In simple words: Postinfectious hypothyroidism means your thyroid isn't making enough thyroid hormone because of a past infection. This can cause symptoms like tiredness, weight gain, dry skin, and feeling cold.

Postinfectious hypothyroidism is a form of hypothyroidism resulting from a previous infection.It is characterized by an underactive thyroid gland that does not produce sufficient thyroid hormones (T3 and T4) due to damage caused by the infection. This leads to a variety of symptoms related to the body's slowed metabolic processes.

Example 1: A patient presents with fatigue, weight gain, and constipation following a recent severe respiratory infection. Blood tests reveal low T3 and T4 levels along with elevated TSH, confirming postinfectious hypothyroidism., A patient with a history of Hashimoto's thyroiditis experiences a worsening of hypothyroid symptoms after a bout of influenza. Lab tests confirm a decrease in thyroid hormone production, indicating exacerbation of the existing condition by the infection., A patient develops hypothyroidism several months after recovering from subacute thyroiditis. The postinfectious hypothyroidism is diagnosed based on the timeline of events and abnormal thyroid function tests.

Documentation should include the type of prior infection, the onset and duration of hypothyroid symptoms, physical exam findings, lab results (thyroid hormone levels, TSH), and imaging results (if any). It is essential to establish the causal link between the infection and the development of hypothyroidism.