Leland M. Heller, M.D.
Okeechobee Family Practice, P.A.
1713 US Hwy 441 N, Suite E Phone: (863) 467-8771
Okeechobee, FL 34972 Fax (863) 467-2825
HYPOTHYROIDISM (low thyroid)
Proper levels of thyroid hormone are critically
important. The hypothalamus (an area of
the brain) measures blood thyroid levels.
When low, it signals the pituitary gland to
secrete thyroid stimulating hormone (TSH) into
the blood. TSH stimulates the thyroid gland
to produce thyroid hormone. There are two
thyroid hormones: T3 (the most active) and T4
(thyroxine) - which are measured by the blood
test "T7" or "FTI (free thyroxine index)."
The body has to convert the relatively inactive
T4 into the very active T3. The actual
level of T3 can be measured ("free T3").
The symptoms of over and underactive thyroid
conditions are listed on the reverse side of
this Newsletter. Children born without
thyroid hormone develop "cretinism" - a syndrome
of severe growth and mental retardation which is
totally preventable by taking thyroid replacement
medication. Many disorders are associated
with abnormal thyroid function. Stress
reduces the conversion of T4 to the more active
T3 - in effect slowing down the entire body.
Some patients need higher doses of thyroid medicine
during periods of intense stress. Some
medicines can give falsely low thyroid blood test
results - especially Tegretol (carbamazepine).
Many psychiatric disorders and symptoms are related
to thyroid hormones. Both underactive
(hypothyroidism) and overactive (hyperthyroidism)
thyroid hormone blood levels can trigger panic
attacks. In approximately 1/3 of patients with
depression, borderline personality disorder, panic
disorder, bulimia, alcoholism in remission, and
anorexia nervosa the pituitary gland does not properly
increase blood levels of TSH when signaled to do so
by the hypothalamus. This can cause
"hypothyroidism" with a normal TSH and/or low FTI
or T7 blood values. "Normal" is a statistic
referring to the middle 96% of the population - it
does not mean that "normal" is normal or healthy for
you. "Normal" cholesterol by the middle 96%
technique includes cholesterol levels of 300, whereas
the middle statistically is 220, and the goal is less
I do not treat lab tests - I treat people. Treating
thyroid problems is much easier when the lab tests are
typical - the TSH is the most sensitive indicator for
most cases of low thyroid. Some patients suffer
from hypothyroidism with "low normal" blood tests -
especially those whose levels have dropped over the
years. Iíve had patients with a normal T7 and a
very high TSH (a clear case of hypothyroidism), as well
as patients with a normal TSH and an unmeasurably low
T7 (also clearly hypothyroidism). They either
have a malfunctioning pituitary system, difficulty
converting T4 to T3, have one of the psychiatric
disorders listed above, or have nothing wrong.
If thyroid replacement hormones are prescribed, the
blood levels must be very carefully monitored to keep
them in the proper range. Treatment of normal
TSH hypothyroidism (called secondary or tertiary
hypothyroidism) can theoretically increase the risk of
osteoporosis (especially if overtreated) and can
occasionally trigger other problems such as high
blood pressure, irregular heartbeats and palpitations,
strokes, and heart attacks - it is a serious problem
if not treated that can be dangerous if overtreated.
The medicine for hypothyroidism is usually generic
T4 (levothyroxine). Thyroid "extract" (from
chopped up animal thyroid glands) is usually not
reliable, and should generally not be prescribed
for routine hypothyroidism. T3 is more expensive
(Cytomel). Some individuals with mental health
problems, especially those taking Tegretol
(carbamazepine) benefit more thyroid extract or T3.
June 30, 2009