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CHAPTER 68: Approach to Infection in Patients Receiving Cytotoxic Chemotherapy for Malignancy 617

vomiting, and diffuse watery or bloody diarrhea are also commonly malignancy within the preceding month and are severely neutropenic.
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observed. Bacteremia with enteric microorganisms (Escherichia coli, Perirectal infection must be suspected if there is focal tenderness,
Klebsiella species) and Pseudomonas aeruginosa is associated with perirectal induration, or erythema with or without fluctuance or tissue
typhlitis in up to 28% of cases. Clinical examination usually reveals necrosis. Although some cases may be associated with a preexisting
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a diffusely tender abdomen; however, localization to the right lower pathologic process such as an anal fissure or thrombosed hemorrhoidal
or upper quadrant is not uncommon. Ultrasonographic or CT tissues, most patients present no obvious predisposing factor. The
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imaging of the abdomen frequently demonstrates thickening and etiology of these infections is polymicrobial. 335,336 The most common
edema of the colonic walls with or without inflammatory changes microorganisms are enteric gram-negative bacilli, obligate anaerobes,
in the surrounding pericolic tissues (Fig. 68-5). Gas in the intestinal enterococci, and peptostreptococci. Recurrent episodes of infection
wall (pneumatosis) or an inflammatory phlegmon may also be seen in are frequent among receiving subsequent cycles of cytotoxic therapy. 334
approximately 20% of cases. CDAD is associated with the greatest The optimal approach to management is controversial. In general,
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degree of bowel wall thickening. There appears to be a correlation neutropenic patients should be managed medically unless local care,
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between the thickness of the bowel wall, presumably reflecting the systemic antimicrobials, and blood product support fail to contain the
degree of inflammation, and mortality. Cartoni and colleagues using infection and if an obvious inflammatory collection must be surgically
ultrasonographic examinations noted mortality rates of 60% among drained. The likelihood of medical management success is increased
those with mural thickness of more than 10 millimeters. Mural if the antimicrobial regimen contains agents effective in severe intra-
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thickness also correlated with prolonged duration of symptoms com- abdominal sepsis. Vancomycin may be added if despite these anti-
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pared to patients without thickening (mean duration of symptoms, microbials the cellulitis appears to progress. The therapeutic role of
7.9 days vs 3.8 days). 332 antimicrobial agents active against Enterococcus spp remains difficult
Neutropenic enterocolitis is associated with significant impairment to evaluate since the role of these bacterial species in the pathogen-
in the functional integrity of the gut mucosa, increasing the risk for esis in these infections is controversial. Cephalosporins are inactive
translocation of bacteria and fungi. Malabsorption of D-xylose has been against Enterococcus spp and the carbapenem-related susceptibility
shown to precede clinical neutropenic enterocolitis by at least a week. profiles tend to mirror that of ampicillin and therefore are less reliable.
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Candida mannoprotein antigen associated with intestinal colonizing Enterococcal colonization must be differentiated from infection. The
Candida spp may be detected in patients with neutropenic enteroco- rising incidence of vancomycin-resistant Enterococcus spp argues to
litis. Translocation of colonizing yeast is part of the pathogenesis of minimize its use. Recent observations with regard to the emergence
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invasive candidiasis with portal fungemia and subsequent hepatosplenic of vancomycin-resistant Enterococcus spp following piperacillin-based
fungal infection. 93,96 antibacterial therapy is of concern given the frequency of use of this
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Management consists of early recognition, bowel rest with naso- agent in cancer patients.
transfusion, and broad-spectrum antibacterial agents. Although early ■ RESPIRATORY VIRUS INFECTIONS
gastric decompression, intravenous fluid replacement, blood product
surgical consultation is recommended before an intra-abdominal catas- Respiratory virus infections in cancer patients may be associated with
trophe occurs, medical management is recommended for the majority considerable morbidity, including respiratory failure. Such viruses
of patients who do not have such a catastrophe. Right hemicolectomy or include respiratory syncytial virus (RSV), influenza viruses types A and
local resection of necrotic segments of bowel with anastomosis or divert- B, parainfluenzaviruses types I-IV, human metapneumovirus (HMPV),
ing ileostomy or colostomy should only be considered with cecal perfora- human coronavirus (hCoV), human bocavirus (hBoV), and human
tion, massive uncontrollable GI bleeding, uncontrollable sepsis, complete rhinovirus (hRhV). 340,341 These viruses cause a spectrum of clinical syn-
bowel obstruction, or pneumatosis cystoides intestinalis. With optimal dromes in immunocompetent patients including common cold symp-
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management, the mortality rate has declined from over 50% to less than toms of rhinorrhea and coryza, croup, bronchiolitis, and pneumonia.
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20%. 330,331 It is important to recognize the high risk of recurrence (up to As a function of contact and aerosol-mediated modes of transmission,
two-thirds of cases) with subsequent cycles of cytotoxic therapy. 328 the initial infection is usually focused in the upper respiratory tract
Perirectal Infections: The majority of cancer patients with this compli- (URTI). Progression to lower respiratory tract infection (LRTI) has been
cation have received cytotoxic therapy for leukemia or lymphoreticular associated with pneumonia or a late onset airflow obstruction syndrome,
particularly in HSCT recipients. In HSCT patients with URTI, the risk
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for progression to LRTI and 30-day mortality, enhanced by severe lym-
phopenia, may occur in approximately 40% and 45% of HSCT patients
with RSV URTI, respectively; 18% to 44% and 35% to 37% of patients
with parainfluenzavirus URTI, respectively; and approximately 18%
and 25% to 28% of patients with influenzavirus URTI, respectively.
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Cancer patients with LRTI from respiratory viruses such as influenza
often develop critical illness, particularly if the time from disease onset
to treatment is delayed beyond 48 hours. 344
■ INVASIVE FUNGAL INFECTIONS

Opportunistic Yeast Infections: This group of opportunistic unicellular
fungal organisms of the form-class Blastomycetes and form-family
Cryptococcaceae includes six genuses: Cryptococcus (eg, C neofor-
mans, the agent of cryptococcal meningitis), Malassezia (eg, M furfur,
the agent of pityriasis versicolor), Rodotorula (eg, R rubra, an agent
causing pulmonary and systemic infections), Candida (eg, C albicans,
the most common etiology of invasive candidiasis), Trichosporon
(eg, T beigelii, the agent of white piedra and systemic infections in
compromised hosts), and Torulopsis (eg, T glabrata, now reclassi-
FIGURE 68-5. CT scan of the abdomen of a woman receiving high-dose cytarabine for fied under the genus Candida). C albicans, C tropicalis, C glabrata,
acute leukemia who complained of severe right lower quadrant pain. The wall of the cecum is and Trichosporon species are part of the normal microflora of the
thickened and edematous consistent with typhlitis. mouth, colon, and vagina. Consequently, it is not surprising to find

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