1 - Unidade de Desenvolvimento, Hospital Dona Estefânia, Centro Hospitalar Universitário de Lisboa Central, Lisboa
2 - Unidade de Infeciologia pediátrica, Hospital Dona Estefânia, Centro Hospitalar Universitário de Lisboa Central, Lisboa
3 - Unidade de Doenças Metabólicas, Hospital Dona Estefânia, Centro Hospitalar Universitário de Lisboa Central, Lisboa
- The 13th Excellence in Pediatrics Conference, publicação sob poster científico.
Inborn errors of metabolism (IEM) are a group of disorders that result from impairment in normal metabolic processes. Many can present with metabolic decompensation. Early recognition and appropriate treatment are vital for reducing morbi-mortality. Furthermore, the signs and symptoms of IEMs may be nonspecific and often overlap with more common disorders, such as infectious diseases. It is important for the pediatrician to know when to suspect, request basic metabolic tests, start medical treatment, and refer to a specialist.
5-year-old girl, 2nd child of consanguineous, healthy parents, born after an uneventful gestation. She had poor weight gain, feeding difficulties with protein aversion, and intellectual disability.
At age four, attended the pediatric emergency department (ED) with a 36-hour history of fever, vomiting and prostration. Examination revealed mild dehydration (3% of body weight), tachycardia, hyperventilation and ataxia. Initial laboratory workout demonstrated severe metabolic acidosis (pH 7,101, pCO2 16mmHg, HCO 3-5,1mmol/L) with increased anion gap (35,7mmol/L), mild hyperketonemia (3,4mmol/L), normal glucose (77mg/dL), normal lactate (1,2mmol/L) and mild hyperammonemia (243µg/dL). She was admitted for intravenous fluid therapy and acidosis correction, after which there was complete recovery. Rotavirus antigen was isolated in the feces. Laboratory investigation in crisis showed massive amounts of urinary methylmalonic acid (3,745µmol/mmol creatinine), elevated propionylcarnitine(C3), normal plasma total homocysteine and B12vitamin. Genetic testing showed a probable pathogenic variant in MMADHC gene, confirming the diagnosis of intracellular vitamin B12 metabolism defect – CbID variant 2. She started weekly intramuscular hydroxicobalamin and relative protein restriction, with good clinical and metabolic evolution.
Infectious etiologies are the most frequent causes of vomiting in the ED. However, this is also an unspecific sign. In this case, the severe clinical presentation raised the suspicion of a metabolic disease, since metabolic acidosis was severe, the anion gap was markedly increased, ketone bodies only mildly elevated (not explaining the anion gap) and there were no other causes, such as severe dehydration, shock, hyperglycemia or hyperlactacidemia. Antecedents of consanguinity, feeding difficulties, failure to thrive, and developmental delay also made the diagnosis more probable. The diagnosis allowed to start adequate therapy and changed the clinical evolution of such an uncommon disorder.
Palavras Chave: metabolic acidosis, metabolic disorders, vomiting