Hematology Flashcards
Overview of ITP (7)
- Benign, acquired, isolated thrombocytopenia with platelets <100,000/ml
- May or may not present with bleeding
- Autoimmune disease without any other underlying disease process
- Secondary ITP is an autoimmune process occurring in response to another process in the body
- Peaks between ages 2 to 4 year old
- Equal gender distribution
- Increased risk for severity and chronicity with increasing age
Primary ITP Definition
Autoimmune disorder characterized by an isolated thrombocytopenia, platelet count <100,000/mL with no other identifiable cause for the thrombocytopenia
Secondary ITP Definition
All other forms of ITP not considered primary
Newly diagnostic ITP Definition
First 3 months after dx
Chronic ITP Definition
Lasting greater than 12 months after diagnosis
Severe ITP Definition
Presence of bleeding at diagnosis that requires intervention; presence of new bleeding symptoms that requires additional interventions with a different agent, or at an increase dose
Persistent ITP Definition
Between 3-12 months after dx
Common ITP Triggers for Primary ITP (6)
- Viral illness
- 72% newly diagnosed cases with history of recent viral illness
- Immunizations
- MMR
- Varicella
- Hepatitis A
Common ITP Triggers for Secondary ITP (6)
Chronic Infections
- H. pylori
- HIV
- Hepatitis C
History of Autoimmune disease in the child
- SLE
- Anti-phospholipid Syndrome
- Autoimmune neutropenia
ITP Pathophysiology (5)
- Platelet surface is covered with increased amounts of IgG
- Autoantibody-coated platelets induce Fc receptor- mediated phagocytosis by mononuclear macrophages, primarily but not exclusively in the spleen.
- The spleen is the key organ in the pathophysiology of ITP, Platelet autoantibodies are formed in the white pulp
- Mononuclear macrophages in the red pulp destroy immunoglobulin-coated platelets, removing affected platelets from circulation
- Platelet production is increased in bone marrow but can’t offset the destruction
ITP Clinical Presentation (9)
- Generally healthy child
a. CBC is normal except for a low platelet count
b. If everything is fine, presentation wise, CBC, etc, then they don’t get a bone marrow biopsy
i. No indication of leukemia - Acute onset of bleeding and bruising
- No history of fever, fatigue, or weight loss
- No family history of bleeding disorders
- Recent “cold” or live attenuated vaccination
- Bruising, petechiae or purpura
- Otherwise normal physical exam—NO
- HEPATOSPLENOMEGALY
- Mucosal bleeding usually indicates lower platelet count and worrisome
Dif Dx: Inherited bleeding disorders (4)
a. Wiskott-Aldrich Syndrome (small platelets)
b. vonWillebrand Disease - #1 disorder of coagulation
c. DiGeorge syndrome
d. Thrombocytopenia with Absent Radii syndrome
Dif Dx: bone marrow failure or infiltrates (3)
a. Intravascular Coagulation
b. Hemolytic-Uremic Syndrome
c. Thrombotic Thrombocytopenia
Dif Dx: Platelet activation and consumption (4)
- Disseminated Intravascular Coagulation
- Hemolytic-Uremic Syndrome
- Thrombotic Thrombocytopenia
- Kasabach-Merritt syndrome
Dif Dx: Immune mediated (4)
- ITP
- Drug-induced
- Systemic Lupus Erythematous
- Evans Syndrome (presence of simultaneous or sequential direct Coombs-positive autoimmune hemolytic anemia (AIHA) in conjunction with immune- mediated thrombocytopenia, with no known underlying etiology)
ITP Diagnostics (5)
- CBC with peripheral smear
a. Platelet count <100,000/mL
b. Isolated thrombocytopenia,
c. Other cell lines are normal
d. Large, well granulated platelets on peripheral smear –
Look at MPV and it will be large - Type and Screen
- Direct Antiglobulin Test, Direct Coombs Test; Direct Anti-human Globulin Test
a. Sign of hemolysis? - Bone Marrow?
a. Not usually done if everything is normal - In general you will refer to hematology for further management
First line recommendations for ITP (3)
- Observation + bleeding precautions IVIG
- Corticosteroids
- Anti-D Immunoglobulin
Second line recommendations for ITP (2)
- Rituximab
2. TPO-R agonists
Third line recommendations for ITP (4)
- Splenectomy
- Mycophenolate (cellcept)
- Azathioprine
- Vincristine