It is a fact that incidence of goitre and brain damage in the newborns and infants will increase if iodine intake in the food in the common population is not made compulsory.

On the other hand, if the modern population, as in many advanced countries, starts increasing its iodine intake, it might lead to an increase in the incidence of hypothyroidism.

So far, this has not been proved. Recently the “Lancet” journal has described a ‘Global Epidemic of Hypothyroidism’ in one of its latest issues.

I am a Physician doing private practice since last 45 years. Earlier, I used to see one case of hypothyroidism every 8-10 days, but at present I see 5 patients or more. This figure is based on blood TSH levels and not on clinical features of hypothyroidism.
Initially, I thought that this was due to the fact that in the past we did not have enough tests to pick up hypothyroidism. Earlier, even in patients presenting with myxoedema, BMR and blood iodine levels were the only tests available to confirm thyroid deficiency. With the advent of radio immunoassay and proliferation of nuclear medicine centres, the facility to test blood for T3, T4, TSH has become commonly available, even in the smallest suburbs. This has made the diagnosis very easy. Even this will not explain the tremendous rise in the incidence of hypothyoidism.

During initial years of my practice when these blood tests were available I only asked for them in cases, where I suspected hypothyroidism clinically. Then came the days of health check-up and automated machine readings! Along with that came a change in the psychology of the patients and possibly their paying capacity. More and more blood tests became a fashion of the day. It is then that I realized that there were a number of patients having blood tests compatible with hypothyroidism, but showing absolutely no symptoms or signs of this illness. In fact, I often wondered whether these patients should be put on thyroxine tablets. Later on, I decided to make it a rule to repeat TSH blood levels every 6 months till TSH levels rose to 20-30 units, when I would start the treatment.

As years passed by, there came another phase in my private practice, when patients hopped into my chamber for an undiagnosed illness after having visited 2 to 3 consultants. I would then look out for some rare causes, which may have been missed by the previous specialists.

In a patient having polyarthralgia, where no cause was found, when I asked for blood TSH levels and found them to be high, I diagnosed hypothyroidism as the cause, especially, when the patient’s symptoms definitely subsided after a small dose of thyroxine. In a condition like peripheral neuropathy, when world literature mentions that in 1/3 of the cases, no cause can be found, I started asking for routine blood TSH levels to see if I could pick up a rare cause. I was rewarded occasionally, though not very frequently. In an anaemic patient, where no cause was found and the patient was not responding to treatment, I picked up hypothyroidism by asking for blood TSH levels. The patient’s response to treatment was excellent. In every patient complaining of muscular cramps in the middle of the night (a condition where no cause can be found in 99% of the cases), I would ask for routine blood TSH levels. If TSH level was elevated, I administered thyroxine, which relieved them of cramps. I would be happy to label them as patients having hypothyroidism as a cause of cramps. Similarly, I picked up patients having hypothyroidism, while managing a few cases of carpal tunnel syndrome. In the last few years, I have also diagnosed hypothyroidism occasionally in the following cases by asking for the blood test for TSH in patients of complaining of:

• an increase in weight (hypothyroidism - very often misdiagnosed by doctors as the cause of obesity)
• mental dullness
• dry skin
• hoarse voice (which even ENT specialists have failed to relieve) or amateur singers unable to sing as before
• asthenia
• menstrual disorders
• increasing constipation - of “recent” origin
• young non-alcoholic and non-diabetics having hyperlipidaemia
• enlarged hearts of unexplained aetiology
• pleural effusion
• ascites of unexplained origin

Finally, can the increased incidence of hypothyroidism be attributed to the iatrogenic causes? This may be because in the past, we never used radio-iodine therapy in thyrotoxicosis or never used amiodarone in cardiac patients for a very long time!

My conclusion is that all the above developments cannot explain the significant rise of hypothyroidism in our modern population, which may be a true rise, a point, which is to be noted by all private practitioners. This also should be noted by all institutions that conduct routine health check ups, since most health check ups include many useless tests like blood uric acid, which may now be replaced by a blood test like TSH.