Diagnosis of Primary Hypothyroidism Based on Endocrine Analysis

The endocrine system is a complex network of glands that produce and release hormones into the bloodstream to regulate many functions in the body, including metabolism, growth, and mood. One crucial aspect of this system is the negative feedback mechanism that maintains hormonal balance. For example, the hypothalamus releases thyrotropin-releasing hormone (TRH), which stimulates the pituitary gland to produce thyroid-stimulating hormone (TSH). TSH, in turn, prompts the thyroid gland to secrete thyroid hormones (T3 and T4). Elevated levels of T3 and T4 inhibit the release of TRH and TSH to prevent excessive hormone production.

Consider a scenario in which a patient presents with symptoms of fatigue, weight gain, and cold intolerance. Laboratory tests reveal decreased levels of T3 and T4 but elevated levels of TSH. This pattern suggests a dysfunction in the mechanisms regulating thyroid hormone production. Based on this information, what endocrine-related condition is most likely affecting the patient?