Severe Late-Onset Vitamin K Deficiency Bleeding Presenting With Subdural Hematoma and Seizures in a 4-Month-Old Infant: A Case Report From a Resource-Limited Setting.

Background: Vitamin K deficiency bleeding (VKDB) remains a preventable cause of severe hemorrhage in early infancy. Late-onset VKDB (2 weeks-6 months) most commonly presents with intracranial hemorrhage (ICH) and can result in death or long-term neurological sequelae. Although routine neonatal intramuscular vitamin K prophylaxis is highly effective, late VKDB may still occur in the presence of contributing factors such as infection or impaired vitamin K availability. Case Presentation: A 4-month-old male infant presented with fever, cough, and poor appetite. He was delivered by cesarean section (birth weight 3200 g) and reportedly received 1-mg intramuscular vitamin K at birth. He was predominantly formula-fed with occasional breastfeeding and had no history of trauma or prior bleeding. Initial laboratory testing showed hemoglobin 9 g/dL and leukocytosis; sepsis with anemia was suspected, and intramuscular ceftriaxone was administered. Shortly after the first dose, he developed an expanding injection-site hematoma with active bleeding. Coagulation studies revealed profound coagulopathy (INR > 4, PT > 120 s, aPTT > 120 s), with a decline in hemoglobin to 6.3 g/dL. Parenteral vitamin K was given, leading to correction of coagulation parameters; however, seizures and deteriorating consciousness developed. Neuroimaging demonstrated a subdural hematoma with hypoxic-ischemic cerebral injury. The patient was managed in the intensive care unit with seizure control, blood transfusion, antimicrobial therapy, and supportive care. Seizures resolved and the neurological status returned to baseline. He was discharged after 10 days without apparent neurological deficits, with long-term neurodevelopmental follow-up advised. Conclusions: This case suggests probable late-onset VKDB presenting with life-threatening ICH despite reported neonatal vitamin K prophylaxis, while acknowledging that the complete exclusion of alternative causes of coagulopathy was limited by resource constraints. Clinicians should maintain a high index of suspicion for VKDB in infants with unexpected bleeding after minor procedures or intramuscular injections, particularly in the setting of intercurrent infection, and initiate prompt vitamin K therapy, coagulation assessment, and neuroimaging when indicated.