Infectious complications in the child with cancer. I. Pathophysiology of the compromised host and the initial evaluation and management of the febrile cancer patient

A long-term prospective clinical study of orofacial herpes simplex virus infection in acute leukemia

Orofacial mucocutaneous infections resulting from herpes simplex virus (HSV) were detected in 40% of patients with acute leukemia. Of the 34 separate episodes, oral mucosal sites were involved in 22 cases. Evidence to support dissemination of HSV was found in 3 patients on 4 separate occasions. The relationship of neutrophil levels to the onset and resolution of lesions is examined. The value of acyclovir for treatment of these HSV-induced lesions is reported, and the question of administering this agent for routine prophylaxis against HSV in these patients is addressed.

The effect of abdominal radiation on spleen function: a study in children with Wilms' tumor

Reports of splenic dysfunction in patients with Hodgkin's disease who received radiation therapy to the spleen raise questions concerning impairment of splenic function and the long-term risk of bacterial sepsis in children who receive abdominal radiation for other diseases. Splenic function was studied in 20 children with Wilms' tumor using a quantitative assessment of vacuolated ("pitted") red cells as a measure of reticuloendothelial function. Fourteen children had received abdominal radiation to a field involving the spleen at a median dose of 2000 rads. Their pitted red cells counts were no different from those of 6 children who received therapy without radiation to the spleen or to those of a group of normal children and adults. We conclude that there is no demonstrable long-term impairment of spleen function with radiation doses at or below 2200 rads.

Management in the febrile, neutropenic patient with cancer: therapeutic considerations

Infection is the principal cause of death in neutropenic children and adults with neoplastic diseases. Various antibiotic regimens have been studied in clinical trials in an attempt to reduce this mortality. Recent trials have compared newer combinations of antibacterial agents (double beta-lactams) or monotherapy with the standard aminoglycoside-beta-lactam combinations. No significant differences are demonstrated in these trials with regard to efficacy. Emphasis has been on the reduction of toxicity. Although nephrotoxicity, ototoxicity, and hypokalemia have been of concern in the past and continue to be important, newer problems have emerged that involve disorders of coagulation, for example, prolongation of prothrombin time, disorders of platelet function, and clinical bleeding. Superinfection and the emergence of resistance during therapy have also been problematic. Cost must be considered an important factor in determining the selection of an antibacterial regimen. The combination of an aminoglycoside and a beta-lactam antibiotic remains the standard against which future combinations or monotherapy must be judged in clinical trials involving the febrile, neutropenic patient with cancer.

Oncologic emergencies II. Hematologic and infectious complications of cancer and cancer treatment

Proper supportive care of the child with cancer is necessary to maximize the child's quality and length of life. This article discusses the pathophysiology, diagnosis, and management of the common hematologic and infectious complications of childhood cancer that the primary care physician must face.

Splenic reticuloendothelial function in children with cancer

We studied splenic function in children with cancer by quantitation of pitted, or pocked, erythrocytes (pocked RBC count), that is, the percentage of erythrocytes containing one or more membrane-bound vesicles, as determined by phase interference microscopy. The mean pocked RBC count in 93 normal children and adults was 0.49% (range 0% to 2.0%), with only 2.4% of normal subjects having values greater than 1.5%. Mean pocked RBC count in 28 children after splenectomy was 37% (range 3.2% to 81%). Among 181 children with cancer (525 specimens), the mean pocked RBC count was 1.06% (range 0% to 12.6%). Fifty-nine (32%) patients had one or more values greater than 1.5%, and 25 (13.8%) children had measurements greater than 3.0%, a level previously suggested to have clinical significance. Elevated pocked RBC counts (greater than 1.5%) occurred in more than one third of children with Wilms tumor and acute lymphoblastic leukemia, and in both patients with juvenile chronic myelogenous leukemia. Elevations in pocked RBC counts were not related to specific chemotherapy regimens or to disease activity. Mild splenic reticuloendothelial hypofunction occurs in many children with cancer and may contribute to the risk of infection in these patients.

The effects of thymic epithelial monolayer-conditioned medium on suppressor cell function following chemotherapy in pediatric patients

Human thymic epithelial monolayer-conditioned medium (TEM-CM) enhanced concanavalin A (ConA)-induced suppressor T-lymphocyte activity in 15 of 17 studies of fractionated light-density bone marrow mononuclear cells (LD-BMMC) obtained from pediatric cancer patients within 7 days of chemotherapy (P less than 0.001). However, TEM-CM depressed ConA-induced suppressor T-lymphocyte activity in 14 of 18 studies of LD-BMMC obtained from patients who had received their chemotherapy 14-21 days previously (P less than 0.05). In studies of LD-BMMC from normal subjects, TEM-CM did not show any significant effect on suppressor cell activity, nor did TEM-CM significantly affect spontaneous suppressor cell activity in patients or normals. The effect of direct culture on thymic epithelial monolayers was equivalent to the effect of TEM-CM in both ConA-induced and spontaneous suppressor cell assays. These data demonstrate thymic factor-mediated changes in suppressor T-cell activity of pediatric cancer patients and suggest a postchemotherapy alteration in the bone marrow population of inducible prethymic T cells.

Granulocytopenia and cancer therapy. Past problems, current solutions, future challenges

Granulocytopenia has been closely associated with cancer and its treatment. The risk for a life-threatening infection when the granulocyte count falls below 500/mm3 not only is an important complication of therapy and a major cause of death in cancer patients but also plays an important role in the design, schedule, and doses of cancer treatment regimens. While granulocytopenia remains an unavoidable complication of current therapy, improved recognition of patients at risk and prompt initiation of aggressive supportive care have had a significant impact on reducing its infection-related morbidity and mortality. In particular, early empiric antibiotic therapy when the granulocytopenic patient becomes febrile has resulted in a significant reduction in the early mortality from undiagnosed bacterial infections. New antibiotics (extended-spectrum penicillins, third generation cephalosporins) provide new options because of their broad efficacy and potential for reducing the toxicity of antimicrobial therapy. However, as bacterial infections have become better controlled, fungi have emerged as important pathogens. Early aggressive empiric antifungal therapy appears to have reduced infectious mortality, although the repertoire of effective antifungal agents is quite limited. Considerable efforts have been expended in trying to replenish granulocytes by transfusion in infected patients, but technical deficiencies have limited this approach. Current and future efforts are directed toward refining management as well as to developing methods to improve host defenses and provide prophylaxis against infections. If the full potential of current cancer therapy is to be realized, control of granulocytopenia and the prevention of infections are essential goals.

Approaching the controversies in antibacterial management of cancer patients

The principles for management of infectious complications in cancer patients are continuing to evolve. The critical element includes the prompt institution of broad-spectrum antibiotic(s) empirically when granulocytopenic patients become febrile and continuation and modification of the regimen in patients with persistent fever and granulocytopenia. The view is presented that antibiotics provide systemic prophylaxis as well as therapy in persistently granulocytopenic patients and that they should be continued until all signs of infection have cleared or the granulocyte count has recovered. Such aggressive therapy, supplemented by continued evaluation and monitoring of the patient, can significantly reduce infection-relation morbidity and mortality.

Randomized controlled trial comparing trimethoprim/sulfamethoxazole and trimethoprim for infection prophylaxis in hospitalized granulocytopenic patients

The clinical and microbiologic efficacy of trimethoprim alone and trimethoprim/sulfamethoxazole for infection prevention was evaluated in 75 patients during 92 episodes of granulocytopenia. Ultimately, 60 patients were evaluable during 77 episodes of granulocytopenia, 36 episodes in the trimethoprim group and 41 episodes in the trimethoprim/sulfamethoxazole group. The incidence of infection was higher in the trimethoprim group (50 percent) than in the trimethoprim/sulfamethoxazole group (39 percent), but this did not reach statistical significance. Trimethoprim did not appear to be as protective as trimethoprim/sulfamethoxazole when the granulocyte count was less than 100/mm3. In patients receiving trimethoprim/sulfamethoxazole, aerobic gram-negative bacilli cleared from fecal surveillance cultures more often and new aerobic gram-negative bacilli were acquired less often than in those receiving trimethoprim alone (p less than 0.05). More myelosuppression was observed among patients receiving trimethoprim/sulfamethoxazole (p less than 0.001). These observations suggest that trimethoprim alone may not be optimal for preventing colonization and infection in granulocytopenic patients and that combination with other agents may be necessary to increase the spectrum of activity. Trimethoprim/sulfamethoxazole itself may predispose toward an increased risk of infection by prolonging myelosuppression.

Management of infections

Over the last decade, significant advances have been made in the management of bacterial and viral infections in the immunocompromised host. These advances have been achieved through carefully performed studies, addressing the need for early antimicrobial therapy. The utilization of the empiric antibacterial therapy has prompted a significant decrease in mortality and morbidity from life-threatening bacterial infections in the immunocompromised patients. Similarly, the development of antivirals for therapy of herpes virus infections in man is significantly changing our ability to improve survival in children who suffer from chickenpox and progressive herpes simplex virus infections. The future demands improved anti-bacterial agents as well as methods of prevention of viral infections in the immunosuppressed host. These latter avenues will take the form of live attenuated viral vaccines.

Successful treatment of pulmonary and cerebral aspergillosis in an immunosuppressed child

A favourable outcome was observed in a 12 year-old boy who developed invasive pulmonary and cerebral aspergillosis during antineoplastic treatment for central nervous system relapse of acute lymphoblastic leukemia. Combination therapy with amphotericin B and 5-Fluorocytosine led to complete regression of pulmonary infiltrates. Despite enlargement of the cerebral lesion monitored by computerized tomography, no viable fungi were found in the completely resected abscess after a 4 weeks' course of antifungal treatment preceding neurosurgery. Histological examination confirmed the diagnosis of an aspergillotic abscess. The initially severe neurological symptoms disappeared after successful surgery. Aspergillus fumigatus was detected in the soil of a potted ornamental plant in the mother's living room, suggesting that this might have been the source of the infectious agent.

The value of protective isolation in preventing nosocomial infections in high risk patients

Since infection is a major cause of death in the patient whose immune responses have been compromised (immunocompromised patient), considerable attention has been focused on developing methods for the prevention of infection. This has primarily been directed at suppressing or eliminating the host's endogenous microbial burden and in decreasing the acquisition of new organisms. The prevention techniques which have been employed vary in complexity from single-room isolation to elaborate systems utilizing air-filtration and decontamination. The most sophisticated of these regimens is the total protected environment (TPE) consisting of a high-efficiency-particulate-air (HEPA)-filtered laminar air flow room which is surface disinfected and in which the patient is fully decontaminated with oral nonabsorbable antibiotics, cutaneous antisepsis, orificial antibiotics and a semisterile diet. The cumulative data to data have shown that the TPE affords a significant (albeit incomplete) reduction in the incidence of serious infections in severely compromised patients. Such protection from infection permits the delivery of novel therapies which might have been precluded because of consequent hematologic or immunologic toxicity. Nonetheless, the TPE is also elaborate, cumbersome and expensive, and its utilization for patients with immunodeficiency syndromes, bone marrow failure states and cancer depends heavily on the success of available therapy (e.g., immunoreconstitution, transplantation, intensive chemotherapy) for the patient's underlying disorder. Critical evaluation of the TPE and alternative prevention strategies are imperative to assure the effective and appropriate utilization of limited hospital resources.