Differentiation Between Clinical and Subclinical Hypothyroidism in Pathophysiology, Symptoms, Diagnosis and Treatment – A Narrative Review
Subclinical hypothyroidism is characterized by elevated thyroid-stimulating hormone (TSH) levels with normal serum free thyroxine (fT4) and free triiodothyronine (fT3) concentrations. In contrast, overt primary hypothyroidism occurs when fT4 levels fall below the normal reference range. Diagnosing s...
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College of Medicine, Al-Nahrain University
2024-09-01
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| Series: | Baghdad Journal of Biochemistry and Applied Biological Sciences |
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| Online Access: | https://www.bjbabs.org/index.php/bjbabs/article/view/285 |
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| author | Mustafa Mohammed Albassam Noor Mohammed Obaid Yasser Kadhim Hashem Al-Zwaini |
| author_facet | Mustafa Mohammed Albassam Noor Mohammed Obaid Yasser Kadhim Hashem Al-Zwaini |
| author_sort | Mustafa Mohammed Albassam |
| collection | DOAJ |
| description | Subclinical hypothyroidism is characterized by elevated thyroid-stimulating hormone (TSH) levels with normal serum free thyroxine (fT4) and free triiodothyronine (fT3) concentrations. In contrast, overt primary hypothyroidism occurs when fT4 levels fall below the normal reference range. Diagnosing subclinical hypothyroidism is challenging due to varying upper limits of normal for TSH. This review explores the differentiation between clinical and subclinical hypothyroidism in pathophysiology, symptoms, diagnosis, and treatment.
Overt hypothyroidism lacks a singular identifying symptom, while subclinical hypothyroidism is often asymptomatic. However, both conditions can present with non-specific symptoms such as mild to moderate weight gain, fatigue, impaired concentration, depressive symptoms, and menstrual irregularities. These symptoms alone are insufficient for diagnosis, necessitating thyroid function tests for confirmation.
Levothyroxine (LT4) is the primary treatment for hypothyroidism and is one of the most widely prescribed medications worldwide. LT4 has a slower onset of action and produces prolonged effects compared to endogenous thyroid hormones. It facilitates the conversion of thyroxine (T4) to triiodothyronine (T3) and normalizes TSH levels, replenishing the body's T3 reserves. While LT4 monotherapy is the standard treatment, a combination of LT4 and Liothyronine (LT3) may be considered for hypothyroid patients. However, some evidence suggests that T3 levels may not be fully restored in patients receiving LT4 therapy alone. The choice of treatment should be individualized based on clinical presentation, symptom severity, and laboratory findings. |
| format | Article |
| id | doaj-art-67212871babb4d9a9e43c5b6acbd50d5 |
| institution | OA Journals |
| issn | 2706-9915 |
| language | English |
| publishDate | 2024-09-01 |
| publisher | College of Medicine, Al-Nahrain University |
| record_format | Article |
| series | Baghdad Journal of Biochemistry and Applied Biological Sciences |
| spelling | doaj-art-67212871babb4d9a9e43c5b6acbd50d52025-08-20T02:15:33ZengCollege of Medicine, Al-Nahrain UniversityBaghdad Journal of Biochemistry and Applied Biological Sciences2706-99152024-09-015314416110.47419/bjbabs.v5i03.285Differentiation Between Clinical and Subclinical Hypothyroidism in Pathophysiology, Symptoms, Diagnosis and Treatment – A Narrative ReviewMustafa Mohammed Albassam0https://orcid.org/0000-0003-0338-5615Noor Mohammed Obaid1https://orcid.org/0000-0002-9859-6687Yasser Kadhim Hashem Al-Zwaini2https://orcid.org/0000-0003-0195-0238College of Pharmacy, Al-Esraa University, Baghdad , IraqCollege of Pharmacy, Al-Esraa University, Baghdad , IraqCollege of Pharmacy, Al-Esraa University, Baghdad , IraqSubclinical hypothyroidism is characterized by elevated thyroid-stimulating hormone (TSH) levels with normal serum free thyroxine (fT4) and free triiodothyronine (fT3) concentrations. In contrast, overt primary hypothyroidism occurs when fT4 levels fall below the normal reference range. Diagnosing subclinical hypothyroidism is challenging due to varying upper limits of normal for TSH. This review explores the differentiation between clinical and subclinical hypothyroidism in pathophysiology, symptoms, diagnosis, and treatment. Overt hypothyroidism lacks a singular identifying symptom, while subclinical hypothyroidism is often asymptomatic. However, both conditions can present with non-specific symptoms such as mild to moderate weight gain, fatigue, impaired concentration, depressive symptoms, and menstrual irregularities. These symptoms alone are insufficient for diagnosis, necessitating thyroid function tests for confirmation. Levothyroxine (LT4) is the primary treatment for hypothyroidism and is one of the most widely prescribed medications worldwide. LT4 has a slower onset of action and produces prolonged effects compared to endogenous thyroid hormones. It facilitates the conversion of thyroxine (T4) to triiodothyronine (T3) and normalizes TSH levels, replenishing the body's T3 reserves. While LT4 monotherapy is the standard treatment, a combination of LT4 and Liothyronine (LT3) may be considered for hypothyroid patients. However, some evidence suggests that T3 levels may not be fully restored in patients receiving LT4 therapy alone. The choice of treatment should be individualized based on clinical presentation, symptom severity, and laboratory findings.https://www.bjbabs.org/index.php/bjbabs/article/view/285clinical hypothyroidismlevothyroxineliothyroninesubclinical hypothyroidism |
| spellingShingle | Mustafa Mohammed Albassam Noor Mohammed Obaid Yasser Kadhim Hashem Al-Zwaini Differentiation Between Clinical and Subclinical Hypothyroidism in Pathophysiology, Symptoms, Diagnosis and Treatment – A Narrative Review Baghdad Journal of Biochemistry and Applied Biological Sciences clinical hypothyroidism levothyroxine liothyronine subclinical hypothyroidism |
| title | Differentiation Between Clinical and Subclinical Hypothyroidism in Pathophysiology, Symptoms, Diagnosis and Treatment – A Narrative Review |
| title_full | Differentiation Between Clinical and Subclinical Hypothyroidism in Pathophysiology, Symptoms, Diagnosis and Treatment – A Narrative Review |
| title_fullStr | Differentiation Between Clinical and Subclinical Hypothyroidism in Pathophysiology, Symptoms, Diagnosis and Treatment – A Narrative Review |
| title_full_unstemmed | Differentiation Between Clinical and Subclinical Hypothyroidism in Pathophysiology, Symptoms, Diagnosis and Treatment – A Narrative Review |
| title_short | Differentiation Between Clinical and Subclinical Hypothyroidism in Pathophysiology, Symptoms, Diagnosis and Treatment – A Narrative Review |
| title_sort | differentiation between clinical and subclinical hypothyroidism in pathophysiology symptoms diagnosis and treatment a narrative review |
| topic | clinical hypothyroidism levothyroxine liothyronine subclinical hypothyroidism |
| url | https://www.bjbabs.org/index.php/bjbabs/article/view/285 |
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