What is Diffuse Toxic Goiter?
Goiter is simply a condition where the thyroid gland in our neck becomes larger than normal. This can happen for many reasons, but the most common cause worldwide is a lack of iodine in our diet. However, in the United States, Graves’ disease and Hashimoto’s disease are the most common causes seen by doctors.
Goiters can be classified in different ways, such as by their shape (whether they are nodular or diffuse), how they affect the thyroid’s function (whether they make the thyroid overactive, underactive or keep it normal), and whether or not they contain cancerous cells. Specifically, when we mention a ‘diffuse toxic goiter’, this means the thyroid gland has uniformly become overactive and is producing too many thyroid hormones. See the attached image to understand what a ‘Toxic Nodular Goiter’ looks like.
What Causes Diffuse Toxic Goiter?
A goiter, which is an enlargement of the thyroid gland, can potentially be caused by several common factors. These include:
– Lack of iodine in the diet
– Autoimmune disorders, where the body’s immune system attacks itself
– Smoking
– Genetic predisposition, meaning it runs in families
– Certain medications, such as lithium, iodides, and interferon-alpha
– Exposure to radiation therapy
– Inflammation and infections
Risk Factors and Frequency for Diffuse Toxic Goiter
Diffuse toxic goiter, most commonly caused by Graves’ disease, is a widespread issue that is the primary reason for hyperthyroidism. It affects 1 in every 200 people both in the United States and around the world.
- Graves’ disease mostly affects people between the ages of 30 and 50.
- However, it can occur in people of any age group.
- The disease is 7 to 10 times more common in females than in males.
- There’s also a noticeable increase in cases among families.
Signs and Symptoms of Diffuse Toxic Goiter
Patients suffering from hyperthyroidism often experience various symptoms that may include:
- Weight loss
- Heat intolerance
- Excessive sweating or thirst
- Tremors
- Nervousness or anxiety
- Fatigue
- Rapid heartbeat
- Shortness of breath
- Frequent need to use the restroom or diarrhea
- Nausea or vomiting
Furthermore, they may notice changes like swelling in the neck or feel as if there is a lump in their throat. They might have difficulty swallowing or feel out of breath while lying down.
Patients with a specific type of hyperthyroidism known as Graves’ disease can also have additional symptoms, such as:
- Eye issues, such as bulging eyes, double vision, swelling around the eyes, or increased tear production. This is called Graves’ orbitopathy and affects around 25% people with Graves’ disease.
- Skin issues that include thickened, discolored skin, often on the shins. This is very rare and only seen in 4% cases.
- Changes in menstrual cycles.
During a physical exam, the doctor might observe the following symptoms:
- Weight loss
- Swelling in the neck, sometimes with noticeable blood flow
- Bulging eyes, eye lid lag, or swelling around the eyes
- Rapid heart rate
- Irregular heartbeat
- High blood pressure in the systolic phase
- Trembling hands
- Overactive reflexes
- Muscle weakness
- Rapid breathing
- Skin that’s warm and damp
- Sweaty hands
- Thickened skin, usually on the lower leg
Testing for Diffuse Toxic Goiter
In order to evaluate toxic diffuse goiter, which is a type of thyroid disorder, doctors often perform a series of tests. These tests typically include checking the levels of T3, T4, and TSH in your blood. These are hormones produced by the thyroid.
The TSH blood test is important because it is the best way to check whether you have too much or too little thyroid hormone. In people with toxic diffuse goiter, TSH levels are usually low or just barely within the normal range, but levels of thyroid hormone in other parts of the body are high.
The methods used to find out the cause of this type of thyroid disorder may vary. It might depend on factors like the population’s traits, economic factors, or cultural backgrounds. Some options include a test that checks how much iodine the thyroid takes up from the bloodstream, using an ultrasound to look at the thyroid together with a test for certain antibodies, or a combination of these methods.
p>If the thyroid takes up a lot of iodine and is enlarged, and the antibodies test is positive, it usually signifies Graves’ disease. This disease is a common cause of toxic diffuse goiter.
Treatment Options for Diffuse Toxic Goiter
Diffuse toxic goiter, also known as Graves’ disease, has multiple treatment options.
The first option is the use of antithyroid drugs like propylthiouracil, methimazole, and carbimazole. Medical groups generally recommend methimazole as the first choice of medication for Graves’ disease, except for patients who can’t tolerate the drug or for women in their first trimester of pregnancy. Methimazole is favored because it’s more effective and easier to use, due to its longer activity period and once-a-day dosing format.
Doctors can administer antithyroid drugs in two ways. One method is a gradual approach in which the doctor lowers the dosage until the patient’s thyroid hormone levels are in a normal range. Alternatively, doctors can use a “block and replace” method in which they prescribe a high dose of antithyroid drugs and then add in thyroid hormone medication to maintain normal hormone levels. However, a major downside to antithyroid drug treatment is the risk of the disease coming back, especially in the first year after treatment ends. Serious, but rare, side effects of antithyroid drugs are a reduced white blood cell count, liver damage, and inflammation of the blood vessels.
The second option is radioactive iodine therapy, a popular treatment for Graves’ disease in the U.S. due to its safety and effectiveness. Restrictions apply to this therapy, which can’t be used if a patient is pregnant, breastfeeding, or has a severe, unchecked case of Graves’ disease. Radioactive iodine therapy can be given as a liquid or a pill and patients usually stop all medications and diets containing iodine for effective treatment. The potential downside to this therapy is the possibility of becoming hypothyroid or, in rare cases, experiencing a temporary hyperthyroid state or worsening eye disease associated with Graves’ disease. It’s important to note that once radioactive iodine therapy has been used, patients will have to keep up with long-term follow-ups for either the return of Graves’ disease or development of hypothyroidism.
Lastly, thyroidectomy, which is the surgical removal of the thyroid gland, stands as the most effective treatment for diffuse toxic goiter. Complete thyroid removal has been shown to be more successful than partial removal. However, surgery is normally held as the last option due to potential complications like a reaction to general anesthesia, nerve injuries, blood vessel complications, and hypothyroidism following the operation. Surgery is recommended for patients who are unable to handle antithyroid medications or radioactive iodine therapy, or those with a significantly enlarged thyroid gland causing uncomfortable symptoms.
What else can Diffuse Toxic Goiter be?
Diffuse toxic goiter, a condition affecting the thyroid, can be accurately identified through different testing methods as highlighted before. However, it’s possible to confuse it with other conditions that present with similar symptoms. These conditions include:
- Factitious thyrotoxicosis, which happens due to excessive intake or overuse of thyroid hormones
- A short-term or sudden inflammation of the thyroid, known as subacute or acute thyroiditis
- Multinodular goiter, a thyroid condition characterized by multiple growths or nodules
- A type of noncancerous tumor in the pituitary gland that produces too much Thyroid Stimulating Hormone (TSH secreting pituitary adenoma)
- Excessive iodine intake as a result of medication or diet (Iatrogenic iodine supplementation)
These potential misdiagnoses highlight the importance of proper testing and careful consideration of symptoms by healthcare professionals.
What to expect with Diffuse Toxic Goiter
Patients with a severe form of overactive thyroid gland, particularly due to a condition known as Graves’ disease, will likely develop an underactive thyroid over time, regardless of the treatment they receive. Long-term thyrotoxicosis, a condition due to excessive thyroid hormones, can lead to thickening of the heart’s ventricular walls, increasing the risk of heart-related health issues and death.
One form of treatment involves using Radioactive Iodine (RAI), which induces a permanent state of underactive thyroid, making patients reliant on thyroid hormone supplements for the rest of their lives. Antithyroid drugs (ATDs), another treatment option, have a 50% rate of bringing about a remission. Furthermore, after four years of ATD treatment, patients have an excellent prognosis and there’s no risk of the disease returning.
Possible Complications When Diagnosed with Diffuse Toxic Goiter
Hyperthyroidism, otherwise known as thyroid storm, is a condition caused by long-term untreated high levels of the thyroid hormone. Other conditions that could occur include heart rhythm abnormalities and congestive heart failure. Rarely, liver problems such as fibrosis might also occur.
Here’s a list of possible conditions:
- Hyperthyroidism or thyroid storm due to prolonged untreated excess of thyroid hormone
- Heart rhythm abnormalities
- Congestive heart failure
- Rare liver problems including fibrosis
- Dermatopathy, mostly related to Graves disease
- Graves ophthalmopathy (eye disease)
Preventing Diffuse Toxic Goiter
Diffuse toxic goiter is a condition that can cause a variety of symptoms. These can include intolerance to heat, increased sweating, and weight loss, which are all signs of a high metabolic rate. Similarly, symptoms like an increased heart rate, shaky hands, and emotional changes are linked to increased adrenaline levels. Along with these symptoms, people with this condition may also experience swelling of the thyroid gland, or goiter.
In contrast, older patients may not show the typical adrenaline-fueled symptoms. Instead, they might experience lack of interest, irregular heart beats known as atrial fibrillation, which can also be signs of depression, cancer, or heart issues.
