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Thrombocytopenia
Essentials
- Discontinue drugs that influence the functioning of platelets, as necessary.
- If the thrombocytopenic patient has symptoms of bleeding, hospitalization is advisable.
Basic rules
- The pathophysiological mechanism of thrombocytopenia (blood platelet count < 150 × 109 /l) may be
- decreased production in the bone marrow
- increasedconsumption
- increased sequestration in the spleen.
- When blood thrombocyte level < 100 × 109 /l is detected in a patient for the first time, examining blood smear or taking a sample in a citrate tube is recommended (investigation of pseudothrombocytopenia)..
- Thrombocytopenia is a symptom, the cause of which should be clarified.
- Typical manifestations of thrombocytopenia are skin bruising and petechiae and mucous membrane bleeding.
- In particular, gum and nasal bleeding is common. Bleeding may also take place in the gastrointestinal and urinary tracts after surgery of the prostate gland or urinary tract.
- Menorrhagia is also common.
- A tendency towards bleeding is uncommon if the platelet count is 50-100 × 109 /l. Platelet concentrations of 10-50 × 109 /l are frequently associated with spontaneous bleeding and haemorrhages may be severe with platelet counts of < 10 × 109 /l. Drugs that affect the platelet function (ASA and ADP receptor blockers, e.g. clopidogrel, ticagrelor, prasugrel) increase bleeding tendency already in a rather moderate thrombocytopenia. Concurrent anticoagulation therapy also increases bleeding risk in a patient with thrombocytopenia.
Causes of thrombocytopenia
Decreased production
- Inborn causes
- Inherited thrombocytopenias (rare)
- Acquired causes
Increased consumption
- Inborn causes
- Non-immunological (haemolytic disease of the newborn, prematurity, maternal pre-eclampsia, infections)
- Immunological alloimmune neonatal thrombocytopenia, maternal idiopathic thrombocytopenia purpura (ITP)
- Acquired causes
- Non-immunological (infections, disseminated intravascular coagulation, thrombotic thrombocytopenic purpura, haemolytic-uraemic syndrome, drug-induced over-consumption of platelets)
- Immunological (drug-induced, following blood transfusion, chronic and acute ITP Bruises and Purpura in Children)
Loss of platelets
- Acute haemorrhage
- Haemoperfusion
Clinical approach
Symptomless patient, platelet count 100-150 × 109 /l
- The general practitioner can safely follow the situation, initially at intervals of a few months, if the blood picture otherwise is normal (no anaemia, no neutropenia etc.). If no underlying disease becomes evident and thrombocytopenia remains stable, no further follow-up is required. All drugs causing thrombocytopenia should be avoided if possible. Alcohol consumption habits should be discussed.
- Many drugs cause thrombocytopenia relatively frequentlyhttp://www.ouhsc.edu/platelets/. These include heparin, quinidine, chloroquine, salicylates, sulphonamides, thiazides, allopurinol, phenytoin, carbamazepine and trimethoprim.
- NSAIDs (especially acetosalicylic acid) and some other medicines (clopidrogel, ticagrelor, prasugrel) frequently impair platelet function and bring about a bleeding tendency. This tendency is disproportionately strong among thrombocytopenic patients.
- Paracetamol does not to impair platelet function.
Symptomless patient, platelet count < 100 × 109 /l
- Besides assessing the medication used by the patient, basic investigations are performed: complete blood count and, at discretion, bone marrow examination.
- If the situation does not improve, referral to a specialist in haematology is advisable.
If a thrombocytopenia patient has symptoms of bleeding
- He/she needs specialist care
- It is important to detect the possible cause. Remember that the list of drugs possibly causing thrombocytopenia is very long. All these drugs should be avoided.
ITP
- Treatment is planned by a haematologist, a specialist in internal medicine or a paediatrician.
- In adults, prednisone or prednisolone is the first-line therapy. The starting dose is 1-2 mg/kg/day orally. Dexamethasone 40 mg/day for 4 days may be used as an alternative.
- With a glucocorticoid, response to treatment is often achieved in 1-4 weeks. A partial response to treatment is achieved in 70-90% of cases, but a good one in only 30-50% of the patients.
- After a response is observed, the drug is tapered to the smallest dose possible; the objective is a platelet count > 50 × 109 /l, with no symptoms of bleeding.
- ITP in children is often a self-limited postinfectious condition Bruises and Purpura in Children.
- Fibrinolysis inhibitors (tranexamic acid) may be used to reduce menorrhagia, severe nasal bleeding, and bleeding in the gastrointestinal or urinary tracts. Massive bleeding is compensated with red cells, fresh-frozen plasma and platelet concentrates.
- In hospital care, intravenous gammaglobulin infusions may induce a response faster than glucocorticoids. This is well suited for situations when it is necessary to normalize the platelet count quickly. As second-line treatment, non-responders are often treated with rituximab; splenectomy can also be considered. Thrombopoietin-receptor agonists (romiplostim, eltrombopag) represent one option for the management of chronic ITP. These treatments are decided by a physician well versed in haematology.
Evidence Summaries ⬆