Page 2132 - Williams Hematology ( PDFDrive )

2106 Part XII: Hemostasis and Thrombosis Chapter 122: The Vascular Purpuras 2107

Focal ecchymosis and other purpuric lesions can manifest as a
result of trauma. Characteristic patterns of purpuric lesions are com-
monly used in forensic science. Traumatic asphyxia, for instance, is
characterized by cervicofacial cyanosis and swelling, petechiae, and
139
subconjunctival hemorrhage. Factitious purpura, often related to
deliberate suction purpura, should be considered in the differential for
purpura. Other physical causes of purpura consist of physical rem-
140
edies, such as spooning (Quat Sha) or coin rubbing (Cao Gio). Exer-
cise-induced purpura results in purpuric, erythematous, or urticarial
lesions distributed on the lower legs. 141

THROMBOCYTOPENIAS
Disseminated Intravascular Coagulation
DIC is defined as widespread, amplified and uncontrolled intravascular
coagulation with a range of causes including sepsis, trauma, and malig-
Figure 122–23. Wegener granulomatosis.
nancy. Petechiae and purpuric plaques result from thrombocytope-
142
nia, and are common manifestations of DIC (Chap. 129).
ANTINEUTROPHIL CYTOPLASMIC
ANTIBODY–ASSOCIATED VASCULITIS Immune Thrombocytopenia Purpura
Immune (or idiopathic) thrombocytopenia purpura is an acquired dis-
Wegener Granulomatosis ease characterized by autoantibody-mediated platelet destruction com-
This small- to medium-vessel vasculitis most commonly affects upper monly resulting in purpuric lesions of the skin and mucosa as well as
and lower respiratory tracts and kidneys and is strongly associated with other sites of abnormal bleeding (Chap 117). 143
the development of circulating antineutrophil cytoplasmic antibodies
(ANCAs). Skin involvement has been reported in 35 to 50 percent of Thrombotic Thrombocytopenia Purpura
128
cases. Cutaneous manifestations include a combination of palpable Thrombotic thrombocytopenia purpura is characterized by nonim-
129
purpura, oral ulcers, and erythematous cutaneous and subcutaneous mune platelet consumption, microvascular hemolysis, and organ
nodules (Fig. 122–23). Necrotizing vasculitis, palisading granulomas, damage. It is associated with a deficiency in the von Willebrand factor
130
and granulomatous vasculitis are characteristic histologic findings. 131 cleaving protease, ADAMTS-13 (a disintegrin and metalloproteinase
with thrombospondin domain 13; Chap. 132). Petechiae and pur-
144
Churg-Strauss Syndrome puric plaques may occur.
Churg-Strauss syndrome (CSS) is characterized by granuloma-
tous inflammation in the lungs associated with asthma and eos-
inophilia. Cutaneous findings such as ulcers, papules, palpable DRUG REACTIONS
132
purpura, cutaneous nodules, and infarcts of fingers and toes are A large number of medications are reported to result in vasculitic and
145
encountered in 50 to 80 percent of cases. CSS limited to the skin nonvasculitic purpuric eruptions. Nevertheless, any drug on the med-
130
was described. Eosinophilia accompanies elevated IgE levels and ication list of a patient with a purpuric lesion (within 2 weeks of start-
133
a positive perinuclear ANCA. Granulomatous inflammation and ing a new drug or a few days if prior sensitization is suspected) may be
necrotizing vasculitis of small- to medium-size blood vessels are involved. 146
present histologically. 131
COAGULATION DISORDERS
NONPALPABLE, NONINFLAMMATORY, A large number of disorders manifest with thrombocytopenia or
ROUND PURPURIC LESIONS impaired thrombocyte function, that result in increased bruising. Also,
impaired fibrin formation, resulting from coagulation factor deficien-
cies, the use of anticoagulants, vitamin K deficiency, or poor hepatic
See Table 122–3.
function may cause bruising and hematomas.
INCREASED TRANSMURAL PRESSURE
GRADIENT AND TRAUMA DECREASED VESSEL INTEGRITY
Acute increases in vascular transmural pressure gradients lead to WITHOUT TRAUMA
extravasation of red blood cells resulting in nonpalpable, noninflamma- Senile Purpura
tory petechial and larger purpuric lesions. Examples include postictal Synonymous with actinic purpura, senile purpura refers to the easy
purpura, weightlifting, postemesis facial purpura, prolonged Val- bruising seen in the aged and sun-damaged skin, commonly appear-
136
134
135
salva, and childbirth. Acute decreases in extravascular negative pres- ing on the dorsal aspect of the hands and forearms (Fig. 122–24). One
sure, referred to as suction purpura from gas mask, kissing, or cupping, proposed etiology is the degeneration of skin extracellular matrix com-
can also increase this gradient, resulting in well-circumscribed lesions ponents that leaves dermal capillaries unsupported and vulnerable to
147
in the shape of the causative device. The development of petechiae shearing injuries, but zinc deficiency is also suspected. 148
137
in mountain climbers, is presumably caused by significantly reduced
atmospheric pressures at high elevations. Lower-extremity venous Excess Glucocorticoid
138
incompetence, predominantly at the medial ankle, can result in macules The presence of excess endogenous (Cushing syndrome) or exoge-
or patches of yellowish-brown purpura. nous (iatrogenic) glucocorticoid use can result in dermal thinning and

Kaushansky_chapter 122_p2097-2112.indd 2107 9/18/15 10:30 AM