An 8-year-old girl is brought to the office due to involuntary movements of the hands and body for a week. The movements get worse when the patient feels anxious, and she cannot suppress them. She has also had an urge for frequent hand cleaning. Vital signs are normal. On examination, the patient has inappropriate laughing and frequent throat clearing. The tonsils are enlarged and hyperemic. Neurologic examination shows generalized, involuntary movements of the body. Grip strength is strong; however, the patient cannot maintain it because of irregular hand and arm movements. Cranial nerve, sensation, and mental status examinations show no abnormalities. Complete blood count, serum chemistries, and liver function studies are normal. What is the most likely cause of this patient's symptoms?

Question

An 8-year-old girl is brought to the office due to involuntary movements of the hands and body for a week.  The movements get worse when the patient feels anxious, and she cannot suppress them.  She has also had an urge for frequent hand cleaning.  Vital signs are normal.  On examination, the patient has inappropriate laughing and frequent throat clearing.  The tonsils are enlarged and hyperemic.  Neurologic examination shows generalized, involuntary movements of the body.  Grip strength is strong; however, the patient cannot maintain it because of irregular hand and arm movements.  Cranial nerve, sensation, and mental status examinations show no abnormalities.  Complete blood count, serum chemistries, and liver function studies are normal.  What is the most likely cause of this patient's symptoms?

Quizplus · Accepted Answer

Explanation: 11ec25c8_d5dc_1549_bc81_1148e8c7bc4d_MD0003_00 This patient has new-onset, irregular movements; obsessive-compulsive behaviors (ie, frequent hand cleaning); and emotional lability (ie, inappropriate laughing). In combination with erythematous, enlarged tonsils, her findings are consistent with Sydenham chorea (SC), an autoimmune complication that can occur months after a group A Streptococcus (GAS) infection. Pathogenesis of SC is comparable to that of carditis in acute rheumatic fever as there are structural similarities between the epitopes of GAS and surface gangliosides of dopaminergic neurons in the basal ganglia. Molecular mimicry, which refers to the cross-reactivity of antistreptococcal antibodies with these neuronal antigens, results in characteristic neurologic and psychiatric manifestations: carditis in acute rheumatic fever Chorea: jerky, irregular, involuntary contractions of the limbs and face that cannot be suppressed Poor execution of motor tasks due to hypotonia and intrusion of choreic movements, which can result in intermittently weakened hand grip (ie, milkmaid grip) Tics (eg, repetitive throat clearing) Behavioral changes: emotional lability, anxiety, irritability, obsessive-compulsive behaviors Diagnosis of SC is supported by evidence of prior GAS infection (eg, positive throat culture). Patients with suspected SC should also undergo cardiac evaluation because SC may be the initial manifestation of acute rheumatic fever. (Choice A) Basal ganglia atrophy occurs with Huntington disease, an inherited disorder characterized by chorea, psychiatric symptoms, and dementia. However, onset is gradual and in adulthood. Tourette syndrome is also associated with decreased caudate nucleus volume and can manifest with tics, which can be distinguished from chorea because they can be temporarily suppressed, and obsessive-compulsive behaviors. Grip would not be affected with Tourette syndrome because tone and strength are normal. (Choice B) Wilson disease is characterized by impaired copper excretion due to defective copper transport. Neuropsychiatric manifestations can include chorea and labile mood, but onset is insidious, not acute, and abnormal liver function studies would be expected. (Choice C) Amyotrophic lateral sclerosis is a degenerative disease of upper and lower motor neurons that can cause weakness and a pseudobulbar affect (eg, inappropriate laughing). However, chorea is not seen, and presentation is in adulthood. (Choice D) Degeneration of the cerebral cortex (eg, Alzheimer disease) results in progressive behavioral changes and cognitive decline, not abnormal movements. In addition, this condition does not occur in childhood. Educational objective: Sydenham chorea is an autoimmune complication of group A Streptococcus infection caused by molecular mimicry, in which antistreptococcal antibodies cross-react with neuronal antigens in the basal ganglia. Neuropsychiatric manifestations include chorea, milkmaid grip, hypotonia, emotional lability, and obsessive-compulsive behaviors. References: Molecular mimicry, autoimmunity, and infection: the cross-reactive antigens of group A streptococci and their sequelae. (http://www.ncbi.nlm.nih.gov/pubmed/31373269) Sydenham's chorea. (http://www.ncbi.nlm.nih.gov/pubmed/31003820)

An 8-Year-Old Girl Is Brought to the Office Due to Involuntary