Definition
Isolated platelet count below the normal range. For patients with bi- or pancytopenia refer to the appropriate RefHelp page.
Please also see the guidance on thrombocytopenia in pregnancy.
Please note:
- Persistent, unexplained thrombocytopenia is an HIV indicator condition
- Thrombocytopenia can be drug-induced, therefore review all medication and consider discontinuing any drugs that might be implicated
- Drugs most often associated with thrombocytopenia include:
- heparin (including LMWH)
- quinine
- bendroflumethiazide
- sulphonamides
- sulphonylureas
- phenytoin
- methotrexate
- ranitidine
- NSAIDs.
- Heparin induced thrombocytopenia (HIT) – please see below for detail.
- For patients with a high alcohol intake, it may be appropriate to repeat the FBC to see if thrombocytopenia has resolved following a period of abstinence.
- For patients with a high alcohol intake, deranged LFTs +/- USS abdomen, consider GI referral initially.
Heparin Induced Thrombocytopenia (HIT)
This is a rare complication associated with significant risk of thrombosis. It usually occurs within 15 days of starting heparin/LMWH. If the platelet count is low – or has dropped by more than 50% – since heparin initiation, please discuss the case with the on-call haematology registrar.
C.M & L.W 26-03-24
Who to refer:
- Patients with platelet counts <100
- Urgent referral for patients with platelet counts <20 (contact on-call Haematology registrar)
Who not to refer:
- Isolated thrombocytopenia if platelet count >100, no other cytopenias and no accompanying clinical findings of concern such as the presence of lymphadenopathy or splenomegaly.
- If platelet count >100 repeat at 6 months and if remains >100 there is no requirement for routine monitoring.
How to refer:
SCI Gateway to the Department of Haematology RIE, WGH or SJH.
Primary care investigations
- Assess patient for symptoms of bleeding and easy or spontaneous bruising
- Review medication (see above)
- Take alcohol history
- Examine for lymphadenopathy and splenomegaly
- Blood film
- B12 and folate. Treat if deficiency is detected
- LFTs inc GGT. Consider US abdominal ultrasound scan, if abnormal
- HIV and HCV serology
- If additional clinical features to suggest a diagnosis of SLE, RA or other connective tissue disorder check CCP, ANF, dsDNA (if ANF positive)
