Chorea is a disorder of the nervous system that is characterized by spasm of the facial muscles and involuntary contortions of the limbs. 
The two common forms of chorea are unrelated:
  1. Sydenham’s chorea and
  2. Huntington’s chorea. 

1.Sydenham's chorea

Sydenham’s chorea is a disorder in which the small arteries of the brain become inflamed. It is an allergic reaction to streptococcal infection, such as meningitis, some forms of pneumonia, and scarlet fever.
Sydenham’s chorea commonly follows several months after an attack of rheumatic fever and is most likely to occur in children between the ages of 5 and 15.

Sydenham's chorea symptoms

The symptoms of Sydenham’s chorea include facial contortions, grunts, and occasional difficulty in speaking. Sometimes only one side of the body is affected.

Sydenham's chorea treatment

Bed rest is essential. Sedative drugs help to control the involuntary contortions, and antibiotic drugs are usually prescribed to fight infection. The disease is often treated with regular high dosages of aspirin. Recovery may be complete within 3 or 4 months, but further attacks occur in about 30 percent of cases.

2.Huntington’s chorea

Huntington’s chorea, or disease, is an inherited disorder of the central nervous system, which usually affects an equal number of males and females between the ages of 30 and 50.

Huntington’s chorea symptoms

The symptoms of Huntington’s chorea are the gradual onset of involuntary, jerky, and contorted movements of the limbs. Mental deterioration and severe personality change are associated symptoms. The patient may eventually need institutional care.

Huntington’s chorea treatment

No effective form of treatment has been found for the disorder. There is a 50 percent chance that a child of someone with Huntington’s chorea will develop it later in life.
The traditional medical advice has been that a person who has a parent with the disorder should not have children. There is now in the experimental stage a blood test that can identify the defective gene responsible for Huntington’s chorea long before any symptoms appear.
The availability of this test may bring up difficult ethical and legal questions concerning who has the right to know the results.