BLEEDING
DISORDERS AND THEIR MANAGEMENT IN DENTAL CLINICS
IN THIS ARTICLE WE WILL DISCUSS THE
FOLLOWING POINTERS:
1) IMPORTANT TERMINOLOGIES TO BE
REMEMBERED
2) POINTERS RELATED TO THE BLEEDING
DISORDERS.
3) PATIENT MANAGEMENT
A)IMPORTANT TERMINOLOGIES:
1) INR:International
Normalized Ratio=(Patient
protime/mean of the normal range) raised to ISI.
The ISI is the
International Sensitivity Index value assigned by the manufacturer to each lot
of thromboplastin calibrated to the world health organization. Reference
material.
The INR standardizes
reporting of anticoagulation activity and monitors patients on stabilized oral
anticoagulant therapy only.
The therapeutic range is
2.0-3.0 for most of clinical situations.
Patients with mechanical
heart valves are maintained at 2.5-3.5.
2)
IVY
BLEEDING TIME: The Ivy Bleeding Time laboratory test has been routinely used as a screening test
for assessing adequacy of platelet function. When performed, the bleeding time test calculates the time
required for a standard skin incision to stop bleeding by the formation of a
hemostatic plug.9 The normal range of the Ivy Bleeding Time test is usually
between 2 and 10 minutes
3) PLATELET
FUNCTION ANALYZER(PFA-100): is a sophisticated laboratory
screening testing devise that is currently
being used in place of the Ivy Bleeding Time test. Platelet function tests or platelet function assay
(PFA) evaluate the qualitative function of platelets.
These tests provide an assessment of
platelet adhesion. platelet activation and platelet aggregation during the development of a
platelet plug, or primary hemostasis.2,12
4) Prothrombin Time (PT), measures the patient’s ability to form a definitive clot by
monitoring the proper functioning of the extrinsic coagulation pathway (Factor
VII) and the common pathway (Factors V, X, prothrombin and fibrinogen). Generally, the
laboratory testing range is between 11–15 seconds.8 Testing results beyond 15 seconds
indicate an abnormal or prolonged PT.
5) Activated Partial Thromboplastin Time
(aPTT) also measures the patient’s ability to effectively
form a definitive clot by evaluating the effectiveness of the intrinsic and
common pathways of the coagulation cascade.2,5,9 It tests for deficiencies in the
intrinsic pathway, specifically factors VIII, IX, XI, XIII; and deficiencies in
the common pathway, specifically factors V and X, prothrombin and fibrinogen. A
normal aPTT is usually 25 to 40 seconds.
6) Thrombin Time laboratory test assesses the
conversion of fibrinogen to insoluble fibrin by adding thrombin to the
patient’s blood sample.2,8 Specifically, this test bypasses the
extrinsic, intrinsic and common pathways to determine the stability of the
clot. Normally, the range of this test is between 9 and 13 seconds.2 A prolonged time, in
excess of 16 to 18 seconds, is considered abnormal
B.POINTERS TO BE REMEMBERED:
1) Vitamin
K and its significance:
a) Clotting factors
II,vII,IX and X require vitamin k for synthesis.
b) Long term antibiotic
therapy can suppress the normal flora in the gastrointestinal tract that are
necessary for the synthesis for vitamin k.Therefore they should be used
cautiously.
c) Vitamin K and
Warfarin:Vitamin K reverses the effect of warfarin.Once vitamin K is
administered ,the patient may be resistant to further anticoagulation with
warfarin for a few days .In certain patients they may have an underlying
tendency that puts them at risk for thrombosis and embolic complications should
the effects of anticoagulant be stopped abruptly..
2) Differentiate Hemophilia A and Hemophilia B:
:Hemophilia A is an X linked disease in which factor VIII is deficient,whereas the affected serine protease in type B is factor IX.Initially the two disorders will appear similar with elevated PTT and Normal PT and bleeding time,but they are managed differently.
3) Transxemic
Acid:It is an antifibrinolytic
agent that is used to promote stability of a formed clot.The final phase in the
common pathway to blood clot formation
is the activation of fibrinogen to fibrin in the presence of thrombin.
Fibrin
forms the basis for the blood clot,fibrinolysis or clot breakdown begins in the
presence of plasmin that is formed from activated plasminogen.Transxemic acid
inhibits the activation of plasminogen,therby
promoting stability of the blood clot.
It can be
used effectively as a topical agent and mouthrinse to promote clot stability in
patients receiving warfarin anticoagulation therapy.
4) The effect of Aspirin on Platelets:
PATIENT MANAGEMENT GUIDELINES:
Step 1: Take accurate, comprehensive
histories: personal, medical, dental and pharmacological. Perform a thorough
extra and intraoral examination to identify lesions indicative of a bleeding
disorder. When a known bleeding disorder is evident, understand the
pathophysiology and its related impact on dental treatment. When an unknown
bleeding disorder is suspected,
Step 2: Consult with the
supervising physician to obtain additional information about the patient’s
disorder or bleeding history. Continue to investigate and/or to obtain medical
clearance to treat. Secondly, retrieve and evaluate the blood laboratory test
results while scheduling the appointment within 24 hours of the results.
Step 3: Develop an appropriate
treatment plan: establish whether or not the invasive dental procedure will be
carried out in the dental office or in a hospital-based dental facility.
Possibly, prior to invasive treatment, consider blood and/or clotting factor
replacement therapy for patients with hemophilia; and, patients with platelet
disorders may require platelet transfusion therapy.
In addition, other medical
interventions may be required beyond infusion therapies for the respective
disorders; for example, fibrinolytic defects, vascular defects or modification
of anticoagulant therapy may require specialized medical care.
When performing
the invasive dental procedure recommendations include: minimize tissue trauma;
consider hemostatic systems for predictable extensive bleeding during and after
complex surgical procedures; consider alternative pain control techniques other
than nerve-block anesthesia
More
importantly, when selecting a hemostatic therapy that achieves adequate
hemostasis when performing invasive dental procedures on patients with bleeding
disorders one must consider the following elements:
• The specific
bleeding disorder.
•
The need for a hemostatic agent and/or intervention.
The
type of local and/or systemic hemostatic agent.
• The need for a consultation with the patient’s
supervising physician to determine the need for coagulation factor replacement
as indicated.
• The severity of the bleeding disorder.
•
The specific invasive dental procedure that will induce a bleed
intraoperatively and postoperatively.
click on the below link to get a pdf of important charts and tables that will help you to solve any case related to bleeding disorder.
The above article is prepared with references from
1) Crest® Oral-B®
at dentalcare.com Continuing Education Course
2) Dental Secrets
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