THROMBOCYTOPENIA

Thrombocytopenia is characterized by a decreased platelet count (less than 150,000/mm3), the most common cause of bleeding disorders.

Etiology

• Decreased platelet production
  • Infiltrative diseases of bone marrow,
  • Leukaemia,
  • Aplastic Anemia,
  • Myelofibrosis,
  • Myelosuppressive therapy,
  • Radiation therapy;
  • Inherited disorders such as
    • Fanconi's anemia (FA, is a rare, inherited blood disorder that leads to bone marrow failure)
    • Wiskott-Aldrich syndrome (a rare X-linked recessive disease characterized by eczema, thrombocytopenia, immune deficiency, and bloody diarrhea).
• Increased platelet destruction—
  • Infection (eg, HIV or hepatitis C),
  • Drug-induced (eg, heparin or quinidine),
  • ITP,
  • DIC.
• Abnormal distribution or sequestration in spleen.
• Dilutional thrombocytopenia—after haemorrhage, RBC transfusions.

Clinical Manifestations

• Usually asymptomatic (with platelet counts greater than 50,000/mm³).
• When platelet count drops below 20,000/mm3:
  • Petechiae occur spontaneously.
  • Ecchymoses occur at sites of minor trauma (venipuncture, pressure).
  • Bleeding may occur from mucosal surfaces, nose, GI and GU tracts, respiratory system, and within CNS. nasal and gingival bleeding
  • Menorrhagia is common.
• Excessive bleeding may occur after procedures (dental extractions, minor surgery, biopsies).
• Thrombotic complications (arterial and venous) and areas of skin necrosis are associated with heparin-induced thrombocytopenia.

Diagnostic Evaluation

• CBC with platelet count
  • Haemoglobin —decreased
  • Haematocrit—decreased
  • Platelets—decreased
• Bleeding time - prolonged.
• Prothrombin time (PT)—prolonged.
• Partial thromboplastin time (PTT)—prolonged.
• Platelet aggregation test for heparin-dependent platelet antibodies—positive.

Medical Management

• Treat underlying cause.
• Platelet transfusions.
  • If platelet production is impaired, platelet transfusions may increase the platelet count and stop bleeding or prevent spontaneous hemorrhage.
  • If excessive platelet destruction occurs, transfused platelets are also destroyed, and the platelet count does not increase. The most common cause of excessive platelet destruction is idiopathic thrombocytopenic purpura.
• Steroids or IV immunoglobulins may be helpful in selected patients.
• Heparin-induced thrombocytopenia:
  • Discontinue heparin,
  • Use alternate anticoagulant therapy due to high risk of venous and arterial thromboses in these patients (direct thrombin inhibitors, such as lepirudin or argatroban hirudin),
  • Avoid platelet transfusions.

Nursing management

Risk for Injury related to bleeding due to thrombocytopenia.

• Institute bleeding precautions.
  • Avoid use of plain razor, hard toothbrush or floss, I.M. injections, tourniquets, rectal procedures, suppositories.
  • Administer stool softeners, as necessary, to prevent constipation.
  • Restrict activity and exercise when platelet count is less than 20,000/mm3 or when active bleeding occurs.
• Monitor pad count and amount of saturation during menses;
• Administer or teach self-administration of hormones to suppress menstruation, as prescribed.
• Administer blood products, as ordered.
• Monitor for signs and symptoms of allergic reactions, anaphylaxis, and volume overload.
• Evaluate urine, stools, and emesis for gross and occult blood.