Subclinical Hyperthyroidism: Understanding Low TSH with Normal T3 and T4 Levels

If you’ve been perplexed by low TSH levels but normal T3 and T4 levels, you’re not alone! Let’s unravel this puzzling thyroid scenario and explore how thermography can lend a helping hand.

Thyroid Hormones 101:

First things first, let’s get acquainted with the key players in the world of your thyroid:

  • TSH (Thyroid-Stimulating Hormone): Produced by the pituitary gland, TSH is like the conductor of the thyroid orchestra. It signals the thyroid gland to release T3 and T4 hormones.
  • T3 (Triiodothyronine) and T4 (Thyroxine): These are the thyroid hormones that control our metabolism, energy levels, and body temperature. T4 is the precursor to T3, which is the more active form.

 

Possible Causes of Subclinical Hyperthyroidism:

Sometimes, the TSH levels drop, but the T3 and T4 levels remain within the normal range.  This refers to a mild form of hyperthyroidism.  Subclinical hyperthyroidism can happen due to different reasons – some from inside the body (internal) and some from outside factors (external). Let’s look at what can cause this imbalance between the TSH levels and the levels of the T3 and T4 hormones:

Internal Causes:

  •  Pituitary Dysfunction: In rare cases, the pituitary gland, which produces TSH, may not be functioning correctly, leading to a dissociation between TSH and thyroid hormone levels.
  • Graves’ Disease: An autoimmune disorder that triggers excessive thyroid hormone production.
  • Multinodular Goiter: This is when the thyroid gland enlarges, forming multiple lumps or nodules.
  • Thyroiditis: Inflammation of the thyroid gland, including various disorders.
  • Thyroid Adenoma: A non-cancerous tumor in the thyroid gland.

External Causes:

  • Medications: Certain medications or supplements can influence TSH levels independently of T3 and T4. It’s essential to inform your doctor about any medications you’re taking.
  • Excessive TSH-Suppressive Therapy: Occurs when TSH levels are intentionally reduced as part of medical treatment.
  • Unintentional TSH Suppression: This may happen during hormone therapy for hypothyroidism, lowering TSH levels more than intended.

 

What Are The Symptoms?

Most people who have subclinical hyperthyroidism have no symptoms of an overactive thyroid. If symptoms of subclinical hyperthyroidism are present, they’re mild and nonspecific. These symptoms can include:

  • rapid heartbeat or heart palpitations
  • tremors, typically in your hands or fingers
  • sweating or intolerance to heat
  • nervousness, anxiety, or feeling irritable
  • weight loss (but not always)
  • difficulty concentrating

 

How It’s Diagnosed

  • If your doctor suspects that you have subclinical hyperthyroidism, they will first assess your levels of TSH.  If the blood test confirms that your TSH levels are low, your doctor will then call for further tests to see whether your T4 and T3 levels are within the normal range. In order to perform these tests, your doctor will need to take a sample of blood from your arm.

 

Effects On The Body If Left Untreated

When subclinical hyperthyroidism is left untreated, it can have several negative effects on the body:

  • Increased risk of hyperthyroidism:  People with low or undetectable TSH levels have a higher risk of developing hyperthyroidism. 
  • Decreased bone density: Untreated subclinical hyperthyroidism can lead to a decrease in bone density in postmenopausal women.
  • Dementia:  Research has found that untreated subclinical hyperthyroidism can lead to dementia.
  • Negative effect on heart health:  If left untreated, subclinical hyperthyroidism can lead to:
    • an increased heart rate
    • reduced tolerance to exercise
    • Irregular heartbeat
    • atrial fibrillation

 

The Role of Thermography

Now, you might wonder, “How does thermography come into play?” Thermography is a non-invasive imaging technique that detects heat patterns in the body. Although it doesn’t directly measure thyroid hormones, it can provide valuable insights:

 

  1. Detecting Thyroid Nodules: Thermography can help identify thyroid nodules, which may contribute to abnormal hormone levels and warrant further evaluation.
  2. Monitoring Thyroid Health: Regular thermographic scans can track changes in thyroid vascularity (how many and how clearly you can see the blood vessels, especially the veins that carry blood back to our hearts), and detect any unusual patterns, prompting early intervention if needed.
  3. Comprehensive Health Assessment: Thermography assesses overall neck and thyroid health, walking hand in hand with conventional thyroid testing.

 

In A Nutshell

Subclinical Hyperthyroidism is very sneaky, and although you can experience a number of symptoms, some people don’t experience any symptoms at all. If left untreated, Subclinical Hyperthyroidism can have many negative effects on the body, including bone density changes and a negative effect on heart health.    If you’re facing the conundrum of low TSH and normal T3 and T4 levels, remember that thyroid health is complex, and individual variations exist.  Thermography, as a complementary tool, can aid in early detection and monitoring of thyroid health, enhancing your overall wellness journey.