Harlequin Syndrome in a Post-COVID-19 Infection Elderly: A Case Report.

Abstract: Harlequin syndrome (HS) is a rare autonomic nervous system disorder caused by blockage of the unilateral upper-thoracic sympathetic pathway that provides vasomotor and sudomotor supply to the face. Infection and the subsequent immune response cascade are proposed as triggers for arterial occlusion due to microvascular ischemia, underlying the pathophysiology of HS in adult cases. We report this unusual case to inform readers about the possibility of causation and pathophysiological pathway of HS in post-COVID-19 infection. An 82-year-old male patient developing HS post-COVID-19 infection, presented with sudden left-hemifacial redness 4 days before admission, with similar recurrent complaints ten times since his resolved symptomatic COVID-19. Other physical and neurological examinations are regular. Laboratory results showed mild microcytic hypochromic anemia with D-dimer five-folds higher than normal limits. D-dimer fluctuated elevation during HS attacks is a sign of inflammatory process and increased thromboembolic risk in a long-COVID. The patient's history of chronic hypercholesterolemia with old lacunar infarction in the brain's frontal lobes suggested worsening microvascular disturbance. The patient was diagnosed as HS in post-COVID-19. To the author's knowledge, this is the first reported HS case in Indonesia and the second HS case post-COVID-19. Moreover, we also provide a schematic approach to the possible pathological process of HS in post-COVID-19. Post-COVID-19 infection is highly possible causing HS because of its persistent pathological inflammation leading to dysautonomic sympathetic fibers. However, its involvement in a specific pathophysiological pathway that disturbs the cervical sympathetic chain and causes HS, without presenting as systemic dysautonomia, should be further investigated.