7.2 Coagulopathies, DIC, Thrombocytopenia, and Factor Deficiencies

7.2 Coagulopathies, DIC, Thrombocytopenia, and Factor Deficiencies

Quick Answer: Classic vitamin K deficiency bleeding (VKDB) occurs at 1-7 days when intramuscular vitamin K was omitted. DIC in sepsis or asphyxia consumes both platelets and clotting factors. Neonatal alloimmune thrombocytopenia (NAIT) can devastate a firstborn whose mother has a normal platelet count; maternal ITP antibodies cause a usually milder neonatal drop. Factor VIII and IX deficiencies prolong PTT with a normal PT. Match PRBCs, platelets, FFP, and cryoprecipitate to the deficit, and conserve blood with fewer draws.

Coagulopathies are the second Hematology/Immunology leaf in the 20% Endocrine, Hematology/Immunology, GI, Renal/GU, and Integumentary domain. OpenExamPrep independent teaching covers these patient problems as they appear on AACN Certification Corporation's current Neonatal CCRN Test Plan. Follow your blood bank and vitamin K policies at the bedside.

The healthy term newborn has a unique hemostatic system: vitamin K-dependent factor levels are physiologically low compared with older children, platelet counts are typically in the adult range (about 150,000-450,000/µL), and you will not diagnose most bleeds with a bleeding time. You will use PT/INR, aPTT, fibrinogen, D-dimer or fibrin degradation products, platelet count, and the clinical bleed. A coagulopathic number without bleeding still matters in a very preterm infant who needs a lumbar puncture or surgery. A bleed with normal numbers is a surgical, traumatic, or vascular problem until proven otherwise.

Vitamin K deficiency bleeding

Vitamin K is required to gamma-carboxylate factors II, VII, IX, and X and proteins C and S. Placental transfer is limited, the neonatal liver is immature, and breast milk is low in vitamin K. Intramuscular vitamin K shortly after birth is the prevention that works. Oral regimens exist in some countries and fail more often if doses are missed. Refusal of IM vitamin K is a counseling and documentation event, not a trivia fact: those infants are the classic-VKDB denominator.

Three clocks belong in your head:

• Early VKDB (first 24 hours): usually maternal medications that interfere with vitamin K (warfarin, some anticonvulsants, antituberculous drugs). Bleeding can be serious and visceral.
• Classic VKDB (day 1-7, often days 2-7): the infant who did not receive IM vitamin K. Gastrointestinal bleeding, umbilical ooze, circumcision bleeding, and skin hemorrhage. PT is markedly prolonged; platelets and fibrinogen are typically normal, which separates this from DIC.
• Late VKDB (week 2-12, sometimes later): exclusively breastfed infants without vitamin K, or infants with cholestasis and fat-soluble vitamin malabsorption. Intracranial hemorrhage is the feared presentation.

A 3-day-old home birth, no IM vitamin K, bloody stool, PT greater than 50 seconds, platelets 280,000, fibrinogen 250 mg/dL is classic VKDB. Give vitamin K immediately, support with fresh frozen plasma if bleeding is life-threatening, and do not call it NAIT. A 6-week-old breastfed infant with a full fontanelle and no vitamin K at birth is late VKDB until imaging and labs say otherwise. Vitamin K begins to correct the carboxylation defect within hours; FFP supplies finished factors while you wait.

DIC in sepsis and asphyxia

Disseminated intravascular coagulation is uncontrolled thrombin generation plus fibrinolysis. Triggers in the NICU include sepsis (early- or late-onset), asphyxia, shock, necrotizing enterocolitis, severe hemolysis, and hypothermia. You consume platelets and clotting factors at the same time. The infant oozes from puncture sites, the umbilicus, and endotracheal tubes. Labs show thrombocytopenia, prolonged PT and PTT, low fibrinogen, elevated D-dimer/FDPs, and sometimes schistocytes. The hematocrit may fall from bleeding or from hemolysis.

Treat the cause. Blood products are support, not the cure: platelets for thrombocytopenia with bleeding or a critically low count, FFP for factor replacement, cryoprecipitate when fibrinogen is low (cryoprecipitate is concentrated fibrinogen, factor VIII, von Willebrand factor, and factor XIII). Do not treat a D-dimer in isolation in a well infant. Do not treat classic VKDB as DIC: fibrinogen and platelets stay normal in pure vitamin K deficiency.

A worked picture: a 28-week infant with gram-negative shock, platelets 22,000, PT 28 seconds, PTT 90 seconds, fibrinogen 80 mg/dL, D-dimer very high, oozing from a PICC site. That is DIC. Antibiotics, hemodynamics, and product replacement travel together. Vitamin K is reasonable if the infant may also be deficient, but it will not by itself restore a consumed fibrinogen. Full sepsis pathways live in Chapter 14; here the heme signature is consumption of both lines.

Thrombocytopenia: NAIT versus maternal ITP versus other

Neonatal thrombocytopenia is commonly discussed below 150,000/µL. Severe counts below 50,000, and especially below 30,000, raise bleeding concern, including intracranial hemorrhage. Causes include placental insufficiency and preeclampsia (usually mild to moderate, recovering), sepsis and NEC (falling counts in a sick infant), DIC, viral infection (CMV, HSV), thrombosis, Kasabach-Merritt physiology in rare vascular tumors, and immune causes.

Neonatal alloimmune thrombocytopenia (NAIT) is the platelet analogue of Rh disease. The mother is negative for a paternal platelet antigen (most often HPA-1a in White populations) that the fetus inherited. Maternal IgG crosses. The mother's own platelet count is normal. NAIT can occur in a first pregnancy. The neonate can have a count under 10,000, petechiae, and ICH. Treatment is antigen-negative platelets (or washed maternal platelets) and IVIG per hematology protocol, plus cranial ultrasound. Random-donor platelets may not last; they are a bridge if antigen-negative units are delayed.

Maternal ITP: the mother has autoimmune thrombocytopenia or a documented history of it. Anti-platelet antibodies can cross and produce neonatal thrombocytopenia, often milder than NAIT, and the mother's count is usually low or she has that history. Management is supportive; IVIG or steroids enter when counts are dangerous. The exam split is clean: mother's platelets normal plus a severe neonatal drop, even in a firstborn, think NAIT. Mother has ITP, think transplacental autoantibody.

Do not confuse either with immune hemolysis (DAT, bilirubin, anemia) or with VKDB (normal platelets, long PT). AACN does not publish an official platelet-transfusion trigger. Many units use sliding thresholds by illness, invasiveness, and bleeding; follow the written protocol rather than inventing a national number.

Factor VIII, factor IX, and liver failure

Hemophilia A (factor VIII) and hemophilia B (factor IX) are X-linked. Male infants present with bleeding after procedures (circumcision, heel sticks that will not stop), intramuscular hematomas, or intracranial hemorrhage. PTT is prolonged; PT and platelet count are normal. Family history is absent in a substantial fraction because of new variants. The birth dose of IM vitamin K is still indicated; use a careful injection and pressure, not a skipped dose that invites classic VKDB on top of hemophilia. Specific factor replacement is hematology-directed. FFP contains both factors but is not elegant long-term therapy.

Liver failure (see also Chapter 8 hepatic teaching) drops liver-made factors (I, II, V, VII, IX, X). Factor VIII is made in endothelium and may be normal or high, a biochemical clue versus DIC (where VIII is consumed) and versus vitamin K deficiency (factor V remains relatively preserved; vitamin K-dependent factors are low). Vitamin K will not fully correct a dying liver. Product support plus treating the liver disease is the path. A prolonged PT in a jaundiced 4-week-old with acholic stools is biliary atresia or liver-failure territory, not classic day-3 VKDB.

Blood products and conservation: testable matches

Match the bag to the hole:

Blood conservation is a testable nursing action, not a slogan:

• Delayed cord clamping when feasible increases initial blood volume and iron stores.
• Batch laboratory draws; use microtainers; avoid daily panels that do not change care.
• Return dead-space blood from arterial lines per protocol; do not discard a preterm blood volume casually.
• Closed blood-gas systems reduce waste.
• Treat the cause of DIC or hemolysis so you are not replacing an ongoing leak.
• EPO and iron are adjuncts in some growing preterms; they do not replace conservation.

O-negative, irradiated, leukoreduced, CMV-safe red cells are common NICU specifications. Platelets are typically ABO compatible when possible. Document volumes, check identity with a second nurse per policy, watch ionized calcium if large citrate loads are given (FFP and large PRBC volumes), and watch for TACO (transfusion-associated circulatory overload) versus TRALI (acute lung injury after transfusion). Those reactions are uncommon but not optional knowledge. Typical platelet volumes are often discussed near 10-15 mL/kg; FFP near 10-15 mL/kg; cryoprecipitate dosing is unit- and fibrinogen-directed rather than an AACN constant.

Putting bleeds together

A circumcision that will not stop on day 2 with a long PT and normal platelets is VKDB if vitamin K was skipped, or hemophilia if vitamin K was given and PTT is the isolated abnormality. Oozing from every line in a septic, asphyxiated infant with low fibrinogen is DIC. A firstborn with a platelet count of 6,000 and a mother whose platelets are 240,000 is NAIT until proven otherwise. A pale former 25-week infant at 6 weeks with a hemoglobin of 8 and no coagulopathy is section 7.1, not a plasma problem.

Exam traps: calling every low platelet count NAIT; treating VKDB with platelets; inventing an AACN-mandated platelet transfusion trigger; using FFP to treat polycythemia; describing this OpenExamPrep section as official blood-bank policy. It is independent teaching covering listed patient problems. Mixed practice items are at /practice/ccrn-neonatal.