A 24-year-old woman has the following haematology and coagulation profile post
admission to the intensive care unit following post partum haemorrhage.
| Parameter | Patient Value | Normal Range |
| White cell count | 5.6 x 109/l | 4.0 – 11.0 |
| Haemoglobin | 60 g/l | 115 – 165 |
| Platelets | 30 x 109/l | 150 – 400 |
| PT | 30.6 sec | 10.5 – 13.5 |
| APTT | >150 sec | 21 – 36 |
| D-dimer | >10 µgm/ml | FEU <0.4 |
| Fibrinogen | 0.8 g/l | 1.1 – 3.2 |
a) What does this pattern of coagulation abnormalities suggest?
b) List three likely causes of this coagulation profile in this patient
c) What does an elevated D-dimer indicate?
a) What does this pattern of coagulation abnormalities suggest
DIC
b) List three likely causes of this coagulation profile in this patient
Pre-eclampsia
Amniotic fluid embolism
Sepsis
Intra-uterine fetal death
Mismatched / massive transfusion
c) What does an elevated D-dimer indicate?
Tests fibrinolysis. Measures the break down of the cross-linked fibrin
This question is one of pattern recognition, and it interrogates the candidate's ability to generate a list of differential causes for DIC at the end of pregnancy.
There isn't much else this list of abnormalities could represent.
There is evidence of accelerated fibrinolysis (D-dimer elevation), a low fibrinogen suggestive of its consumption, evidence for the depletion of clotting factors (high PT and APTT) and thrombocytopenia with anaemia, suggestive of microangiopathy.
The causes of DIC are numerous, but in the context of pregnancy and PPH one can narrow down one's list of possibilities.
There are actually quite a large number of potential peripartum causes for DIC:
An excellent review article lists these, and others, and delves deep into their pathophysiology and management.
So, what indeed does an elevated D-dimer indicate? The college seems to have expected a one-line answer.
It seems to be a valuable adjunct for the laboratory diagnosis of DIC.
In essence, a D-dimer is a small protein degradation product, consising of two crosslinked D-fragments of fibrin.
A longer explanation, with pictures and extensive bibliography, is also available. The presence of an elevated D-dimer confrms that somewhere fibrin is being degraded.
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