Acute Hypotonia in an Infant.

Area of Science:

• Neurology
• Pediatrics
• Infectious Diseases

Background:

• Acute flaccid myelitis (AFM) incidence is rising in the U.S., presenting a diagnostic challenge in emergency departments.
• AFM is characterized by acute paralysis and gray matter MRI changes in children under 21, with unknown etiology but often preceded by viral illness.
• No established treatment guidelines exist for AFM, necessitating further research and clinical awareness.

Observation:

• A 4-month-old infant presented with decreased arm movement, hypotonia, and a history of upper respiratory illness.
• MRI revealed gray matter hyperintensity (C2-C6) without white matter changes; the patient tested positive for enterovirus.
• Initial treatment included intravenous steroids and immunoglobulin, with slight improvement observed.

Findings:

• The case highlights a pediatric patient with confirmed enterovirus infection presenting with AFM.
• The clinical presentation and MRI findings are consistent with AFM, distinguishing it from other paralytic conditions.
• The patient showed minimal improvement with current supportive care, underscoring the need for specialized management.

Implications:

• Emergency physicians must be aware of the increasing incidence of AFM and its distinct clinical presentation.
• Differentiating AFM from other causes of acute flaccid paralysis based on history and physical exam is critical in the ED.
• Prompt transfer to a pediatric hospital for further evaluation and care is recommended for suspected AFM cases, avoiding aggressive ED diagnostics.