Question

Following a full term normal delivery (FTND), a woman develops postpartum hemorrhage after 2 days. Activated partial thromboplastin time (APTT) is raised, factor VIII is 10% of the normal value, while prothrombin time (PT) and thrombin time (TT) are normal. What is the likely diagnosis?

• A. Acquired factor VIII deficiency
• B. Hereditary factor VIII deficiency
• C. DIC
• D. Antiphospholipid syndrome

Hint:

Isolated raised APTT with low factor VIII, normal PT and TT, and no bleeding history before delivery points to an acquired factor VIII inhibitor, not a hereditary defect or DIC.

Answer 1

The Correct Option is A

Step 1: Understanding the Question.
A woman bleeds two days after a normal delivery. Her APTT is long, her factor VIII activity is only 10% of normal, but her PT and TT are both normal. We need the diagnosis that fits this exact lab pattern.

Step 2: Key Concept or Approach.
APTT tests the intrinsic pathway, factors VIII, IX, XI, and XII, plus the common pathway. PT tests the extrinsic pathway, factor VII, plus the common pathway. TT tests only the last step, fibrinogen turning into fibrin.
A long APTT with a normal PT and a normal TT means the defect sits only in the intrinsic-pathway factors, VIII, IX, XI, or XII, and not in fibrinogen or the extrinsic pathway.

Step 3: Detailed Explanation.
Her factor VIII is measured directly and is only 10% of normal, so factor VIII is the specific factor at fault, matching the isolated APTT rise.
Hereditary factor VIII deficiency (hemophilia A) is X-linked and present from birth, so a woman with this disease would almost always have a bleeding history since childhood, such as bleeding after minor cuts, dental work, or an earlier delivery. A first bleed only now, after an otherwise normal delivery, does not fit a lifelong hereditary defect.
A new antibody that appears after delivery and attacks factor VIII, called acquired hemophilia A, is a recognized rare postpartum complication. The antibody neutralizes circulating factor VIII, so its activity drops even though the person was never a hemophiliac before. Since only factor VIII is knocked down, APTT rises while PT and TT, which do not depend on factor VIII, stay normal. This matches the case exactly.
DIC would consume clotting factors from both pathways, so PT would also rise, fibrinogen would fall and lengthen TT, and platelets would usually drop too. Here PT and TT are both normal, so DIC does not fit.
Antiphospholipid syndrome, through the lupus anticoagulant, can make the APTT look long in the test tube because the antibody interferes with the phospholipid used in the assay, but the true factor VIII level stays normal and the clinical problem this syndrome causes is clotting, not bleeding. A real drop of factor VIII to 10% does not match this diagnosis.

Step 4: Final Answer.
An isolated long APTT, a true fall in factor VIII, normal PT and TT, and a fresh onset after delivery point to an acquired inhibitor against factor VIII.
\[ \boxed{\text{Acquired factor VIII deficiency}} \]