Thrombocytopenia

Thrombocytopenia is a pathological condition manifested by a reduced number of platelets in the blood count below the norm, i.e. 150,000 / mm3. The haemostatic state is ensured by a platelet count of approximately 100,000 / mm3. Spontaneous bleeding usually occurs when platelets fall below 20,000 / mm3.

Thrombocytopenia – what is it and what are its causes?

Congenital thrombocytopenias are extremely rare. In most cases, low blood plaquets count is acquired. It often co-occurs with pathological pregnancy or systemic disease (systemic lupus erythematosus, rheumatoid arthritis, RA). The incidence of post-heparin thrombocytopenia is approximately 5% in patients after exposure to heparin.

Risk factors for thrombocytopenia include haemorrhages such as perioperative bleeding, which may require transfusion of blood components. Platelets should be replenished before surgery if the platelet count is less than 50,000 / mm3.

Diagnosis of low blood plaquet counts

The diagnosis of thrombocytopenia includes the following tests: blood count, coagulation panel including prothrombin time, fibrinogen, D-dimers, antiplatelet antibodies, bone marrow tests (myelogram), imaging tests (abdominal ultrasound, chest X-ray, computed tomography). 

Thrombocytopenia associated with excessive platelet destruction may have an immunological basis in the following conditions: 

• Immune thrombocytopenia/idiopathic thrombocytopenic purpura (ITP), 
• Rheumatological diseases, 
• Haemolytic uraemic syndrome (HUS), as a mechanism of drug-induced damage.

Thrombocytopenia due to non-immune causes includes disseminated extravascular coagulation (DIC) conditions, Moschowitz’s disease (TTP), pre-eclampsia, thyroid disease. 

Decreased platelet production may accompany neoplastic diseases due to displacement of the platelet-forming system from the bone marrow by the proliferative process in acute leukaemia and lymphoma with bone marrow involvement and in metastases of solid tumours to the bone marrow. 

Low plaquet count can be one of the side effects of chemotherapy, radiotherapy or an effect of alcohol abuse. It also co-occurs in hypersplenism in the course of cirrhosis or portal or splenic vein thrombosis.

On physical examination, depending on the underlying disease, this condition may be accompanied by the following signs: 

• Petechiae on the skin, 
• Oral mucous membranes, 
• Tachycardia, 
• Hypotension, 
• Orthostatic syncope, 
• Paradoxical pulse, 
• Pericardial friction murmur, 
• Focal signs, 
• Haemoptysis, 
• Nasal bleeding, 
• Gingival bleeding, 
• Prolonged monthly bleeding, 
• Bruising.

Treatment of low plaquet counts

Therapeutic management of thrombocytopenia primarily includes treatment of the underlying disease/cause, discontinuation of medicines that cause platelet deficiency/destruction and treatment of infection. In some cases, a splenectomy is necessary. Corticosteroids, thrombopoietin receptor agonists and plasmapheresis may be helpful in the treatment of autoimmune thrombocytopenia.