P2.236: Generalized weakness, gait difficulty, and hyporeflexia in a 4-year-old male with negative CSF studies and unremarkable imaging

Introduction: Miller-Fisher syndrome (MFS), a type of immune-mediated neuropathy, is a rare variant of Guillan-Barre syndrome (GBS) that typically presents with ataxia, areflexia, ophthalmoplegia, or a combination of these findings. We present a case of a child with severe weakness and respiratory failure consistent with MFS; however, without ophthalmoplegia and negative imaging of the brain and spine.

Case Description: 4-year-old with no significant past medical history, who presented with one day of generalized weakness and bilateral upper and lower extremity weakness. Symptoms were associated with cough. His physical examination included an antalgic gait and diffuse hyporeflexia. He was afebrile with unremarkable vital signs and initial imaging. Due to concern for GBS, a lumbar puncture was completed that revealed normal CSF findings and no growth in CSF culture. MRI of the brain and total spine revealed no abnormalities. Shortly afterward, he developed worsening weakness and hypoxemic respiratory failure, which required mechanical ventilation. Although his preliminary workup was negative, with a high clinical suspicion for MFS versus GBS, he was treated with two courses of IVIG and showed slow improvement. He had a prolonged PICU course complicated by Moraxella catarrhalis and Acinetobacter baumannii tracheitis that was treated with IV antibiotics. During his admission, he failed multiple attempts to wean him off of the ventilator, and through shared decision-making, a tracheostomy was placed. Repeat MRI of the brain and total spine showed smooth enhancement of the ventral greater than dorsal cauda equina nerve roots. Repeat CSF studies showed albuminocytologic dissociation. As his clinical status slowly improved, he completed inpatient physical, speech, and occupational therapy and was discharged to another facility to complete inpatient rehabilitation.

Discussion: MFS has a mean age of onset of 43 years affecting more men than women. Lower cranial and facial nerve palsies may present, while motor weakness of the limbs is a less common finding. MFS is believed to result after a preceding infection. Laboratory findings include albuminocytologic dissociation in the CSF. However, only about half will show these findings and CSF will initially appear normal. Our patient presented with generalized weakness including the extremities, associated gait difficulty, and hyporeflexia. Labs revealed multiple previous infections, including EBV, CMV, and Enteropathogenic Escherichia coli. Initial CSF findings were normal, as is typical for early cases of MFS; however, subsequent CSF analysis revealed an albuminocytologic dissociation. MRI findings supported the diagnosis of GBS, specifically the MFS variant.

Conclusion: As most cases present with nerve palsies rather than motor weakness, as seen in this patient, this case provides a less common presentation of MFS. If a patient presents with high clinical suspicion for MFS or GBS, consider prompt initiation of therapy to decrease morbidity. In our case, CSF studies and neuroimaging only revealed MFS after therapy had begun.