Secondary Intracranial Hypertension Mimicking Meningitis in an Immunosuppressed Patient With Systemic Lupus Erythematosus.

Intracranial hypertension can mimic acute meningitis, especially in immunosuppressed patients presenting with fever and meningism, often prompting urgent empirical treatment. Distinguishing infectious from non-infectious causes is crucial to avoid unnecessary antimicrobials and delayed diagnosis. We report a 20-year-old woman with systemic lupus erythematosus on rituximab and a recent corticosteroid taper who presented with fever, severe headache, photophobia, and neck stiffness. She was started on empirical antibiotics for suspected meningitis. Lumbar puncture showed a markedly raised opening pressure (43 cm H2O) with otherwise normal cerebrospinal fluid (CSF). Neuroimaging excluded structural lesions and cerebral venous sinus thrombosis, while ophthalmologic examination confirmed papilloedema. Her symptoms improved after a therapeutic lumbar puncture and acetazolamide. This case highlights the value of measuring CSF opening pressure and reconsidering the diagnosis in immunosuppressed patients with meningitic features.