Low platelets (platelets <150 x 10^9/L)

South Tees Hospitals NHS Foundation Trust

Definition/Description

A low platelet count is defined a count <150 x10⁹/L until the platelet count falls <50 x10⁹/L. This is usually asymptomatic, with spontaneous bleeding being more common once <20-30 x10⁹/L.

Symptoms tend to include bruising, petechiae and mucosal bleeding, however more serious bleeds, e.g. intra-cerebral, can also occur. Due to the risk of bleeding, drugs such as NSAIDs or anticoagulants should generally be avoided when the platelet count is <70 x10⁹/L.

Red Flag Symptoms

None provided

Guidelines on Management

Differential diagnosis:

Spurious: e.g. platelet aggregation in an EDTA blood sample.
Infection related, especially viral, including HIV.
Alcohol excess
Liver disease / splenomegaly
Autoimmune, especially if history of autoimmune disease, e.g. SLE.
Vitamin B12 / folate deficiency
Chronic DIC, e.g. malignancy
Drug effect or post-radiotherapy
Bone marrow failure - for example haematological malignancy or metastatic solid tumour. Often with low haemoglobin / white cell count and suspicious blood film features.

Examination should include assessment of haemorrhagic features, e.g. bruising, petechiae or mucosal bleeding. Also check for lymphadenopathy, hepatomegaly or splenomegaly.

Baseline testing: FBC, blood film, coagulation screen (PT, APTT, fibrinogen), U+E, LFT, TSH. Patients should be considered for HIV testing, especially if no other cause of thrombocytopenia is apparent.

Referral Criteria/Information

Referral:

Consider Haematology referral if:

Co-existing unexplained anaemia or leucopenia.
Immediate referral if platelet count 3 months.
Urgent referral if platelet count <20-50 x10⁹/L (repeat immediately to ensure not a sample error).
Unexplained platelet count 50-100 x10⁹/L for >3 months.

Haematological referral is inappropriate where there is a known non-haematological cause, for example metastatic solid tumour or liver disease.