Pretreatment strategies for infection prevention in chemotherapy patients.

It is important to understand the pathogenesis of acute oral infections in patients with chemotherapy-induced myelosuppression in order to develop strategies to prevent such complications. Four distinct oral sites that can either be acutely infected or contribute to acute systemic infection are the oral mucosa, dental pulp and periapical tissues, periodontium, and salivary glands. Many cytotoxic drugs can be directly stomatotoxic to replicating oral mucosa. Once mucosal integrity is affected, secondary acute infection can occur. Even without clinical ulceration, deleterious shifts in the oral microbial population can develop. Gram-negative bacilli have been identified as frequent colonizers of myelosuppressed patients, although coagulase-negative staphylococci are being recovered with increasing frequency. Strategies to prevent oral mucosal infection include reducing trauma and preventing proliferation of organisms. Dental pulpal infection is most commonly caused by extensive dental caries. Most pulpal infection is of bacterial origin and can progress to involve the periapical tissues of the involved tooth if not treated. Specific endodontic interventions will usually stabilize or eliminate the source of the infection until the patient's hematologic status returns to normal and definitive pulpal therapy can be provided. In part because acute pulpal complications in the myelosuppressed cancer patient are relatively infrequent, research on the causative organisms and the appropriate therapy of acute, systemic infection of pulpal origin has been limited. Many adults have chronic, asymptomatic periodontal disease. In its advanced stages, extensive ulceration may be present that is not clinically observable. In patients with reduced host defenses, exacerbation of preexistent periodontal disease can have systemic sequelae and is associated with elevated levels of periodontopathic organisms or pathogens typically associated with systemic infection in myelosuppressed cancer patients. Mechanical and chemical antimicrobial techniques are available to reduce prevalence and improve patient comfort and oral hygiene. Dental extractions may be indicated to eliminate the nidus of infection of either pulpal or periodontal origin in patients who are scheduled to receive myelosuppressive chemotherapy. Data indicate that such procedures may be performed without undue risk. Unlike patients who undergo bone marrow transplantation or radiotherapy, patients who receive chemotherapy do not commonly experience subjective salivary gland dysfunction. Occasionally, a transient xerostomia may occur; this condition is frequently attributed to the patient's oral habits, such as breathing through the mouth. The dessicating effect of breathing through the mouth can contribute to oral mucosal injury during function as well as provide a setting for acute infection of commensal origin. More research is needed on the effects of chemotherapy on salivary host defenses.