Superficial siderosis as a rare cause of visual and auditory pseudohallucinations: a case report

BACKGROUND: Superficial siderosis is a rare disease involving hemosiderin deposits on the surface of brain or spinal cord that are thought to cause clinical symptoms, which usually consist of cranial nerve dysfunction, cerebellar ataxia, or myelopathy. Pseudohallucinations have been described as the patient being aware of the nonreality of hallucination-like phenomena. Data on pseudohallucinations of cerebral somatic origin are sparse. We present a case of auditory and visual pseudohallucinations due to superficial siderosis. Siderosis was diagnosed using cerebrospinal fluid analysis and magnetic resonance imaging as part of the clinical routine for newly emerged psychiatric symptoms. CASE PRESENTATION: An 84-year-old white/european female presented to our hospital with no prior history of psychiatric or neurological disease and no history of trauma. She reported seeing things and hearing voices singing to her for some days. She was aware these phenomena were not real (pseudohallucinations). On examination, no relevant abnormalities were detected. Cerebrospinal fluid analysis showed elevated ferritin. Magnetic resonance imaging with susceptibility-weighted sequences revealed diffuse superficial siderosis in several parts of the brain, among other occipital and temporal gyri. The pseudohallucinations resolved with a risperidone regime. The patient was treated with rivaroxaban because of atrial fibrillation. Potentially elevating the risk of further hemorrhage, this therapy was discontinued, and an atrial appendage occlusion device was implanted. CONCLUSION: We report the first case of pseudohallucinations in superficial siderosis. The risk of missing this diagnosis can be reduced by applying a standardized diagnostic pathway for patients presenting with the first episode of psychiatric symptoms. Somatic and potentially treatable causes should not be missed because they might lead to unnecessary treatments, stigmatization, and legal restrictions of self-determination, especially for elderly people.