Introduction

It is estimated that 5 out of 100 Americans aged 12 years and older have hypothyroidism (National Institute of Diabetes and Digestive and Kidney Diseases, 2021). Hypothyroidism is a severe and prevalent endocrine disorder resulting from an underactive thyroid gland, which leads to insufficient production of essential thyroid hormones. These hormones regulate physiological processes such as metabolism, growth, and energy levels. Their deficiency can manifest through a range of symptoms, from subtle changes in energy to severe metabolic disruptions, underscoring the importance and urgency of addressing this disorder.

The global prevalence of hypothyroidism highlights its significance as a public health concern. It is categorized into primary, secondary, and tertiary forms. Primary hypothyroidism, the most common type, can be caused by autoimmune thyroiditis (such as Hashimoto’s thyroiditis), iodine deficiency, or the surgical removal of the thyroid gland. Secondary and tertiary hypothyroidism results from dysfunction in the pituitary or hypothalamus.

This condition can affect individuals of all ages and backgrounds, though it is particularly prominent in women over 40 and the elderly. Symptoms are often subtle and nonspecific, including fatigue, weight gain, cold intolerance, and cognitive impairment, making prompt diagnosis and treatment challenging.

Recent advancements in diagnostic techniques and therapeutic options for hypothyroidism have led to improved accuracy in diagnosis and management. Despite these progressions, challenges are still in refining treatment and addressing the unique needs of individual patients. It is crucial to recognize that untreated hypothyroidism can lead to increased morbidity and mortality (Patil et al., 2024). This article will explore desiccated thyroid extract (DTE) in-depth.

Understanding Hypothyroidism: An Analysis of Causes, Symptoms, Diagnosis, Treatment, and Management

Causes of Hypothyroidism

Adequate knowledge of the numerous factors that can contribute to the development of hypothyroidism is essential for effective management and treatment of the condition. Several elements, including genetic predisposition, autoimmune disorders, iodine deficiency, certain medications, radiation therapy, and aging, can play a role in the onset of hypothyroidism (Cleveland Clinic, 2022). By recognizing and addressing these contributing factors, healthcare professionals can better tailor treatment plans to meet individual patient needs.

Autoimmune Disorders

Hashimoto's thyroiditis is a prevalent autoimmune condition and the leading cause of hypothyroidism. In this disorder, the body's immune system erroneously targets the thyroid gland, leading to persistent inflammation and eventual damage to the thyroid tissue (Cleveland Clinic, 2022). This leads to reduced production of thyroid hormones, causing hypothyroidism. Hashimoto's thyroiditis is more often diagnosed in women and often manifests in middle age, although it can occur at any stage of life.

Iodine Deficiency

Iodine is essential for synthesizing thyroid hormones (National Institutes of Health, 2024). In areas where dietary iodine is insufficient, hypothyroidism can develop. While iodine deficiency was once a significant issue globally, it is now less common in developed countries due to iodine fortification in salt and other foods. However, in developing regions, iodine deficiency is still a concern.

Thyroid Surgery

Thyroidectomy involves partial or complete thyroid gland removal (Johns Hopkins Medicine, 2024). This surgical intervention is performed to address conditions such as thyroid cancer or severe goiter. However, one potential consequence of this procedure is the development of hypothyroidism. In cases where only a part of the thyroid is removed, the remaining tissue may not produce sufficient thyroid hormones, leading to lifelong hormone replacement therapy to support the body's proper functioning.

Radiation Therapy

Individuals who have received radiation therapy for cancers affecting the head and neck region are at risk of developing damage to the thyroid gland as a potential side effect (Roonet et al., 2023). The radiation can disrupt the gland's normal function, leading to a reduction in hormone production and potentially resulting in a condition known as hypothyroidism.

Medications

Certain drugs can interfere with thyroid function. Lithium, commonly used in the treatment of bipolar disorder, is known to affect thyroid hormone levels. Seven medications have been identified that treat other conditions that may have thyroid-disrupting effects, although this is less common. Other drugs include amiodarone, sulfonylureas, thalidomide, nitroprusside, interleukin, perchlorate, and interferon (Rizzo et al., 2017).

Congenital Conditions

Congenital hypothyroidism (CH) can result from thyroid dysgenesis. Thyroid dysgenesis accounts for 80% of cases, including defects like agenesis, ectopia, or gland hypoplasia (Bowden & Goldis, 2023). This congenital hypothyroidism is detected early through newborn screening programs, allowing for prompt treatment to prevent developmental delays.

Postpartum Thyroiditis

This is an inflammation of the thyroid that occurs within one year after childbirth (Moleti et al., 2020). It can cause temporary hyperthyroidism followed by hypothyroidism. While symptoms may resolve in some women, others may develop permanent hypothyroidism.

Symptoms of Hypothyroidism

Hypothyroidism symptoms can be subtle and may develop gradually over time. They can vary widely among individuals, but common symptoms are noted in Table 1.

How Hypothyroidism Affects the Body

Common Complaints and Presentation of Symptoms

Differential Diagnosis

• Heart failure
• Depression
• Dementia
• Chronic fatigue syndrome
• Anemia
• Kidney failure

Diagnosing Hypothyroidism

Diagnosing hypothyroidism involves gathering a comprehensive medical history to identify any symptoms or risk factors that may be present. A physical examination assesses the thyroid gland and looks for any associated physical signs, such as swelling or nodules. Various laboratory tests are conducted, including blood tests to measure thyroid hormone levels and function and potentially more tests such as ultrasound or imaging studies to evaluate further the thyroid gland (Wilson et al., 2021). This combination of approaches allows healthcare providers to make an exact diagnosis of hypothyroidism.

Medical History and Physical Examination

When diagnosing hypothyroidism, as the healthcare provider, you will start by assessing symptoms and reviewing the patient's medical history. Next, you will complete a physical examination, encompassing the palpation of the thyroid gland, in order to assess for any indications of enlargement or nodules. To confirm the diagnosis, you will order blood tests to measure thyroid function, which is essential for deciding whether hypothyroidism is present. The critical tests include:

• Thyroid-Stimulating Hormone (TSH): Elevated levels of TSH typically show an underactive thyroid, as the pituitary gland produces more TSH in response to low thyroid hormone levels.
• Free Thyroxine (Free T4): Low levels of free T4 confirm that the thyroid is not producing adequate hormone levels.
• Free Triiodothyronine (Free T3): Although T3 levels are less commonly used for diagnosis, they can provide more information about thyroid function.

In some cases, added tests may be performed, including thyroid antibodies to confirm autoimmune causes or ultrasound and biopsy to evaluate thyroid nodules or potential malignancies. Compiling a differential diagnosis list is the first key step when diagnosing your patient with hypothyroidism. Your patient may present with subtle symptoms such as weight gain and constipation or more severe symptoms such as mental status changes or pretibial myxedema. 

Treatment and Management of Hypothyroidism

The primary aim of treating hypothyroidism is to restore thyroid hormone levels to normal. This can be achieved through synthetic hormone replacement therapy or natural treatment options such as dietary changes and herbal supplements. It is essential to consider individual patient factors, such as the condition's severity and potential side effects, in deciding the most suitable treatment approach.

Synthetic Treatment Options

Levothyroxine & Liothyronine

The gold standard of primary treatment for hypothyroidism is levothyroxine (Synthroid, Eltroxin), a synthetic form of thyroxine (T4) that raises hormone levels and alleviates symptoms (Mayo Clinic, 2022). Dosage is tailored based on blood tests, and regular monitoring is needed. The medication should be taken with a full glass of water in the morning. Another possibility is liothyronine (Cytomel), a synthetic form of triiodothyronine (T3), used less often and typically reserved for specific cases where T4 conversion is impaired (Johns Hopkins Lupus Center, 2024).

Emerging Natural Treatment Option

Desiccated Thyroid Extract (DTE)

Desiccated thyroid extract (DTE) is derived from pigs' thyroid glands and has T4 and T3 hormones. Its use began in the 1890s and was the standard treatment for hypothyroidism until the mid-1970s (Shomon, 2022). Then, it was replaced by synthetic T4, levothyroxine. It is again emerging as a natural alternative to synthetic thyroid hormones and is marketed under brand names such as Armour Thyroid and Nature-Thyroid. Some patients prefer DTE for its natural origin and the presence of both T3 and T4. For patients who have been on levothyroxine and are looking for the resolution of hypothyroidism symptoms, the combination therapy may prove beneficial. When transitioning patients who have been on a stable dose of levothyroxine (LT4) with normal serum TSH levels to a combination of levothyroxine (LT4) and liothyronine (LT3), the basic principle is to reduce the dose of LT4 and introduce an equivalent dose of LT3 (Bianco, 2024). This approach allows for a smooth transition while supporting thyroid hormone levels within the normal range.

According to Bianco (2024), a reasonable starting point is an LT4:LT3 dose ratio similar to what is found in the human thyroid gland, which ranges between 13:1 and 20:1. For instance, if a patient maintains a normal serum TSH while taking 100 μg of LT4 per day, the LT3 dose is calculated by dividing 100 by 20, resulting in 5 μg. This dose is split into two daily doses, the second ~8 hours after the first or 1–2 hours before dinner. The new dose of LT4 will be 100 μg minus the dose of LT3×3 [100–(5×3) = 85 μg] (round off 88 μg). So, a patient on LT4 100 μg daily can be switched to LT4 88 μg daily plus LT3 2.5 μg twice daily (Bianco, 2024). The usual starting dose is 30 mg of Armour Thyroid with increments of 15 mg every 2 to 3 weeks (Drugs.com, 2024) (Heald et al., 2024). A lower starting dosage, 15 mg/day, is recommended in patients with long-standing myxedema, particularly if cardiovascular impairment is suspected, in which case extreme caution is recommended. Researchers found that the proportion of hypothyroid patients treated with DTE has doubled from 5% to 10% in the last decade (Heald et al., 2024) (Endocrine Society, 2023). Advocates of desiccated thyroid extract argue that its use can more closely mimic the natural hormone balance of the human thyroid, potentially offering benefits over synthetic thyroid hormone preparations that primarily provide T4.

Desiccated thyroid extract is controversial due to concerns about inconsistent hormone levels and potential variability in the formulation (Heald et al., 2020). While some individuals report positive outcomes with this treatment, others may experience fluctuations in thyroid function due to the lack of standardization in desiccated thyroid products. Despite these concerns, it is still a viable choice for certain patients, particularly those who do not achieve optimal results with synthetic hormone therapies, underscoring the need for individualized treatment approaches in managing hypothyroidism. However, it can be more variable in hormone content and may not be suitable for everyone. The FDA has approved Nature Thyroid or Amour Thyroid. However, these medications can increase your patient's risk for cardiac arrhythmia. Also, these formulations are not approved for pregnant individuals because of the T3 or for patients with thyroid cancer because strict TSH levels are needed (Patil et al., 2024).

Patient Experience and Perceptions

After discussing DTE, it’s essential to highlight patients' experiences and perceptions regarding the medication. A qualitative study by Toloza et al. (2020) analyzed patients’ insights from four online forums. The findings revealed that 46% of participants felt motivated to explore DTE due to recommendations from their clinicians. Many reported switching from their previous treatment plan due to a lack of improvement in hypothyroidism-related symptoms (58%) and the occurrence of side effects (22%). Most of these individuals reported DTE as moderately to majorly effective over previous treatment plans related to improving symptoms and overall well-being. Some individuals experienced unwanted symptoms related to DTE, including challenges in achieving the optimal dosage. Reported side effects included insomnia, tremors, rashes, and hair loss. Additionally, some participants noted abnormalities in blood tests, which they attributed to incorrect dosing. Others reported issues such as hyperthyroidism and elevated blood glucose levels (Toloza et al., 2020).

DTE Concerns

According to Jonklaas et al. (2014), there are clinical concerns associated with desiccated thyroid preparations, specifically about the T3 component. The ratio of T4 to T3 in these preparations is 4.2:1, significantly lower than the 14:1 ratio found in the secretion by the human thyroid gland (Hannoush & Weiss, 2016). In addition, due to the shorter half-life of T3, fluctuations of T3 occur over the course of the day, with peak levels shortly after dosing, leading to a concern for thyrotoxicosis if thyroid extract therapy is not adjusted according to the serum TSH (Jonklaas et al., 2014) (Hannoush & Weiss, 2016). A systematic review conducted by Riis et al. (2024) revealed that most studies on DTE lack long-term data and side effects. They concluded that two randomized clinical trials did not reflect a difference in quality of life or symptoms while comparing DTE with other thyroid substitutions. “Future trials of DTE in patients with hypothyroidism should be based on adequate study designs, validated measures of quality of life, patients with reduced quality of life, and the assessment of biomarkers reflecting long-term adverse effects” (Riis et al., 2024, para. 1).

Lifestyle and Dietary Considerations

In addition to medical treatments, managing hypothyroidism effectively involves adopting a healthy lifestyle. A diet high in whole foods such as fruits, vegetables, lean proteins, whole grains, healthy fats, dairy, fiber, and Omega-3s can promote overall health and assist in weight management. (Hobbs, 2024). Also, remind your patients to avoid taking their thyroid medication within 4 hours of taking iron or calcium supplements. Physical activity helps combat fatigue, supports weight management, and improves mood. Aim for a mix of aerobic exercises and strength training. Chronic stress can affect thyroid function and overall well-being. Techniques such as yoga, meditation, and deep breathing exercises can help manage stress levels. Keeping regular follow-up appointments, in addition to adherence to prescribed medications, is essential. Educate your patients to inform you of any new symptoms or changes in health, as these may require adjustments to their treatment plan. It is crucial to recognize the signs and symptoms of under-treatment or insufficient treatment, as this can lead to a myxedema coma, which is a life-threatening emergency.

Living with Hypothyroidism

It should be noted that your patients should be referred to an endocrinologist for hyperthyroidism, but hypothyroidism can be treated in primary care. Individuals should be informed that they can usually lead every day and fulfilling lives with the proper treatment. Open and regular communication with your patients to stay on top of prescribed treatments and make any necessary adjustments to their lifestyles is necessary. This includes taking medication as directed, making dietary changes, and incorporating regular exercise into your routine. By following these recommendations, individuals with hypothyroidism can effectively manage their condition and enjoy an improved quality of life. Joining support groups or counseling can offer emotional and practical help for managing chronic conditions such as hypothyroidism.

Conclusion

Hypothyroidism is a manageable condition through prompt diagnosis and proper treatment. Synthetic and natural treatment options are available, presenting specific benefits and considerations. Individuals can implement a comprehensive treatment plan by thoroughly understanding the underlying causes and recognizing the symptoms associated with thyroid issues. This approach enables them to effectively manage their thyroid health and significantly enhance their overall quality of life.