The broad differential diagnosis associated with progressive subacute encephalopathy can be intimidating, especially in a young, pregnant woman. In this case, a 24-year-old woman at 21 weeks of gestation presented with persistent, drug-resistant fronto-parietal headache, with subsequent progressive development of psychomotor lentification and inappropriate behavior. Physical examination was normal, as were routine laboratory parameters and CT findings, and these symptoms were initially interpreted in the context of chronic depression. Later, the patient developed generalized dystonia and fever, with rapid clinical deterioration, depression of consciousness and, eventually, progression to coma. This case emphasizes the complexity and challenges involved in the diagnostic approach to a patient with progressive subacute encephalopathy framed by worsening CNS symptoms. It highlights the clinical considerations and complementary investigation of various etiologies, in a step-by-step approach, ultimately leading to the final diagnosis. Early recognition and appropriate treatment of these conditions can lead to more favorable outcomes, particularly in gestating patients, where prompt intervention is crucial, and where critical decisions may have to be made regarding pregnancy and the safety of treatment options.

与进行性亚急性脑病相关的广泛鉴别诊断可能令人生畏，尤其是对于年轻的孕妇。在该病例中，一名 24 岁女性在妊娠 21 周时出现持续性、耐药性额顶头痛，随后逐渐出现精神运动性迟钝和不当行为。体格检查、常规实验室参数和 CT 检查结果均正常，这些症状最初被解释为慢性抑郁症。后来，患者出现全身肌张力障碍和发烧，临床迅速恶化，意识下降，最终进展为昏迷。该病例强调了对伴有中枢神经系统症状恶化的进行性亚急性脑病患者的诊断方法的复杂性和挑战。它强调了临床考虑和各种病因的补充研究，以逐步的方式，最终得出最终诊断。早期识别和适当治疗这些病症可以带来更有利的结果，特别是对于妊娠患者，及时干预至关重要，并且可能必须就妊娠和治疗选择的安全性做出关键决定。