Hemorrhagic disease of the newborn, also known as vitamin K deficiency bleeding affects term and preterm infants and causes unexpected blood loss at various sites, including cerebral bleeding, with potentially severe consequences. Traumatic birth and hemophilia are predisposing factors.
While assessing hemorrhagic disease of the newborn, the physician should first inquire about maternal conditions, medication and feeding preferences, in order to determine a deficiency of vitamin K during the pregnancy. In the infant, the classical signs may present during the 2nd and 7th day. The illness is classified based on the timing the initial blood loss event is observed . In early-onset, bleeding starts during the first 24 hours of life. This is the case if mothers used anticonvulsant or antituberculosis drugs during gestation. The severe type may be partly prevented by administering vitamin K to the mother during the last 2 to 4 weeks of pregnancy.
Affected children exhibit gastrointestinal, brain, skin or mucous membrane bleeding or blood loss from the umbilical stump. Late-onset symptoms usually appear between 2nd and 12th week. However, they can be noticed till 6 months of age. It affects breastfed babies who failed to receive prophylactic vitamin K at birth and have undiagnosed cholestasis leading to vitamin K malabsorption  and may also cause intracranial hemorrhage . This manifests as apnea, seizures, and shock, while other parenchymal organs blood loss may be difficult to detect by clinical examination. However, if suspicion arises, urgent imaging evaluation is required. Cases have been reported in Europe  and Australia  .
Infants may report with blood-stained sputum, respiratory distress, irritability or melena. If the hemorrhage is significant, the baby will be tachycardic and the blood pressure will be low. The late form of the illness may also be a manifestation of several underlying conditions, such as cystic fibrosis, diarrhea, hepatitis, alpha 1-antitrypsin deficiency, Alagille syndrome, galactosemia, and abetalipoproteinemia.
When facing a child with evident bleeding, the physician should order a complete coagulation panel, including a complete cell blood count, fibrinogen level, fibrin degradation products, prothrombin time, activated partial thromboplastin time and thrombin clotting time, as well as the international normalized ratio (INR). These tests have orientation values and only point to the existence of a vitamin K deficiency, they do not directly establish the diagnosis. The prothrombin time will be increased, while fibrinogen and platelets are normal. A more useful test is represented by protein induced by vitamin K antagonism, that will be increased, but it is not widely available. Thrombocytopenia or an increased activated partial thromboplastin time are not consistent with hemorrhagic disease of the newborn diagnosis, but rather with antiplatelet antibody maternal transmission by breastfeeding, for instance . Fibrin degradation products are increased in liver diseases, after blood transfusion or in disseminated intravascular coagulation in children. An INR 1.4 or less excludes vitamin K deficiency. Factor VIII may be congenitally low or decreased due to disseminated intravascular coagulation.
A qualitative assessment of platelets concerning mass, as well as their total number is a reliable predictor for intracranial hemorrhage in gram-negative sepsis newborns . If suspected, liver pathology can be demonstrated using classical biochemistry tests and imaging methods like endoscopic retrograde cholangiopancreatography. A liver biopsy is occasionally needed in order to exclude biliary atresia or inherited metabolic liver diseases . In case neurologic symptoms are present and intracranial hemorrhage is suspected, a magnetic resonance imaging cranio- cerebral scan should be performed. Intrathoracic bleeding is ruled out using radiographs and ultrasound examination.