Two Cases of Right-Sided Pleural Effusion as the Initial Manifestation of Severe Ovarian Hyperstimulation Syndrome.

Introduction: Severe ovarian hyperstimulation syndrome (OHSS) occurs less frequently due to increased knowledge of potential risk factors and implementation of preventive strategies. Right-sided pleural effusion as a presentation of severe OHSS is rare, and the symptoms can be nonspecific, which may delay diagnosis. However, early recognition is essential, as the condition can deteriorate rapidly and patients often need hospitalisation and supportive treatment. Case Presentation: We describe two patients with right-sided pleural effusion as the initial manifestation of severe OHSS following controlled ovarian stimulation for in vitro fertilisation. Both patients reported sharp chest pain and progressive dyspnoea when the pleural effusion was diagnosed. They developed symptoms 5 and 13 days after oocyte pick-up (OPU) and were admitted to hospital 4 and 3 days after the onset of symptoms, respectively. The first patient required two paracenteses and one thoracentesis, and the second one thoracentesis. Supportive treatment during hospitalisation consisted of intravenous fluids, supplemental oxygen, electrolyte correction and thromboprophylaxis. The durations of hospitalisation were 12 and 2 days, respectively, and both patients recovered within 3 weeks after discharge. Conclusion: Right-sided pleural effusion may be the initial manifestation of severe OHSS. Although the exact pathogenesis remains unclear, several hypotheses have been proposed. We review the available evidence regarding its pathogenesis and therapeutic options, and highlight the importance of early recognition.