Neuropsychiatric manifestations of Fahr's disease pathogenesis and potential for treatment.

Fahr's disease (FD) is a rare neuropsychiatric disease consisting of bilateral basal ganglia calcification with neurological, cognitive, and psychiatric manifestations. We report here a sporadic case of FDs with its neuropsychology.

Fahr's disease (FD) is commonly called as idiopathic basal ganglia calcification and it was found that lateral thalamus, dentate nucleus of cerebellum as well as the frontal cortex also get affected as the disease progresses.[12] FD is a clinically heterogeneous condition and may manifest in the form of a broad range of psychiatric, cognitive impairments, and neurological features.[3] FD needs to be differentiated from Fahr's syndrome, where similar clinical features are produced by underlying preexisting diseases.[3] Sporadic,[1] autosomal dominant[4] and autosomal recessive[5] forms of FD have been reported in the literature. There are just a few reports of this condition from the Indian subcontinent.[67] Here, we report a sporadic case of FD with its neuropsychological findings.

ILLUSTRATIVE CASE

25-year-old bachelor was brought for psychiatric consultation with history of irrelevant talk of 3 months duration.

History

He had been undergoing treatment for epilepsy for 10 years, but apparently was doing well as he passed his 12th standard examination 7 years ago and worked well as a shop assistant. Due to increased frequency of fits since 1 year ago, he stopped going to work: On some days, he would get as many as 3-6 generalized tonic-clonic seizures. Over the previous 3 months, he was noted to be talking irrelevantly, becoming forgetful, and complained that people on the road and television talked about him. There was no history of head trauma. Physical and neurological examination revealed no abnormality.

Extended mental status examination revealed a well groomed, but somewhat perplexed individual. Took the time to respond, talked slowly and persevered. Expressed worry about fits, but felt no concern for other events. Affect was restricted. Thinking was retarded but connected. He was convinced others talked about him in the street and on the T.V (delusions of reference). Heard people talking about him and felt insects crawling on his body (auditory hallucinations and haptic kinesthetic hallucinations). He saw that his penis had become very tiny (hyposchemazia - he was not worried about it though). Attention and concentration was impaired (digit span 6/3, performed serial sevens until three stages only). Recalled remote events fairly well, but memory for events of previous few months was poor and associated with confabulations of embarrassment. New learning was impaired. Interpreted proverbs concretely, but had good fund of information. Had ideomotor apraxia but constructional praxis, ideational praxis and gnosis (somatic, visual, and finger) were intact? Made perseverative errors in calculations, but calculated well. Mini-mental state examination score was 25.

Investigations

Hematological and biochemical parameters were within normal range. Serum calcium was 8.5 mg/dl, electroencephalogram showed bilateral generalized spike and wave, computed tomography (CT) scan brain revealed bilateral calcification of the globus pallidus with mild ventricular dilatation (left >right).

Neuropsychological evaluation (NIMHANS battery, PGI battery for brain damage)

Vigilance 44 percentile, speed of information processing (digit symbol) 12 percentile, word fluency (Controlled Oral Word Association) 5 percentile, verbal working memory (N back) 10 percentile, memory (auditory verbal learning test) delayed recall, recognition and long term percent retention 5, 15, and 5 percentiles, respectively. Performance intelligence 71 and verbal quotient 92.

Treatment follow-up

He was treated with carbamazepine 1000 mg/day and olanzapine 10 mg/day. He became seizure free after a month; delusions and hallucinations also resolved. Though cognitive impairments persisted, the patient found a job as an assistant to a grocer. We lost the patient from follow-up after 6 months.

DISCUSSION

The illustrative case presented with classical features of FD with schizophrenia such as psychosis, seizures, cognitive impairment, and chorea. However, he also manifested ideomotor apraxia, hyposchemazia and formications, which have not been reported in the literature.[3] Cognitive dysfunction in FD has been reported.[7]

In this case, there was neuropsychological evidence of widespread brain damage with features of frontal lobe involvement in impaired sustained attention, divided attention, working memory, word fluency, speed of information processing, and mental flexibility; parietal involvement with ideomotor apraxia, body image disturbance; temporal lobe involvement with impaired recent memory and new learning and finally basal ganglia involvement with chorea, apathy, and psychomotor slowing. This widespread cortical and subcortical involvement stood in marked contrast to the radiological finding of just symmetrical bilateral globus pallidus calcification. Widespread cognitive dysfunction with minimal calcification, but much generalized cerebral hypo function detected by single-photon emission CT and positron emission tomography has been reported by several workers.[78]

More and more FDs may come to light with increased utilization of imaging facilities in psychiatric practice. With the distinct possibility of rational treatments emerging for this condition in the not too distant future, FD merits to be considered seriously.