A Case of Torticollis in an 8-Month-Old Infant Caused by Pos
An 8-month-old male infant presented to the emergency department with 2 months of increased left neck muscle tone and rightward chin tilt consistent with acquired torticollis. Symptomatically, the patient had chronic cough, congestion, drooling, disordered breathing and poor weight gain for the same amount of time. In terms of birth history, the patient was born full term at 40 weeks with an uncomplicated pregnancy with proper prenatal care, planned cesarean section, and standard neonatal discharge to home.

On examination, the patient had normal vital signs but was notably fussy with a hoarse cry, drooling, increased leftward neck flexion and rotation and rightward chin tilt, which raised the concern for neurologic deficits. Basic labs including complete blood count, basic metabolic panel and coagulation studies were within normal limits. Preoperative magnetic resonance imaging (MRI) of the brain and cervical spine was obtained as the patient’s respiratory difficulties and failure to thrive suggested a lesion localizing to the brainstem. MRI showed a large cystic lesion at the right CPA measuring 2.7 × 2.5 × 3.0 cm (anteroposterior (AP) × transverse (TV) × cephalocaudal (CC), respectively), hypointense on T1 and hyperintense on T2, without gadolinium enhancement, diffusion restriction or susceptibility artifact, most consistent with an arachnoid cyst (Figure 1). The lesion was causing overt flattening of the pons and mass effect along the length of the right superoanterior and lateral medulla, mild mass effect on the right cerebellum, and displacement and mild effacement of the fourth ventricle. There was no abnormal vascularity, syrinx, or chiari malformation or extension down to the cervical spine. Ventricles were otherwise normal in morphology and size.

The patient was admitted to the pediatric intensive care unit for neurologic monitoring and underwent a right retrosigmoid craniotomy for fenestration of the arachnoid cyst. Upon opening of the dura, cerebrospinal fluid (CSF) was allowed to drain for brain relaxation. Dynamic retraction revealed the cyst walls, with cranial nerve 7 (facial nerve), cranial nerve 8 (vestibulocochlear nerve), as well as the lower cranial nerve complexes embedded within the cyst and posterior cyst wall. The cerebellum was protected, and the posterolateral cyst wall was sharply opened with egress of CSF. The inner walls of the cyst were lined with arachnoid and did not contain any abnormal tissue. CSF cytology was sent which showed no evidence of malignancy. The cyst was fenestrated toward the prepontine cistern and thoroughly irrigated prior to dural closure and bone replacement. There were no changes in neuromonitoring. At his 2-week follow-up evaluation, the patient’s head and chin were straight, their cry was no longer hoarse, and there was no abnormal drooling. He was tolerating age-appropriate oral feeds. On physical therapy evaluation, he could rotate his head symmetrically in both directions and was meeting his neonatal motor milestones. There was some expected mild muscle weakness of the right lateral neck flexors compared to the left, which is expected to improve with continued physical and occupational therapy.