From the Research
Neuronal intermediate filament inclusion body disease (NIFID) is a rare neurodegenerative disorder that presents as a form of frontotemporal dementia, and its management should focus on symptomatic treatment to improve quality of life, as there is no cure or reversal of the disease. The disease is characterized by abnormal protein aggregates in neurons, particularly intermediate filaments, and presents with symptoms including behavioral changes, language difficulties, and motor dysfunction. According to the most recent study 1, NIFID can present with predominantly upper motor neuron features, and its pathology is distinct from other forms of frontotemporal dementia.
Clinical Features
The clinical features of NIFID include:
- Behavioral changes
- Language difficulties
- Motor dysfunction
- Cognitive impairment
- Extrapyramidal features, such as parkinsonism
- Upper motor neuron signs, such as spasticity and hyperreflexia
Pathology
The pathology of NIFID is characterized by:
- Neuronal loss and gliosis
- Sponginess in the fronto-temporal cortices, caudate, and putamen
- Hyaline conglomerate inclusions (HC) and granular and small round FUS-immunoreactive (FUS-ir) neuronal cytoplasmic inclusions (NCI)
- FUS-ir large compact inclusions (so-called Pick-like) in some cases
Management
The management of NIFID should focus on symptomatic treatment, including:
- Cholinesterase inhibitors (donepezil 5-10mg daily, rivastigmine 1.5-6mg twice daily, or galantamine 8-12mg twice daily) for cognitive symptoms
- Antipsychotics (risperidone 0.25-1mg daily or quetiapine 25-100mg daily) for behavioral disturbances, used cautiously due to increased stroke risk in elderly patients
- Antidepressants such as SSRIs (sertraline 50-100mg daily or escitalopram 10-20mg daily) for depression and anxiety
- Physical therapy, occupational therapy, and speech therapy to improve quality of life
Prognosis
The prognosis of NIFID is poor, with a typical disease duration of 5-7 years from diagnosis to requiring comprehensive care, as reported in the study 2. However, the disease progression can vary, and some cases may have a longer or shorter disease course.