<unk>  is characterized by the abrupt onset (sometimes within a few hours) of neurologic symptoms, classically chorea, which are non-rhythmic, writhing or explosive involuntary movements. Usually all four limbs are affected, but there are cases reported where just one side of the body is affected (hemichorea). Typical chorea includes repeated wrist hyperextension, grimacing, lip pouting. The fingers can move as if playing the piano. There may be tongue fasciculations ("bag of worms") and motor impersistence for example the "milk maid sign" (grip strength fluctuates, as if hand milking), or inability to sustain tongue protrusion or eye closure. There is usually loss of fine motor control, particularly obvious in handwriting if the child is of<unk> hool age. Speech is often affected (dysarthria), as is walking; legs will suddenly give way or flick out to one side, giving an irregular gait and the appearance of skipping or dancing. Underlying the abnormal movements is often low tone (hypotonia) which may not become obvious until treatment is started to suppress the chorea. In severe cases, the loss of tone and weakness predominate (chorea paralyticum). The severity of the condition can vary from just some instability on walking and difficulty with hand writing, to the extreme of being wholly unable to walk, talk, or feed yourself. Movements cease during sleep. The eye muscles are not affected, curiously. It is a neuropsychiatric disorder, so besides the motor problems there is classically emotional lability (mood swings, or inappropriate mood), anxiety, attention deficit. These can precede the motor symptoms. Non-neurologic manifestations of acute rheumatic fever may be present, namely carditis (up to 70% of cases, often subclinical, so echocardiography required), arthritis, erythema marginatum, and subcutaneous nodules. Erythema marginatum Differentiating these signs from other involuntary movements such as tics and stereotypies can be difficult, and since these things are not uncommon they can potentially co-exist. Diagnosis is often delayed and attributed to another condition such as tic disorder or conversion disorder. The controversial PANDAS (pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections) hypothesis has overlapping clinical features but<unk>  is one of the exclusion criteria. PANDAS can present with chorea but more typically there are tics, stereotypies with a psychological component (e.g., OCD).
Sydenham's chorea
Huntington's disease
Benign hereditary chorea
Parkinson-plus syndrome
Wernicke–Korsakoff syndrome
Huntington's disease-like syndrome
X-linked dystonia parkinsonism
Stratton Parker syndrome