Fuel for Thought – Case series of Beta-Ketothiolase patients presenting with metabolic encephalopathy

Swikaar Panchal, Ami Shah, Lakshmi Shobhavat, Rekha Solomon, Isha Bhagat

Introduction: Beta-ketothiolase deficiency is an inherited disorder of isoleucine and ketone body metabolism. Those affected predominantly present during an intercurrent illness with severe acute ketoacidosis, dehydration and encephalopathy in late neonatal or early childhood period. Metabolic disorders being one of the many causes for encephalopathy, prompt diagnosis and appropriate intensive care management is crucial for a favorable outcome. Diagnosis is often a challenge due to variable phenotype, inconsistent biochemical markers and nonavailability of enzyme assays. Case Series: We describe 4 infants with acute decompensation following febrile gastric illness.(Table1) They presented in encephalopathic state with severe ketoacidosis and ketonuria. TMS showed abnormal acylcarnitine profile in 3 infants. Urinary GCMS showed increased urinary excretion of ketone and isoleucine catabolic intermediates suggestive of ketolytic disorders in all. Most had a stormy PICU course - 3 required peritoneal dialysis and prolonged bicarbonate supplementation. Neuroimaging done in 2 patients showed hyperintense signals in the basal ganglia along with volume loss in the cerebrum and cerebellum. Poor neurological outcome followed by death was seen in 3 infants and only 1 child recovered and is neurologically well conserved. Genetic testing done in 3 patients revealed compound heterozygous variant in 2 and homozygous variant in 1 patient in the ACAT1 gene. Conclusion: We highlight the phenotypic variability and practical challenges in diagnosis of ketolytic disorders. Encephalopathy is a medical emergency, reversible with early institution of treatment. Thus, a strong clinical suspicion and early diagnosis is required to prevent complications and improve prognosis of these disorders.
Keywords: Beta-Ketothiolase, Encephalopathy, IEM

Swikaar Panchal
B J Wadia hospital for Children
India

Ami Shah
B J Wadia hospital for Children
India

Lakshmi Shobhavat
B J Wadia hospital for Children
India

Rekha Solomon
B J Wadia hospital for Children
India

Isha Bhagat
B J Wadia hospital for Children
India
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Ami Shah 
B J Wadia hospital for Children India