Strategy for the Laboratory Evaluation of Patients with Suspected Hypothyroidism - Flowchart
Strategy for the Laboratory Evaluation of Patients with Suspected Hypothyroidism - Flowchart Hypothyroidism Hypothyroidism
«Flowchart»

Symptoms and signs suggesting hypothyroidism

Symptoms and signs suggesting hypothyroidism

Symptoms and signs suggesting hypothyroidism

Central hypothyroidism

Central hypothyroidism

Central hypothyroidism

Primary hypothyroidism

Primary hypothyroidism

Primary hypothyroidism

Serum TSH and free T4 or free T4I

Serum TSH and free T4 or free T4I

Serum TSH and free T4 or free T4I

4 4

TSH increased
Free T4 low or low normal

TSH increased
Free T4 low or low normal


4 TSH increased

TSH normal or low
Free T4 low or low normal
No phenytoin
No salicylates
No recent thyrotoxicosis

TSH normal or low
Free T4 low or low normal
No phenytoin
No salicylates
No recent thyrotoxicosis


4


TSH normal or low

? transient hypothyroidism?
Postviral thyroiditis

? transient hypothyroidism?
Postviral thyroiditis

? transient hypothyroidism?
Postviral thyroiditis


Hashimoto disease

Hashimoto disease

Hashimoto disease

TPO antibody

TPO antibody

TPO antibody

Present

Present

Present

Absent

Absent

Absent

T4

T4

T4

4

End

End

End

T4
~4 mo

T4
~4 mo

T4
~4 mo

4

Normal thyroid

Normal thyroid

Normal thyroid

Permanent hypothyroidism

Permanent hypothyroidism

Permanent hypothyroidism

Reduce T4 by 50% for 6 wk
Check TSH

Reduce T4 by 50% for 6 wk
Check TSH

Reduce T4 by 50% for 6 wk
Check TSH

4

Normal

Normal

Normal

Increased

Increased

Increased

T4

T4

T4

4

Congenital TRH, TSH deficiency infiltrative disease of pituitary, hypothalamus

Congenital TRH, TSH deficiency infiltrative disease of pituitary, hypothalamus

Congenital TRH, TSH deficiency infiltrative disease of pituitary, hypothalamus

Pituitary or hypothalamic lesion

Pituitary or hypothalamic lesion

Pituitary or hypothalamic lesion

MRI

MRI

MRI

Abnormal

Abnormal

Abnormal

Normal

Normal

Normal

Check adrenal, prolactin, gonads

Check adrenal, prolactin, gonads

Check adrenal, prolactin, gonads

Treat with surgery or drugs after correction of adrenal, thyroid, other deficiencies

Treat with surgery or drugs after correction of adrenal, thyroid, other deficiencies

Treat with surgery or drugs after correction of adrenal, thyroid, other deficiencies