A wide array of neurometabolic disorders may first appear during a severe metabolic derailment presenting to the Pediatric Intensive Care Unit (PICU). These include, among others, mitochondrial disorders. Reaching a diagnosis in such cases may raise many challenges, for numerous reasons: First, diagnosis is usually of great urgency due to extreme conditions and potential of deterioration. Secondly, diagnosis may require several tests, which are both time consuming and do not necessarily lead to a final diagnosis. Thus, often requiring further testing. There is no gold standard for diagnosis, and as of the present, diagnosis of a metabolic disease can be made by a combination of biochemical investigations and Next Generation Sequencing techniques, or by either method alone. In this report, we present two illustrative cases of neurometabolic disorders, both in 5 months old female patients admitted to the PICU. The patients both presented symptoms of neuromuscular dysfunction and lactic acidosis, and were in need of PICU admission. Diagnosis of a molecular etiology was reached in both cases, although the work up and final diagnoses were made differently. The patients reported herein illustrate that in some cases mitochondrial diseases can be diagnosed without necessarily performing a tissue biopsy but rather pursuing Next Generation Sequencing, while other cases do necessitate intrusive investigations. In addition, we encourage the use of Next Generation Sequencing as a diagnostic strategy in selected PICU cases, as it enables the diagnosis of numerous metabolic disorders and may unravel the molecular basis in cases which otherwise would remain elusive.
