Transient Mumps-associated Vasculopathy Presenting as Ischemic Stroke in an Infant

Dear Editor, Mumps, caused by an RNA virus of the Paramyxoviridae family, is generally a self-limiting illness that typically presents with fever, malaise, and parotid swelling.[1] Neurological complications such as aseptic meningitis, acute necrotizing encephalopathy, encephalitis, and post-infectious extrapyramidal syndromes occur in 1%–10% of cases.[1] Isolated ischemic stroke without evidence of encephalitis is an extremely rare complication of mumps.[2] We report a case of ischemic stroke in an infant following mumps infection, with complete recovery, suggestive of a transient parainfectious vasculopathy. A previously healthy 12-month-old male infant presented with a 2-day history of low-grade fever and new-onset left-sided focal seizures, which progressed to secondary generalization. The mother also noticed that the infant was not moving the left side of the body following the seizure. One week prior to admission, he had an episode of fever associated with bilateral parotid swelling during a documented mumps outbreak in his community. The infant had received one dose of measles–rubella vaccine as per the national immunization schedule. On examination at admission, the infant was alert and had transient left hemiparesis that resolved within 12 h. There was mild residual parotid swelling. Rest of the neurological and systemic examination was normal. Mumps IgM serology was strongly positive. Cerebrospinal fluid (CSF) examination revealed six lymphocytes, with normal glucose and protein levels, and sterile cultures. Magnetic resonance imaging (MRI) of the brain demonstrated multiple acute lacunar infarcts in the right temporal and parietal lobes, showing diffusion restriction without features of encephalitis [Figure 1]. Cardiac evaluation, coagulation profile, autoimmune workup, and metabolic screening were normal. A diagnosis of mumps-associated parainfectious vasculopathy was made, and levetiracetam (20 mg/kg/day) and low-dose aspirin (3 mg/kg/day) were initiated. The infant remained seizure-free and neurologically normal at the 6-month follow-up, with complete radiological resolution of lesions on repeat MRI [Figure 1]. Based on the antecedent parotitis, acute focal seizures with transient hemiparesis, and supportive laboratory and neuroimaging findings, a diagnosis of mumps-associated parainfectious vasculopathy presenting as ischemic stroke was considered.Figure 1: (A and B) Diffusion-weighted images (b1000) showing restricted diffusion in the splenium of the corpus callosum and gray–white junctions of the right parietal and temporal lobes. (C and D) Follow-up images showing complete resolution of the lesionsIn addition to varicella zoster virus, several other viruses, including cytomegalovirus, Herpes simplex virus, Epstein–Barr virus, human immunodeficiency virus, severe acute respiratory syndrome Coronavirus 2, and enterovirus, are recognized triggers of pediatric stroke.[3] Mumps-related ischemic stroke without encephalitis is exceedingly rare. Viral infections may predispose to the risk of stroke through immune activation, endothelial dysfunction, or coagulation abnormalities.[3] Our patient developed imaging-confirmed lacunar infarcts without encephalitis, which points to an immune-mediated parainfectious vasculopathy. The likely mechanism involved inflammatory vascular narrowing causing transient hypoperfusion and cytotoxic edema, which mimicked infarction on MRI. Elevated C-reactive protein and lactate dehydrogenase indicated a strong systemic inflammatory response. The diagnosis of transient parainfectious vasculopathy, without encephalitis, is further supported by normal CSF findings and the complete resolution of the lesions on follow-up MRI. Management of parainfectious vasculopathy due to mumps is primarily supportive with antiepileptics and low-dose aspirin to reduce the risk of further thrombotic events. Steroids may help immunocompetent patients with severe Varicella-Zoster virus encephalitis or viral encephalitis showing progressive vasculitis or cerebral edema.[4] In conclusion, this case highlights a rare but serious complication of mumps-associated ischemic stroke in children, likely resulting from transient parainfectious vasculopathy. Prompt recognition, supportive care, and follow-up imaging are key, and measles, mumps, and rubella vaccination remains critical to prevent these rare complications. Author contributions SAZ and AS: conceived and designed the study, collected data, analyzed the study, and prepared the manuscript and done editing. JA: wrote the first draft of the manuscript and managed the patient. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.