Though it has been reported to occur at a variety of ages, the median age of onset is in the seventh decade, as in all of the cases presented here. Likewise, these cases illustrate the range in course of the illness, which can be from a few weeks to eight years. However, the average survival from onset of disease is six months. CJD is uniformly fatal.
Most patients succumb to pneumonia or from inanation.
Early clinical features can be subtle and include malaise, altered personality, emotional lability, and sleep disturbances. Other findings may include hallucinations or delusional ideation. Later manifestations are a rapidly progressive dementia and ataxia with myoclonus. Patients may become mute, or exhibit cortical blindness, with rigidity and spasticity. The subacute form, the most common, is characterized by presence of prodromal symptoms before onset of worsening dementia and ataxia.