Hypothyroidism and TFT interpretations

Thyroid hormone plays a crucial role right from conception to old age

The endocrine   system finely  tuned by hypothalamus & its beloved Pituitary gland.

meticulously manages the body ,based on a negative feedback 

Thyroid  function tests are often prescribed by physicians to evaluate high liver enzymes, constipation etc.

it is extremely important to identify hypothyroidism in Pregnancy and in Infancy to prevent mental retardation in the newborn

When should you suspect hypothyroidism?

When you feel cold and others do not .

When you have experienced a puffy face and an increase in your weight.

When you feel fatigue so easily 

In addition your doctor may need to know the reason for your fatty liver , muscle weakness or elevated cholesterol .

It takes years to develop  symptoms.   

If you are diagnosed with hypothyroidism , your doctor will  give you thyroxine replacement. It has to be taken daily and on follow up monitored.

Old patients should take in small , incremental doses to prevent osteoporosis and precipitation of ischemic heart events and follow the doctors advice.

It takes few weeks to start good effects and your doctor may ask you to repeat Thyroid function test after 6-8 weeks

There are no specific diet restrictions . Avoid processed food .You should take goitrogenic containing foods  in moderation like cabbages, broccoli,  spinach, soya been  etc .

How to interpret thyroid function tests:

Step 1 :First choose TSH, 

Step 2: Free T4 or index,

Step 3: Radioactive Iodine uptake (RAIU) 

See the number. Is it low, normal or high?

A) TSH high and FT4 low= PRIMARY HYPOTHYROIDISM

B)TSH low and FT4 LOW = SECONDARY HYPOTHYROIDISM( Pituitary) if TRH low (Hypothalamus)

C)TSH high FT4 normal= SUBCLINICAL HYPOTHYROIDISM

D))TSH high and FT4 HIGH= PITUITARY HYPERTHYROID (TUMOR)

E)TSH low and FT4 normal= SUBCLINICAL THYROTOXICOSIS

F)TSH low FT4 high, diffuse RAIU +TSI & Anti-TSH-receptor Ab. =GRAVE’S DISEASE

G)TSH low and FT4 high, focal RAIU= ADENOMA

H)TSH high and FT4 LOW + Anti-thyroglobulin ab.+ Anti TPO= HASHIMOTO’S THYROIDITIS

I) FT4 NORMAL and low T3 + rT3 high+TBG low= SICK EUTHYROID .

References

Surks MI, Ortiz E, Daniels GH, et al. Subclinical thyroid disease: scientific review and guidelines for diagnosis and management. JAMA. 2004 Jan 14;291(2):228–238.

Have a good day.