Diagnosis Challenge:
The Patient With Aches and Changes
After months of fatigue, depression, achy
muscles and an intolerance to cold temperatures,
Michelle* made an appointment to see Cleveland
Clinic endocrinologist Christian Nasr, M.D. For
the entire story, go to the Spring/2006 issue of
Cleveland Clinic Magazine, page 8.
After a careful history and physical
examination, Dr. Nasr determined that Michelle's
stress levels were real but not an explanation
for other symptoms like achy muscles, dry skin
and sensitivity to cold.
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Christian Nasr, M.D. |
Michelle was definitely experiencing the onset
of menopause and body changes as a result of
normal aging, such as slower metabolism
(resulting in weight gain) and irregular
menstrual periods.
Depression was likely a psychological response
to Michelle's condition. Still, this did not explain
many of her other physical symptoms.
Dr. Nasr was concerned about Michelle's
just-above-normal thyroid stimulating hormone (TSH)
level, which was 5.9 milliunits per liter of
blood. At Cleveland Clinic labs, 0.4 to 5.5 is
considered normal. In the absence of symptoms,
and if other thyroid tests are normal, TSH
levels between 5.6 and 10 are considered
subclinical, a level that indicates possible
early-stage disease. A TSH level above 10
indicates a thyroid disorder. TSH is the
barometer of thyroid function; it rises when the
glands are failing.
Individuals with a TSH of 10 would not require
additional screening, but Dr. Nasr could not
diagnose Michelle with hypothyroidism without
conducting another critical lab test: the free
T4 (thyroxine). TSH levels are prone to change
based on proteins in the blood or estrogen
levels, among other causes.
Dr. Nasr knew he would get a more accurate
reading by measuring the two active thyroid
hormones, T3 (triiodothyronine) and T4. When
these hormone levels are low, TSH levels are
high, indicating potential hypothyroidism.
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The thyroid gland weighs less than an ounce, but affects all of the body's systems |
The Diagnosis: Subclinical Hypothyroidism
When Dr. Nasr measured Michelle's free T4 level,
it was 0.9 nanogram/deciliter. Because the
normal level is between 0.8 and 1.8, Michelle's
results were borderline. However, her combined
free T4 and 5.9 TSH levels indicated subclinical
hypothyroidism. Michelle's physical symptoms
supported Dr. Nasr's diagnosis: weight gain,
achy muscles, low tolerance to cold temperatures
and dry skin. Further, Michelle's fatigue and
psychological symptoms - depression - also are
signs of hypothyroidism.
The thyroid gland weighs less than an ounce, but
it affects all of the body's systems, from heart
rate to how quickly you burn calories. When the
thyroid does not release the proper amount
thyroid hormones, it upsets the balance of
chemical reactions in your body. Significant
hypothyroidism can boost blood pressure and
cholesterol levels, which in turn increases a
patient's risk of cardiovascular disease.
Hypothyroidism is linked with increased estrogen
levels, which could explain why women,
particularly those older than 40, are more
likely to have hypothyroidism than men. Age also
is a factor. As a person ages, his or her
likelihood of being diagnosed with a thyroid
disorder increases. Female patients experience
menstrual dysfunction, even losing their period
for months at a time. Because many hypothyroid
patients are aging and their bodies changing, it
is easy to overlook these symptoms as signs of a
possible thyroid problem.
In fact, depending on a person's threshold for
pain and fatigue, a hypothyroidism candidate may
overlook symptoms entirely. Some people can
tolerate achy muscles, dry skin and fatigue;
others can't imagine being tired or sore for too
long. This is why the biochemical tests that Dr.
Nasr conducted are critical to properly
diagnosing hypothyroidism.
Treatment
Because of the low severity of Michelle's
hypothyroidism, Dr. Nasr presented her with a
couple of options. She could choose to take a
thyroid hormone replacement therapy to normalize
her TSH to 1.5 or 2.0, which might lower her
cholesterol and blood pressure and also
alleviate her achiness, fatigue and depression.
Or Michelle could choose not to take medication
and see whether her TSH level naturally dropped.
Because she was borderline "normal" and TSH can
fluctuate, it is possible that her body
chemistry would change over time.
Michelle chose the prescription. Dr. Nasr
started her on a low dose and ordered a
reassessment in four months so he could retest
her TSH and free T4 levels. Some patients who do
not suffer from severe symptoms and are
subclinically hypothyroid choose not to take
medication. Michelle, on the other hand, wanted
to try hormone replacement therapy because her
symptoms were affecting her quality of life.
Even if Michelle would not have chosen hormone
replacement therapy, she still would have needed
to have her TSH measured every six to 12 months
or if her symptoms worsened.
* The patient and history presented in "Diagnosis Challenge" are fictional.
To learn more about thyroid disorders, check out the following book from Cleveland Clinic Press:
Thyroid Disorders
(A Cleveland Clinic Guide)
by Mario Skugor, M.D.
http://www.clevelandclinicpress.org/
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