When the immune system strikes twice: SLE-associated pulmonary arterial hypertension: a case report.

Background: Pulmonary arterial hypertension (PAH) is a rare but potentially severe manifestation in patients with connective tissue diseases (CTDs) like systemic lupus erythematosus (SLE). While immunosuppressive therapy is not indicated in most PAH subtypes, it plays a pivotal role in SLE-associated PAH due to its immune-mediated pathophysiology. Case summary: This case report describes a 43-year-old woman with SLE who experienced two severe PAH flares, each following discontinuation of maintenance immunosuppression. The first episode was complicated by circulatory shock following β-blocker administration and treated with a combination of corticosteroids and pulmonary vasodilators. The second episode responded well to immunosuppressive therapy alone, without the need to escalate pulmonary vasodilator treatment. Discussion: Both SLE-PAH flares followed discontinuation of maintenance immunosuppressive therapy, underscoring that continuous immunosuppression might reduce flare risk. The clinical course during flares aligns with evidence that SLE-associated PAH benefits from immunosuppression, in contrast to other PAH forms. Finally, the case highlights that negative chronotropic-inotropic agents (e.g. β-blockers) can induce life-threatening haemodynamic shock in patients with PAH.