The bleeding child diagnostic approach

The bleeding child diagnostic approach

By rafat mosalli

HEMOSTASIS: The ability of the body to control the flow of blood following vascular injury is paramount to continued survival. The process of blood clotting and then the subsequent dissolution of the clot, following repair of the injured tissue.

Is sum total of specialized function within the circulating blood & its vessels designed to stop hemorrhage.

HEMOSTASIS: is composed of 4 major events that occur in a set order following the loss of vascular integrity:

Vascular constriction -limits the flow of blood to the area of injury.

Platelet aggregation –Blood platelets clump when binding to collagen that becomes exposed following rupture of the endothelial lining of vessels.

-Blood platelets become activated and aggregate at the site of injury (thrombin and fibrinogen-mediated effects). Upon activation, platelets release ADP and TXA2 (which activate additional platelets).

Clot formation -to insure stability of the initially loose platelet plug, a fibrin mesh (also called the clot) forms and entraps the plug.

Fibrinolysis -the clot must be dissolved in order for normal blood flow to resume following tissue repair. The dissolution of the clot occurs through the action of plasmin.

The bleeding child diagnostic approach

Vascular Phase Platelet Phase Coagulation Phase Fibrinolytic Phase

Vascular Phase

Vasoconstriction Exposure to tissues activate

Tissue factor and initiate coagulation

Tissue Factor

Platelet phase Non-nucleated - arise from magakaryocytes blood vessel wall (endothelial cells) prevent platelet

adhesion and aggregation platelets contain receptors for fibrinogen and von

Willebrand factor after vessel injury Platelets adhere and aggregate. Release permeability increasing factors (e.g. vascular

permeability factor, VPF) Loose their membrane and form a viscous plug

Platelets and Thrombo embolism

Arteries : White Thrombus

Platelets adhere Release ADP More adhesion/

aggregation Reduced blood flow

(stasis) Fibrin clot

Veins low pressure : Red thrombus is formed

Especially in valve pockets

Contains a long tail of fibrin

Can detach and form emboli

Coagulation Phase Two major pathways

Intrinsic pathway Extrinsic pathway

Both converge at a common point 13 soluble factors are involved in clotting Biosynthesis of these factors are dependent on

Vitamin K1 and K2 Most of these factors are proteases Normally inactive and sequentially activated Hereditary lack of clotting factors lead to

hemophilia -A

Intrinsic cascade: initiated when contact is made between blood and exposed endothelial cell surfaces.

Extrinsic pathway: initiated upon vascular injury which leads to exposure

of tissue factor (TF), a sub endothelial cell-surface glycoprotein that

binds phospholipids.

Intrinsic Pathway All clotting

factors are within the blood vessels

Clotting slower Activated partial

thromboplastin test (aPTT)

Extrinsic Pathway

Initiating factor is outside the blood vessels - tissue factor

Clotting - faster - in Seconds

Prothrombin test (PT)

Bleeding time It is the primary ,oldest test for the

primary hemostasis( vascular &platelets phase).

Measure interval time required for hemostasis following standard superficial incision 1-2mm deep & up to 5mm length in the skin of forearm with venous pressure maintained at 40mmHg.

Gives information immediately Ideally done with help of template and

related to age usually in children 4-7 minutes.

When performed with the standard methods I t depend on the following: platelet no., vascular factors, temperature& hormones.

Could be affected when Aspirin and other drugs ingested within 7d.

Prolongation doesnot correlate with bleeding risk.

Prothrombin time (PT) Tissue Thromboplastin factor III Mix with phospholipids extract Add calcium and blood sample Determine clotting time Generally 12 - 14 seconds Used to detect defects in

extrinsic &common pathway. i.e. 7, 10, 5, 2,1

Activated partial thromboplastin time (APTT) Blood sample + EDTA or Citrate No clot ( recalcification will result in clot in

about 2 - 4 min) Add calcium Mix with negatively charged phospholipids Kaoline (aluminum silicate) Determine clotting time Generally clotting occurs in 26 to 33

seconds Used to detect defects in the intrinsic

pathway I.e. 12,11,9,8,10,5,2,1

Diagnosis of coagulation defects

Prolonged APTT Defective in intrinsic No change in PT

No change in APTT Defective in Extrinsic

Prolonged PT

Prolonged APTT Defective in common Prolonged PT

NB : the bleeding disorders might not be associated with any abnormalities in the screening tests:

Mild factors deficiency Factors 13 deficiency. HSP. Ehler danlos syndrome . Scurvy. Hereditary hemorrhagic telengectasia.

Blood Vessel Injury

IX IXa

XI XIa

X Xa

XII XIIa

Tissue Injury

Tissue Factor

Thromboplastin

VIIa VII

X

Prothrombin Thrombin

Fibrinogen Fribrin monomer

Fibrin polymerXIII

Intrinsic Pathway Extrinsic Pathway

Factors affectedBy Heparin

Vit. K dependent FactorsAffected by Oral Anticoagulants

Activation

Inactive XI Active XIa

XIIa

+

Thrombosis

Arterial Thrombosis : Adherence of platelets to arterial walls -

White in color - Often associated with MI, stroke and ischemia

Venous Thrombosis : Develops in areas of stagnated blood

flow (deep vein thrombosis), Red in color- Associated with Congestive Heart Failure, Cancer, Surgery.

Fibrinolysis

Enhance degradation of clots Activation of endogenous protease Plasminogen (inactive form) is

converted to Plasmin (active form) Plasmin breaks down fibrin clots

Bleeding child diagnostic approach

The bleeding child my present as: 1-an increase in severity or frequency

of bleeding from one site e.g.; nose. 2-asc bleeding from unusual sites

such as joints or internal organs. 3- As excessive bleeding for the

degree of the trauma experienced.


Abnormal bleeding can be the result of an acquired or congenital disorders of coagulants, platelets, or the vessel wall.

It is necessary to decide whether the bleeding is –Nature of bleeding?

-Significant or not? -Generalized or localized?. -Acquired or hereditary? Consider child abuse with unusual bruising

Bleeding child diagnostic approach Nature of bleeding;

is the bleeding due to vascular, platelet, coagulation or a combination of this?

It is not always possible to categorize. Vascular and platelet dysfunction usually present with :

Spontaneous subcutaneous or mucus membrane bleeding eg; purpura, petechiae, epistaxis

Usually precipitate by injury. Continue for hours. Often controlled by pressure, once controlled doesn't

recur easily


Coagulation factors deficiency:

Usually occur deep into joins, muscles,retroperotineal space.

Post traumatic bleed are often delayed (sometimes hours).

May recur& bleeding my not get controlled by direct pressure.

Diagnostic approach Phase one: -Thorough history& physical examination as

well as standard screening laboratory test. Phase two: If the initial screening test is negative then

test for VWD, platelets dysfunction, factor 13 and or dysfibrongenemia.

Phase three: Interprets the abnormal result&&try to

define the specific disorders.


History: Spontaneous bleeding? Bleeding in unusual site without significant

trauma? Bruising and bleeding disproportionate to

injury? large or palpable bruising? Poorly controlled epistaxis?is it unilateral Excessive bleeding with tooth extraction? Abnormal bleeding at or after circumcision

or surgical procedure?


Excessive bleeding following fracture or minor cuts?

Time of the presentation & detailed Family history of bleeding disorders?

1- sex linked recessive (hemophilia A,B,WAS)2-autosomal recessives disease( clotting

factors defeciency2,5,7,10,11,13.3- autosomal dominant( VWF, qualitative

platelet disorders, dysfibronogenimia.)


-Questions that help target the defective components of hemostasis:

-mucosal bleeding(gum, nose)? -Petechiae? -Menorrhagia?Recent medications?-Presence of chronic disease e.g.; renal or liver disease?-Nutritional status? significance: scurvy, decreased hepatic synthesis


Physical examination: General stability, vitals signs, evidence of

chronic disease, evidence of malignancy. Skin stigmata : petechiae purpura ecchymosis hematoma


Delayed wound healing? Factor 13 deficiency, dysfibrinogemia

Musculoskeletal examination for bleeding and extensibility.


Laboratory aids: Phase one; Initial laboratory screening . platelet count,PT,PTT, bleeding time. Phase two;

special confirmatory tests - If qualitative platelets defect suspected platelet aggregation studies with restocetin, collagen,

thrombin,and ADP.- VWF analysis for VWF disease .- Thrombin time or fibrinogen for dys fibronegenimia..


phase three : discriminating laboratory studies for abnormal phase one tests:

1-when thrombocytopenia is present: -inspection of blood film (for bone marrow disease). Mean platelet volume(elevated in destruction,low in WAS) -Bone marrow aspiration .

Bleeding child diagnostic approach Prolonged PTT -Inhibitor

screen (50:50 mixing study of patients and normal plasma) if PTT fully corrected factors assay in the following order:8,9,11,10 partial or no correction after mixing inhibitor present ,check for lupus anticoagulant .

Prolonged PT inhibitor screen factors 7,10,5,2,1.

Prolonged PTT, PT: Test for DIC, liver disease, sever vitamin K

deficiency.factor 10, 2.

Indications for referral If the history and physical examination or

the screening tests strongly suggest the presence of a bleeding disease.

If the VWF disease is suspected, to determine the exact type and treatment.

Patient with hemophilia for regular visit follow up and coordination of care.

Prior to invasive procedure, surgery, dental work.

summary When you face a child with bleeding

problem what should I do? Careful history including past and family

history. Detailed clinical examination. Few screening test then appropriate

specialized tests Appropriate referral This will help in proper diagnosis and

hence better management of bleeding child.

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The bleeding child diagnostic approach