Frontotemporal dementia

Related Subjects: | Dementias |Abbreviated Mental Test Score (AMTS) |Alzheimer disease | Dementia with Lewy bodies | Frontotemporal dementia | Corticobasal degeneration | Creutzfeldt Jakob disease | Vascular Dementia | Primary progressive aphasia | Anti Dementia Drugs | AIDS Dementia Complex | Normal Pressure Hydrocephalus | Acetylcholinesterase inhibitors | Mental Capacity Act 2005 | Behavioural and Psychological Symptoms of Dementia

Some cases demonstrate intracytoplasmic tau positive inclusion bodies so sometimes termed a tauopathy (also seen with AD)

About

• Rare form of dementia with anterior temporal and frontal lobe features
• Altered behaviour and disinhibition .
• Age 50-70 years old. Onset mean age is 58

Aetiology

• Mutations in microtubule-binding protein tau.
• Right prefrontal lobe or anterior temporal involvement leads to the typical syndrome.
• Left prefrontal involvement leads to aphasia.

Pathology

• Neuronal loss and gliosis
• Spongiform degeneration in superficial layers of frontal/temporal lobes
• Pick bodies in 1/4 round intracellular inclusions in small cells
• Pick cells - large ballooned neurons in the superficial cortex
• Tau positive inclusion bodies seen in the cytoplasm

Variants

• Corticobasal degeneration - alien limb on the side contralateral to cortical atrophy, apraxia, stiff jerky limb movements
• Behavioural variant FTD
• Primary progressive aphasia: deficits in language and speech. Difficulties with grammar and reading/writing predominate. Fluent (semantic dementia) and non-fluent forms.
• Motor neurone disease type dementia: may precede the diagnosis of MND. Usually men less than 65.

Clinical

• Behavioural symptoms predominate early. Loss of empathy
• Apathy, Overactive, Impulsive, Overeating, weight gain
• Personality change - inappropriate sexual behaviour
• Socially disinhibited e.g. poor hygiene, unkempt
• Loss of safety awareness, Emotional Lability
• Abnormalities in speech and language may be seen
• Loss of executive functions, Apathetic, Memory loss is later, No insight
• Asymmetrical akinetic rigid. Limb apraxia, Pseudobulbar palsy, Spastic dysarthria
• Vertical gaze palsy and axial rigidity and dystonia and alien hand syndrome or MND

Investigations

• Dementia tests: FBC, U&E, CRP, LFT, TFT, B12, Folate, Syphilis serology
• CT/MRI may show frontal and temporal loss
• EEG : normal
• MRI: Right prefrontal and anterior temporal atrophy. Atrophy may be asymmetrical. Left frontal/temporal changes in PPA.
• EMG in those with Motor neurone disease type dementia
• SPECT/PET shows anterior perfusion deficits

Management

• No known treatments available. No role for cholinesterase inhibitors or memantine.
• Some symptoms may be helped with SSRIs - depression, hyperorality, compulsiveness
• Management is supportive with social services and support to allow the patient to remain independent.
• Quetiapine may be used to manage behavioural changes