Defying the Odds: A Case Report of ACTG2-Related Megacystis-Microcolon-Intestinal Hypoperistalsis Syndrome With Complete Recovery

Visceral myopathy is a rare and complex congenital disorder primarily impacting the gastrointestinal and urologic systems. Among its manifestations, megacystis-microcolon-intestinal hypoperistalsis syndrome (MMIHS) represents the most severe form. Typically, this condition has a poor prognosis, with all reported cases necessitating lifelong parenteral nutrition, frequent surgical interventions, and intermittent catheterization. We present the case of a three-month-old female infant with a history of <i>ACTG2</i>-related MMIHS who presented with oliguria, emesis (non-bilious to bilious), and fever of 38.9°C over a two-day period. A gastrointestinal panel identified enteroaggregative <i>Escherichia coli</i>, and imaging revealed distended bowel loops without evidence of ischemia, microcolon, or obstructive lesions. The distended bladder required temporary catheterization, which was later removed. Initial parenteral nutrition was discontinued after eight days as the infant tolerated oral feeds well. The hospitalization was further complicated by a urinary tract infection and thrombocytosis, but the patient was ultimately discharged on full oral feeds with spontaneous urine output. This case contrasts the typical poor prognosis of visceral myopathy and MMIHS with a favorable outcome. The patient, who led an asymptomatic life until three months of age, avoided surgical interventions, long-term parenteral nutrition, and intermittent catheterization, interventions commonly required for MMIHS. After identifying an underlying infection that triggered pseudo-obstructive symptoms, symptomatic management was implemented. Once the infection resolved, no further interventions were necessary. This approach was not only cost-effective but also reduced the physical and emotional burden of the family, underscoring the importance of early diagnosis and targeted treatment for positive outcomes.