Acute thyroiditis

This code represents an acute inflammatory condition of the thyroid gland, often characterized by sudden onset of pain, tenderness, and swelling in the neck. It can be caused by viral, bacterial, or fungal infections, leading to transient hyperthyroidism followed by hypothyroidism.

Use this code when documentation clearly indicates a diagnosis of acute thyroiditis, such as subacute granulomatous thyroiditis (de Quervain's thyroiditis) or suppurative thyroiditis. Supporting documentation would include clinical findings like neck pain, fever, elevated inflammatory markers, and thyroid function test abnormalities consistent with an acute inflammatory process.

• Differentiate from chronic thyroiditis (e.g., Hashimoto's) which has a different ICD-9-CM code.
• Specify the underlying cause (e.g., viral, bacterial) if known and documented, using an additional code.
• Ensure the "acute" nature of the condition is explicitly stated or clearly implied in the physician's notes.