Due to concerns of possible airway obstruction, a CT scan of the neck is obtained to rule out any acute pathology, such as epiglottitis compromising his airway. The scan shows some inflammation and edema in the soft tissues that is thought to be secondary to his acute viral illness. B is able to maintain his airway and oxygenation, so intubation is not necessary.
A CPK test is ordered because there are concerns of sustained muscle contraction of B’s left wrist and elbow. The CPK level is 884 U/L (reference range 26 to 192 U/L). The elevation in CPK is consistent with prior laboratory findings of dehydration and indicating skeletal muscle breakdown from sustained muscle contraction. All other laboratory results, including a comprehensive metabolic panel, urine drug screen, and thyroid screening panel, are within normal limits.
EVALUATION No variation in facial expression
B is admitted to the general pediatrics service. Maintenance IV fluids are started due to concerns of dehydration and possible rhabdomyolysis due to his elevated CPK level. Risperidone is held throughout the hospital course due to concerns for an acute dystonic reaction. B is monitored for several days without clinical improvement and eventually discharged home with a diagnosis of inflammatory mononeuropathy due to viral infection. The patient is told to discontinue risperidone as part of discharge instructions.
Five days later, B returns to the hospital because there was no improvement in his left extremity or walking. His left elbow remains extended with left wrist in flexion. Psychiatry is consulted for further diagnostic clarity and evaluation.
On physical examination, B’s left arm remains unchanged. Despite discontinuing risperidone, there is evidence of cogwheel rigidity of the left wrist joint. Reflexes in the upper and lower extremities are 2+ and symmetrical bilaterally, suggesting intact upper and lower motor pathways. Babinski sign is absent bilaterally, which is a normal finding in B’s age group. B continues to have difficulty with ambulating and appears to “fall forward” while trying to walk with assistance. His parents also say that B is not laughing, smiling, or showing any variation in facial expression.
Continue to: Additional family history...