Thyroid Troubles A Case Study in Negative Feedback Regulatio

Thyroid Troubles: A Case Study in Negative Feedback Regulation

Fill out the chart below. Record whether the hormone levels are expected to be high, low, or either. For antibody/immunoglobulins and goiter, answer yes, no, or possible. (The antibodies and immunoglobulins in question are those specific to the thyroid disorder.) Use the chart below to record whether the hormone levels are expected to be high, low, or either. For antibody/immunoglobulin and goiter, answer yes, no, or possible.

Solution

Answer No. 6.

Hypothyroidism

Hyperthyroidism

TSH levels

High

Low

T3 and T4 levels

Low

High

Antibodies or Immunoglobulins?

No (exception – Antibodies in Hashimoto’s disease)

No (exception – Antibodies in Grave’s disease)

Goiter ?

No (exception – Hashimoto’s disease)

No (exception – Grave’s disease)

Answer No. 5.

Note : Levels of T₃ and T₄ are normal in tumors, i.e. Medullary thyroid cancer and Pheochromocytoma

Primary Hypothyroidism

Grave’s disease

Hashimoto’s disease

TRH secreting tumor

TSH secreting tumor

TRH suppressing tumor

TSH suppressing tumor

TRH LEVELS

High

Low

High

High

Normal to Low

Low

Normal to Low

TSH LEVELS

High

Low

High

High

High

Low

Low

T₃ AND T₄ LEVELS

T3 Normal

T4 Low

High

Low

Normal

Normal

Normal

Normal

Antibodies or Immunoglobulins present ?

No

Yes

Yes

No

No

No

No

GOITER PRESENT ?

No

Yes

Yes

No

No

No

No

Is patient hyper or hypo thyroid

Hypothyroid

Hyper

thyroid

Hypo

throid

Hypo

thyroid

Hypo

thyroid

Hyperthroid

Hyperthroid

	Hypothyroidism	Hyperthyroidism
TSH levels	High	Low
T3 and T4 levels	Low	High
Antibodies or Immunoglobulins?	No (exception – Antibodies in Hashimoto’s disease)	No (exception – Antibodies in Grave’s disease)
Goiter ?	No (exception – Hashimoto’s disease)	No (exception – Grave’s disease)