medical surgical

1. PLATELET DISODERS
DR LALITHA M
Assistant Professor,
Department of Paediatrics

2. OBJECTIVES
🠶What is hemostasis
🠶Sequence of events
🠶Platelet normal morphology and counts
🠶Thrombocytopenia
🠶Immune thrombocytopenic purpura
🠶Platelet function disorders
🠶Thrombocytosis

3. HEMOSTASIS
🠶 Hemostasis is an active process that clots blood in areas of
blood vessel injury and limit the bleeding
🠶 Over time, the clot is lysed by the fibrinolytic system, and
normal blood flow is restored
🠶 The main components of the hemostatic process are :
i. vessel wall
ii. platelets
iii. coagulation proteins
iv. anticoagulant proteins and
v. fibrinolytic system

4. General sequence of events
leading to hemostasis
Arteriolar vasoconstriction
Primary hemostatic plug formation
Secondary hemostatic plug formation
Clot stablisation and resorption

8. Coagulation cascade

10. Prothrombotic effects of
endothelial cells
Antithrombotic effects
of endothelial cells

12. PLATELET DISORDERS

13. PLATELETS
🠶Platelets are disc shaped anucleate cell fragments
🠶 They are shed from megakaryocytes in the bone marrow
into the bloodstream.
🠶 Their function depends on several glycoprotein receptors
and two types of cytoplasmic granules: Alpha-Granules
AND Dense (or ) delta granules
🠶 Main regulator of its production is the hormone
thrombopoietin (TPO), which is synthesized in the liver.
🠶 Normal platelet count = 150,000–400,000/mm3.
🠶 Circulate with an average life span of 7–10 days.

14. Disorders of
platelets
Disorders in the number
of platelets
(quantitative)
Functional Disorders
(Qualitative)

15. Thrombocytopenia Thrombocytosis
decreased platelets
< 150000/mm3
increased platelets
> 400000/mm3
Quantitative Platelet disorders

17. Diagnostic Tools
🠶Bleeding time(3-12min)
🠶 Peripheral blood smears-platelet number & morphology
🠶 In vitro platelet function analyzer 100
🠶Platelet aggregation tests
🠶Bone marrow examination

18. INFECTIONS-Dengue,malaria,scrub typhus

19. IMMUNE THROMBOCYTOPENIC
PURPURA
🠶 The most common cause of acute onset of
thrombocytopenia(<100 000/mm3) in an otherwise well
child
🠶 Occurs due to production of autoantibodies against the
platelet glycoprotein complexes, αIIb-β3 and GPIb.
🠶 After binding of the antibody to the platelet surface,
circulating antibody-coated platelets are recognized by
the Fc receptor on splenic macrophages and destroyed.

20. Current definitions
🠶 Newly diagnosed ITP : From diagnosis to 3 months
🠶Persistent ITP : 3-12 months after diagnosis
🠶 Chronic ITP : >12 months after diagnosis
(previously defined as >6 months after diagnosis)

21. Clinical features
🠶 A previously healthy child presents with sudden onset of
generalized petechiae and purpura
🠶 There may be bleeding from the gums and mucous
membranes
🠶 Usually there is a history of a preceding viral infection 1-4
wk before the onset of thrombocytopenia
🠶Rare below 2 years of age

23. Examination
🠶 Findings on physical examination are normal, other than the
finding of petechiae and purpura
🠶The presence of abnormal findings such as:
hepatosplenomegaly, bone or joint pain, remarkable
lymphadenopathy ,other cytopenias, or congenital anomalies
suggests other diagnoses (leukemia, syndromes)

24. SEVERITY OF ITP
The severity of bleeding in ITP is based on symptoms and
signs, but not platelet count:
1. No symptoms
2. Mild symptoms: bruising and petechiae, occasional minor
epistaxis, very little interference with daily living
3. Moderate: more severe skin and mucosal lesions, more
troublesome epistaxis and menorrhagia
4. Severe: bleeding episodes—menorrhagia, epistaxis,
malena— requiring transfusion or hospitalization,
symptoms interfering seriously with the quality of life

25. Diagnosis
🠶 Complete blood count and blood film examination are
usually sufficient
🠶 large platelets are seen on a peripheral blood and an
adequate or increased number of megakaryocytes in the
BM
🠶 Indications for bone marrow aspiration/biopsy :
- abnormal WBC or differential count
-unexplained anemia as well as findings on history and
physical examination suggestive of a bone marrow failure
syndrome or malignancy.
Rule out infections especially if child is febrile

26. Treatment
🠶 The majority of children achieve spontaneous remission
and do not suffer major bleeding complications
🠶 The expectant ‘watch and wait’ policy of management is
recommended for such patients
🠶 Platelet transfusion in ITP is usually contraindicated unless
life-threatening bleeding is present
🠶Only in life threatening bleeds like intracranial hemorrhage
transfusion of platelets is recommended

27. 🠶For emergency treatment :
 intravenous methyl prednisolone or
 oral prednisolone1 mg/kg PO × 7 d &taper over 3 wk OR
4 mg/kg PO for 4 d or
 IVIG(1 g/kg IV single dose)
 anti-D(50-75 ug/kg IV single dose)
🠶 Antifibrinolytics such as tranexamic acid 10-15 mg/kg
intravenously 6-hourly are useful to control bleeding
🠶 Splenectomy is the definitive treatment when refractory to
above treatment

28. Acquired Abnormalities of Platelet
Function
MYELOPROLIFERATIVE DISEASE
DYSPROTEINEMIA
CARDIOPULMONARY BYPASS
UREMIA
LIVER DISEASE
DRUG INHIBITION

29. Congenital disorders of platelet function
Grey platelet syndrome,dense body
disease(deficiency of storage
granules)
Glanzmann’s Thrombasthenia
Bernard-soulier Syndrome

31. Bernard-Soulier Syndrome
🠶Occurs due to defect in the genes forming the GPIb complex
of glycoproteins Ibα, Ibβ, V, and IX resulting in defective
platelet adhesion
🠶 This syndrome is characterized by thrombocytopenia, with
giant platelets and markedly prolonged bleeding time (>20
min)
🠶 Platelet aggregation tests show absent ristocetin-induced
platelet aggregation but normal aggregation to all other
agonists.

32. Glanzmann’s Thrombasthenia
🠶caused by deficiency of the platelet fibrinogen receptor
αIIb-β3 resulting in defective platelet aggregation
🠶Platelets have normal size
🠶 PFA-100 or bleeding time are markedly abnormal
🠶 Aggregation studies show abnormal or absent aggregation
with all agonists used except Ristocetin
.

33. Treatment
🠶 In all but severe platelet function defects, desmopressin
(0.3 μg/kg IV/nasal) may be used for mild to moderate
bleeding
🠶 platelet transfusions of 1 unit/5-10 kg may be life saving
in severe bleeding

34. Thrombocytosis
🠶Primary thrombocytosis
🠶Secondary thrombocytosis

35. Thrombocytosis –secondary causes
1. Iron deficiency;
2. Inflammation, cancer, or infection (reactive thrombocytosis); or
3. An underlying myeloproliferative process [essential thrombocythemia
or polycythemia vera or, rarely, myelodysplastic process.
4. Medications that can cause reactive thrombocytosis include:
🠶 Epinephrine (Adrenalin Chloride, EpiPen)
🠶Tretinoin
🠶Vincristine
Patients should be evaluated for underlying inflammation or malignancy,
and iron deficiency
Usually does not cause any symptoms

36. 🠶 Essential thrombocythaemia (ET) is a condition affecting
the cells in the bone marrow leading to overproduction of
platelets, leading to an increased propensity to thrombosis
formation and blockage of blood vessels
🠶 Some people have a change (mutation) in a gene, called
the JAK2 gene
🠶Rare in children

37. Signs and Symptoms of
essential thrombocytosis
🠶Heart attack or stroke
🠶Headache
🠶Burning or throbbing pain, redness, and swelling of the
hands and feet
🠶Bruising
🠶Gastrointestinal bleeding or blood in the urine

38. Treatment
🠶Low-dose aspirin -- may treat headache and burning
pain in the skin
🠶Hydroxyurea or anagrelide -- reduces number of blood
cells.
🠶Aminocaproic acid -- reduces bleeding. This treatment
may be used before surgery to prevent bleeding

39. Thank you

40. QUESTIONS
🠶 Write the sequence of events in hemostasis
🠶What is the normal platelet count
🠶What is thrombocytopenia
🠶Platelets deficiency manifest with: a) superficial bleed
b) deep bleed??
🠶 Write four important causes of thrombocytopenia in
children
🠶What is the only Indication for platelet transfusion in
ITP
🠶Name platelet function disorders