New guidelines on investigating thyroid dysfunction.

Equipment for all seasons. (Dr. Noorali Bharwani)
Equipment for all seasons. (Dr. Noorali Bharwani)

The thyroid gland produces hormone called thyroxine. The gland is in the front of the neck, below Adam’s apple, consisting of two lobes (left and right) connected by an isthmus.

In fact, the thyroid gland secretes three hormones: the two thyroid hormones, thyroxine (T4) and triiodothyronine (T3); and calcitonin.

The thyroid hormones influence the metabolic rate and protein synthesis, and in children, growth and development. Calcitonin is involved in helping to regulate levels of calcium and phosphate in the blood.

Many things can go wrong with the thyroid gland. Examples of thyroid disorders include hyperthyroidism (increased activity), hypothyroidism (reduced activity), thyroid inflammation (thyroiditis), thyroid enlargement (goitre), thyroid nodules, and thyroid cancer.

In iodine-sufficient regions, the most common cause of hypothyroidism is the autoimmune disorder Hashimoto’s thyroiditis.

Most adults who go for regular annual physical examination get tested for thyroid function. Is this necessary?

The Canadian Task Force on Preventive Health Care (CMAJ November 18, 2019) strongly recommends against screening for thyroid dysfunction in asymptomatic nonpregnant adults. Why? Guidelines say, “Treating asymptomatic adults for screen-detected hypothyroidism may result in little to no difference in clinical outcomes.”

These recommendations do not apply to patients with previously diagnosed thyroid disease or thyroid surgery; exposure to medications known to affect thyroid function; exposure to thyroid radioiodine therapy, or radiotherapy to the head or neck area; or pituitary or hypothalamic diseases.

Guidelines suggest clinicians should remain alert to signs and symptoms suggestive of thyroid dysfunction and investigate accordingly. This is not always easy. The signs and symptoms of thyroid dysfunction are variable between patients and often nonspecific.

Symptoms of hypothyroidism may include tiredness, sensitivity to cold, dry skin, hair loss, weight gain and slowed movements and thoughts. If left untreated, hypothyroidism may increase the risk of cardiac dysfunction, hypertension, dyslipidemia, cognitive impairment and, in rare cases, myxedema coma.

If the thyroid is overactive (hyperthyroidism), symptoms may include regular rapid heartbeat (sinus tachycardia), atrial fibrillation, hyperactivity or irritability, intolerance to heat, tremor and weight loss.

Some people with thyroid dysfunction have no symptoms.

Thyroid dysfunction is diagnosed based on abnormal levels of serum thyroid-stimulating hormone (TSH) and can be characterized as either hypo- or hyperthyroidism.

Minor variations in thyroid function as measured by abnormal levels of TSH are often self-limiting. Observational studies have reported that levels of TSH appear to revert to normal without treatment in 37 to 62 per cent of patients with initially elevated levels and 51 per cent with initially low levels, particularly for milder cases of thyroid dysfunction (mean follow-up 32–60 months).

Summary of recommendation for clinicians, policy-makers and patients

The guidelines recommend against screening asymptomatic nonpregnant adults aged 18 years and older for thyroid dysfunction in primary care settings.

Screening results in overuse of resources without a demonstrated benefit.

These recommendations do not apply to patients with previously diagnosed thyroid disease or thyroid surgery; exposure to medications known to affect thyroid function (e.g., lithium, amiodarone); exposure to thyroid radioiodine therapy, or radiotherapy to the head or neck area; or pituitary or hypothalamic diseases.

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The thyroid gland has an enormous impact on your health.

Lake Louise, Alberta. (Dr. Noorali Bharwani)
Lake Louise, Alberta. (Dr. Noorali Bharwani)

In my last column we discussed the management of a thyroid tumour. Today, we will discuss another aspect of thyroid disease: under active (hypo-thyroid) and over active (hyper-thyroid) thyroid gland.

It is estimated thyroid disorders affect one in 20 Canadians and most thyroid disorders are five to seven times more common in women.

Thyroid hormones are produced in the thyroid gland from iodine and an amino acid, tyrosine. The normal function of the thyroid gland is to produce and secrete hormones. There are two hormones which are closely related: T3 (triiodothyronine) and T4 (thyroxine).

These hormones have enormous impact on our health, affecting all aspects of our metabolism. They maintain the rate at which our body uses fats and carbohydrates, help control our body temperature, influence our heart rate, and help regulate the production of protein. These hormones are important for normal growth and development of children.

Hypothyroidism

Hypothyroidism causes many symptoms: weight gain, lethargy, cold intolerance, menstrual irregularities, depression, constipation, and dry skin. Deficiency of thyroid hormones in children leads to dwarfism and mental retardation.

There are many causes of hypothyroidism. Thyroid function can be diminished due to congenital development defect or acquired conditions like radiation therapy or autoimmune disease (Hashimotos’ disease).

Hashimoto’s disease is a condition in which your immune system attacks your thyroid. Inflammation from Hashimoto’s disease, also known as chronic lymphocytic thyroiditis, often leads to hypothyroidism. Hashimoto’s disease is the most common cause of hypothyroidism in North America. It primarily affects middle-aged women but also can occur in men and women of any age and in children.

Thyroid function is tested to help detect Hashimoto’s disease. Treatment of Hashimoto’s disease with thyroid hormone replacement usually is simple and effective.

Good news is accurate thyroid function tests are available to diagnose hypothyroidism. Treatment of hypothyroidism with synthetic thyroid hormone is usually simple, safe and effective. Finding an adequate replacement dosage of thyroid may take a little time.

Hyperthyroidism

On the other hand hyperthyroidism is not that easy to manage.

Clinically, hyperthyroidism presents with palpitations, nervousness, tremor, heat intolerance, weight loss, muscular weakness and quite often there is goitre.

Hyperthyroid gland can cause Graves’ disease that accounts for at least 90 per cent of all patients with hyperthyroidism. But the cause of hyperthyroidism is not very clear.

Graves’ disease is a condition where eyes are affected. It is called exophthalmos – protrusion of the eyeballs. Graves’ disease is an autoimmune disorder in which antibodies produced by your immune system stimulate your thyroid to produce too much thyroid hormone.

It is not clear what causes Graves’ disease, although several factors, including a genetic predisposition, are likely involved.

Unfortunately, there is no satisfactory treatment to prevent Graves’ eye disease. Because hyperthyroidism seems to affect the eyes, it is very important to treat hyperthyroidism quickly and effectively. In most patients, the eyes tend to get somewhat better when the thyroid abnormality has been treated.

Patients who are hyperthyroid are often treated with radioactive iodine or anti-thyroid medications to reduce and normalize thyroid function. However, in some cases, treatment of hyperthyroidism can result in permanent hypothyroidism.

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Thyroid lumps need investigations to rule out cancer.

Sunset in Saint Martin, Caribbean. (Dr. Noorali Bharwani)
Sunset in Saint Martin, Caribbean. (Dr. Noorali Bharwani)

Thyroid is a small gland located at the base of the neck, just above the breastbone. Thyroid nodules are solid or fluid-filled lumps that form within the thyroid gland. Most of them are benign. Thyroid cancer accounts for only a small percentage of thyroid nodules.

Small thyroid lumps are not visible to the naked eye. Some nodules are big enough to be seen. Sometimes your doctor will feel the lump when he examines your neck.

A solitary nodule, within an otherwise apparently normal gland, is of more concern than a thyroid gland with multiple nodules (multi-nodular goiter). Multi-nodular goiters are usually benign.

Thyroid nodules are more common in women. Single nodule is four times more common in women than men.

About 45 to 75 per cent of nodules are simple cysts (colloid nodules); 15 to 40 percent are benign tumours (adenomas); and only eight to 20 per cent are cancerous.

A patient with a history of radiation treatment to the neck, or any radiation exposure near the thyroid gland, has increased risk of developing nodules. These nodules tend to develop long after the radiation exposure. Family history of thyroid cancer increases the likelihood of a thyroid nodule being malignant.

How do we investigate a solitary thyroid nodule?

The most recent guideline from the American Thyroid Association recommends measurement of thyroid stimulating hormone (TSH) level in the blood and ultrasound of the neck in all patients with a thyroid nodule, says an article in the Canadian Medical Association Journal (CMAJ December 6, 2016).

Ultrasound is a good test for thyroid lumps. It can tell us if there is more than one nodule, if the lump is solid, cystic or mixed; and it is the best method to determine the size of the nodule.

Blood test is also useful. A low TSH level (< 0.3 mU/L) suggests an autonomously functioning nodule, and a thyroid scan with iodine-123 should be performed.

Although nodules are present in 20 to 70 per cent of individuals, most do not require biopsy.

If the nodule is hyper-functioning then it requires medical treatment. Surgery is rarely indicated.

If the TSH level is normal or high (> 5 mU/L), then fine-needle aspiration (FNA) biopsy should be considered. All thyroid nodules do not need a needle biopsy. Only non-cystic nodules greater than one to two cm need to be biopsied. FNA biopsy is recommended for nodules with features on ultrasound that indicate higher risk of malignant disease.

If the needle biopsy is negative for cancer in the first instance then the new guidelines recommend a repeat needle biopsy after three months. Repeat needle biopsy yields a more definitive diagnosis in up to 90 per cent of cases based on high-quality studies, says the CMAJ article.

After two benign needle biopsy results, ultrasound surveillance is no longer indicated. However, if the lump gets bigger or causes symptoms then there is an indication for surgical treatment.

So, a solitary thyroid nodule is not always malignant. But it should not be ignored. Appropriate investigations should be done to rule out cancer.

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Making Sense of Celiac Disease and Non-Celiac Gluten Allergy is Not Easy

Gordon Wright waiting for birds to fly by so he can take pictures in Police Point Park on a beautiful spring afternoon in Medicine Hat. (Dr. Noorali Bharwani)
Gordon Wright waiting for birds to fly by so he can take pictures in Police Point Park on a beautiful spring afternoon in Medicine Hat. (Dr. Noorali Bharwani)

“Celiac disease is common and is associated with other immune diseases,” says an article in the Canadian Medical Association Journal (CMAJ January 8, 2013).

The symptoms of celiac disease are triggered by gluten (a protein found in wheat, rye, barley and triticale) in people who are genetically susceptible. Triticale is a hybrid of wheat and rye first bred in laboratories during the late 19th century.

Ten things to remember about celiac disease as summarized from the CMAJ article:

  1. A first-degree relative with celiac disease has a 10-fold increased risk of acquiring the condition. It affects one in 133 North Americans.
  2. The risk is increased among people with autoimmune thyroid disease (three to five per cent), type one diabetes mellitus (five to 10 per cent) and Down syndrome (5.5 per cent).
  3. Gluten perpetuates the destruction of villi in the small intestine. Intestinal villi are small, finger-like projections that help in digestion.
  4. The disease can develop at any age.
  5. Clinical symptoms can be diverse from abdominal pain to diarrhea, weight loss and malnutrition.
  6. Screening for celiac disease is recommended for people who have associated symptoms, an associated condition or a family history of celiac disease.
  7. The most widely available test is the tissue transglutaminase IgA antibody test, which has an estimated 95 per cent accuracy rate. If antibody testing is negative and celiac disease is suspected, the IgA level should be measured.
  8. All adults with an abnormal screening result should undergo a small-bowel biopsy to confirm the diagnosis of celiac disease.
  9. Because of an increasing awareness of celiac disease, people may choose to adopt a gluten-free diet before diagnostic testing. That is not the right way to manage the problem. Further diagnostic testing should be performed following a medically supervised gluten challenge of at least four weeks, with sufficient gluten to produce symptoms.
  10. Treatment is lifelong adherence to a gluten-free diet. Examples of gluten-free grains are oats, buckwheat, millet, rice and quinoa. Gluten-free diet reduces the risk of complications such as osteoporosis and intestinal lymphoma.

Is there an illness called non-celiac gluten sensitivity?

Yes. You have symptoms of celiac disease but it cannot be confirmed. Then you may have non-celiac gluten sensitivity.

An article by Sapone et al. (BMC Medicine 2012) titled, “Spectrum of gluten-related disorders: consensus on new nomenclature and classification,” says in only 10 years, key milestones have moved celiac disease from obscurity into the popular spotlight worldwide.

What has generated more interest is the spectrum of illnesses associated with ingestion of gluten. These are: 1. Allergy to wheat 2. Autoimmune celiac disease, dermatitis herpetiformis and gluten ataxia 3. Possible immune-mediated gluten sensitivity.

Research estimates that 18 million Americans have non-celiac gluten sensitivity. That’s six times the amount of Americans who have celiac disease. Researchers are just beginning to explore non-celiac gluten sensitivity.

These individuals seem to be sensitive to gluten often also experience headaches, rashes and fatigue. It is possible that it may in fact be other proteins or sugar in wheat (other than gluten) that may be triggering the reaction. There is no inflammation or damage to the intestinal lining as in celiac disease. More research is needed to understand this problem. Did I hear you say, “If only things in life would be simple and straight forward?”

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