Acute Encephalopathy Caused by Inherited Metabolic Diseases

Abstract

Acute encephalopathy is a critical medical condition that typically affects previouslyhealthy children and young adults and often results in death or severe neurological sequelae. Inherited metabolic diseases that can cause acute encephalopathy include urea cycle disorders, amino acid metabolism disorders, organic acid metabolism disorders, fatty acid metabolism disorders, mutations in the thiamine-transporter gene, and mitochondrial diseases. Although each inherited metabolic disease is rare, its overall incidence is reported as 1 in 800–2500 patients. This narrative review presents the common inherited metabolic diseases that cause acute encephalopathy. Since diagnosing inherited metabolic diseases requires specific testing, early metabolic/metanolic screening tests are required when an inherited metabolic disease is suspected. We also describe the symptoms and history associated with suspected inherited metabolic diseases, the various tests that should be conducted in case of suspicion, and treatment according to the disease group. Recent advancements made in the understanding of some of the inherited metabolic diseases that cause acute encephalopathy are also highlighted. Acute encephalopathy due to inherited metabolic diseases can have numerous different causes, and recognition of the possibility of an inherited metabolic disease as early as possible, obtaining appropriate specimens, and proceeding with testing and treatment in parallel are crucial in the management of these diseases.

Urea cycle disorders in critically Ill adults

“…UCDs typically present in the neonatal window, where severe hyperammonemia results after protein intake from breastmilk or formula [11]. Ammonia levels are often high enough to result in irreversible neurologic injury.…”

“…Diagnosing a mild UCD hinges upon capturing an elevation in ammonia, but this laboratory evaluation is often omitted from the initial assessment. For critically ill patients without previously diagnosed UCDs or other inborn errors of metabolism (IEMs), screening for hyperammonemia in the setting of a broad grouping of unexplained neurologic symptoms is recommended (Table 1) [1 ▪▪ ,2 ▪ ,11,15]. It is important to note that elevated ammonia levels are sometimes the result of sampling technique, and mild-to-moderate elevations should be rechecked [1 ▪▪ ,2 ▪ ].…”

Acute Encephalopathy in a 10-Year-Old Patient With Maple Syrup Urine Disease: A Challenging Diagnosis

“…This enzymatic deficiency leads to the toxic accumulation of leucine, isoleucine and valine, resulting in a spectrum of clinical manifestations. Although MSUD is renowned for its impact on the neurological and metabolic systems, particularly in newborns, occurrences of necrotizing encephalopathy linked to this condition, especially in adolescents, are exceedingly infrequent [ 2 ].…”