PO-34 | Febrile headache in an immunosuppressed patient with autoimmune disease: a probable case of neurosarcoidosis

Background: Headache in the context of systemic inflammation and fever represents a diagnostic challenge, especially in patients under immunosuppressive therapy. Neurosarcoidosis, a rare manifestation of systemic sarcoidosis, may present with secondary headache and is included in ICHD-3 classification (7.3.1).   Methods: A 48-year-old woman with axial seronegative spondyloarthritis (on adalimumab since 2021), HLA-B51 positivity, and fibromyalgia presented with progressively worsening pulsating occipital headache radiating retro- and periocularly, associated with fever (up to 38 °C), nausea, and photophobia. Neurological examination was normal except for right facial hypoesthesia (residual from prior cervical surgery). Brain MRI showed no signs of intracranial hypertension.  Chest CT after dyspnea and desaturation revealed bilateral ground-glass opacities and mediastinal lymphadenopathy (up to 60×30 mm). Lab tests showed elevated CRP. The patient developed diffuse arthromyalgia, erythematous papulo-nodular skin lesions (one over a surgical scar), and contrast-induced hyperthyroidism. Extensive infectious workup (blood cultures, TEE, BAL cultures, swabs, urinary antigens, Quantiferon) was negative. Whole-body PET-CT showed hypermetabolic mediastinal nodes. Bronchoscopy with BAL and EBUS-TBNA was performed; BAL cytology revealed non-caseating granulomas, confirming sarcoidosis.   Results: Excluding infectious and neoplastic disorders, a probable diagnosis of neurosarcoidosis was made using established criteria. Oral corticosteroids were initiated, resulting in rapid improvement of systemic and neurological symptoms.   Conclusion: Although rare (5–10% of sarcoidosis), neurosarcoidosis should be considered in immunosuppressed patients with systemic symptoms and new-onset headache. According to ICHD-3 and neurosarcoidosis diagnostic frameworks, both active systemic disease and neurological involvement are required. The presence of non-caseating granulomas in BAL and favorable steroid response support a probable diagnosis. This case highlights the diagnostic value of headache in complex multisystem cases and underscores the importance of a multidisciplinary, criteria-based approach integrating imaging, histopathology, and updated clinical guidelines.