Quand la douleur chronique annonce une démence débutante

Frontotemporal dementia (FTD) is one of the neurodegenerative pathologies that present the most psycho-behavioral disorders. These may even appear before cognitive disorders, but atypical symptomatic expression is not rare, several recent studies tend to demonstrate a correlation between FTD (behavioral), C9ORF72 mutation and abnormal pain behaviors. We report a case of familial FTD that began with a repetitive low back pain complaint with the onset of psychiatric behavioral disorders. In this observation, the clinical and radiological arguments were not suggestive of a FTD. The diagnosis was made through genetic exploration. There is a close link between the mutation C9ORF72 and the localization of chronic pain by localization of neurodegenerative lesions in regions involved in pain control. The comparison of painful behaviors with the mapping of the regions affected by the FTD enriches the understanding of these semiologies; they are complex because grafting episodic memory disorders making difficult to analyze the complaint of the patient.