title: Metabolic decompensation in methylmalonic aciduria: which biochemical parameters are discriminative?
abstract: Recurrent, life-threatening metabolic decompensations often occur in patients with methylmalonic aciduria (MMAuria). Our study evaluated (impending) metabolic decompensations in these patients aiming to identify the most frequent and reliable clinical and biochemical abnormalities that could be helpful for decision-making on when to start an emergency treatment. Seventy-six unscheduled and 179 regular visits of 10 patients with confirmed MMAuria continuously followed by our metabolic centre between 1975 and 2009 were analysed. The most frequent symptom of an impending acute metabolic decompensation was vomiting (90% of episodes), whereas symptoms of intercurrent infectious disease (29%) or other symptoms (such as food refusal and impaired consciousness) were found less often. Thirty-five biochemical parameters were included in the analysis. Among them, pathological changes of acid-base balance reflecting metabolic acidosis with partial respiratory compensation (decreased pH, pCO(2), standard bicarbonate, and base excess) and elevated ammonia were the most reliable biochemical parameters for the identification of a metabolic decompensation and the estimation of its severity. In contrast, analyses of organic acids, acylcarnitines and carnitine status were less discriminative. In conclusion, careful history taking and identification of suspicious symptoms in combination with a small number of rapidly available biochemical parameters are helpful to differentiate compensated metabolic condition and (impending) metabolic crisis and to decide when to start an emergency treatment.
authors.affiliation: Department of General Pediatrics, Division of Inherited Metabolic Diseases, University Children's Hospital Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany. tamaris.zwickler@med.uni-heidelberg.de
authors.forename: Tamaris
authors.initials: T
authors.lastname: Zwickler
authors.forename: Gisela
authors.initials: G
authors.lastname: Haege
authors.forename: Alina
authors.initials: A
authors.lastname: Riderer
authors.forename: Friederike
authors.initials: F
authors.lastname: Hörster
authors.forename: Georg F
authors.initials: GF
authors.lastname: Hoffmann
authors.forename: Peter
authors.initials: P
authors.lastname: Burgard
authors.forename: Stefan
authors.initials: S
authors.lastname: Kölker
mesh_terms: D000136:Acid-Base Equilibrium; D000138:Acidosis / Q000097:blood / Q000175:diagnosis / Q000378:metabolism; D000293:Adolescent; D000328:Adult; D000592:Amino Acid Metabolism, Inborn Errors / Q000097:blood / Q000175:diagnosis* / Q000378:metabolism*; D000641:Ammonia / Q000097:blood; D001639:Bicarbonates / Q000378:metabolism; D002331:Carnitine / Q000031:analogs & derivatives / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D055815:Young Adult
chemical_list: D001639:Bicarbonates; C116917:acylcarnitine; D000641:Ammonia; D002331:Carnitine