CHOREA/BALLISM
Chorea is characterized by random jerky movements jumping from one body part to another. They are irregularly timed, nonrepetitive, and abrupt in character, varying in severity. In mild cases, they may lead to restlessness, intermittent exaggeration of facial expression, or fidgetiness of the hands or toes. In more severe cases, the gait has a dancing quality and limbs exhibiting violent and ballistic movements. It can involve proximal and distal muscles. Patients often attempt to mask such movements by incorporating them into voluntary activities. Ballism can be conceptualized as a severe form of chorea affecting the proximal limb muscles, giving a “throwing” character to the movement. The most common form of ballism is seen in parkinsonian patients with severe levodopainduced abnormal involuntary movements (dyskinesias) or in patients with contralateral subthalamic lesion (infarct, demyelination). Patients may have difficulties maintaining a sustained posture. When asked to grip the examiner’s hand, pressure cannot be sustained, resulting in the “milkmaid’s grip”; when asked to protrude the tongue, the tongue will pop out, resulting in the “catch fly sign” or “harlequin’s” tongue The bonbon sign may be present (the tongue moves involuntarily inside the mouth, hitting the inside wall of the cheeks). This latter sign is particularly prominent in patients with druginduced orolingual chorea (neurolepticinduced tardive dyskinesia).
There
are many causes of chorea, such as pregnancy (chorea gravidarum), Huntington
disease, benign hereditary chorea, neuroacanthocytosis, Sydenham chorea,
systemic lupus erythematosus, focal vascular lesions, medications
(particularly the chronic use of neuroleptics and oral contraceptives), various
metabolic and endocrine disorders (hyperthyroidism, hypoparathyroidism, or
hyperparathyroidism and hypoglycemia or hyperglycemia), and others.
In
adults, the most common cause of chorea is medication, especially the use of
levodopa in Parkinson patients or the longterm use of neuroleptic drugsor metoclopramide, which
causes tardive dyskinesia. In children, Sydenham chorea remains the most common
cause.
The
second most common cause of chorea in adults is Huntington disease (HD).
First described by George Huntington in1872, this autosomal dominant
neurodegenerative disorder, with a 100% penetrance, has an abnormal
trinucleotide (CAG) gene expansion, with the defective gene located in the
short arm of chromosome 4. The disorder is characterized by choreiform movements
and dementia or behavioral changes. In the United States, the estimated
prevalence is 5 to 10 cases per 100,000 people. Age at onset is in the fifth to
sixth decades of life, with duration of illness of 15 years in the adult and 8
to 10 years with the Westphal variant. Because of its insidious onset, the
onset of symptoms is often not recognized, and abnormal movements are
erroneously attributed to anxiety. Patients often have personality and
behavioral changes early in the disease and these may be the initial
manifestation in more than 50% of cases. Eventually, symptoms become prominent
and disabling. Speech becomes dysarthric. Oculomotor alterations, such as
impaired saccade initiation, particularly an inability to initiate saccadic eye
movement without blinking or head thrusts, are common. Loss of optokinetic
nystagmus can occur after some years. The only laboratory study available to
confirm the diagnosis is genetic testing. In early stages of the disease, brain
magnetic resonance imaging (MRI) may show nonspecific changes in the
neostriatum, caudate, and putamen; striatal atrophy, most notably the caudate
head, occurs later in the disease.
Benign
hereditary (familial) chorea, an autosomal dominant disorder, begins early in
childhood. Mild generalized chorea, affecting the distal extremities more than
the proximal muscle groups, is the characteristic movement disorder; when
present, minor neuropsychiatric features, such as mildly lower scores on
cognitive tests, complete the clinical picture. Benign hereditary chorea has
been associated with mutations in the TITF-1 gene. Sydenham chorea is
a manifestation of acute rheumatic fever. It is also called “St. Vitus’s
dance,” acute chorea, chorea minor, or rheumatic chorea. Although more common
in adolescent girls, it is also seen in adults. The clinical features of chorea
are similar to those described for Huntington disease. Obsessivecompulsive and impulsive
disorders and emotional lability may also occur. Prophylaxis with antibiotics
is recommended until adulthood for children with Sydenham chorea because
rheumatic fever recurs in up to one third of patients.
Athetosis is a slow writhing movement of the fingers and toes, seen most often in patients with cerebral palsy, particularly when excited or when trying to communicate. Dystonic posturing, tremor, ataxia, or scissoring gait usually accompanies athetotic movements.
.webp "Scrotal Skin Diseases: Causes, Symptoms, Diagnosis, and Treatment")
