Why may nasal congestion or rhinorrhea occur in hypothyroidism?

Nasal congestion or rhinorrhea in hypothyroidism can be attributed to turbinate edema, which results from an imbalance in thyroid-stimulating hormone (TSH) levels. In hypothyroidism, the reduced production of thyroid hormones leads to increased levels of TSH, which can act on various tissues in the body, including those in the nasal passages. This stimulation can lead to vasodilation and increased vascular permeability, causing swelling or edema of the nasal turbinates. The resulting edema contributes to nasal congestion and the development of rhinorrhea.

The other options suggest mechanisms that do not directly relate to the known pathophysiology of hypothyroidism. For example, there is no increase in fluid production from the thyroid itself, as thyroid function is impaired in hypothyroidism. Additionally, while hormonal imbalances can affect tissues, the type of damage that would cause nasal symptoms is not established to be direct tissue damage in this context. Lastly, dryness of the nasal passages would not typically be linked to decreased metabolism in a manner that causes nasal congestion or rhinorrhea; instead, it may lead to other symptoms. Thus, the connection between TSH release and turbinate edema provides the most accurate explanation for these symptoms in the context of