0071643192.pdf

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HEMATOLOGY, ONCOLOGY, ALLERGY,

AND IMMUNOLOGY

SYMPTOMS/EXAM


■ Petechiae or ecchymosis of mucus membranes or skin
■ Epistaxis, gum bleeding, menorrhagia, or GI bleeding


DIAGNOSIS


■ Increased bleeding may occur when platelets are below 50,000/μL.
■ Risk of life-threatening spontaneous hemorrhage occurs with counts
<20,000/μL and substantially increases with counts <10,000/μL.


TREATMENT


■ Treat underlying cause.
■ Significant hemorrhage or major procedure with platelets <50,000/μL


PK
HK

XII

XI

IX IXa

XX

XIII

XIIIa
Fibrinogen Fibrin

Cross-linked fibrin

Xa

VIIIa

Va

Prothrombin Thrombin

VIIa
TF

Extrinsic pathway

XIa

XIIa

Intrinsic pathway

HK

FIGURE 9.1. The coagulation cascade. The intrinsic pathway is measured by the
activated partial thromboplastin time (PTT). The extrinsic pathway is measured by the
prothrombin time (PT).


(Reproduced, with permission, from Lichtman MA, Beutler E, Kipps TJ, et al. Williams Hematology,
7th ed. New York: McGraw-Hill, 2006:1684.)


TABLE 9.6. Use of Laboratory Values to Identify Cause of Increased Bleeding


LABORATORYFINDING CAUSES

Low platelets See Table 9.9.

Prolonged PT Liver disease, vitamin K deficiency, warfarin

Prolonged PTT Hemophilia A and B, von Willebrand disease, heparin

Low fibrinogen level Disseminated intravascular coagulation, large volume
transfusion, liver disease, severe malnutrition

Patients with clotting-factor
problems tend to suffer from
prolonged bleeding after an
injury or surgery and bleeding
into joints; patients with
platelet problems tend to
suffer from petechiae,
epistaxis, gum bleeding, and
vaginal bleeding.

Thrombocytopenia in patients
with alcoholism results from
direct toxicity to the bone
marrow from alcohol, folic
acid deficiency, and increased
sequestration from
splenomegaly.
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