Fatal Familial Insomnia is an extremely rare disorder. The exact incidence and prevalence of the disorder is unknown. The sporadic form of FFI, known as sporadic fatal insomnia (SFI), is extremely rare and has only been described in the medical literature in about two dozen people.
FFI sufferers fall into a state in which they are neither fully asleep nor awake. The inability to sleep wreaks havoc on their lives. Sleeplessness deteriorates into exhaustion, dementia and ultimately, death.
Fatal familial insomnia (FFI) is a genetically transmitted neurodegenerative prion disease that incurs great suffering and has neither a treatment nor a cure. The clinical literature is devoid of management plans (other than palliative)
FFI patients are more likely to have longer disease durations, and severe insomnia and dysautonomia, and are less likely to have typical Creutzfeldt–Jakob disease like cortical ribboning in DWI.
Gerstmann Sträussler Scheinker disease (GSS) is another prion disease that shares similar clinical manifestations with FFI. It typically presents as a subacute progressive ataxic and/or parkinsonian disorder with a later onset of cognitive impairment. The mean disease duration is around 5 years, ranging from 3 to more than 8 years.
Paraneoplastic and non-paraneoplastic limbic encephalitis can also present with RPD and behavior and movement disturbances. Unlike FFI, patients with paraneoplastic and non-paraneoplastic limbic encephalitis have acute/subacute onsets, and symptoms peak within days to weeks; CSF tests usually show pleocytosis (the presence of an abnormally large number of lymphocytes in the cerebrospinal fluid) and an increased protein level.
The main MRI findings that allow the differentiation of encephalitis from FFI are cortical swelling, petechial hemorrhages, and patchy enhancement postcontrast agent administration in the subacute stage. Antibody testing in both CSF and serum is especially crucial.
FFI is an extremely rare disease and causes death usually within 12-18 months. There is neither a known treatment nor a cure.
Treating FFI is a different issue altogether. But diagnosing FFI is what makes it rather interesting.
Categories: Medical Science