Juvenile Paralysis Agitans of Hunt

The association of progressive extrapyramidal neurologic disorder presenting in teenagers or even earlier and mild form of Parkinson disease. Characterized by tremor, bradykinesia, dysarthria, rigidity, and fixed facies. The disorder may be familial (genetically transmitted) or secondary to other heredodegenerative disorders, such as Huntington disease.

Corpus Striatum Syndrome; Dyssynergia Cerebellaris Myoclonica; Hunt Paralysis; Hunt Syndrome II; Juvenile Parkinson Disease of Hunt; Willige-Hunt Syndrome.

Degeneration of lenticular nuclei. First clinical report by Huchard in 1875.

In Parkinson disease cases, 25% are genetically inherited, of which a small number of cases are represented by juvenile Parkinson disease.

Familial forms may be transmitted as an autosomal dominant or autosomal recessive trait. The recessive form, called “Parkin type of juvenile Parkinson disease,” is caused by mutations within the Parkin gene PARK2, which is located on chromosome 6q25.2-q27. The dominant form is caused by mutations in the alpha-synuclein gene PARK1 (on chromosome 4q21); a fragment of the product of this gene is a known constituent of Alzheimer disease plaques. A few dominant forms of the disease involve other dominant loci, including ubiquitin cyclohydrolase L1 (UCHL1) on chromosome 2p12 (PARK3) and chromosome 4p (PARK4). These enzymes are part of the ubiquitin proteolytic system (UPS), which plays a central role in the regulation of many cellular processes, including removal of abnormal, misfolded, or damaged proteins.

Whatever the genetic transmission, the disease is associated with loss of dopaminergic neurons in the substantia nigra and dopamine deficiency in the striatum. There is a subsequent increase in the activity of the subthalamic nucleus and the globus pallidus, which is responsible for the extrapyramidal movements. Other nondopaminergic neurons are affected (serotonin, norepinephrine), the depletion of which causes psychological and behavioral disorders.

Clinical diagnosis. An antiserum that is immunoreactive to the Parkin immunizing peptide by enzyme-linked immunoabsorbent assay (ELISA) is available.

Clinical features are very similar to the adult form of parkinsonism and begins between 5 and 15 years of age. Tremors appear first, then rigidity, dyskinesia, and unexpressive face. Disturbed gait and dysarthria. Ameliorated by l-dopa (levo-dopamine), monoamine oxidase (MAO) inhibitors, and anticholinergic agents.

Check carefully the child's medication (l-dopa and MAO inhibitors). Do not stop medication; give the morning dose of l-dopa. l-Dopa has a short half-life and stopping it for more than 6 to 12 hours can lead to severe muscular rigidity and worsening of the ventilation.

Light anesthesia can favor muscular rigidity. Prevent hyperventilation (hypocarbia) which may trigger seizures. Monitor carefully the hemodynamics because of MAO inhibitors.

There is frequent interaction between drugs commonly used to treat the condition and anesthetic agents. Drugs with antidopaminergic properties such as butyrophenones (DHBP) and phenothiazines, as well as alfentanil (dystonia), should be avoided. Ketamine is controversial because it may enhance hypertension and tachycardia. Theoretically, the association of l-dopa and halothane could predispose to cardiac arrhythmias. The use of sevoflurane must be carefully weighted against the risk of intraoperative activation of seizure activities. It may occur even at lower concentrations, and the depth of anesthesia should be monitored with intraoperative electroencephalography. Take usual precautions when patients are taking MAO inhibitors.

Spinocerebellar Ataxia (SCA) Type 1: Characterized by progressive cerebellar ataxia, supranuclear ophthalmoplegia, pyramidal or extrapyramidal signs, mild dementia, and peripheral neuropathy. Age at onset is in the third or fourth decade of life, most often around age 30. Involuntary choreiform movements may occur. It is believed to be an autosomal dominant spinocerebellar ataxia.

Parkin-Related Diseases: Mutation in the Parkin gene, autosomal recessive. Clinically, patients affected with Parkin gene disease present with symmetrical involvement and dystonia at onset, hyperreflexia at onset or later, a good response to levodopa therapy, and levodopa-induced dyskinesias during treatment.

Parkinson Disease: Extrapyramidal neurologic disorder resulting from progressive loss of dopaminergic neurons in the substantia nigra and nigrostriatal pathway of the midbrain, not necessarily a genetic disorder.

Segawa Syndrome: Characterized by extrapyramidal symptoms, periodic neurologic episodes, generalized hypertonia with opisthotonos, and conjugate upward deviations of both eyes lasting several minutes, followed by severe hypotonia, poor contact, and excessive salivation and perspiration for several hours. Cerebrospinal fluid biochemical abnormalities are severe. Uncharacteristically, a strikingly abnormal urinary catecholamine metabolite pattern is consistently observed.

Shy-Drager Syndrome: Syndrome with mild parkinsonism, encephalomyelopathy of adult onset and consisting of orthostatic hypotension, bladder and bowel incontinence, anhidrosis, iris atrophy, amyotrophy, ataxia, rigidity and tremor, and normal intellect.

Progressive Supranuclear Palsy (Steele-Richardson-Olszewski Syndrome):Progressive supranuclear palsy is the second most frequent cause of degenerative parkinsonism. Clinical symptoms include early postural instability and supranuclear gaze palsy. Progressive supranuclear palsy is transmitted as an autosomal dominant trait. This disorder begins with axial rigidity, slowness of movement, and gait difficulty, followed by complete vertical gaze palsy, axial dystonia, retrocollis, and severe akinesia. It is often described as a Parkinson-like syndrome without the tremor. The term “Pick complex” has been suggested to represent the overlapping with syndromes of frontotemporal dementia (FTD), primary progressive aphasia, corticobasal degeneration, progressive supranuclear palsy, and FTD with motor neuron disease.