Frontotemporal dementia — assessment and management (MEQ)

(i) Formulation and differentials. Working diagnosis: probable behavioural variant frontotemporal dementia. Core features already suggested include disinhibition, loss of empathy, dietary/ritual change, and progressive functional/occupational decline with poor insight; preserved MMSE is compatible because early bvFTD may spare routine orientation/memory items.[1][6] Apply Rascovsky framework: possible requires enough of the six behavioural/cognitive features with progressive decline; probable adds imaging support (frontotemporal pattern) once obtained; definite would require pathology or pathogenic mutation.[1] Differentials: late-onset bipolar or primary personality change (usually non-neurodegenerative tempo); frontal Alzheimer disease; vascular frontal syndrome; alcohol-related injury; space-occupying lesion; autoimmune encephalitis if subacute; DLB if hallucinations/RBD/parkinsonism dominate; bvFTD phenocopy if non-progressive on follow-up. Prior psychiatric labels are common before correct FTD diagnosis — do not stop at "midlife crisis."[6][12]

(ii) Genetics. Family ALS plus maternal behavioural dementia strongly raises C9orf72 hexanucleotide expansion (GGGGCC) as leading candidate — the major shared genetic cause of FTD and ALS.[2][3] Also discuss MAPT (tau/FTDP-17 spectrum) and GRN (progranulin haploinsufficiency with TDP-43 pathology) as the classic Mendelian triad.[4][5] Offer testing only with pre-/post-test counselling; implications for children and siblings; do not force predictive testing of asymptomatic relatives outside a genetics pathway.

(iii) Assessment and investigations. Risk: driving, finances, exploitation, workplace safety, weapons, dependent children, sexual disinhibition. Capacity is decision-specific (understand, appreciate, reason, communicate choice).[11] Collateral history, broader cognitive/social-cognition testing, full motor exam. Bloods for reversible contributors; MRI for structural pattern and to exclude mass lesions; consider FDG-PET if structural imaging equivocal; EMG given fasciculations; genetics with counselling; avoid inventing scan reports.[1][6][9]

(iv) Management. No routine disease-modifying drug. First-line: structured environment, carer education, OT/speech as needed, financial/driving restrictions, social work, advance care planning. Symptomatic options for disinhibition/compulsions: SSRI trial (e.g. sertraline 25–50 mg orally daily with monitoring) based on limited serotonergic treatment literature; trazodone has RCT behavioural signal in FTD (start low, watch sedation/falls).[7][8] Avoid automatic cholinesterase inhibitors in pure FTD. Antipsychotics only for severe dangerous aggression/psychosis after non-drug measures, time-limited, with mortality risk counselling from dementia antipsychotic meta-analysis.[6][10]

(v) ALS-FTSD. Fasciculations plus FTD place the patient on the amyotrophic lateral sclerosis–frontotemporal spectrum; involve neurology urgently for motor staging, respiratory/bulbar surveillance, and joint care under revised ALS-FTSD concepts.[9]