SUPERFICIAL SIDEROSIS OF the central nervous system (SSNS) is a rare disease; as of mid-2006 approximately 270 cases of SSNS had been reported.1 SSNS results from hemosiderin deposition in the subpial layers of the brain and spinal cord due to repeated leakage of blood into the cerebrospinal fluid (CSF) caused by various pathologies, including chronic subarachnoid and subpial hemorrhage.2 Clinical presentations are typically sensorineural deafness, cerebellar ataxia, cognitive impairment and myelopathy. SSNS presenting with hallucination and delusion has not been previously reported. We obtained informed consent from the patient to publish this letter and describe such a case.
A 68-year-old man was admitted to the hospital because of auditory and visual hallucinations and persecutory delusions. Twenty years ago, he was diagnosed with chronic subdural hematoma after hitting his head, and he had been cured. Ten years earlier, he had visited a neurologist for gait instability and hearing impairment. Axial T2-weighted magnetic resonance imaging (MRI) scans revealed a rim of hypointensity around the cerebrum, brain stem and cerebellum. CSF analysis showed xanthochromia, an increased number of red blood cells and elevated iron and ferritin levels. The diagnosis of SSNS was made. His first experience of hallucination and delusion occurred at age 65 after moving to another city. After the move, he complained that neighbors were intentionally making loud noises, had bugged their home, changed their TV screen to red color and turned down his air conditioner. As the symptoms escalated in the following 3 years, he caused disturbances in the neighborhood and was taken to the hospital by his wife. On admission he showed auditory hallucinations and persecutory delusions. Physical examination showed tremor in upper limbs, dysarthria, complete hearing loss, and visual impairment. Laboratory tests and electroencephalography showed no significant abnormalities. MRI scans showed abnormal temporal cerebral and cerebellar atrophy in addition to the findings of 10 years ago. Single photon emission computed tomography showed mild low perfusion in the left frontal and the left temporal cerebral cortex and preserved perfusion in the other cerebral cortex, which indicated that the diagnosis of Alzheimer's disease was unlikely. Psychological tests showed mild cognitive impairment with the Mini Mental State Examination 20–23 points (indicating poor calculation and recall). The patient's Beck Depression Inventory II score was 14 and Hamilton Depression Scale score was 9, indicating an absence of severe depression. After admission, risperidone was started and increased to 5 mg/day over 12 days. After 12 days he rarely hallucinated, and gradually stopped talking about delusions. On the 17th day he was discharged. At follow up, 23 days later, he showed neither hallucination nor delusion.
In view of its pathology, SSNS can present with a variety of psychiatric symptoms, as occurred in this case. Iron is the cofactor for tyrosine hydroxylase, the late limiting enzyme in the synthesis of dopamine.3 The excessive iron may cause the overproduction of dopamine and lead to psychotic symptoms. A serotonin dopamine antagonist was effective in alleviating the psychotic symptoms. During differential diagnosis of psychotic patients, SSNS should be considered as a contributing factor, because the psychotic symptoms of SSNS can be sensitive to treatment with antipsychotic drugs, although the physical symptoms are progressive.