Fatal insomnia
| Fatal insomnia | |
|---|---|
| Longitudinal comparison of 18F-FDG PET/MRI in brain in a patient with fatal insomnia, demonstrating normal brain parenchyma on MRI, but prominent hypometabolism of the thalamus | |
| Specialty | Neurology, psychiatry, sleep medicine, neuropathology |
| Symptoms | Progressive insomnia, ataxia, double vision, weight loss, high blood pressure, excessive sweating |
| Complications | Permanent state of hypnagogia later in the illness |
| Usual onset | 45–50 years old |
| Types | Fatal familial insomnia, sporadic fatal insomnia |
| Causes | Genetic mutation, sporadic form (very rare) |
| Risk factors | Family history |
| Diagnostic method | Suspected based on symptoms, supported by sleep study, PET scan and genetic testing (if familial form is suspected) |
| Differential diagnosis | Alzheimer's disease, frontotemporal dementia, other transmissible spongiform encephalopathies |
| Prevention | None |
| Treatment | Supportive care |
| Medication | None |
| Prognosis | Invariably fatal |
| Frequency | 70 families worldwide are known to carry the gene associated with the disease, 37 sporadic cases diagnosed (as of 20 September 2022) |
| Deaths | <1 per year |
Fatal insomnia is a neurodegenerative disease that results in trouble sleeping as its hallmark symptom. The majority of cases are familial (fatal familial insomnia [FFI]), stemming from a mutation in the PRNP gene, with the remainder of cases occurring sporadically (sporadic fatal insomnia [sFI]). The problems with sleeping typically start out gradually and worsen over time. Eventually, the patient will succumb to total insomnia (agrypnia excitata), most often leading to other symptoms such as speech problems, coordination problems, and dementia. It results in death within a few months to a few years, and there is no known disease-modifying treatment.