Which type of encephalopathy is marked by lethargy, hypotonia, and seizures?

The identification of moderate encephalopathy as the correct answer is based on the clinical presentation that includes lethargy, hypotonia, and seizures. Moderate encephalopathy typically presents with a range of neurologic symptoms that can vary in severity, but it commonly includes significant changes in alertness (lethargy), muscle tone abnormalities (hypotonia), and the potential for seizures.

In contrast, mild encephalopathy usually involves negligible symptoms, where the infant might be alert and active, showing few or no significant clinical manifestations. Severe encephalopathy, on the other hand, is associated with more profound clinical signs, such as severe neurologic dysfunction, significant alterations in consciousness, and may necessitate immediate medical intervention. Chronic encephalopathy generally refers to long-standing or persistent neurological issues, often resulting from prior injury or insults rather than the acute presentation characterized by lethargy, hypotonia, and seizures.

Therefore, moderate encephalopathy aligns closely with the symptoms presented in the question, as it captures the essence of an elevated but not maximal level of neurologic compromise.