ANEC is a severe, rapidly progressive neurological disorder that typically emerges in the wake of systemic infections, most often viral. It is characterized by a distinctive pattern of injury: bilateral lesions concentrated in the thalami, the paired structures deep within the brain that act as relay stations for sensory and motor signals. Unlike infectious encephalitis, in which a pathogen directly invades brain tissue, ANEC is thought to be driven by a dysregulated host immune response, sometimes described as a cytokine storm, in which inflammatory signaling molecules damage the small blood vessels of the brain and cause localized swelling, hemorrhage, and tissue death. The result is a condition that can evolve from fever and lethargy to seizures, coma, and profound neurological impairment within hours to days.

In the case described by the Iranian team, the diagnostic journey was far from straightforward. When the child was admitted to the tertiary center, laboratory testing revealed evidence of widespread systemic inflammation and multiorgan involvement. Her liver enzymes were markedly elevated, with aspartate aminotransferase measured at 130 units per liter and alanine aminotransferase at 210 units per liter, indicating hepatic injury. Lactate dehydrogenase, an enzyme released when cells are damaged or destroyed, was severely elevated at 6910 units per liter, a level consistent with extensive tissue breakdown. She also developed coagulopathy, a disorder of blood clotting, reflected in an international normalized ratio of 2.0 and a platelet count that had fallen to 51,000 per microliter. Together, these findings painted a picture of a body under systemic inflammatory assault.

One of the most instructive aspects of the case, the authors note, was the initial misdirection of the diagnostic workup. The child presented with severe hyperglycemia, an abnormally high blood sugar level, and metabolic acidosis, an accumulation of acid in the blood. These findings strongly suggested diabetic ketoacidosis, a well-known emergency in children with new-onset diabetes in which insulin deficiency leads to dangerous levels of blood glucose and acidic ketone bodies. However, in this patient the metabolic derangement was instead a manifestation of the overwhelming inflammatory process. This distinction matters enormously, because diabetic ketoacidosis and ANEC demand entirely different treatment strategies, and anchoring on the more familiar diagnosis can delay recognition of the underlying neuroimmune catastrophe.

Neuroimaging ultimately provided the key to the correct diagnosis. Computed tomography of the brain revealed characteristic bilateral thalamic hypodensities, regions of reduced density within both thalami that correspond to the edema and necrosis typical of ANEC. Notably, the team could not perform magnetic resonance imaging, which is normally the preferred modality for characterizing these lesions in greater detail, because the patient was too clinically unstable to undergo the prolonged scanning and monitoring that MRI requires. The case therefore highlights a practical reality of pediatric critical care: in the sickest children, clinicians may have to rely on CT findings alone, making familiarity with the CT signature of ANEC, symmetric thalamic involvement in the appropriate clinical context, an essential diagnostic skill.

As if the neurological injury were not enough, the clinical course was further complicated by concurrent fulminant myocarditis, a sudden and severe inflammation of the heart muscle. Echocardiography revealed an ejection fraction of just 20 percent, meaning the heart’s main pumping chamber was ejecting only a fifth of the blood it contained with each contraction, compared with a normal value of roughly 55 to 70 percent. This level of cardiac dysfunction constitutes a life-threatening emergency in its own right. The combination of ANEC and severe myocarditis in the same patient is particularly noteworthy, because both conditions are believed to share an inflammatory mechanism, and their co-occurrence suggests that the cytokine-mediated injury in this child was not confined to the central nervous system but swept through multiple organ systems at once.

Management of the patient required a multimodal approach coordinated across pediatric intensive care, cardiology, and neurology. The team deployed immunomodulatory therapy, including intravenous immunoglobulin, a preparation of pooled antibodies that can dampen harmful immune activity, and pulse methylprednisolone, high-dose corticosteroid therapy delivered in short bursts to suppress inflammation. Alongside these immune-targeted treatments, the clinicians provided neuroprotective care and intensive cardiovascular support to sustain perfusion of the brain and other organs while the heart recovered function. This combination reflects the current best available strategy for ANEC, which is grounded not in a single proven therapy but in early, aggressive control of the inflammatory response combined with meticulous supportive care.

Despite the aggressiveness of the intervention, the outcome was sobering. The child survived, but she sustained residual neurological deficits, including spasticity, a condition of abnormal muscle stiffness caused by damage to the motor pathways of the brain, and persistent abnormalities on electroencephalography, the recording of the brain’s electrical activity. These sequelae illustrate a central and frustrating truth about ANEC: even when the acute inflammatory storm is brought under control, the structural damage it inflicts on the thalami and surrounding structures can leave lasting functional impairment. Neurological outcomes in ANEC are highly variable, ranging from full recovery in milder cases to severe disability or death in the most fulminant presentations, and clinicians currently have limited ability to predict which trajectory an individual patient will follow.

The authors argue that their case carries several broader lessons for pediatric practice. First, recognition of the characteristic neuroimaging findings, particularly bilateral thalamic lesions in a child with fever and rapidly progressive encephalopathy, can substantially accelerate diagnosis and allow immunomodulatory therapy to begin before irreversible damage accumulates. Second, the metabolic disturbances seen in ANEC, including hyperglycemia and acidosis, can mimic more common conditions such as diabetic ketoacidosis, and clinicians should interpret these findings in the full clinical context rather than in isolation. Third, the involvement of extraneural organs, exemplified here by fulminant myocarditis and hepatic injury, means that ANEC should be understood as a multisystem inflammatory disorder rather than a purely neurological one, warranting a genuinely multidisciplinary treatment response.

Looking forward, the case report points to the gaps that remain in the field. The authors emphasize the need for improved diagnostic strategies that can identify ANEC earlier and more reliably, optimized therapeutic approaches built on stronger evidence than individual case experience currently allows, and long-term multidisciplinary rehabilitation programs to address the spasticity, cognitive impairment, and other deficits that survivors frequently carry. Because ANEC is rare, progress will likely depend on the accumulation and comparison of carefully documented cases such as this one, together with research into the immune mechanisms that drive the thalamic injury. For now, the message for clinicians is clear: in a child who deteriorates neurologically after an infection, especially when laboratory markers of systemic inflammation are extreme and other organs begin to fail, ANEC deserves a place high on the differential diagnosis, because time is the one variable that most strongly shapes the outcome.

Subject of Research: Acute necrotizing encephalopathy of childhood with concurrent severe myocarditis in a pediatric case report

Article Title: A challenging case of acute necrotizing encephalopathy of childhood with severe myocarditis

Article References: Hosseinzade, Z., Moshfegh, F., Javanbakht, M., & Javid, A. (2026). A challenging case of acute necrotizing encephalopathy of childhood with severe myocarditis. BMC Pediatrics. https://doi.org/10.1186/s12887-026-07649-x

Image Credits: AI Generated

DOI: 10.1186/s12887-026-07649-x

Keywords: acute necrotizing encephalopathy, ANEC, myocarditis, cytokine storm, thalamic lesions, pediatric critical care, neuroinflammation, immunomodulation, IVIG, methylprednisolone, neuroimaging, BMC Pediatrics