Asian Journal of Case Reports in Medicine and Health

Holocarboxylase synthetase deficiency is a rare inherited disorder of biotin metabolism that impairs the activity of multiple biotin-dependent carboxylases. Although it usually presents during the neonatal period or infancy, clinically significant metabolic decompensation may occur later when long-term biotin supplementation is interrupted. This report describes a 16-year-old girl with known holocarboxylase synthetase deficiency who presented with recurrent vomiting, irritability, dehydration, tachypnoea and tachycardia after missing biotin therapy for approximately one month. Her condition deteriorated rapidly, with drowsiness, reduced responsiveness, hypotension and severe high-anion-gap metabolic acidosis. Laboratory investigations also showed hyperkalaemia, elevated lactate, raised inflammatory markers and acute renal involvement. She required endotracheal intubation, mechanical ventilation and vasopressor support. Following specialist consultation, high-dose biotin was administered with intravenous glucose, lipid supplementation, fluid resuscitation and supportive intensive care. Broad-spectrum antimicrobial therapy was also given because an intercurrent infection was suspected. Her haemodynamic, renal and metabolic abnormalities improved progressively, allowing withdrawal of vasopressor support and mechanical ventilation. The biotin dose was subsequently reduced, and the patient regained full consciousness and mobility. This case highlights the risk of life-threatening metabolic decompensation during adolescence in patients with holocarboxylase synthetase deficiency, particularly after interruption of maintenance treatment. A careful medication history, early recognition of an inherited metabolic disorder and prompt specialist-guided treatment may support a favourable clinical outcome.