Thrombocytopenia

• A normal platelet count usually lies within the range 150–450 × 109/L.

  Thrombocytopenia is defined as a platelet count below 150 × 109/L.
• Bone marrow disorders can cause thrombocytopenia:

  Malignancy, myelofibrosis, sarcoidosis, nutritional deficiency, congenital disorders.
• Increased platelet destruction can cause thrombocytopenia

  Immune thrombocytopenic purpura, disseminated intravascular coagulations, thrombotic thrombocytopenic purpura, autoimmune thrombocytopenia, drug-related thrombocytopenia (quinidine, quinine, NSAIDs, penicillin, anticonvulsants).
• Increased platelet sequestration can cause thrombocytopenia

  Splenomegaly due to portal hypertension that may be caused by cardiac failure, hepatic vein thrombosis or vena cava thrombosis (Budd-Chiari syndrome), cirrhosis (chronic viral hepatitis or alcoholic liver disease) and rarely arteriorvenous malformation of the splenic vessels.
• Dilution may cause thrombocytopenia

  After blood transfusion (1 or 2 units of blood) or pregnancy.
• Cancer-related thrombocytopenia

  Myelosupression due to bone marrow infiltration or myelodysplasia (Acute leukaemias). It can also be caused by small cell lung cancer or paraneoplastic syndromes such as idiopathic thrombocytopenic purpura as part of an association with some solid tumours such as breast and lung cancer.

  Treatment-induced can be caused by radiation or systemic chemotherapy.
• Pseudo-thrombocytopenia

  Some people have an ethylene diamine tetra acetic acid (EDTA) dependent antibody in their circulation. These individuals have no history of bleeding and have normal circulating counts. Can be confirmed by reviewing blood film.

  Platelet clumping in EDTA so use citrate tube instead!
• Symptoms of thrombocytopenia:

  • Bone pain. 
  • Change in bowel habit. 
  • Chills, night sweats, fever, rigors. 
  • Diarrhoea, nausea, vomiting.
  • Epistaxis. 
  • Excessive thirst, urination, and constipation.
  • Fatigue.
  • Gastrointestinal bleeding. 
  • Genitourinary bleeding. 
  • Gum bleeding. 
  • Heavy menstrual bleeding. 
  • Night sweats. 
  • Post-menopausal bleeding. 
  • Skin bruising/bleeding. 
  • Weight loss. 
• Signs of thrombocytopenia:

  ·       Bleeding at the back of the buccal mucosa advancing to the front.

  ·       Bruising or rashes.

  ·       Digital ischaemia, swollen extremities.

  ·       Hair loss, bradycardia, enlarged thyroid gland.

  ·       Jaundice and hepatomegaly.

  ·       Joint deformity.

  ·       Pallor.

  ·       Petechiae or ecchymoses.

  ·       Retinal haemorrhage, retinal changes.

  ·       Skeletal abnormalities.

  ·       Spider telangiectasis on the chest, palmar erythema, ascites, pedal oedema, spider angiomas.

  ·       Splenomegaly or lymphadenopathy.

  ·       White spots on the tongue.
• Thrombocytopenia is a platelet count below 150 × 10 9 /L — this can be further subdivided into: Mild: over 100 × 10 9 /L. Moderate: 50–100 × 10 9 /L. Severe: less than 50 × 10 9 /L.
• With a platelet count of 100–150 × 109/L where no underlying cause is identified — repeat the full blood count in 4–6 weeks.
• Low platelet count + suspected cancer = 2ww pathway
• Treatments of thrombocytopenia:

  ·       Blood/platelet transfusion

  ·       Splenectomy

  ·       Corticosteroids to slow down platelet destruction (prednisone)

  ·       Immunoglobulin therapy in the case of autoimmune disorders to suppress the immune system