Thrombocytopenia resident survival guide

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Ogheneochuko Ajari, MB.BS, MS [2]

Introduction

Thrombocytopenia refers to relatively few platelets in blood. A normal platelet count ranges from 150,000 to 450,000 per microliter of blood, determined by the 2.5th lower percentile of the normal platelet count distribution.

Causes

Life Threatening Causes

Life-threatening causes include conditions which may result in death or permanent disability within 24 hours if left untreated.

• Disseminated intravascular coagulation

Common Causes

• Bone marrow suppression (for example chemotherapy, irradiation)
• Chronic alcohol use
• Chronic liver disease
• Congenital thrombocytopenia
• Disseminated intravascular coagulation
• Drug-induced thrombocytopenia (DITP)
• Gestational thrombocytopenia
• HELLP syndrome
• Hemolytic uremic syndrome
• Heparin-induced thrombocytopenia
• Immune thrombocytopenic purpura
• Infections
• Preeclampsia
• Pseudothrombocytopenia
• Thrombotic thrombocytopenic purpura

Management

Shown below are algorithms summarizing the approach to thrombocytopenia.

Characterize the symptoms: ❑ Easy bruising ❑Petechiae ❑ Rashes ❑ Melena ❑ Fevers ❑ Bleeding ❑ Headaches ❑ Abdominal pain ❑ Visual disturbances ❑ Weight loss ❑ Night sweats ❑ Bone pain History/Epidemiological factors: ❑ Recent medications ❑ Pregnancy ❑ Family history ❑ Medical history ❑ Recent vaccinations ❑ Recent travels ❑ Recent transfusions ❑ Chronic alcohol use ❑ Recent hospitalization ❑ Recent organ transplantation ❑ Recent valve replacement surgery ❑ Dietary habits ❑ Sexual history ❑ Ingestion of quinine containing beverages

Examine the patient: ❑ Bleeding location ❑ Assess bleeding severity ❑ Hepatomegaly ❑ Splenomegaly ❑ Mucocutaneous bleeding ❑ Skeletal abnormalities ❑ Joint or soft tissue bleeding ❑ Rash ❑ Generalized lymphadenopathy ❑ Ischemic limb/Skin necrosis ❑ Neurologic

Order tests

❑ Peripheral blood smear ❑ CBC ❑Reticulocyte count ❑ LDH ❑ LFT ❑ Renal function test ❑ Blood group (Rh)

Viral screening ❑ HIV ❑ HCV ❑ HBV

Clotting screen: ❑ PT ❑ aPTT ❑ Fibrinogen ❑ Haptoglobin ❑ D-dimer ❑ FDP

Bone marrow examination: ❑ Bone marrow aspiration ❑ Bone marrow biopsy

Other Investigations: ❑ H. pylori ❑ Abdominal ultrasound scan ❑ Chest X-ray ❑ Flow cytometry ❑Antiphospholipid antibody ❑ ANA ❑ ELISA

Any abnormality, suspect DIC TTP/HUS

Bone marrow disorder

Algorithm for Diagnosis of Thrombocytopenia based on the Peripheral Blood Smear

Thrombocytopenia Platelet count <150,000 per microliter

Platelet clumping

Examine peripheral blood smear

Pseudothrombocytopenia

True thrombocytopenia

Giant platelets ±WBC inclusions

Congenital/Hereditary thrombocytopenia

Schistocytes

Spherocytes

Dacrocytes

Hypersegmented neurophils Macrocytosis

Neutrophilia Lymphocytosis Leukopenia Toxic granulations

Blasts

Isolated thrombocytopenia

DIC TTP/HUS

Evans syndrome Hypersplenism

Myelofibrosis

Vit. B12 deficiency Folate deficiency

Infections

Bone marrow disorders

ITP DITP HIV, HCV H. pylori HIT DIC Gestational thrombocytopenia

Algorithm based on the 2012 American Society of Hematology Evidence-Based Approaches to Cytopenias.

Treatment of Thrombocytopenia

The treatment of thrombocytopenia depends on or is determined by the underlying cause of thrombocytopenia.

Do's

• Bone marrow biopsy should be done for patients that are older than 60 years of age to rule out myelodysplastic syndrome or lymphoproliferative disorders.
• Treatment should be considered for patients with platelet counts less than 30,000 per microliter.

Dont's

• Do not initiate cancer chemotherapy or antiviral therapy in the presence of thrombocytopenia.
• Do not start treatment for platelet counts greater than 50,000 per microliter unless actively bleeding.
• Don't give warfarin (coumadin) monotherapy to an acutely bleeding patient because it may induce thrombosis.