Acute management of propionic acidemia

Propionic academia (PA) is a autoressesive inborn error of metabolism disease, and has been reported among those of Amish ancestry. PA occurs within the first few days or weeks of life and presents with lethargy, poor feeding, vomiting, and metabolic decomposition. Caused by mutations in the propionyl-CoA carboxylase (PCC) gene, a mitochondrial biotin dependent enzyme leading to catabolism of valine, isoleucine, methionine, threonine, cholesterol, and odd chain fatty acids.

 

A block in propionyl pathway causing accumulation of organic acids in the blood, cerebrospinal fluid, and urine. Neonates experience neurological deterioration, feeding refusal, vomiting, weight loss, hypotonia, abnormal posturing/movements, lethargy, seizures, coma, severe brain damage, or death within days. Late manifest results in Immune and bone morrow suppression, recurrent infections, neurological sequlae, mental retardation.

Nutritional implications include: metabolic crisis, feeding changes secondary to infections, recurrent episodes, metabolic decomposition due to inadequate oral intake, Illness with fever endogenous catabolism, dehydration, constipation, essential fatty acid deficiency, and gastrointestinal bacteria producing propionic acid.

Medical nutrition therapy focuses on eliminating the amino acids (AA) causing exacerbation of this disease; isoleucine, threonine, valine, and methionine.  Reducing protein foods containing these or restriction of AA (dietary precursors) to reduce toxic organic acids (OA).

Synthetic AA based formulas provide 50% protein daily along with intact protein such as low biological value proteins of fruits, veggies, and limited grains.

Infant protein intake is around 1-1.5 g Pro/kg and can be achieved by diluting standard formula and adding protein free formula to the standard formula.

The recommended diet is similar to requirements of PKU, such as a moderate protein with high energy coming from carbohydrates and fat. Increased fluid needs of two liters or more are needed to increase removal of abnormal metabolites. Avoid fasting to prevent muscle pro catabolism and OA build up with frequent meals every two to three hours. Preventative measurements

May include a PEG tube or Nasogastric, which is effective in decreasing hospitalization and chronic management for adequate nutrition, acute relapse, and feeding aversion.

Adjunct treatment involves carnitine supplement, laxatives, biotin, IV fluids, and multivitamin to combat micronutrient deficiencies.

Chapman, K. A., Gropman, A., MacLeod, E., Stagni, K., Summar, M. L., Ueda, K., ... & Pena, L. (2012). Acute management of propionic acidemia. Molecular genetics and metabolism, 105(1), 16-25.

MA