Background
It is estimated that 30 to 40% of all strokes have no identifiable cause; these are classified as cryptogenic strokes. Often, the unknown nature is secondary to delayed or incomplete investigation of cerebrovascular pathology. At times, strokes are considered truly cryptogenic as extensive stroke workup leads to no identifiable cause or etiology. Acute ischemic strokes in young adults without identifiable risk factors present a diagnostic and therapeutic challenge. Prompt recognition and treatment are critical to optimize outcomes.
Case Presentation
A 32-year-old African American male with a past medical history of a cerebrovascular accident in 2023 at an outside hospital with no residual symptoms presented to the emergency department with a one-day history of left-sided facial droop, dysarthria, and left upper and lower extremity weakness. Initial CT of the brain without contrast showed an area of hypoattenuation in the right temporal lobe without any space-occupying lesion. CT of the neck showed a partially occlusive thrombus in the distal right MCA M1 segment extending into the superior division of the M2 segment with decreased flow in the distal M2 and M3 branches.
As the patient’s initial presentation was within the treatment window for TNK, the patient received TNK. A comprehensive stroke workup, including cardiac monitoring, echocardiography, hypercoagulability panel, vascular imaging, and drug screening, revealed no identifiable etiology or conventional risk factors.
Further imaging with MRI of the head/brain without contrast showed acute small‑volume infarcts in the right insular cortex and posterior frontal lobe, with smaller foci of restricted diffusion involving the right superior and posterior temporal lobe and the left superior cerebellum, without any acute hemorrhage. Bilateral venous Doppler ultrasound did not show any identifiable DVTs.
Lessons Learned / Conclusion
This case underscores the importance of maintaining a high index of suspicion for ischemic stroke in young adults even in the absence of traditional risk factors. It also highlights the need for further investigation into potential underlying mechanisms of cryptogenic stroke in this population.