Hemorrhagic disease of the newborn refers to spontaneous bleeding in newborns caused by vitamin K deficiency.

bubble_chart Etiology

The following reasons cause vitamin K deficiency: (1) The fetus mainly relies on its own synthesis for vitamin K, but due to the immature liver function of the fetus, the synthesis of vitamin K is affected; (2) At birth, the newborn's intestines are sterile, which affects the synthesis of vitamin K in the intestines; (3) The vitamin K content in breast milk is low, and breastfeeding infants receive less vitamin K; (4) Liver and gallbladder diseases, antibiotic use, diarrhea, etc., all affect the synthesis and absorption of vitamin K.
The coagulation biological activity of clotting factors II, VII, IX, and X directly depends on the presence of vitamin K. The levels of these vitamin K-dependent factors are low at birth, especially factors II and VII, which are only 25–60% of normal levels. When they drop below 20% within 48–72 hours, there may be a tendency for spontaneous bleeding. Levels gradually return to birth levels after 10 days.

bubble_chart Clinical Manifestations

1. Bleeding usually occurs 2 to 4 days after birth, and in premature infants, it may occur as late as within 2 weeks after birth. It can happen spontaneously or be triggered by minor injuries. The onset and severity of bleeding vary, with significant bleeding most commonly occurring in the gastrointestinal tract, manifesting as hematemesis and hematochezia, often presenting as fresh blood. Umbilical bleeding is also relatively common, and there may be static blood in the skin or subcutaneous tissues. Renal and pulmonary bleeding are rare. If intracranial bleeding or other hemorrhages occur more than two weeks after birth, it is referred to as late-onset vitamin K deficiency.
2. The general condition varies depending on the amount and site of bleeding. Severe bleeding can lead to anemia or even shock, while pulmonary and intracranial bleeding have their respective clinical manifestations.

﹝Auxiliary Examination﹞

Red blood cell count and hemoglobin levels decrease, platelet count remains normal, clotting time is prolonged, and prothrombin time is extended.

bubble_chart Diagnosis

For newborns who experience bleeding within the first week of birth, have no other disease manifestations, and appear normal, this condition should be considered. A prothrombin time prolonged to more than twice the control value is diagnostically significant; rapid improvement with vitamin K treatment can serve as an important diagnostic basis.

bubble_chart Treatment Measures

﹝Treatment﹞

(1) For cases with bleeding but no significant anemia, administer intravenous vitamin K1 at 3–5 mg/kg for 3 consecutive days; (2) If bleeding is severe, transfuse fresh whole blood or plasma at 10–15 ml/kg; (3) For massive bleeding leading to pallor and shock, transfuse 15–20 ml/kg within 5–10 minutes. If there is no significant improvement, with persistent low blood pressure and hemoglobin below 80–100 g/L, repeat the transfusion. If necessary, administer furosemide at 1 mg/kg simultaneously. Maintain hemoglobin above 120 g/L, along with normal blood pressure and pH.

bubble_chart Prevention

(1) Intramuscular injection of 1 mg vitamin K1 after birth; (2) Intramuscular injection of 3-5 mg vitamin K1 for those with perinatal asphyxia or congenital gastrointestinal malformations; (3) Intramuscular injection of vitamin K for 3-5 days before delivery if there is a possibility of vitamin K deficiency during pregnancy.

bubble_chart Differentiation

1. Necrotizing small intestine colitis with hematochezia is an important clinical manifestation, but often presents with significant abdominal distension and fullness and toxic symptoms. X-ray plain films show pneumatosis intestinalis.
2. Congenital bleeding disorders: (1) Thrombocytopenia manifests as petechiae and ecchymoses on the skin, and may also involve major bleeding. However, the prothrombin time is normal while the platelet count is reduced. (2) Hemophilia often results in prolonged bleeding after injury, with a frequent family history. Vitamin K treatment is ineffective.
3. For other cases of gastrointestinal bleeding, the possibility of gastrointestinal malformations and ulcers should be considered, and differentiation from swallowed blood syndrome is necessary. The method involves mixing 1 part of vomitus with 5 parts of water, taking 4 ml of the pink supernatant, and adding 1 ml of 1% sodium hydroxide. If the solution remains pink after 1–2 minutes, it indicates fetal blood; if it turns brown, it suggests swallowed maternal blood from purgation.