Thoracic Outlet Syndrome due to Intramuscular Hematoma Following Removal of Central Venous Catheter

Dear Editor, Central venous catheterization is routinely performed to manage patients undergoing cardiac surgery. The incidence of mechanical complications after central venous catheterization was around 7.7%, of which 0.4% were major complications.[1] We report a case of scalenus anterior muscle hematoma following removal of a central venous catheter (CVC), which caused thoracic outlet syndrome. A 15-year-old boy, a case of post-intracardiac repair for tetralogy of Fallot, was planned for pulmonary valve replacement. In the operation room, he had an uneventful CVC insertion under ultrasound guidance in the right internal jugular vein (IJV). His postoperative period was uneventful, and the CVC was removed on the 3rd postoperative day. He was started on anticoagulation with tablet warfarin and discharged home on the 7th postoperative day. There was no neurological deficit, and the muscle power grade was 5/5 in all four limbs at the time of removal of CVC and hospital discharge. Four days later, he presented with complaints of pain in the right neck and right upper limb with a muscle power grade of 1/5 in the right upper limb. Ultrasound imaging of the right side of the neck revealed a large circular collection posterior and lateral to the IJV, causing brachial plexus compression [Figure 1a]. Magnetic resonance imaging of the right neck revealed a circular hematoma within the right scalenus anterior muscle measuring 2.5 × 2.7 × 6.8 cm, with a few thin enhancing septae within the collection [Figure 1b]. The hematoma volume was calculated to be around 22 to 24 mL, and it was displacing the IJV superiorly and the C5 to T1 nerve roots of the brachial plexus inferiorly. Under general anesthesia, the organized hematoma within the right scalenus anterior muscle was evacuated. Postoperatively, the patient showed an improvement in right upper limb muscle power.Figure 1: (a) Ultrasound imaging of the right neck and (b) Magnetic resonance imaging of the neck axial plane showing a large intramuscular hematoma compressing the IJV anteromedially and brachial plexus nerve roots postero-medially. CA: Carotid artery; IJV: Internal jugular vein; IMH: Intermuscular hematoma; SAM: Scalene anterior muscle. T: tracheaNerve injury complications following central venous catheterization were Horner’s syndrome, accessory nerve injury, phrenic nerve injury, and direct brachial plexus injury.[2,3] In our case, a large hematoma [Figure 1a] was formed within the anterior scalene muscle, which lies lateral and posterior to the IJV. We believe that during the IJV cannulation, the needle tip pierced the posterior wall and entered the anterior scalene muscle and caused bleeding. The hematoma enlarged after the initiation of anticoagulation and removal of the CVC and caused thoracic outlet syndrome. Since the hematoma was intramuscular, it did not manifest externally as visible swelling or skin discoloration, and it was diagnosed only when the patient presented with thoracic outlet syndrome and was investigated by ultrasound and magnetic resonance imaging. The other differential diagnoses are post-traumatic intramuscular hematoma, spontaneous soft tissue hematoma after anticoagulation, and neck hematoma after central venous catheterization.[1,4,5] Prompt diagnosis and intervention may be critical for improved outcomes. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.