Distal Subclavian Artery Occlusion Causing Multiple Cerebral Infarcts Consequence of Retrograde Flow of a Thrombus?
A 47-year old female presented in our emergency room with a confused mentality, left side weakness, and left forearm pain. She had no relevant medical history; however, upon questioning, she revealed that she had been prescribed medication at another orthopedic clinic for left shoulder pain 2 weeks previously. Swelling and tenderness of the left forearm was noted, and blood pressure was not measurable, and no pulse was detected in the left upper limb. On the right side, blood pressure was 130/80 mmHg with a regular radial pulse of 80 beats per minute. Disorientation with respect to time and place, a slightly lethargic mental status, and left side hemiparesis with hyperreflexia and Babinski's sign were observed during neurologic examination. The routine battery of blood tests, which included electrolyte analysis, complete blood count, thyroid function test, coagulation factors, and erythrocyte sedimentation rate, did not indicate any abnormalities, except a decrease in protein S activity (48%) and an elevated erythrocyte sedimentation rate (51 cm/hr). Brain magnetic resonance imaging (MRI) with angiography showed acute infarctions in the left posterior cerebral artery (PCA) territory, right thalamus, right medial temporal lobe, and right superior cerebellar artery territory of the cerebellum with mild stenosis of the right PCA and the carotid portion of the right internal carotid artery, suggestive of an embolic source proximal to the origins of common carotid and vertebral arteries bilaterally. Normal transesophageal echocardiography and 24-hour holter monitoring were performed in order to exclude possible explanations for cerebral thromboembolism from the heart. Brachial computed tomography (CT) angiography showed occlusion of the left axillary and brachial arteries. Based on suspicion of a cerebral thromboembolism originating from the occluded subclavian artery, intravenous infusion of non-fractionated heparin was administered daily at 1000 units/h with careful monitoring of activated partial thromboplastin.\nOn day 3, the patient complained of aggravated left arm pain; her left hand was found to be cold to the touch and pale in appearance. Emergent thrombectomy was performed, resulting in rapid subsidence of the left arm pain and recovery of the left radial pulse. Pathologic examination of the thrombus revealed that it contained fibrin, blood clots, and arterial tissue, suggesting organizing thrombi. Anti-coagulant therapy with warfarin was continued postoperatively. The patient was discharged with mild left arm weakness and a left side tingling sensation. Repeat testing for protein S activity after 3 months showed a 2-fold decrease in protein S activity (20%), which was also compatible with protein S type I deficiency.