October 27, 2009

Generalized Dystonia

Watch the video.

Dystonia is a movement disorder that consists of directional, sustained muscle contractions that result in abnormal, twisting postures. There are usually combined contractions of agonist and antagonist muscles. The movements are frequently stereotyped.

Dystonia is also described by the region or regions it involves, a limb, the neck, the face, or in this case the whole body. This latter form, generalized dystonia, is disabling, and usually begins in young people. At 26 years old, this woman is old to develop generalized dystonia, but the onset of her disease is not typical of primary dystonia. Neurologic disorders can be divided into primary diseases and those that are acquired or secondary. Since this condition began acutely and in association with a flu shot - association not proving causality - it should be characterized as a secondary dystonia.

Secondary dystonia has a long list of potential causes, but it is not fully necessary to review them. The initial evaluation of a movement disorder begins with phenomenology. It frames the search for an etiology and the eventual treatment. The video demonstrates one of the features of dystonia: it is frequently activity-dependent, so walking backward and running can be completely normal while walking forward is completely abnormal. One way to conceptualize why this might happen is to consider running, walking forward, and walking backward as drawing on different motor programs. Task-specific dystonia vividly illustrates this idea. In this case, however, the complete resolution of all symptoms with running and walking backward is not consistent with dystonia. Additionally, her pattern of speech is not consistent between interviews and is typical of a psychogenic dysarthria.Here is a more definitive statement from the Dystonia Medical Research Foundation.

This young woman is ill and should be seen by a movement disorder neurologist at an academic center. I mention an academic center because she needs to see a doctor who will be able to take the amount of time with her she needs. And if she is not seen by someone with a practiced eye, she may receive unnecessary and potentially harmful medical and even surgical treatment.

Here's another news account.
This story is certainly not a reason to forgo a flu shot, especially if you're in a high risk group.

Neuron Images

Technology Review published pictures tracing the development of neuronal imaging through time. Starting with Ramon y Cajal, here are two examples of modern imaging techniques. The following is a cortical pyramidal neuron imaged with confocal laser microscopy.
This is a picture of a hippocampal neuron's cytoskeleton after the cell membrane was stripped away with detergents.

October 11, 2009

Bill Clinton and Parkinson's Disease

This story has been bouncing around for a while. I'm not sure when it started but it was given a boost by a visible tremor during his appearance on The Daily Show with Jon Stewart in September 2008.

Bill, 63 years old, may have Parkinson's Disease (PD). The mean age of onset for PD is around 58 or 59, around the time Bill began having his tremor, hardly proof, however. If anything, this episode in the life of Bill offers an opportunity to clear up a few things.

Here's what he had to said on Larry King about the rumors.

He's a politician and not a physician, so understandably some of what he says needs to be clarified.
1. There is no test for PD. It is a clinical diagnosis with tremor as only one component. The tremor is present mainly at rest, but may be present with action. The two other cardinal signs are rigidity or passive resistance to movement; and bradykinesia, small and slow movement. There may be postural instability characterized as imbalance, shuffling, and an increased tendency to fall. If the disease is suspected, there should be an evaluation by a movement disorders specialist or a neurologist. It is not clear if he was evaluated by a movement disorder specialist whose opinion would be more trustworthy since they spend the majority of their time treating Parkinson's.
2. Benign essential tremors rarely begin later in life. By definition they are chronic and slowly progressive without other neurologic dysfunction.
3. Fatigue and stress worsen all movement disorders, essential tremor and Parkinson's Disease included. Whether a tremor is affected by being tired does not play a role in the diagnosis.

A few more points: There are good symptomatic treatments for PD. There isn't a cure. Some genes have been identified, but they still account for the minority of patients. Motor symptoms in Parkinson's often present asymmetrically. Masked facies or decreased facial expression is a symptom frequently encountered. It has been suggested that Bill's facial expression is decreased. Tremor-predominant Parkinson's Disease (which would characterize Bill's symptoms) has the mildest, more benign course.

Another blog post about this topic (with some misleading comments hopefully addressed above). Without an exam it is difficult to be sure whether our former President has Parkinsons's or not, but there are elements of his history that suggest he may.