A low platelet count (less than 150 x 109/L) is extremely common in clinical practice.
- Spurious e.g. ethylenediaminetetraacetic acid (EDTA) induced clumping, clotted sample.
- Physiological e.g. pregnancy
- Reduced production e.g. post viral, congenital, drugs, alcohol, B12 / folate, myelodysplastic syndrome (MDS)
- Increased destruction e.g. drugs, idiopathic thrombocytopenic purpura (ITP), auto-immune, disseminated intravascular coagulation (DIC)
History and Examination
- Bleeding symptoms - usually only when platelets are less than 10 x 109/L
- Drugs e.g. aspirin, quinine, non-steroidal anti-inflammatory drugs (NSAIDs). Also consider over-the-counter drugs, herbal medications, and supplements
- Recent viral illness, night sweats, weight loss, arthralgia and rashes
- Family history of bruising or bleeding, or low platelets
- Nutritional and alcohol history
- Lymphadenopathy and/or hepatosplenomegaly may suggest underlying systemic disease
- Skin for sites of bleeding
- Consider neurological assessment and confusion screen if patient at increased risk of CNS bleed (risk increases with age)
Assess the risk of bleeding according to the platelet count.
If the platelet count is:
- 50 to 150, no risk of bleeding
- 30 to 50, rarely causes bleeding even with trauma
- 10 to 30, may cause bleeding with trauma but is unusual with normal day to day activity. Many patients are asymptomatic
- Less than 10, may have spontaneous bruising or bleeding. Many are still asymptomatic
Note: Bleeding risk is also dependent on whether other parts of the haemostatic process are involved, e.g. coagulation factor abnormalities in liver disease.
- If significant bleeding and acute admission may be necessary, phone the on-call haematologist
- Arrange urgent assessment if severe thrombocytopenia (less than 10 x 109/L), as this is associated with an increased risk of bleeding
- Platelet count more than 80 and asymptomatic, repeat full blood count (FBC) and blood film to confirm within the next week
- Platelet count less than 80 or symptomatic, repeat FBC, blood film, and coagulation screen the next day
Low platelet count confirmed. According to clinical suspicion, consider:
- Coagulation screen
- Liver function tests
- Serum B12 and folate
- human immunodeficiency virus (HIV) serology (low platelets may be the only feature in early disease)
- Anti-nuclear factor (idiopathic thrombocytopenic purpura (ITP) may be secondary to systemic lupus erthematosus (SLE))
On retesting, if platelet count is:
- Normal, repeat testing in one month
- Less than 80 x 109/L or symptomatic, request haematologist assessment. As bleeding is unlikely to be solely due to thrombocytopenia at a platelet count more than 30, consider whether another cause of bleeding is more likely e.g. GI pathology, vasculitis.
- More than 80 x 109/L and asymptomatic:
- Consider stopping any drugs started in the last 3 months
- Treat any deficiencies and follow up other abnormalities
- Treatment is not necessary
- Monitor FBC monthly for 2 months and then yearly if stable
- Advise patient to report any petechial rash, bruising, or bleeding
- Phone the on-call haematologist if the patient has significant bleeding and may need acute admission.
- Request haematologist assessment if platelet count less than 80 or the patient is symptomatic.
- Where appropriate written advice may be available.
e-Referral Service Selection
- Specialty: Haematology
- Clinic Type: Not otherwise specified
DRSS Referral Form
This guideline has been signed off by NEW Devon CCG.
Publication date: July 2016
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Thrombocytopenia (Low Platelets)
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