Early clinical diagnosis of Behavioral Variant Frontotemporal Dementia: Biol.psych.April.2014.

09.04.2014

Frontotemporal dementia (FTD) is  the second most common neurodegenerative dementia in patients under the age of 65 and the third most common neurodegenerative dementia in all age groups . (The term Picks disease is now  reserved for pathological diagnosis ( with picks bodies)  and FTD is used to refer to the clinical syndrome). FTD has three  subtypes ( behavioral variant frontotemporal dementia (bvFTD) ,semantic variant of primary progressive aphasia (svPPA), and nonfluent variant primary progressive aphasia (nfvPPA) . The behavioural variant of FTD dementia  shares many symptoms with psychiatric disorders and many are mistaken for primary psychiatric disorders and hence high clinical suspicion is required for early diagnosis.

The mean age at presentation for bvFTD is approximately 58 years, ( can be as early as  2nd decade and as late as the 9th decade). Prevalence  is reported between 15-25/100,000 in the age group of 45–64 years.

Clinical presentation:  Initial changes include social disinhibition and impulsivity. Social norms can be infringed. offensive remarks made/ inappropriate behaviours seen.  become insensitive, distant and detached. Patient may have difficulty to recognise and react to others emotions , empathy is affected. May become more irritable and might commit antisocial or criminal acts.  Inability to judge potential for reward or punishment  (atrophy of orbitofrontal cortex) is also seen. Various obsessive-compulsive behaviours (simple repetitive motions, like foot tapping or pacing, to  very repetitive complex actions/ rituals). Hoarding is common. Some patients become more  rigid and resistant to changes.Eating habits  change (e.g.: Hyperorality and attempts to eat non edible objects). Langauage dysfunctions like  stereotypy of speech and echolalia are also seen. Memory can be better than in AD, but episodic memory can be impaired even in early stages of the disease.  Drawing and other visuospatial functions are often remarkably spared in all of the FTD clinical subtypes.

 All individuals eventually develop symptoms of apathy and inertia. This might progress to mutism and immobility

Neuro psychology evaluation reveal executive dysfunctions, with relative sparing of visuospatial ability. Memory is relatively spared but might be involved especially later in the disease.

MRI: selective atrophy on MRI.Imaging might be normal early in the  course

PET: hypometabolism  of frontal, anterior cingulate, and anterior temporal regions  ( help to distinguish from AD). PET might be more sensitive than MRI in early stages.

Care: Important care themes in all dementing disorders remain relevant here.

Serotonergic network disruption can explain some of the symptoms and SSRIs are used to control symptoms like disinhibition, impulsivity, repetitive behaviors, and eating disorders. Trazodone is effective in treating agitation, aggression and insomnia.  Agents with relatively less D2 receptor antagonism such as quetiapine are preferred if antipsychotics are required.  The cholinergic system is relatively preserved in FTD  (unlike AD) and Choline esterase inhibitors are not useful.

Summary of the article:

Diagnosis and Management of Behavioral Variant Frontotemporal Dementia.

Pressman PS, Miller BL. Biol Psychiatry. 2014 Apr 1;75(7):574-581

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