Background: Acute hemorrhagic leukoencephalitis (AHL) is a rare immune-mediated disease of the central nervous system (CNS) with an often fatal course and is considered a fulminant variant of acute disseminated encephalomyelitis (ADEM). Neurologic involvement (seizures, aseptic meningitis, leukoencephalopathy or encephalitis) in adult-onset of Still´s disease (AOSD) is uncommon. We present a life-threating case of AOSD with rapid development of unusual CNS involvement.

Case presentation: A 44-year-old female with a history of autoimmune thyroiditis was admitted to the rheumatology and internal medicine department for rapidly progressing disorder of consciousness. Additionally found to have been preceded by 2 months of intermittent fevers, arthralgia and fleeting exanthema. Laboratory tests revealed mild pancytopenia, elevation of CRP (117 mg/L) and high value of serum ferritin (14420 ug/L). Analysing cerebro-spinal fluid (CSF), moderate lymphocytic pleocytosis and a mildly elevated CSF protein (0.92 g/L) were detected. Neuro-infections were excluded. Neurologic examination and magnetic resonance imaging (MRI) of brain led to the diagnosis of AHL (picture of symmetrical involvement of the thalamus and cerebellum with oedema and petechial haemorrhage). At the same time, the patient fulfilled Yamaguchi criteria for AOSD, but the suspicion of macrophage activation syndrome was not confirmed. The treatment with intravenous pulses of methylprednisolone (1000 mg) was promptly started with partial effect on the state of consciousness, therefore interleukin 1 (IL-1) inhibitor anakinra was added to the therapy after 3 days. This combined treatment resulted in expeditious and substantial resolution of neurological symptoms, fever, exanthema and rapid decline in acute phase reactants including ferritin. A subtle expressive aphasia remained the only sign of previous CNS damage. Follow-up brain MRI after 1 month showed significant regression of basal ganglia involvement, however without no complete disappearance of pathological signal. After one year the treatment with anakinra was discontinued at the patient´s request, but within a month, joint pain, headache, visual disturbances, elevation of CRP and ferritin developed. Resuming IL-1 inhibitor, the condition improved very quickly. Currently, the patient is stable and in good condition on anti-IL-1 therapy for two years.

Learning points for clinical practice: The hyper-cytokine status apparently plays a role in both AOSD and AHL which is why combined therapy with high-dose of glucocorticoids and IL-1 inhibitor led to the patient´s survival and almost complete recovery. Early recognition of both rare diseases is difficult but absolutely essential for the patient´s prognosis.

REFERENCES: NIL.

Acknowledgements: NIL.

Disclosure of Interests: Jan Toms AbbVie, Elli Lilly, GSK, Medac, MSD, Novartis, Pierre Fabre, SOBI, Jan Kopriva: None declared, Zuzana Kapicakova: None declared, Tomas Soukup AbbVie, Elli Lilly, GSK, Medac, MSD, Novartis.

© The Authors 2025. This abstract is an open access article published in Annals of Rheumatic Diseases under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ ). Neither EULAR nor the publisher make any representation as to the accuracy of the content. The authors are solely responsible for the content in their abstract including accuracy of the facts, statements, results, conclusion, citing resources etc.