is usually .5 to 5. A low value would suggest you need more tests to confirm that your thyroid is underactive.

Hyperthyroidism can be treated in several ways, including antithyroid agents, radioactive iodine, surgery, and iodine (temporary measure only).

If you are diagnosed with hyperthyroidism, ask your doctor to refer you to a board-certified endocrinologist to help you determine which treatment is best for you.

Implications between the Association of Sprue and Thyroid Disease

You and your doctor should have a lower threshold for testing for thyroid disease in people with sprue. If you have sprue and an underactive thyroid, you need to be concerned about thyroid hormone absorption. If your sprue is not adequately treated (resulting in malabsorption), you will not absorb all of your thyroid hormone and your condition will worsen.

With regard to an overactive thyroid, the symptoms may be confusion and may mimic sprue (particularly, increased bowel movements and weight loss).

Osteoporosis and Sprue

While not necessarily related to thyroid disease, osteoporosis is another endocrine disorder for which persons with sprue are at risk. Persons with undiagnosed sprue for a long time have a greater risk for osteoporosis because of poor calcium and vitamin D absorption intake. Vitamin D is obtained through intestinal absorption and through sun exposure. Its role is to increase intestinal calcium absorption. Calcium is important for normal bone mineralization.

A DEXA bone density measurement may be appropriate for persons with sprue, particularly if sprue was untreated for long periods of time. Since osteoporosis is more common in women than in men, all women with sprue should have a bone density test at menopause, or earlier if you have experienced fractures or loss of height.

 

 

CSA Library Series
CSA Library Series is a collection of articles that pertain to celiac disease and dermatitis herpetiformis. Most of these articles have appeared in CSA’s quarterly newsletter, Lifeline, which all CSA members receive. Historic articles included in these resources may or may not include updated notes. Updated information indicated in red type. Articles represent the work of the author.