Coagulation disorders: Pathology review

At the hematology ward, there’s Braden, a 5 year old male, who developed prolonged bleeding after circumcision.

His mother is worried because he has a history of recurrent hemarthrosis after minor falls.

Family history reveals a relative of his mother who suffered from bleeding diathesis.

Now, there’s also a 3 day old preterm baby, called Harlow, who is bleeding severely from the umbilicus.

Her mother states that she did not get the standard care after delivery. CBC, PT and PTT are ordered for both patients.

They both have normal platelet count.

Now, Braden has normal PT but elevated PTT, while Harlow has both PT and PTT elevated.

Both Braden and Harlow are suffering from a hemostasis disorder.

Hemostasis disorders, also known as bleeding disorders, can be broadly divided into three groups.

The first includes problems with primary hemostasis, which is the formation of the platelet plug, so they are also called platelet disorders.

The second group includes problems with secondary hemostasis, which is making a strong fibrin clot through activation of the intrinsic, extrinsic and common coagulation pathways, and so they’re known as coagulation disorders.

And the last group includes disorders that affect both primary and secondary hemostasis and are known as mixed platelet and coagulation disorders.

Let’s focus on coagulation disorders that are usually due to a decrease in the number of clotting factors and causes include hemophilia and vitamin K deficiency.

So, let’s look at hemophilia first.

They are a group of inherited bleeding disorders caused by deficiencies in various coagulation factors.

Hemophilia A and B are X-linked recessive disorders so a high yield fact is that they almost exclusively affect males while females are carriers.

A big hint for hemophilia is a family history of a maternal relative with a bleeding disorder.

Hemophilia A causes a deficiency in factor VIII, while hemophilia B leads to a deficiency in factor IX.