Differential Diagnosis for a 58-year-old Female with Suspected TIA

Single Most Likely Diagnosis

• Migraine with aura: Given the patient's history of "priority eyes" (possibly referring to visual disturbances or migraines with aura), an elevated TSH which could indicate hypothyroidism (a condition sometimes associated with migraine), and negative imaging for vascular causes, migraine with aura is a plausible explanation for her symptoms.

Other Likely Diagnoses

• Hypothyroidism-related symptoms: Elevated TSH suggests hypothyroidism, which can cause a variety of neurological symptoms, including fatigue, depression, and possibly transient neurological symptoms that could be mistaken for a TIA.
• Vasculitis or autoimmune disorders: Conditions like giant cell arteritis or systemic lupus erythematosus can cause transient neurological symptoms and should be considered, especially if there are other systemic symptoms.
• Seizure disorder: Certain types of seizures, particularly complex partial seizures, can present with transient neurological symptoms that might be confused with a TIA.

Do Not Miss Diagnoses

• Cervical artery dissection: Although imaging is negative, it's crucial to consider this diagnosis due to its potential for severe consequences, including stroke. Sometimes, dissections may not be immediately visible on initial imaging.
• Cardiac source embolism with normal echocardiogram: Even with no apparent cardiac dysfunction, sources of embolism like patent foramen ovale or atrial septal defects might not be evident on routine echocardiography and could lead to TIA-like symptoms.
• Venous thromboembolism with paradoxical embolism: Though less common, this should be considered, especially if there's any suggestion of deep vein thrombosis or pulmonary embolism.

Rare Diagnoses

• Mitochondrial disorders: Conditions like MELAS syndrome can present with stroke-like episodes, though they are rare and typically associated with other systemic symptoms.
• CADASIL (Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy): A rare hereditary condition leading to stroke and dementia, usually presenting in mid-adult life.
• Fabry disease: A genetic disorder that can cause stroke, among other symptoms, due to vascular dysfunction.

Each of these diagnoses requires careful consideration of the patient's full clinical picture, including detailed history, physical examination, and potentially additional diagnostic tests to confirm or rule out these conditions.