You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is A three day-old term infant borne at home, breast-fed exclusively, presented with lethargy, bulging fontanel, and bright red blood from rectum. What is the most likely etiology of his disease? and explain in detail?
Vit K deficiency is associated with hemorrhagic disease of newborn which has manifested in this baby as Intracranial hemorrhage (bulging fontanel) and GI bleed (blood per rectum). Moreover home delivery (Vit K may not have been given at bih) and exclusive breast feeding (Vit K is deficient in breast milk) clearly point to Vit K deficiency as etiology.