Page 1825 - Hall et al (2015) Principles of Critical Care-McGraw-Hill

1294 PART 11: Special Problems in Critical Care

■ PURPURA purpura, because these patients are unable to mount the appropriate

Purpura is a clinical term that describes the extravasation of blood into immune response to cause dermal inflammation. In such patients,
biopsy is important to assist with diagnosis.
surrounding tissues. Purpura is a common skin condition that has
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Palpable purpura indicates underlying vasculitis (also called cutane-
many causes. The type of lesion depends on the depth of the vascular ous necrotizing venulitis or leukocytoclastic vasculitis). For the first 24
plexus involved, the size of the vessel injury, precipitating factors, and
coextravasated circulating substances. Visual and tactile assessments of to 48 hours, the lesions are a deep erythematous color that eventually
becomes violaceous. The pathologic process results from segmental
a lesion are crucial. An approach to the patient with purpura focusing on
the dermatologic decision-making algorithm is discussed. Lesions are vascular inflammation, swelling and necrosis of endothelial cells, and
neutrophilic infiltration of vessel walls with fragmentation of nuclei.
placed into three main categories: palpable, nonpalpable, and retiform
As outlined in Figure 129-21, many factors may lead to vasculitic
purpura (Table 129-16). The patient’s underlying conditions, potential injury. Precipitating factors include infections, drugs, autoimmune dis-
precipitating events, current and past laboratory values, and medication
history are analyzed. eases, and immunoglobulin-mediated complement activation. Common
infectious agents include Staphylococcus aureus, hepatitis B, and
Nonpalpable (macular), nonblanching purpura arises from simple
hemorrhage into tissue. The dermal vascular network consists of super- hepatitis C. Drugs commonly associated with vasculitis include
ampicillins, thiazides, phenytoin, sulfa-containing compounds, allo-
ficial and deep vascular plexuses. The superficial plexus possesses arte-
riovenous loops that ascend into the dermal papilla. Petechiae are lesions purinol, hydralazine, and propylthiouracil.
Workup includes identification of a potential primary cause and
smaller than 0.2 cm in diameter that result from superficial vascular
hemorrhage. Larger areas are termed ecchymoses. Nonpalpable purpura evaluation for systemic involvement. In addition to a biopsy, a com-
plete blood count, chemistry panel, liver function tests, urinalysis, stool
is most commonly attributed to fragility of the vascular tissue or defects
in hemostasis. Examples include actinic or solar purpura (owing to the guaiac, hepatitis B and C viral serologies, cryoglobulins, and comple-
ment levels are evaluated. Antinuclear antibody titers are evaluated in
age-related loss of collagen in the basement membrane of blood vessels)
and purpura secondary to systemic corticosteroids (related to inhibition patients with suspected connective tissue diseases. In patients with a
fever and heart murmur, blood cultures and echocardiography should
of lysyl oxidase that is required for synthesis of type IV collagen, the 83
principal collagen associated with blood vessel basement membrane be performed.
Retiform purpura (Fig. 129-22) is referred to as purpura fulminans,
integrity). Cutaneous amyloid, primary or secondary resulting from
myeloma, may be deposited in endothelial cells. Deposition results a pattern usually indicative of micro-occlusion. In contrast to inflam-
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matory purpura, this type immediately manifests as violaceous purpura
in vascular fragility so that nonpalpable lesions representing common
bruises, sometimes called pinch purpura, may occur after minor trauma. that may or may not be palpable. Lesions appear abruptly and display
a retiform or jagged edge, sometimes blending into a livedo pattern at
This occurs mainly on the face, especially periorbitally. Other common
causes of flat purpura include platelet disorders (thrombocytopenia, the periphery. The major causes of micro-occlusive disease include DIC,
meningococcemia (Fig. 129-30), acquired protein C or S deficiency,
thrombocytopathia, and thrombocytosis), disseminated intravascular
coagulation (DIC), and warfarin-associated necrosis. If the diagnosis warfarin-induced skin necrosis (Fig. 129-8), antiphospholipid antibody
syndrome, sepsis of various causes, cryoglobulinemia (Fig. 129-23),
cannot be made on clinical grounds, a skin biopsy may be helpful. Flat
purpura in neutropenic patients is approached as if it were palpable cryofibrinogenemia, paroxysmal nocturnal hemoglobinuria, and cho-
lesterol emboli. Figure 129-24 represents a case of purpura fulminans
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with peripheral gangrene which can occur in many different settings,
TABLE 129-16 Causes of Purpura but mostly in association with DIC and meningococcal septicemia.
Nonpalpable Purpura Palpable Purpura Retiform Purpura ■ GRAFT-VERSUS-HOST DISEASE
Platelet disorders Idiopathic leukocytoclastic Systemic coagulopathies Graft-versus-host disease (GVHD) is a complex syndrome which
Thrombocytopenia vasculitis Acquired protein C typically occurs between days 10 and 30 after allogeneic bone marrow
Thrombocytosis Drug-induced leukocyto- deficiency transplantation, but may appear at any time. The skin is often the first
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Impaired platelet function clastic vasculitis Acquired protein S and most frequent organ involved. Skin changes consist of a generalized
Vascular tissue defects Small vessel vasculitis deficiency morbilliform eruption progressing to extensive redness, blistering, or
Senile purpura Henoch-Schönlein Systemic infection skin necrosis. The earliest sign is pruritus and tenderness of the palms
Steroid purpura purpura Meningococcus and soles, with reddening of the dorsal aspects of the fingers and peri-
Collagen vascular disorders Erythema elevatum Gonococcus ungual skin. Diffuse erythema of the hands and feet soon follows. In
Scurvy diutinum Pseudomonas addition, the ears are commonly affected. Unusual clinical patterns may
Amyloidosis Acute hemorrhagic DIC/sepsis be seen due to the polymorphous nature of this disease. Confluence of
Dysproteinemias edema of infancy Opportunistic fungal lesions occurs on the trunk as the disease progresses. Blisters (with a
Capillaritis Urticarial vasculitis infections positive Nikolsky sign) and generalized desquamation portend a poor
Schaumberg disease Small and medium-sized Lucio phenomenon of prognosis. The palmar and plantar erythemas of acute GVHD need to
Coagulation disorders vessel vasculitis leprosy be differentiated from those of palmar-plantar erythrodysesthesia due
Lupus anticoagulant Cryoglobulinemic Embolization to chemotherapeutic agents. This syndrome may occur with GVHD or
syndrome vasculitis Cholesterol in similar clinical situations. The erythrodysesthesia begins as spotty
Clotting factor defects Microscopic polyangiitis Oxalate erythema on the thenar and hypothenar eminences and progresses to
DIC Churg-Strauss syndrome Infective endocarditis severe pain and swelling.
Thrombi and emboli Wegener granulomatosis Marantic endocarditis Several features of GVHD are recognized: (1) 72% of transplanted
Monoclonal Medium-sized vessel Atrial myxoma patients develop clinically recognizable GVHD; (2) an increase in the
cryoglobulinemia vasculitis Libman-Sacks serum aspartate aminotransferase concentration is related to the onset
TTP Polyarteritis nodosa endocarditis or worsening of the skin eruption; (3) cutaneous symptoms precede
DIC Large-sized vessel Platelet Occlusion systemic involvement by 2 to 3 days; and (4) the severity of GVHD does
Cholesterol vasculitis Heparin necrosis not correlate with the underlying disease process, the conditioning regi-
Fat Takayasu arteritis TTP men, or the day of onset after grafting. The initial management strategy
Warfarin associated Giant cell arteritis when GVHD is suspected includes obtaining a skin biopsy to look for
DIC, disseminated intravascular coagulation; TTP, thrombotic thrombocytopenic purpura. the characteristic changes. Unfortunately, the diagnostic yield of skin

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