Differential Diagnosis for the Patient's Condition
The patient's initial presentation with transient garbled speech and subsequent development of right facial droop and weakness, confirmed as a striatocapsular infarct on MRI, suggests a vascular event. The following differential diagnoses are considered:
- Single most likely diagnosis:
- Recurrence of Transient Ischemic Attack (TIA) leading to a Completed Stroke: The initial episode of transient garbled speech was likely a TIA, which is a warning sign for a future stroke. The patient's decline of antiplatelet therapy and subsequent development of a confirmed stroke suggest a relationship between the initial TIA and the current stroke. The time frame of 3-4 days between the initial TIA and the stroke is plausible, given that TIAs are known to increase the risk of a completed stroke, especially within the first few days.
- Other Likely diagnoses:
- Evolution of an initial stroke that was not detected on CTA: Although the initial CTA did not show an acute stroke, it is possible that the initial event was a small stroke or a stroke in evolution that was not detectable at the time of the initial imaging. The subsequent MRI showing a striatocapsular infarct could represent the progression or completion of the initial stroke.
- New stroke in a different vascular territory: The patient could have had a new, separate stroke in a different vascular territory, unrelated to the initial TIA. However, the temporal relationship and the fact that the patient declined antiplatelet therapy make this less likely.
- Do Not Miss diagnoses:
- Dissection of the carotid or vertebral artery: Although less likely, dissection of the carotid or vertebral artery could lead to stroke and should be considered, especially if there are any suggestive symptoms or signs such as neck pain or Horner's syndrome.
- Cardioembolic stroke: A cardiac source of embolism, such as atrial fibrillation, could lead to stroke. Given the potential for serious consequences if missed, cardioembolic stroke should be considered and ruled out with appropriate investigations like echocardiography.
- Rare diagnoses:
- Vasculitis or vasculopathy: Conditions like vasculitis or vasculopathy (e.g., Moyamoya disease) are rare but could present with stroke-like symptoms. These diagnoses would typically require specific diagnostic tests and would be considered if more common causes are ruled out.
- Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS): This is a rare mitochondrial disorder that can present with stroke-like episodes. It would be an unusual diagnosis to consider in this context but should be kept in mind if other explanations are exhausted and there are suggestive clinical features.