Not Feeling Swell: Superior Vena Cava (SVC) Syndrome Falsely Attributed to COVID-19 Vaccine Reaction

BACKGROUND: The mass immunization campaign against Coronavirus disease 2019 (COVID-19) has resulted in more patients presenting to the emergency department (ED) with concern for a vaccine reaction. CASE REPORT: A 68-year-old man presented to the ED reporting an allergic reaction to the COVID-19 vaccine. He initially noted swelling of his face, neck, and right arm after receiving the first dose of the vaccine. After his second dose of the vaccine, the swelling became more pronounced and prompted him to seek care. On examination, he had fullness of the neck and engorgement of the left external jugular vein, which were exacerbated when the patient raised his arms above his head, consistent with Pemberton's sign. Apart from the swelling of the head and neck, there were no other findings consistent with an allergic reaction. The presence of Pemberton's sign prompted a computed tomography scan of the chest with contrast, which revealed a paratracheal mass measuring 4.5 × 2.0 cm with marked narrowing of the superior vena cava (SVC). The patient was admitted to the hospital for SVC syndrome, and further workup revealed a non-small cell lung cancer. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS? Patients may misattribute their symptoms to a COVID vaccine reaction when they are, in fact, experiencing a more serious underlying disease. This case highlights the importance of a thorough physical examination and maintaining a broad differential diagnosis. In this case, the presence of Pemberton's sign raised suspicion for SVC syndrome, and prompted further workup.