Post Viral Acute Cerebellar Ataxia following Chickenpox (Varicella) in a toddler

Background: Varicella-zoster virus (VZV) is one of the most common infections of childhood causing chickenpox, which in a majority of cases is self-limiting without any complicating consequences. However, in a meagre 0.01-0.03% cases, chickenpox may lead to serious neurological complications. Among them is acute cerebellar ataxia, which presents with the characteristic sign of broad-based gait abnormality, progressing gradually over the course of days, the mechanism of which is still debated upon. As a treatment option, the use of antiviral remains controversial, and some recommend it for better prognosis while others do not base on its autoimmune pathogenesis. This case is being communicated due to its rarity. Case Presentation: A case of a two-year-old female with a recent history of chickenpox eruption presented with the complaint of progressive loss of normal gait and difficulty in talking followed by generalized to-and-fro movements of her body leading to a diagnosis of post-viral acute cerebellar ataxia. There was no significant history of any past illnesses. Bacille Calmette Guerin (BCG) vaccine was given at birth, later followed by a single dose of pentavalent (Penta) vaccine. Management: Central nervous system (CNS) examination showed ataxic gait, pupils bilaterally equally reflective to light (BERL), nystagmus, dysmetria, and decreased muscle tone. Laboratory investigations were within the normal range. Imaging modalities that were all normal excluded other causes, including metabolic, tumors, and toxins. The patient was empirically treated with IV acyclovir BD for one week. Conclusion: As the rash of chickenpox resolves spontaneously in most cases, it is important that children infected with VZV should be closely observed for any neurological symptoms for timely and effective intervention.