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Thyroid problems: hypothyroidism and hyperthyroidism explained

How to tell an underactive thyroid from an overactive one: the symptoms, the tests, the warning signs that need urgent care, and which doctor to see in Bangladesh.

The thyroid is a small gland shaped like a butterfly. It sits at the front of your neck, just in front of the windpipe. It makes hormones (chemical messengers) that help control how your body uses energy. These hormones affect things such as your heart rate and body temperature. If the gland makes too little hormone, or too much, you can feel unwell in many different ways.

This article explains the two main thyroid problems: hypothyroidism (an underactive thyroid) and hyperthyroidism (an overactive thyroid). It also covers when to get help urgently and which kind of doctor to see.

How common are thyroid problems in Bangladesh?

No national survey has measured how many people in Bangladesh have thyroid disease. A nationwide survey of physicians, published in Frontiers in Endocrinology in January 2024, pointed out this gap. Researchers in south-eastern Bangladesh, writing in Health Science Reports, said thyroid disease is widely thought to affect about 10% to 20% of the general population. That is a rough estimate, not an exact count. Thyroid problems are more common in women than in men.

Getting too little iodine can cause health problems that UNICEF calls iodine deficiency disorders. Adding iodine to salt is the main way to prevent them, and Bangladesh has run a salt iodisation campaign for many years. Even so, the National Salt Iodization Survey of 2015 found that only about half of households (50.5%) had adequately iodised salt. A 2023 analysis described this as the most recent national survey.

Hypothyroidism: an underactive thyroid

In hypothyroidism, the thyroid does not make enough hormone. The NHS (the UK’s National Health Service) describes it as a common condition that can be managed with treatment.

Common symptoms

  • Feeling very tired
  • Feeling the cold more than usual
  • Putting on weight
  • Constipation
  • Low mood or depression
  • Dry skin, or dry or thinning hair
  • A hoarse (croaky) voice
  • Muscle aches or joint pain
  • Heavy or irregular periods, or problems getting pregnant

Symptoms usually come on slowly, so you may not notice them for months or even years. They are similar to those of many other conditions. For example, a woman of the right age might think she is starting the menopause. Older people may mainly notice memory problems or depression.

Causes

One cause is Hashimoto’s thyroiditis, an autoimmune condition. In this condition, the body’s immune system attacks the thyroid by mistake and slowly damages it. Thyroid surgery, or radioactive iodine treatment for an overactive thyroid, can also lead to hypothyroidism.

Babies can be born with it

Congenital hypothyroidism means a baby is born with an underactive thyroid. Most affected newborns look completely normal and have no clear signs. If it is not found early, it can cause lasting harm to the brain. When it is found early through newborn screening and treated, most children develop normally or nearly normally. Screening uses a heel-prick blood test. Ask your baby’s doctor whether newborn thyroid screening is available where your baby is born.

Hyperthyroidism: an overactive thyroid

In hyperthyroidism (also called thyrotoxicosis), the thyroid makes too much hormone. The NHS says it is about 10 times more common in women than in men, and it usually starts between the ages of 20 and 40.

Common symptoms

  • Nervousness, anxiety, irritability or mood swings
  • Difficulty sleeping
  • A fast or irregular heartbeat (palpitations)
  • Trembling or shaky hands
  • Weight loss, often even though you are eating more
  • Sweating and finding heat hard to bear
  • Frequent bowel movements or diarrhoea
  • Tiredness and muscle weakness
  • A swelling in the neck, called a goitre (an enlarged thyroid)

Older adults may show different signs, such as losing their appetite or withdrawing from other people. These symptoms are sometimes mistaken for depression or dementia.

Causes

The most common cause is Graves’ disease, another autoimmune condition. Here, the immune system makes antibodies that cause the thyroid to make too much hormone. Graves’ disease can also affect the eyes, causing irritation, double vision or bulging eyes. Lumps in the thyroid (nodules) can sometimes become overactive, mostly in older adults. Inflammation of the thyroid (thyroiditis) can make stored hormone leak into the blood.

Why treatment matters

If an overactive thyroid is not treated, it can cause an irregular heartbeat, which can lead to blood clots, stroke or heart failure. It can also cause thinning bones, problems with periods and fertility, and complications in pregnancy.

How thyroid problems are diagnosed

Many thyroid symptoms are the same as those of other illnesses. The NHS says the only accurate way to find out is a blood test, called a thyroid function test. It measures:

  • TSH (thyroid-stimulating hormone): a hormone made by the pituitary gland that controls the thyroid
  • T4 (thyroxine): a hormone made by the thyroid

Your doctor may also check for thyroid antibodies, or ask for an ultrasound scan or other scan of your neck. What counts as a normal result depends on things like your age and the laboratory. Tell the doctor if you are pregnant or have recently had a baby.

What treatment generally involves

Your doctor will choose treatment based on your test results, the cause, your age and whether you are pregnant or planning a pregnancy.

Underactive thyroid Overactive thyroid
Main approach Daily tablets that replace the missing hormone, usually taken for life Medicines that reduce hormone production, radioactive iodine, or surgery
Symptom relief Treatment can help with symptoms such as tiredness, weight gain and low mood Other medicines may ease a fast heartbeat, shaking and nervousness until the main treatment starts working
Follow-up Check-ups and blood tests so the doctor can adjust treatment Check-ups and blood tests. After surgery or radioactive iodine, many people later need hormone replacement

Taking too much or too little thyroid medicine can cause problems of its own. Talk to your doctor before making any change to your thyroid medicine, and do not take medicine prescribed for someone else.

Pregnancy

An overactive thyroid that is not treated or well controlled can lead to pregnancy complications, such as pre-eclampsia (high blood pressure in pregnancy), premature birth or miscarriage. If you have a thyroid condition and are planning a pregnancy, or think you might be pregnant, see your doctor early.

Warning signs: get urgent care

Two rare thyroid emergencies can be life-threatening. Go to the nearest hospital emergency department straight away if you notice any of the following.

Thyroid storm (a sudden, severe flare of an overactive thyroid)

  • A very fast or pounding heartbeat
  • High fever and heavy sweating
  • Agitation, restlessness or confusion
  • Becoming less alert, or losing consciousness
  • Severe shaking, vomiting or diarrhoea
  • Yellowing of the skin or the whites of the eyes

Myxoedema coma (a dangerous drop in thyroid hormone)

  • Confusion, or becoming unconscious
  • Unusually low body temperature
  • Slow, shallow breathing and a slow heartbeat
  • Swelling of the body

Also get medical help urgently if:

  • You have an overactive thyroid and feel dizzy, become less alert, or have a fast, irregular heartbeat. Go to the emergency department.
  • You are taking medicine for an overactive thyroid and get a fever, chills or a sore throat that won’t go away. These can be signs of a rare but serious side effect. Contact a doctor straight away.
  • You are taking that medicine and your skin or the whites of your eyes turn yellow (jaundice), or you have a rash, itching, easy bruising, dull pain in your belly or loss of appetite. Contact a doctor straight away.
  • A swelling in your neck makes it hard to swallow or breathe.

Which doctor should you see?

  • Medicine specialist or general physician: a good first step if you have symptoms. They can arrange thyroid blood tests.
  • Endocrinologist: a specialist in hormone conditions. They treat thyroid problems, especially Graves’ disease, hard-to-control cases and thyroid disease in pregnancy.
  • Paediatrician or paediatric endocrinologist: for babies and children, including those born with an underactive thyroid.
  • Obstetrician (pregnancy doctor): works alongside the endocrinologist if you are pregnant.
  • ENT (ear, nose and throat) surgeon or endocrine surgeon: for a large goitre, a thyroid lump, or when surgery is advised.
  • Eye specialist (ophthalmologist): if Graves’ disease affects your eyes.

For general health advice from a doctor by phone, you can call the government health call centre, Shasthyo Batayon, on 16263.

Key points

  • An underactive thyroid means the gland makes too little hormone. An overactive thyroid means it makes too much.
  • Symptoms are easy to miss, and a blood test is the only accurate way to confirm a thyroid problem.
  • Both conditions can be treated.
  • Use iodised salt at home, and tell your doctor about any thyroid condition before and during pregnancy.
  • Confusion, a very fast heartbeat, high fever, or becoming less alert or unconscious need emergency care.

Find a doctor

Browse Endocrinology doctors in Bangladesh on ratings.com.bd, with chambers and, where listed, visiting hours and phone numbers.

Sources

This article is general information, not medical advice. It was written by AI from the sources above. It did not pass the automatic check, and an administrator chose to publish it; no doctor or editor has reviewed it. For a diagnosis or treatment, see a registered doctor.

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