Thrombotic thrombocytopenic Purpura

This guideline is generally aimed at specialists and there’s nothing new for us. However, if you want a quick reminder of this rare, but extremely dangerous condition, read on! Skip the first paragraph to avoid the sciency bits…

The Science…

Thrombotic Thrombocytopenic Purpura (TTP) can be acquired or congenital. In the congenital form they lack a particular protein (ADAMTS13 if you really want to know). In the acquired form, they produce antibodies to the protein. This protein normally cleaves Von Willebrand factor to allow it to work. When Von Willebrand Factor isn’t cleaved, it causes platelets to aggregate abnormally in the small vessels, hence causing the thrombosis. Because they’ve all aggregrated, you end up with an overall lack of them.

The acquired form can be triggered by infections (eg HIV, hepatitis), pregnancy or drugs (eg oestrogen, quinine).


Generally patients present with bleeding (either heavy bleeding, eg menorrhagia, or abnormal bleeding from anywhere) and anaemia. They will often feel generally fatigued, achey and unwell and can be in renal failure and have neurological or cardiac impairment.

The FBC will show low platelets (normally 10 to 30) and an anaemia. The clotting will likely be normal.

Hopefully the lab will already have phoned and told us what to do, but otherwise, they need emergency referral as they need treatment the same day (otherwise mortality is high).

Contraception – avoid COC in women who’ve previously had TTP as oestrogens can trigger it.

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