Tehran University of Medical Sciences Frontiers in Emergency Medicine 2717-3593 9 1 2024 12 21 e2 e2 Nahideh Khosroshahi Department of Pediatric Neurology, Bahrami Children’s Hospital, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. Seyedeh-Fatemeh Marzani Department of Pediatric Nephrology, School of Medicine, Hakim Children’s Hospital, Tehran University of Medical Sciences, Tehran, Iran. Ali-Reza Tavasoli Department of Pediatric Neurology, Children’s Medical Center, Tehran University of Medical Sciences, Tehran, Iran. Effat Hosseinali-Beigi Department of Pediatric Intensive Care Unit, School of Medicine, Bahrami Children’s Hospital, Tehran University of Medical Sciences, Tehran, Iran. Kambiz Eftekhari Pediatric Gastroenterology and Hapatology Research Center, Department of Pediatric Gastroenterology, Bahrami children's Hospital, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. 2024 06 27 2024 09 03 Objective: Hypotonia in children is an important and common clinical symptom that can manifest in various neurological disorders. It often poses a serious diagnostic challenge for physicians, frequently leading to inaccurate evaluations and unnecessary investigations. The purpose of this study was to investigate the causes of hypotonia, various diagnostic methods, and the final outcomes of these patients.  Methods: Children with hypotonia who were hospitalized in the pediatric intensive care unit (PICU) of Bahrami Children's Hospital and Children's Medical Center during a two-year period (2017-2018) were enrolled. All relevant information, including key points from their medical history, clinical examinations, and paraclinical data that could lead to diagnosis, were recorded. The patients was followed up for two years after hospitalization through phone calls or visits to the neurology clinic.  Results: Out of 65 children examined, 28 patients (43.07%) had peripheral nervous system involvement, 20 (30.76%) had central nervous system involvement, and 4 (6.17%) had both central and peripheral nervous system involvement. The most common causes for peripheral and central involvement were spinal muscular atrophy (SMA) and syndromic causes, respectively. In 20% of cases however an,  specific underlying cause  was  found. The most common diagnoses were SMA (16.9%) and Guillain-Barre syndrome (13.8%). Finally, 15 children (23.1%) recovered, 31 (47.7%) had neurological sequelae, and 19 (29.2%) died.  Conclusion: Understanding the underlying causes and outcomes of patients hospitalized with hypotonia in the PICU enhances physicians’ diagnostic skills. It is also useful for selecting effective treatment strategies and avoiding the complications associated with delayed diagnosis. https://fem.tums.ac.ir/index.php/fem/article/view/1438 https://fem.tums.ac.ir/index.php/fem/article/download/1438/504