Page 30 - Summer2009

QHUYHV SDUWO\ EHFDXVH 7 SDVVHV PRUH UHDGLO\ also another endocrine organ, the hypothalamus, in the base of the brain,
through the choroid plexus (the “blood-brain immediately above the pituitary gland, which can either stimulate or sup-
EDUULHU´ LQWR WKH FHUHEURVSLQDO ÀXLG %XW PRVW press the function of the pituitary gland in relation to thyroid function by
T3 is present in the blood stream. The level of the increased or decreased action of its thyrotropin-releasing hormone
free or unbound T3—meaning unbound to serum (TRH).
proteins—by the accurate tracer-dialysis-method When all these types of hypothyroidism (thyroid underactivity) are
blood test, corresponds well to its function inside taken into account (see sidebar below), my estimation is that 20 percent
the tissues and cells of the body and brain. of the adult U.S. population suffers from some degree of hypothyroidism.
2
When the thyroid gland does not produce This prevalence increases after middle age and into old age.
HQRXJK WK\URLG KRUPRQHV PRVWO\ 7 DQG VRPH In practice, any combination of two or more of these types of hypo-
T3), a feedback mechanism in the pituitary gland thyroidism can occur simultaneously, confusing the diagnosis and the
(situated in a bony cage at the base of the skull) SHUFHSWLRQ RI WKH GHJUHH RI K\SRWK\URLGLVP VLJQL¿FDQWO\ 7KHUH GRHV
comes into play. This causes the pituitary gland not need to be a known pathology in any of these glands or body tissues
to secrete increasing amounts of thyroid stimu- for the function of that gland or hormone to be compromised and leave
lating hormone (TSH or thyrotropin), which, as the patient with the “bottom line” of low thyroid hormone function, as
its name implies, stimulates the thyroid gland indicated by a low serum free-T3 level (especially when measured by the
WR SURGXFH PRUH 7 DQG 7 KRUPRQHV 7KHUH LV tracer-dialysis method, the only consistently accurate method). Much too

THE TYPES OF HYPOTHYROIDISM 7

PRIMARY HYPOTHYROIDISM: This occurs when the primary problem is in the thyroid gland itself, which does not produce
sufficient T4 and T3 to drive the metabolism of the cells of the body and brain. The feedback mechanism with the pituitary
gland then kicks in—if the pituitary and hypothalamus are functioning properly—causing increased secretion into the
blood stream of TSH, with blood level rising above its normal range. This mechanism may be sufficient, at least at first, to
keep the levels of T4 and T3 in the blood high enough, at least by day, to be in their normal ranges. At night, when all func-
tions diminish, including pituitary function, T4 and/ or T3 levels may drop below their normal ranges and all the metabolic
functions that depend on the thyroid hormones may not occur adequately at night. The most common cause of primary
hypothyroidism is autoimmune (Hashimoto’s) thyroiditis, an autoimmune disease in which the immune system attacks the
thyroid tissue, usually causing it to become underactive. Occasionally the opposite occurs and overactive thyroid function,
hyperthyroidism, or Graves’ disease is the result.

SECONDARY (OR PITUITARY) HYPOTHYROIDISM: This occurs when there is no problem within the thyroid gland itself
but the pituitary gland, from which the thyroid gland expects a normal amount of TSH in order to produce a normal amount
of T4 and T3 hormones, does not secrete adequate amounts of TSH. In this scenario, the free T4 and T3 serum levels will
be below normal and the TSH level will be below or at the low end of its normal range. The thyrotropin-releasing hormone
(TRH) level, if tested, would show an increase but is ineffective in raising the TSH level from the malfunctioning pituitary
gland.

TERTIARY, CENTRAL OR HYPOTHALAMIC HYPOTHYROIDISM: This occurs when there is no malfunction within the
thyroid or pituitary glands but there is inadequate secretion of TRH by the hypothalamus to keep the pituitary gland se-
creting enough TSH to produce enough T4 and T3 from the thyroid gland. This can occur in depression. T4, T3, TSH and
TRH levels would all be low, and the thyroid functional level would be determined by the free T3 level (preferably by the
dialysis method).

NON-THYROIDAL-ILLNESS (NTI) HYPOTHYROIDISM: This occurs when there is no problem in the thyroid, pituitary or
hypothalamic glands but another illness in the body that interferes with the peripheral or tissue conversion of T4 into T3.
T4, TSH and TRH levels are all normal but the serum free-T3 level, depicting the only active thyroid hormone level, is low.
In an acute cardiac or pulmonary or other life-threatening condition, it may be temporarily advantageous for the body’s
metabolism to be slowed by a low circulating level of free T3, so T3 treatment may not be indicated at that point. But,
when chronic, non-life-threatening conditions, like chronic fatigue syndrome, chronic liver and other diseases, cause a low
free T3 serum level, there is no advantage to the body and brain’s metabolism being slowed and T3—or combination T4/
T3 treatment—is usually not only beneficial but even essential in restoring normal energy and function to that person’s
body and brain tissues. 8
28 Wise Traditions SUMMER 2009