Clinical Problem Solving: A 35-Year-Old Pregnant Woman With Subacute Encephalopathy.

A previously healthy 35-year-old woman in her third trimester of pregnancy presented with 2 weeks of progressive cognitive dysfunction, behavioral changes, and headache. Neurological examination was nonfocal, without evidence of meningeal irritation. Brain MRI showed multifocal punctate diffusion-restricting lesions in the subcortical white matter. The etiology was initially unclear despite extensive testing, Several days later, the patient presented again with worsening symptoms and interval radiographic progression. Ultimately, the constellation of clinical features and diagnostic findings suggested a unifying diagnosis. We discuss her clinical course and highlight the diagnostic reasoning. This case emphasizes the importance of maintaining a broad differential diagnosis and integrating evolving clinical and radiographic features, while balancing pregnancy-specific diagnostic and therapeutic considerations, in the evaluation of subacute encephalopathy.