Cerebral Venous Infarction Due to Deep Medullary Venous Thrombosis in a Neonate with Severe Milk-induced Non-IgE-mediated Gastrointestinal Food Allergy: A Case Report.

Cow's milk-induced non-IgE-mediated gastrointestinal food allergies (non-IgE-GIFAs) are common and generally considered to have a favorable prognosis; however, severe cases can occur. We report a case of a neonate who presented with hypovolemic shock and subsequently developed cerebral infarction due to deep medullary venous thrombosis. A female infant, born at 35 weeks of gestation, was initially fed formula but transitioned to exclusive breastfeeding within a few days. After discharge on day 17, mixed feeding was resumed, leading to frequent pale-colored diarrhea. On day 19, she developed hypovolemic shock and was admitted to the intensive care unit. Her symptoms improved with nil per os management; however, on day 20, her hemoglobin levels declined despite no signs of bleeding on ultrasonography. She was treated with red blood cell transfusion and intravenous vitamin K. An amino acid-based formula was introduced on day 22 without adverse events, which suggested a possibility of non-IgE-GIFAs. However, the patient developed intermittent transient fevers thereafter; a cranial ultrasound performed on day 41 revealed a low-echoic area in the right frontal lobe. Subsequent magnetic resonance imaging revealed a cystic lesion in the right frontal lobe accompanied by surrounding parenchymal degeneration, leading to a diagnosis of venous infarction due to deep medullary vein thrombosis. Blood tests ruled out vitamin K deficiency and protein C or S defects. Despite this neurologic complication, she exhibited no neurologic symptoms throughout the clinical course. At 10 months of age, her neurodevelopment remains normal without any delays. This case highlights the potential for severe complications, including cerebral venous infarction, in neonatal non-IgE-GIFAs. Close monitoring for systemic complications is crucial in severe cases.