Chapter 082. Infections in Patients with Cancer (Part 7)

Typhlitis Typhlitis (also referred to as necrotizing colitis, neutropenic colitis, necrotizing enteropathy, ileocecal syndrome, and cecitis) is a clinical syndrome of fever and right-lower-quadrant tenderness in an immunosuppressed host. This syndrome is classically seen in neutropenic patients after chemotherapy with cytotoxic drugs. It may be more common among children than among adults and appears to be much more common among patients with acute myelocytic leukemia (AML) or ALL than among those with other types of cancer; a similar syndrome has been reported in patients infected with HIV type 1. Physical examination reveals right-lower-quadrant tenderness, with or without rebound tenderness....
Nội dung trích xuất từ tài liệu:
Chapter 082. Infections in Patients with Cancer (Part 7) Chapter 082. Infections in Patients with Cancer (Part 7) Typhlitis Typhlitis (also referred to as necrotizing colitis, neutropenic colitis,necrotizing enteropathy, ileocecal syndrome, and cecitis) is a clinical syndrome offever and right-lower-quadrant tenderness in an immunosuppressed host. Thissyndrome is classically seen in neutropenic patients after chemotherapy withcytotoxic drugs. It may be more common among children than among adults andappears to be much more common among patients with acute myelocytic leukemia(AML) or ALL than among those with other types of cancer; a similar syndromehas been reported in patients infected with HIV type 1. Physical examinationreveals right-lower-quadrant tenderness, with or without rebound tenderness.Associated diarrhea (often bloody) is common, and the diagnosis can be confirmedby the finding of a thickened cecal wall on CT, MRI, or ultrasonography. Plainfilms may reveal a right-lower-quadrant mass, but CT with contrast or MRI is amuch more sensitive means of making the diagnosis. Although surgery issometimes attempted to avoid perforation from ischemia, most cases resolve withmedical therapy alone. The disease is sometimes associated with positive bloodcultures (which usually yield aerobic gram-negative bacilli), and therapy isrecommended for a broad spectrum of bacteria (particularly gram-negative bacilli,which are likely to be found in the bowel flora). Surgery is indicated in the case ofperforation. Clostridium difficile–Induced Diarrhea Patients with cancer are predisposed to the development of C. difficilediarrhea (Chap. 123) as a consequence of chemotherapy alone. Thus, they mayhave positive toxin tests before receiving antibiotics. Obviously, such patients arealso subject to C. difficile–induced diarrhea as a result of antibiotic pressure. C.difficile should always be considered as a possible cause of diarrhea in cancerpatients who have received antibiotics. Central Nervous System–Specific Syndromes Meningitis The presentation of meningitis in patients with lymphoma or CLL, patientsreceiving chemotherapy (particularly with glucocorticoids) for solid tumors, andpatients who have received bone marrow transplants suggests a diagnosis ofcryptococcal or listerial infection. As noted previously, splenectomized patientsare susceptible to rapid, overwhelming infection with encapsulated bacteria(including S. pneumoniae, H. influenzae, and N. meningitidis). Similarly, patientswho are antibody-deficient (such as patients with CLL, those who have receivedintensive chemotherapy, or those who have undergone bone marrowtransplantation) are likely to have infections caused by these bacteria. Other cancerpatients, however, because of their defective cellular immunity, are likely to beinfected with other pathogens (Table 82-3). Encephalitis The spectrum of disease resulting from viral encephalitis is expanded inimmunocompromised patients. A predisposition to infections with intracellularorganisms similar to those encountered in patients with AIDS (Chap. 182) is seenin cancer patients receiving (1) high-dose cytotoxic chemotherapy, (2)chemotherapy affecting T cell function (e.g., fludarabine), or (3) antibodies thateliminate T cells (e.g., anti-CD3) or cytokine activity. Infection with varicella-zoster virus (VZV) has been associated with encephalitis that may be caused byVZV-related vasculitis. Chronic viral infections may also be associated withdementia and encephalitic presentations, and a diagnosis of progressive multifocalleukoencephalopathy should be considered when a patient who has receivedchemotherapy presents with dementia (Table 82-6). Other abnormalities of thecentral nervous system (CNS) that may be confused with infection includenormal-pressure hydrocephalus and vasculitis resulting from CNS irradiation. Itmay be possible to differentiate these conditions by MRI. Table 82-6 Differential Diagnosis of Central Nervous System Infectionsin Patients with Cancer Underlying Predisposition Findings on Prolonged Defects in CellularCT or MRI Neutropenia Immunitya Mass lesions Aspergillus brain Toxoplasmosis abscess EBV-LPD Nocardia brain abscess Cryptococcus brain abscess Diffuse PML (J-C virus) Infection with VZV, CMV,encephalitis HSV, HHV-6, J-C virus (PML), Listeria a High-dose glucocorticoid therapy, cytotoxic chemotherapy. Abbreviations: CMV, cytomegalovirus; EBV-LPD, Epstein-Barr viruslymphoproliferative disease; HHV-6, human herpesvirus type 6; HSV, herpessimplex virus; PML, progressive multifocal leukoencephalopathy; VZV, varicella-zoster virus.