Most neurodegenerative diseases such as Frontotemporal degeneration or Alzheimer’s disease have a slow, gradual progression over several years. In some patients, however, cognitive, motor or behavioral symptoms may emerge and progress over the course of weeks to months. These conditions are collectively referred to as “Rapidly-Progressive Dementias.”
There are multiple etiologies that could potentially cause the sub-acute neurological decline in “Rapidly-Progressive Dementias.” First, there are complications of medical conditions that can cause a subacute decline, including metabolic, infectious, inflammatory, neoplastic or vascular conditions. Each of these disease categories have specific treatment strategies that are important to identify early in the disease course. Examples of medical conditions that could cause a rapid decline in cognition include thyroid abnormalities, auto-immune diseases (i.e. the body’s immune system attacking itself as in systemic lupus erythematosis), infections of the nervous system (i.e.meningitis), and cardiac or pulmonary insufficiency. Second, there are conditions that specifically target the central nervous system. Examples include the neurodegenerative condition subacute spongiform encephalopathy, or Creutzfeldt-Jakob disease, auto-immune diseases of the central nervous system (i.e. anti-NMDA receptor-antibody disorder or limbic encephalitis), and certain types of seizures (i.e. partial complex status epilepticus). Common symptoms include confusion, memory loss, balance difficulty, seizures, or rigidity; however, symptoms can vary widely between individuals and often differ depending on the underlying cause of the condition. Diagnosis of these conditions involves a careful neurologic exam and clinical history together with systematic investigation of serological, neuroimaging, and other supportive tests. The Penn Frontotemporal Degeneration Center actively evaluates patients to identify these non-neurodegenerative conditions so that the appropriate treatments can be initiated.