Differential Diagnosis
- Single most likely diagnosis
- Thyroid Storm: This condition is characterized by an excessive production of thyroid hormones, leading to symptoms such as atrial fibrillation (Afib), which is consistent with the patient's repeated episodes of Afib. The low TSH and high T3 levels also support this diagnosis, as they indicate hyperthyroidism.
- Other Likely diagnoses
- Graves' Disease: This is an autoimmune disorder that leads to hyperthyroidism, which could explain the patient's low TSH and high T3 levels. The normal thyroid ultrasound does not rule out this diagnosis, as the thyroid gland may appear normal in the early stages of the disease.
- Toxic Multinodular Goiter: This condition is characterized by the presence of multiple nodules in the thyroid gland that produce excess thyroid hormones, leading to hyperthyroidism. Although the thyroid ultrasound is normal, it is possible that the nodules are not yet visible or are not causing significant thyroid enlargement.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Thyroid-Associated Cardiac Disease: Hyperthyroidism can lead to cardiac complications, including Afib, which can increase the risk of stroke and other cardiac conditions. It is essential to consider this diagnosis to prevent potential cardiac complications.
- Pheochromocytoma: Although rare, pheochromocytoma can cause episodic hypertension, tachycardia, and arrhythmias, including Afib. This diagnosis is crucial to consider, as it can be life-threatening if left untreated.
- Rare diagnoses
- Struma Ovarii: This is a rare condition where thyroid tissue is present in the ovaries, leading to hyperthyroidism. Although unlikely, it is essential to consider this diagnosis in patients with unexplained hyperthyroidism.
- TSH-Producing Pituitary Adenoma: This is a rare tumor that produces excess TSH, leading to hyperthyroidism. However, the low TSH level in this patient makes this diagnosis less likely.