Background Arterial thoracic outlet syndrome (TOS) is extremely difficult to diagnose as the symptoms appear benign until a stroke occurs. Ischemic strokes are rare in adolescents, with a prevalence of 0.54 to 2.4 per 100,000. The burden of stroke on children, however, is tremendous. Among adolescents with stroke, nearly half of them have an unknown etiology. Therefore, a good review of the patients’ symptoms, along with a thorough history, can help with early diagnosis and treatment of arterial TOS, a known critical cause of ischemic strokes in children and adolescents.

Case Presentation We report an atypical case of a 16-year-old female who had an acute ischemic stroke due to arterial TOS. The patient’s mother reported a three-year history of syncopal episodes, headaches, and diminished blood flow to her right hand. The syncopal episodes occurred during activities with arm elevation, such as styling her hair or playing softball. Sports or occupations with repetitive arm elevation are a risk factor for TOS as they lead to increased thoracic outlet compression. Her headaches increased in frequency and severity leading up to the stroke. Her right hand would turn white and cold, and her grip strength decreased. The patient saw a physician a few months before the stroke for her syncopal episodes; her bloodwork came back normal, and she was sent home. A brain Magnetic Resonance Imaging showed diffusion restriction in the pons, basilar artery thrombus, and suspected right cerebellar hemisphere infarct. During an emergency thrombectomy, an incidental right cervical rib was found compressing the subclavian artery. Right upper extremity Doppler ultrasound found axillary, brachial, and radial arteries occlusive thrombi, with retrograde thromboembolism a likely etiology of her infarcts.

Discussion Treatments of arterial TOS include cervical rib resection and anticoagulant therapy. It causes compression of the subclavian artery. This can damage the artery and lead to clot formation, as well as, in this case, retrograde thromboembolism, in which a distal vein thrombosis travels up the artery to the brain, causing a stroke. The most common cause of arterial TOS is the presence of a cervical rib, which is present in 0.5-1% of the population. This case report aims to highlight the clinical symptoms and an important risk factor that should raise suspicion of arterial TOS before a major debilitating event such as a stroke occurs and to raise awareness these symptoms may present in children or adolescents.