A 11-year-old girl is brought to the office due to a 2-day history of rapid-onset, abnormal movements of the body. The abnormal movements began bilaterally in the upper limbs, followed by the trunk and then lower extremities. As a result, the patient has had difficulty performing daily activities such as bathing and eating. However, she has no abnormal movements during sleep. Vital signs are normal. Examination shows a restless child with irregular, jerky movements involving the entire body and generalized hypotonia. Mental status examination, cranial nerves, and sensations are normal. Which of the following is the best next step in diagnosis?

Question

A 11-year-old girl is brought to the office due to a 2-day history of rapid-onset, abnormal movements of the body.  The abnormal movements began bilaterally in the upper limbs, followed by the trunk and then lower extremities.  As a result, the patient has had difficulty performing daily activities such as bathing and eating.  However, she has no abnormal movements during sleep.  Vital signs are normal.  Examination shows a restless child with irregular, jerky movements involving the entire body and generalized hypotonia.  Mental status examination, cranial nerves, and sensations are normal.  Which of the following is the best next step in diagnosis?

Quizplus · Accepted Answer

11ec25c8_d59f_340c_bc81_8bd7bc9281d6_MD0003_00 This patient's abnormal, jerky movements that disappear during sleep are consistent with chorea, a movement disorder characterized by involuntary, unpredictable contractions of the limbs and face due to abnormal signaling within the basal ganglia. The majority of acute-onset chorea in children is Sydenham chorea (SC), a sequela of group A Streptococcus (GAS) infection that can also be a manifestation of acute rheumatic fever. Pathogenesis involves the cross-reactivity of antistreptococcal antibodies and host neuronal antigens. SC is most common in girls and can present months after the initial GAS infection. In addition to irregular movements, which are typically bilateral and progressive, other characteristic findings of SC include hypotonia and behavioral changes (eg, irritability, obsessive-compulsive behaviors). Motor and psychiatric symptoms tend to wax and wane; although chorea often self-resolves within months, recurrence is common. Evaluation of SC includes GAS testing with throat culture and antistreptolysin O (ASO) and antideoxyribonuclease (anti-DNAse) B titers. Although throat culture is typically negative after resolution of GAS pharyngitis, ASO and anti-DNAse B are antistreptococcal antibodies that can be elevated for months after infection. Additional testing includes evaluation for rheumatic fever with echocardiography, ECG, and inflammatory markers. (Choice B) Cerebrospinal fluid analysis is performed for encephalitis, which can cause abnormal movements, but fever and altered mental status would be present. Lumbar puncture is not indicated for SC. (Choice C) Although psychiatric assessment may be appropriate for new behavioral concerns, GAS testing should be prioritized to confirm a suspected diagnosis of SC because timely antibiotic therapy can decrease the risk of progression to rheumatic heart disease, as well as the recurrence risk of SC. (Choices D and F) Chorea can rarely be caused by hypocalcemia or hyperthyroidism (elevated T4, low TSH). However, there would be other manifestations, such as muscle cramps and tetany (eg, paresthesia, stiffness, spasms) with hypocalcemia and tachycardia and tremor with hyperthyroidism; none of these symptoms are seen in this patient. (Choice E) Iron deficiency with low serum ferritin is associated with restless legs syndrome. In contrast to this case, fidgety movements occur primarily at night. Educational objective: Sydenham chorea, a sequela of group A Streptococcus (GAS) infection, is the primary cause of chorea (ie, abnormal, jerky movements that disappear during sleep) in children. Hypotonia and behavioral changes are commonly seen, and evaluation includes GAS testing with throat culture and antistreptolysin O and antideoxyribonuclease titers. References: Sydenham's Chorea (http://www.ncbi.nlm.nih.gov/pubmed/31003820)

A 11-Year-Old Girl Is Brought to the Office Due to a 2-Day