Trembling, medically known as tremors, is a specific symptom in which the hands, arms, head, legs or any other body part shakes. Certain medical illnesses can lead to tremors. Tremors can also be a side effect of prescription medications. Learn about the diseases that cause trembling.

According to the National Institute of Neurological Disorders and Stroke (NINDS), Parkinson's disease is a neurological disorder that results from the lack of cells that produce dopamine, a brain chemical needed for movement, learning and mood.

The NINDS says specific symptoms of Parkinson's disease include tremors in the hands, arms, jaw, legs and face. It also leads to slowness in movements (bradykinesia) and stiffness of the extremities. Other Parkinson's disease manifestations include lack of coordination, unsteadiness, depression, problems chewing or speaking and trouble sleeping.

Treatment for Parkinson's disease involves a combination medication of levidopa and carbidopa, which can quell the symptoms of Parkinson's disease. Anticholinergic medications can also be given to reduce tremors and stiffness. Additional medications include pramipexole, ropinirole and bromocriptine. These medications act like dopamine in the brain and prevent manifestations of Parkinson's disease. Another treatment option is deep brain stimulation. This is an implantable device in which electric currents stimulate certain parts of the brain to reduce Parkinson's disease symptoms.

Essential tremor is a condition that can occur at any age, according to the Mayo Clinic. In fact, 14 percent of individuals older than 65 years are stricken with this disease. The Mayo Clinic says essential tremors are typically due to alterations in certain genes in the body.

Essential tremors initially start in the hands and can progress to affect the head and voice. Stress, fatigue, caffeine and temperature changes may make these tremors worse, according to the Mayo Clinic.

Beta-blocker medications such as propanolol, anti-seizure medications such as primidone, tranquilizers such as diazepam and botulism type A toxin may be used to reduce tremors. Also, physical therapy can help people implement certain exercises to help with controlling muscles and movement coordination. Like in Parkinson's disease, deep brain stimulation may be utilized to treat essential tremors.

Multiple sclerosis is another neurological disorder that involves trembling. The Mayo Clinic says that this is an autoimmune disease in which the body begins to attack the covering of its nerve cells (myelin). This gradually leads to nerve deterioration.

The National Multiple Sclerosis Society says tremors are one of the most frustrating manifestations of the disease. These tremors typically affect the body, extremities, head and muscles necessary for speech and sexual function. The Mayo Clinic says other multiple sclerosis symptoms include numbness on one side of the body, blurry or double vision (diplopia), visual loss, trouble walking and lack of coordination. Multiple sclerosis also causes an electric-shock feeling with specific head movements.

Multiple sclerosis has no cure. However, corticosteroid medications, such as prednisone, interferon drugs, glatiramer, natalizumab and mitoxantrone, can be taken to decrease multiple sclerosis manifestations, according to the Mayo Clinic. Physical therapy can help stretch and exercise the muscles. In some cases, plasmaphoresis is utilized to separate the blood cells from the plasma (fluid component of blood). This may help reduce multiple sclerosis symptoms.