- By Liza Torborg
Tuesday Q and A: Parkinson’s disease not the only cause of parkinsonism
ANSWER: Your husband’s situation is not uncommon for people who have atypical parkinsonism. When symptoms of parkinsonism begin, the condition may at first be diagnosed as Parkinson’s disease. But over time, it becomes clear that a different disorder is really the underlying cause of the symptoms. Treatment for atypical parkinsonism depends on several factors, including the specific diagnosis, symptoms, and how quickly the disease progresses.
To understand atypical parkinsonism, it is helpful to know a bit about parkinsonism in general. First, parkinsonism is not a disease itself. It is a name used to describe a group of symptoms, which include: tremor when a limb is at rest, slowed movement, rigid muscles and impaired balance and posture. When someone has at least two out of these four symptoms, they are said to have parkinsonism.
Parkinsonism has many causes. Parkinson’s disease is the most common cause, but it is not the only one. Parkinsonism can be a result of certain medications. A type of progressive dementia, called Lewy body dementia, which includes a decline in both mental and physical abilities, may lead to parkinsonism.
Parkinsonism also can be caused by three other rare movement disorders: multiple system atrophy, progressive supranuclear palsy and corticobasal degeneration. When a neurologist suspects one of these three disorders as the source of parkinsonism, but an exact diagnosis has not yet been made, it is often labeled atypical parkinsonism.
Another term for this group of disorders is “Parkinson’s-plus.” That’s because people who have one of these diseases show symptoms of parkinsonism along with additional features. For example, multiple system atrophy affects the autonomic nervous system, which controls unconscious activity in the body, such as blood pressure and bowel and bladder function. People with this disorder often have low blood pressure and incontinence in addition to their other parkinsonism symptoms.
Those with progressive supranuclear palsy typically have eye movement abnormalities. They also have gait instability with falls early in the disease. People with Parkinson’s disease usually do not have that problem until much later in the course of their illness.
Corticobasal degeneration generally affects only one side of a person’s body. Symptoms tend to become severe and are difficult to treat. Parkinson’s disease usually starts on one side and then moves to both sides, with symptoms that typically respond to treatment.
The challenge in accurately identifying the diseases that make up atypical parkinsonism is that no one test or exam can be used to diagnose them. Although certain tests such as brain MRI can be helpful, diagnosis is largely based on symptoms and physical and neurological examinations.
With these three disorders, symptoms develop slowly, sometimes over the course of five years or more. So, as in your husband’s case, what first looks like Parkinson’s disease may change as more features of the underlying disease appear.
Another clue that a movement disorder may be one of the group of atypical parkinsonism diseases is that symptoms do not improve with standard Parkinson’s disease medications. This is especially true of the drug levodopa, which is the most commonly used and most effective medication prescribed for Parkinson’s disease. People with an atypical parkinsonism disorder generally see little or no difference in their symptoms with levodopa.
Treatment for atypical parkinsonism usually cannot be determined until the exact disorder causing the symptoms has been identified. Once that happens, then your husband can work with his neurologist to create an effective treatment plan. Because atypical parkinsonism disorders are uncommon, your husband may want to consider working with a neurologist who specializes in movement disorders. Such specialists are familiar with these diseases and often have considerable experience managing them. — James Bower, M.D., Neurology, Mayo Clinic, Rochester, Minn.