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Bleeding disorders

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					Bleeding disorders
    Normal haemostasis

                Trauma

            ** Vasoconstriction

**Coagulation          **Platelet adhesion and release



Fibrin                 Platelet aggregation
                       (Unstable haemostatic plug)

         Stable haemostatic plug
HEMOSTASIS




Blood vessel




   Platelet




   Fibrin clot
             Vasoconstriction
•   Injury
•   Temporary reflex nervous vasoconstriction.
•   Slowing of blood flow helping haemostasis.
•   Abnormalities of blood vessels can lead to
    bleeding disorders eg.   Scurrvy
                             Vasculitis
                             Telangiectasis
Ultra structure of a platelet
RESTING PLATELET
ADHERING PLATELET
       Platelet aggregation
• Platelets adhere to subendothelial fibrin via VWF

• Platelets change the shape and release contents of
  the granules.

• Platelet aggregation
                     Platelet role in hemostasis



1.adhesion through vWF

2. Release of ADP, etc

3. Aggregation,                                    vWF

4, Clot retraction



               Damaged endothelium
Platelet function and number of
  platelets and bleeding time
Coagulation – the formation of a
          fibrin plug
          Coagulation factors
• All the coagulation factors except F VIII are
  produced by the liver hepatocyte. FVIII is
  produced by the vascular endothelial cells.
• Some of the coagulation factors are vit K
  dependent. V, VII, IX and X.
• In obstructive jaundice, vit K absorbtion is
  defective leading to a coagulopathy.
• Factor VII has the shortest half life (7 hrs).
FUNCTIONS OF VWF

1.vWF mediates platelet
adhesion at site of injury

2.Stabilizes FVIII in
circulation
CLASSICAL COAGULATION CASCADE
INTRINSIC PATHWAY                 EXTRINSIC PATHWAY

      surface contact                   TISSUE FACTOR
XII                     XIIa                  +
      PK / HMWK                              VII
XI                 XIa                        +
IX                 IXa                      PL + Ca
  + VIIIa + Ca + PL

                   COMMON PATHWAY
                   X               Xa
                           +
                      Va + Ca + PL
           PROTHROMBIN            THROMBIN
           FIBRINOGEN             FIBRIN   + XIII
                                  STABLE POLYMER
           Blood coagulation
XII        XIIa
      XI          Xia
           IX           Ixa             VII+TF
                  X           Xa
           VIII                     V
                        II          IIa
           Fibrinogen         Fibrin    Crosslinked
                                    XIII fibrin
Modern concept of the
 coagulation cascade
        THE INITIATION PHASE


INITIATION PHASE
                   FVII




                   TF
                   FVIIa




FX
FXa
  Prothrombin              Thrombin
              THE PROPAGATION PHASE

               FIX




                                          PROPAGATION PHASE
                        FXIa      FXI


               FIXa
                       FVIIIa     FVIII
  FX                  FXa
                            FVa   FV

Prothrombin                       Thrombin
           THE STABILIZATION PHASE




                           Thrombin
Cross-linked   Fibrin   Fibrinogen
   fibrin      FXIIIa     FXIII
PLATELET PLUG AND FIBRIN CLOT
          Bleeding disorders
• Due to abnormalities in the blood vessels

• Due to platelet abnormalities
 (Platelet number/ platelet function)
• Due to coagulation abnormalities
  Deficiency of coagulation factors
    Investigation of bleeding disorders
• Full Blood count
• Platelet count: thrombocytopenia
• Bleeding time: Platelet number and function
• Hess’s test: Vascular abnormalities
• Blood picture: thrombocytopenia
                  Platelet function
• Platelet function tests
• Clotting time: Coagulation
  Haemorhagic disorders due to
       capillary defects
• Hereditary haemorhagic telangictasia
  Auto/dominant
  Skin and mucous membranes of the nose and
  mouth
  Epistaxis/haemoptysis
  F/H +
Treatment: ethynyl oestradiol by squamous
  metaplasia of the epithelium
       Henoch-shonlein purpura
• Hypersensitivity reaction (bacterial/drug/food) with
   inflammation of capillaries and arterioles.
 Mediated via IgA
Clinically
• Childhood and adolescence
• Purpuric rash
• Joint pain and swelling
• Abdominal pain and malaena
• Renal manifestations (haematuria/albuminuria/casts)
Investigations
UFR/ ASOT/ Stools for occult blood/blood full count/bleeding
   time
Treatment:
 self limiting
               corticosteroids
Haemorrhagic disorders due to
   platelet abnormalities
           • Platelet production
           • Abnormalities of platelets could be
             due to
             Low platelet number
             Platelet function abnormalities
           • Relationship of platelet count to
             platelet number
             < 30-40x10/l-Bleeding is common
             <10x10/l-bleeding is usual &severe
             40-80x10 /l no bleedingusually
Idiopathic thrombocytopenic purpura
• Thrombocytopenia due to antibody formation
• Two forms of the disease: Acute, Chronic,
• Occur at any age, common in children and young
  adults
• Type of bleeding: spontaneous/ following trauma
     Skin bleeding is common: purpura
     Mucous membrane bleeding
     Internal bleeding
 O/E purpurae, no LNE, Liver Spleen not palpable
Laboratory investigations
             • Full blood count
               Low platelet count
               WBC/DC normal
             • Blood picture
               Thrombocytopenia
             • Bone marrow
               Normal bone marrow
               Normal or increased
               megakaryocytes
               To excude other causes of
               thrombocytopenia
    Treatment of childhood ITP
• Depends on the platelet count
• If platelet count more than 20 treatment not
  indicated
• Counts less than 20 needs observation
• Counts less than 10 need treatment
• Short course of corticosteroids
• Splenectomy not considered as a treatment
• Rapid increase in platelets by IVIg, anti D,
  short course of dexamethasone
       Treatment of chronic ITP
•   Corticosteroids
•   Splenectomy
•   Immunosuppressive therapy
•   IVIg
•   Anti D
•   Dexamethasone pulse therapy
Other causes of thrombocytopenia

• Acute leukaemia
• Aplastic anaemia
• Thrombocytopenia secondary to viral
  infection
• Drug induced thrombocytopenia and
  platelet functional abnormalities eg. Aspirin
  therapy

				
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Description: Bleeding disorders and blood transfusion