Thrombocytopenia in an adultBMJ 2013; 346 doi: http://dx.doi.org/10.1136/bmj.f3407 (Published 10 June 2013) Cite this as: BMJ 2013;346:f3407
- Jecko Thachil, consultant haematologist1,
- David Fitzmaurice, professor of primary care clinical sciences2
- 1Department of Haematology, Central Manchester University Hospitals NHS Foundation Trust, Manchester M13 9WL, UK
- 2University of Birmingham, Birmingham B15 2TT, UK
- Correspondence to: J Thachil
- Accepted 19 December 2012
A 40 year old woman visits her general practitioner with symptoms of dyspepsia and increasing tiredness. On a routine blood count, her platelet count is noted to be 40×109/L with normal haemoglobin and white cell count. She has no medical history and is not taking any medication. Clinical examination reveals no bruises or bleeding.
What issues you should cover?
Ask about recent or current symptoms of bleeding, which are commonly epistaxis or easy bruising with minor trauma. Haematuria and gastrointestinal bleeding are unusual, but menorrhagia can be a common symptom. In general, a platelet count above 30×109/L is unlikely to cause bleeding unless abnormal platelet function exists in the form of antiplatelet agents or myelodysplasia. Substantial bleeding tends to happen only if the count drops much below 20×109/L. Spontaneous intracranial haemorrhage secondary to thrombocytopenia usually occurs only with platelet counts less than 10×109/L. Further questions may be directed to identifying the possible causes of thrombocytopenia.
Pointers to diagnosis
Recent viral infections (such as glandular fever) are probably the commonest reason for a low platelet count in young adults.1 Occasional cases of moderate thrombocytopenia have been reported after flu vaccinations.1 Bacterial infections tend not to cause low platelet counts, unless associated with septicaemia.
Many common drugs can lead to thrombocytopenia, including H2 blockers, paroxetine, furosemide, and metronidazole. A temporal relation between the decrease in platelet count and the start of drug treatment is a clue. In these cases, stopping the drug usually improves the platelet count within a week, confirming the causality of the thrombocytopenia by the drug. Although well recognised as antiplatelet agents, aspirin and clopidogrel do not cause thrombocytopenia, but they can exacerbate the bleeding associated with lower platelet counts. The website www.ouhsc.edu/platelets provides a useful comprehensive guide to drugs that may induce thrombocytopenia.
Herbal remedies (such as Chinese herbal tea and tahini) are overlooked reasons for thrombocytopenia. Reports of a precipitous drop in the platelet count have been noted after ingestion of English walnuts. These cases are difficult to diagnose, but ask about frequent intake of the above and advise abstinence if they might be causative.
Immune thrombocytopenia is a common cause of low platelet count in young adults and is often seen in young women of reproductive age, who may also have symptoms and signs of autoimmune diseases (such as thyroid disease, systemic lupus erythematosus, and pernicious anaemia). In older adults, immune thrombocytopenia occurs with equal frequency in both sexes.
Chronic liver disease, including cirrhosis, leads to thrombocytopenia because of the lack of the platelet hormone thrombopoietin and associated splenomegaly. Excess alcohol intake can also induce bone marrow suppression, leading to thrombocytopenia.
Hepatitis C and HIV infections can cause substantial decrease in platelet count.
Helicobacter pylori infection is increasingly being recognised as a cause of thrombocytopenia, with some evidence that eradication may improve the platelet count.
It is rare for bone marrow disorders such as leukaemia or lymphoma to cause isolated thrombocytopenia (in the absence of other abnormalities in the full blood count).
In an otherwise healthy individual, thrombocytopenia may be a laboratory artefact, caused by platelet clumping due to the anticoagulant used for blood collection. This phenomenon is not associated with any untoward consequences and is usually flagged up on an automated analyser or easily identified by examination of a blood film.
The presence of skeletal abnormalities or history of recurrent infections and a family history of thrombocytopenia are noted in the very rare inherited platelet disorders.
Rare conditions like thrombotic thrombocytopenic purpura and haemolytic uraemic syndrome can present with severe thrombocytopenia and associated haemolytic anaemia. Clinical symptoms can vary from being asymptomatic to neurological disturbances such as headache and confusion and renal impairment. Acute folate deficiency in older individuals can also present with thrombocytopenia. A thorough review of the blood film by an experienced observer can help in diagnosing or excluding these and other underlying pathologies.
Tiredness is a recognised symptom of immune thrombocytopenia, which has been noted to improve with increasing platelet count.
What you should do?
Examine the patient for any signs of bruising, which would warrant urgent referral. Any history of bleeding—including epistaxis, gum bleeds, or melaena—also requires urgent hospital assessment, as does a platelet count below 30×109/L. Patients who are taking aspirin or other antiplatelet agents or warfarin should stop these medications if there are signs of bleeding or if the platelet count is less than 50×109/L.
Patients with a platelet count above 50×109/L usually do not have a high risk of bleeding and may be referred on a semi-urgent basis (in about 2-4 weeks). For many surgical procedures, a safe platelet count is deemed to be at least 50×109/L to avoid excess perioperative bleeding. For this reason, patients who may require surgery in the immediate future should be referred to a specialist. Patients with counts above 50×109/L may need investigations and possibly treatment to allow them to continue taking “blood thinning” agents. Those whose platelet count is over 100×109/L may be monitored on a monthly basis, and if the count repeatedly remains over 100×109/L the frequency of tests may be decreased. If there is shift to lower counts, the patient may be referred on a non-urgent basis. All pregnant women with thrombocytopenia should be seen by specialists, who may have to make decisions about treatment, sometimes early in pregnancy. The figure⇓ shows a flow chart to guide referral.
The patient was tested for Helicobacter pylori infection, which came back positive. Successful eradication normalised the platelet count and the patient’s energy levels. A repeat blood count three months later confirmed a normal full blood count.
For healthcare professionals
Neunert C, Lim W, Crowther M, Cohen A, Solberg L Jr, Crowther MA, et al. American Society of Hematology 2011 evidence-based practice guideline for immune thrombocytopenia. Blood 2011;117:4190-207, doi:10.1182/blood-2010-08-302984.
Provan D, Stasi R, Newland AC, Blanchette VS, Bolton-Maggs P, Bussel JB, et al. International consensus report on the investigation and management of primary immune thrombocytopenia. Blood 2010;115:168-86, doi:10.1182/blood-2009-06-225565.
Cite this as: BMJ 2013;346:f3407
This is part of a series of occasional articles on common problems in primary care. The BMJ welcomes contributions from GPs.
Competing interests: We have read and understood the BMJ Group policy on declaration of interests and have no relevant interests to declare.
Contributors: JT conceived and drafted the article. DF revised it critically for important intellectual content. Both authors approved the final version.
Provenance and peer review: Not commissioned; externally peer reviewed.