title: Challenges in diagnosing a metabolic disorder: error of pyruvate metabolism or drug induced?
abstract: Certain drugs are known to cause metabolic changes resulting in altered metabolic profiles. We report here a case where a combination of antiepileptic drugs resulted in a profile that mimicked a metabolic disorder. A 16month-old female child on antiepileptic drugs (valproate and topiramate) was suspected to have the inherited metabolic disorder, dihydrolipoamide dehydrogenase deficiency, based on clinical symptoms and metabolic profile showing hyperalaninemia, elevated branched-chain amino acids, and lactate-pyruvate ratio. Suspecting that the observed metabolic changes could have also arised from medication, current medication was weaned off and replaced with levetiracetam, clonazepam, and levocarnitine (supportive therapy). Metabolic profiling conducted after 47 days showed normal alanine, branched-chain amino acids, ornithine, and lactate-pyruvate ratio, suggesting that the earlier abnormalities could have been medication induced. We stress that metabolic changes resulting from chronic medication should be considered while interpreting a positive result when investigating an inherited metabolic disorder.
authors: Department of Physical Medicine and Rehabilitation, National Institute for Empowerment of Persons with Multiple Disabilities, Muttukadu, Chennai, India.
authors: George Tomy
authors: GT
authors: Mampilly
authors: Department of Physical Medicine and Rehabilitation, National Institute for Empowerment of Persons with Multiple Disabilities, Muttukadu, Chennai, India tomymampilly@gmail.com.
authors: Tomy Kochuvareed
authors: TK
authors: Mampilly
authors: Department of Neurochemistry, National Institute of Mental Health and Neurosciences, Bangalore, India.
authors: Rita
authors: R
authors: Christopher
authors: Department of Clinical Psychology, National Institute for Empowerment of Persons with Multiple Disabilities, Muttukadu, Chennai, India.
authors: Neeradha
authors: N
authors: Chandramohan
authors: Department of Physical Medicine and Rehabilitation, National Institute for Empowerment of Persons with Multiple Disabilities, Muttukadu, Chennai, India.
authors: Vijayalakshmy
authors: V
authors: Janaki
mesh_terms: D000927:Anticonvulsants / Q000009:adverse effects*; D005260:Female; D005632:Fructose / Q000009:adverse effects / Q000031:analogs & derivatives; D006801:Humans; D007223:Infant; D008659:Metabolic Diseases / Q000139:chemically induced* / Q000175:diagnosis*; D019289:Pyruvic Acid / Q000378:metabolism*; D000077236:Topiramate; D014635:Valproic Acid / Q000009:adverse effects
chemical_list: D000927:Anticonvulsants; D000077236:Topiramate; D005632:Fructose; D014635:Valproic Acid; D019289:Pyruvic Acid
keywords: false positives; metabolic disorder; valproate