Tremor is the medical term for trembling or shaking. A person with tremor has a body part that shakes, and the person cannot control the shaking. Most often this shaking affects the hands or the head, but other body parts can be affected, too. The tremor can be a problem on its own, or it can be caused by another health problem. There are several different types of tremors with different causes. Resting tremors happen while one is sitting or lying down and relaxed. People who have a resting tremor can usually stop the tremor by making a point of moving the part of their body that shakes. Postural tremors happen when one tries to hold a body part still in a position other than its resting position. If one has a postural tremor, their arms might shake if they hold them out in front of you. There are also action tremors which happen when one tries to move on purpose. The most common cause of resting tremor is Parkinson’s disease. If that is the cause of one’s tremor, the doctor will probably focus on treating the disease, and this will reduce the tremors. Other problems that can cause resting tremors include diseases that damage parts of the brain, and a rare condition called Wilson’s disease, which causes copper to build up in the body. The most common cause of postural and action tremors is something called a “physiologic” tremor. Everyone, even people who are healthy, has a little bit of shaking of the hands. This is what doctors refer to as “physiologic tremor”. It is normal, and you don’t usually notice it, because it is very mild. But in some cases this “physiologic” or normal tremor can become exaggerated. This can happen mostly in certain conditions such as, if one takes certain medicines, such as those used to treat depression, or asthma and other breathing problems, or if one drinks coffee, smoke cigarettes, or take drugs called “stimulants”. Also, being anxious, excited, or afraid, or if one’s muscles are very tired, for example, because they just worked out, as the effects of alcohol or other drugs are wearing off. Having an overactive thyroid gland or fever can cause a postural or action tremor. If you have a tremor that is caused by one of the problems listed above, the tremor should go away as soon as the problem goes away. If your tremor is caused by a medicine, you might not be able to stop taking it but it might be possible to switch medicines or to lower the dose. Essential tremor is the medical term used to describe tremors that do not seem to be physiologic or linked to any health problem. The cause of an essential tremor is currently not known, but known to be passed on in families. People who have essential tremor usually shake when they try to hold their arms out straight. They also tend to shake when they move their hands with a goal in mind. For instance, their hands might shake when they try to write, drink from a glass, or touch their nose with their finger. Essential tremor sometimes even affects the head. This makes it look as though the person is nodding their head “yes-yes” or shaking their head “no-no.” If a tremor is caused by another medical problem, treating that problem, if it can be treated, sometimes helps reduce the tremor too. For example, people whose tremor is caused by high thyroid hormone levels often stop shaking when their hormone levels go back to normal. Even when no other medical problems are involved, there are treatments that can help. There are a few medicines that can reduce a person’s tremor. If the medicines are not effective enough and the tremor is severe, it is even possible to have a device implanted in the brain that can help control tremor in some developed hospital settings. Dr. Ian Shyaka , Resident in Surgery, Rwanda Military Hospital, iangashugi@gmail.com