Which of the following is classified as a metabolic disorder?

Hepatic encephalopathy is classified as a metabolic disorder because it results from liver dysfunction, which leads to an accumulation of toxic substances in the bloodstream, notably ammonia. The liver plays a crucial role in metabolizing nutrients and detoxifying harmful byproducts of metabolism. When the liver is impaired, as in the case of liver diseases, its ability to filter and metabolize toxins diminishes, resulting in neurological disturbances. Symptoms of hepatic encephalopathy can range from subtle cognitive changes to profound confusion and even coma, all stemming from this metabolic derangement.

In contrast, multiple sclerosis is primarily an autoimmune condition that affects the central nervous system, involving inflammatory demyelination rather than a metabolic issue. Sturge-Weber syndrome is a neurological disorder associated with a congenital malformation and vascular abnormalities, making it more of a developmental rather than a metabolic disorder. Pick's disease is a type of frontotemporal dementia caused by neurodegeneration, which is also distinct from metabolic conditions since it does not arise from metabolic dysfunctions. Thus, hepatic encephalopathy stands out as the correct answer within the context of metabolic disorders.