Thrombocytopenia

Thrombocytopenia ( thrombopenia for short ; from ancient Greek θρόμβος thrómbos 'lump', κύτος kýtos 'cavity', 'vessel', 'shell' and πενία penía 'deficiency') denotes a lack of thrombocytes (blood platelets) in the blood . Humans normally have around 150,000–450,000 platelets per µl of blood; if this value is not reached, one speaks of thrombocytopenia. Thrombocytopenia can occur as a result of decreased formation, disturbed distribution, or increased breakdown. The opposite of thrombocytopenia is thrombocytosis .

Clinically, thrombocytopenia is relevant at values ​​below 80,000 / µl, as an increased tendency to bleeding is only to be expected from this level, as long as there are no functional disorders of the platelets ( thrombocytopathies ). At values ​​below 50,000 / µl, spontaneous bleeding such as nosebleeds , hematomas , petechiae of the skin and mucous membranes, cerebral haemorrhages and gastrointestinal bleeding are to be expected. With educational disorders from 10,000 / µl platelet concentrates must be administered. The partial thromboplastin time (PTT) is not influenced by thrombocytopenia, as the laboratory test may require a. Phospholipid (obsolete platelet factor 3 ) is added from the platelets .

causes

Possible triggering factors for thrombocytopenia are:

• hematological diseases, e.g. B.
  • Leukemias
  • Thrombotic Thrombocytopenic Purpura (TTP)
  • chronic immune thrombocytopenia
  • Antiphospholipid Syndrome
• fetal or neonatal alloimmune thrombocytopenia (FAIT or NAIT)
• Consumption thrombocytopenia with intravascular coagulation or bleeding
• Pregnancy-associated thrombocytopenia ( English gestational thrombocytopenia ) occurs in 5 - 10% at the time of birth, but can also occur in the context of preeclampsia . With a complication-free pregnancy, the platelet count falls in the first trimester and reaches its lowest value around birth, only to return to the original values ​​after an average of seven weeks. On average, the concentration falls by 17% and only reaches values ​​below 100,000 / µl in 1% of pregnant women.
• Heparin-induced thrombocytopenia (HIT)
• allergic, toxic, post-infectious, deficiency diseases ( vitamin B12 , folic acid), paraneoplastic
• Liver cirrhosis with portal hypertension (lack of platelet growth factor )
• increased breakdown in the spleen ( hypersplenism )
• Side effect of taking medication, e.g. B. ibuprofen. The damage is reversible after stopping the drug.
• Infectious diseases
  • Malaria tropica
  • Rubella virus
  • Epstein-Barr Virus
  • Helicobacter pylori (bacterial infection of the stomach).

Differential diagnosis

A distinction must be made between pseudothrombopenia , a false measurement caused by platelet aggregation as a result of EDTA- dependent antibodies . Correct values ​​are determined by measuring with citrated blood.

therapy

Thrombocytopenia is an emergency. Therapy must be given immediately after the diagnosis is made:

• Search for a treatable underlying disease (infections!),
• Withdrawal from any medication that may be a trigger.
• Plasma exchange is the most effective form of therapy.

The use and status of additional drugs such as glucocorticoids , rituximab , vincristine , immunosuppressants , ASA and / or prostaglandin preparations are unclear.

The Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) recommended Avatrombopag for approval for the treatment of severe thrombocytopenia (trade name: Doptelet , manufacturer Dova Pharmaceuticals ) at its meeting in April 2019 . As a rule, the European Commission follows such a recommendation and grants approval. The preparation was approved in the USA since May 2018.

One treatment option for immune thrombocytopenia (ITP) is the administration of non-structurally analogous thrombopoietin preparations (e.g. Eltrombopag from Novartis and Romiplostim from Amgen ), so-called thrombopoietin analogues.

Web links

• Guideline "Thrombocytopenias" on onkopedia

Individual evidence

1. ↑ ^{a b c} Wolfgang Gerok: The internal medicine . Schattauer, 2007, ISBN 978-3-7945-2222-4 , p. 93.
2. ↑ Wolfgang Gerok: The internal medicine . Schattauer, 2007, ISBN 978-3-7945-2222-4 , p. 94 ff.
3. ↑ Jessica A. Reese, Jennifer D. Peck, David R. Deschamps, Jennifer J. McIntosh, Eric J. Knudtson, Deirdra R. Terrell, Sara K. Vesely, James N. George: Platelet Counts during Pregnancy New England Journal of Medicine 2018, Volume 379, Issue 1 of July 5, 2018, pages 32–43, DOI: 10.1056 / NEJMoa1802897
4. ↑ HCI Solutions AG: Brufen ® - compendium.ch. Retrieved July 2, 2018 . 
5. ↑ 2002 British Journal of Hematology, 118, pp. 584-588.
6. ^ Stasi R. Effects of eradication of Helicobacter pylori infection in patients with immune thrombocytopenic purpura: a systematic review. Blood 2009 Feb 5; 113 (6): 1231-1240. Epub 2008 Oct 22.
7. ↑ Meeting highlights from the Committee for Medicinal Products for Human Use (CHMP) April 23-26, 2019 , PM EMA of April 26, 2019, accessed on May 5, 2019
8. ↑ Dova Pharmaceuticals Announces US FDA Approval of DOPTELET® (avatrombopag) , PM Dova of May 21, 2018, accessed on May 5, 2019
9. ↑ Kuter DJ et al. Efficacy of romiplostim in patients with chronic immune thrombocytopenic purpura: A double-blind randomized controlled trial. Lancet 2008 Feb 2; 371: 395.

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