MR images of mycobacterial infection

With the progress of imaging technologies such as CT and MR imaging, we can obtain various informations from CT and MR images. Especially, thin-section high resolution CT (HRCT) provides very useful information for the diagnosis of mycobacterial infection and other diseases of pulmonary parenchyma. Advantages of MR images over HRCT are higher tissue contrast and multidirection capability. The T2-weighted images and Gd-DTPA enhanced T1-weighted images accurately reflect pathologic structure of the lesion. Therefore, MR images can add many useful findings to CT on the selected cases which are differentiation of tubercloma from lung cancer, chronic empyema from mesothelioma, aspergiloma from lung cancer and lymphadenopathy from lymph node metastasis. We describe the usefulness of MR images for diagnosing mycobacterial infection and its differentiation from other pulmonary diseases.     

Nontuberculous mycobacterial infection of the central nervous system in patients with AIDS

Infections due to nontuberculous mycobacteria (NTM) are especially common in patients with AIDS. Meningitis due to NTM, however, is rare. A search for CSF cultures positive for NTM over the past 11 years at our hospital yielded 16 cases. Of these, 15 were caused by Mycobacterium avium-intracellular (MAI), and one was caused by M fortuitum. All patients with MAI infection had widespread dissemination and at least one risk factor for AIDS. Clinical features included weight loss, altered mentation, and seizures. Analysis of cerebrospinal fluid revealed a mildly elevated leukocyte count with lymphocyte predominance and normal protein and glucose values. All direct smears were negative for acid-fast bacilli. In-hospital mortality was 67%. The patient with infection due to M fortuitum had a preexisting diagnosis of AIDS and had a right upper lobe pneumonia and headaches. Cranial CT showed an enlarged infundibulum of the pituitary gland. Results of CSF analysis were essentially normal, and direct smears were negative. He left the hospital against medical advice. Our study indicates that the finding of MAI in the CSF in patients with AIDS is associated with an in-house mortality of 67% indicating a very poor prognosis.     

Immune response to recombinant mycobacterial proteins in patients with tuberculosis infection and disease

The capacity of four Mycobacterium tuberculosis recombinant antigens to elicit proliferation and cytokine production by human T cells was evaluated. Proliferative responses of peripheral blood mononuclear cells (PBMC) to all antigens were greater in healthy tuberculin reactors than in pulmonary tuberculosis patients, and proliferative responses of pleural fluid cells were greater than those of PBMC from patients with tuberculous pleuritis. The proliferative responses to the four recombinant antigens were similar in all patient groups, and there was no selective unresponsiveness to any antigen in pulmonary tuberculosis patients. The 38-kDa antigen induced less interferon-gamma than did the 10-, 30-, and 65-kDa antigens, and all four antigens induced similar amounts of interleukin-10. These results suggest that none of the four recombinant antigens are immunodominant, and that the 10-, 30-, and 65-kDa antigens are similar in their capacity to induce a potentially protective Th1-like response.     

Cytokine patterns at the site of mycobacterial infection

Distinct patterns of T cell cytokine production have been shown to influence the outcome of infection in mouse models and humans. Th1 or Type 1 cytokines, interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) are generally associated with resistance to infection, whereas Th2 or Type 2 cytokines, IL-4 and IL-10 are associated with progressive disease. Leprosy is a useful model for studying the role of cytokines in modulating T cell responses in human infectious disease. Infection by Mycobacterium leprae results in disease manifestations that encompass an immunological spectrum. Tuberculoid patients are able to restrict the growth of the pathogen and mount strong T cell responses to M. leprae. In contrast, lepromatous patients manifest disseminated infection and their T cells weakly respond to M. leprae. We have found that tuberculoid leprosy lesions have a predominance of CD4+ T cells producing the Type 1 cytokine pattern. Secondly, IL-12 mRNA was expressed at 10-fold higher levels in tuberculoid lesions as compared to lepromatous lesions and that IL-12 promotes the selective expansion of the Type 1 cytokine producing cells. In contrast, lepromatous lesions contain CD8+ IL-4-producing cells that suppress antigen-specific T cell responses and promote the outgrowth of additional suppressor T cells. IL-10, also expressed at higher levels in lepromatous as compared to tuberculoid lesions, was found to be produced by macrophages, effectively inhibiting cytokine production and macrophage activity.     

Atypical mycobacterial infection in childhood: a "surgical disease''

Frequency data for the STR system HumFGA were obtained from a North Italian population sample (Milano area) of 201 unrelated individuals. PCR products were detected by horizontal polyacrylamide gel electrophoresis and a total of 15 alleles were identified by side-by-side comparison with a commercially available sequenced allelic ladder. The observed genotype distribution showed no significant deviation from Hardy-Weinberg equilibrium. The high information content (discrimination power > 0.96, polymorphism information content > 0.84) render this system a useful tool in forensic routine casework both in criminal and paternity cases.     

Human immunodeficiency virus infection alters antigen-induced cytokine responses in patients with active mycobacterial diseases

Peripheral blood cells from 29 patients with active Mycobacterium avium (MAC) or Mycobacterium tuberculosis diseases were tested for mycobacterial antigen-induced interferon (IFN)-gamma and interleukin (IL)-4 production. Among MAC patients, human immunodeficiency virus (HIV) infection was associated with an 80% decrease in those who produced IFN-gamma, resulting in a predominantly type 2 cytokine profile. HIV infection in patients with tuberculosis correlates with a 37% increase in those producing IL-4 and a type 1 to type 0 profile shift. These qualitative changes were independent of CD4+ or CD8+ cell numbers. The amounts of both IFN-gamma and IL-4 were decreased in the HIV-infected population. Quantitative reduction of IFN-gamma was the result of fewer secreting cells rather than a down-regulation at the single-cell level. Disseminated disease was restricted to 2 of 5 HIV-infected MAC patients with a type 2 cytokine profile and 4 of 5 HIV-infected tuberculosis patients with a type 0 profile. These results demonstrated a shift in mycobacterial antigen-specific cytokine profiles from type 1 to type 0 and to type 2, in parallel with AIDS progression.     

Cytokine networks with infection: mycobacterial infections, leishmaniasis, human immunodeficiency virus infection, and sepsis

Distinct cytokine profiles are clearly associated with and relate to the severity of several types of infections. Cytokine networks are apparent with selected human infectious diseases, such as mycobacterial infections (leprosy, tuberculosis), the parasitic infection leishmaniasis, human immunodeficiency virus (HIV) infection, and gram-negative sepsis. Cytokine profiles are determined to some extent by two functional subsets of T lymphocytes, Th1 and Th2. The Th1 cytokines (interferon gamma, interleukin-2 [IL-2], IL-12) enhance cell-mediated immunity, inhibit humoral immunity, and result in protective effect for pathogens that are removed primarily through cell-mediated immunity (Mycobacterium tuberculosis, Mycobacterium leprae, Leishmania). The Th2 cytokines (IL-4, IL-5, IL-10, IL-13) enhance humoral immunity and inhibit cell-mediated immunity, and result in protective effect for pathogens removed primarily through humoral mechanisms. Progression of HIV infection is associated with a switch from a Th1 to a Th2 profile. For sepsis, uncontrolled activation of proinflammatory cytokines (IL-1, tumor necrosis factor-alpha, interferon-gamma) may be a fundamental defect that promotes the detrimental aspects of inflammation, whereas Th2 cytokines may be beneficial in controlling inflammation. Knowledge of basic cytokine immunopharmacology, networks, and relationships with infectious processes will aid clinicians in determining treatment approaches that are likely to be effective.     

Atypical mycobacterial pulmonary disease and bronchial obstruction in HIV-negative children

Atypical mycobacterial infection in HIV-negative children usually presents with cervical lymphadenopathy. We report on 10 children who are HIV-negative and who presented with pulmonary disease, in whom either culture-proven atypical mycobacterium infection (four), positive avian Mantoux test (five), or lack of response to human tuberculosis treatment (one) had been observed. One case was subsequently diagnosed as chronic granulomatous disease and illustrates that children with atypical mycobacterial pulmonary infection should have their immune status fully investigated. Bronchial obstruction was observed in eight cases, and of these, endobronchial disease was found in six children. The diagnosis of atypical mycobacterial disease is difficult, and a negative avian Mantoux test does not exclude the diagnosis. The availability of clarithromycin and rifabutin has offered new therapeutic options in treating atypical mycobacterial pulmonary infection, but management of these cases can be prolonged and difficult.     

Varicella-zoster virus infection in children with underlying human immunodeficiency virus infection

This article describes a prospective longitudinal study of varicella-zoster virus (VZV) infections in human immunodeficiency virus (HIV)-infected children, designed to determine their natural history of VZV infection and possible effects of VZV on the progression of HIV infection. Varicella was usually not a serious acute problem, and it did not seem to precede clinical deterioration. The rate of zoster was high: 70% in children with low levels of CD4+ lymphocytes at the time of development of varicella. It is predicted that immunization with live attenuated varicella vaccine is unlikely to be deleterious to HIV-infected children. Moreover, if they are immunized when they still have relatively normal levels of CD4+ lymphocytes, they may have a lower rate of reactivation of VZV than if they were allowed to develop natural varicella when their CD4+ cell counts have fallen to low levels as a result of progressive HIV infection.     

Rifabutin versus placebo in combination with three drugs in the treatment of nontuberculous mycobacterial infection in patients with AIDS

OBJECTIVE: Most endoscopic perforations of the colon occur in the rectosigmoid area and are thought to be secondary to direct injury from the endoscopic instrument. The aim of this study was to describe the mechanisms of injury and clinical outcome of endoscopic perforation involving the cecum. METHODS: Retrospective review of 6684 consecutive colonoscopic procedures performed at a university hospital over a 7-yr period. RESULTS: Colonoscopy was complicated by perforation in 0.22%. Five of the 15 perforations occurred in the cecum. The mean age of these five patients was 79.6 +/- 17.7 yr (mean +/- SD). Indications for the procedure were bleeding (n = 4) and suspected obstructing cecal mass (n = 1). Abnormal endoscopic findings included diverticulosis, vascular malformations, cecal ulcer/inflammation, mass, and polyps. Perforation was directly attributable to an ancillary procedure (three routine biopsies, one electrocautery) in the cecal area in four patients, and cecal pathology (inflammation, ulceration) was a contributing risk factor in three patients. Mortality was 80%. In contrast, a noncecal perforation usually occurred at the sigmoid region and was associated with technical difficulties, e.g., inability to traverse a stricture or reach the cecum. CONCLUSIONS: Routine forceps biopsy (without electrocautery) is an under-recognized cause of cecal perforation. Ancillary endoscopic interventions in the cecal region should be minimized in elderly patients with evidence of cecal inflammation. Pneumatic injury may be an additional risk factor for cecal perforation in patients with a colonic stricture or a tortuous colon.     

Conservative approach in children with central line infection

In 1994-1995, central venous lines were placed in 47 children. All except 1 were of the Broviac type, with subcutaneous tunneling via the internal or external jugular vein. Ages were between 7 days and 16 years. Indications for central venous cannulation were chemotherapy (35 cases), TPN (5), prolonged parenteral antibiotics (4), and repeated blood transfusions (3). The catheter was the source of infection in 13 children (28%), 11 of whom were immunocompromised. The commonly identified bacteria were Staphylococcus aureus (4 cases), Pseudomonas aeruginosa (4), coagulase-negative Staphylococcus (2), and various gram-negative rods (3). All cases were treated with antibiotics through the catheter. The most commonly used were oxacillin (4), ceftazidime (4), and amikacin (4). In 10, treatment succeeded without having to remove the line. In 2 others, tunnel infection developed and the catheter had to be removed. 1 child forcefully removed his catheter before treatment could be started. There were no further complications in the group treated conservatively, except for a case of superior vena cava thrombosis in a girl with recurrent infection of the tunnel. In 7 out of 13 treatment was continued and completed at home. This saved 65 days of hospitalization out of 210. We conclude that the conservative approach to treatment is feasible in most cases of infection when the source is the central venous catheter itself. However, when the tunnel is infected, conservative treatment may be ineffective. Treatment can be carried out in the home, with economy in cost and in use of hospital beds, and is preferred by patients and their parents.     

Clostridial infection in children

A survey of the isolation of Clostridium spp. from 1543 specimens sent to anaerobic microbiology laboratories revealed 113 isolates from 107 specimens (7.0% of all specimens) from 96 children. The isolates comprised 43 (38%) unidentified Clostridium spp., 37 (33%) C. perfringens, 13 (12%) C. ramosum, five (4%) C. innocuum, six (5%) C. botulinum, three (3%) C. difficile, two (2%) C. butyricum, and one isolate each of C. bifermentans, C. clostridiiforme, C. limosum and C. paraputrificum. Most clostridial isolates were from abscesses (38), peritonitis (26), bacteraemia (10), and chronic otitis media (7). Predisposing or underlying conditions were present in 31 (32%) cases. These were immunodeficiency (12), malignancy (9), diabetes (7), trauma (7), presence of a foreign body (6) and previous surgery (6). The clostridia were the only bacterial isolates in 14 (15%) cases; 82 (85%) cases had mixed infection. The species most commonly isolated with clostridia were anaerobic cocci (57); Bacteroides spp. (B. fragilis group) (50), Escherichia coli (22), pigmented Prevotella or Porphyromonas spp. (18) and Fusobacterium spp. (10). Most Bacteroides and Escherichia coli isolates with clostridia were from abdominal infections and skin and soft tissue infections adjacent to the rectal area; most pigmented Prevotella and Porphyromonas isolates were from oropharyngeal, pulmonary, and head and neck sites. Antimicrobial therapy was given to all patients, in conjunction with surgical drainage in 34 (35%). Only two patients died. These data illustrate the importance of Clostridium spp. in paediatric infections.     

Dural sinus thrombosis in children with cancer

Dural sinus thrombosis (DST) has been reported in association with cancer in both adults and children. We describe the seven patients seen with this complication in our centre between 1981 and 1995. Diagnosis was confirmed by either cerebral CT scanning, MRI or angiography. Median age was 13 years (range 8-15). Six patients were boys. Six children were being treated for non-Hodgkin lymphoma and one for neuroblastoma. Presenting symptoms were seizures and transient neurologic deficit, often preceded by headaches. The probable cause of DST was found in two cases. Tumour localisation in the central nervous system (CNS) probably caused DST in one patient who was treated for ki 1 lymphoma. Dehydration in combination with a poor general condition seemed to be the cause of DST in the patient with neuroblastoma. In five children with stage III or IV non-Hodgkin lymphoma (three lymphoblastic lymphoma; two Burkitt's lymphoma), etiology remained unknown. In these children, DST occurred early in the course of therapy. The median interval between start of chemotherapy and onset of symptoms was 19 days (range 8-40). No child had received L-asparaginase. Prognosis was favourable, with symptoms completely disappearing without therapy within 1 to 5 days. The incidence of DST in patients with advanced stage non-Hodgkin lymphoma during induction and consolidation was calculated to be below 3%. We conclude that DST is rarely diagnosed in children with cancer. Occurrence during the initial phase of therapy for non-Hodgkin lymphoma is associated with a benign prognosis.     

Resection of the right middle lobe and lingula for mycobacterial infection

BACKGROUND: In a series of 229 patients infected with mycobacterial organisms, we noted a specific female phenotype that involves isolated infections of the middle lobe and lingula. METHODS: Thirteen patients were found to have infections of the middle lobe, lingula, or both. All of them were infected with Mycobacterium other then Mycobacterium tuberculosis, all were women, 12 of the 13 were slender, and most had variable combinations of skeletal abnormalities. All underwent resection of the middle lobe, lingula, or both. RESULTS: There were no operative deaths. Only 2 patients have had reactivation requiring additional antibiotic therapy. All patients have had a decreased number of pulmonary infections in the postoperative period. Anatomic findings at operation included a complete major fissure and at least a partially complete minor fissure with middle lobe resections or an elongated lingula. CONCLUSIONS: Mycobacterial infection of the middle lobe and lingula is primarily a disease of asthenic women and is often associated with skeletal abnormalities and complete fissures or an elongated lingula. We recommend that surgical intervention be performed early once the condition is identified.     

Repressive adaptation in children with cancer.

The constructs of repressive adaptive style and avoidant coping (blunting) were assessed as possible explanatory factors for previously reported findings of lower self-reported depression in children with cancer. Pediatric oncology patients 7–16 years old (n?=?107) and healthy control participants (n?=?442) completed measures of depressive symptoms, trait anxiety, defensiveness, and approach and avoidant coping. Oncology patients scored significantly lower on measures of depression and trait anxiety, and higher on defensiveness. Applying the adaptive style paradigm, the oncology group showed a significant excess of repressors. Depressive symptoms differed as a function of adaptive style, with repressors demonstrating the lowest levels of self-reported depression. Children with cancer also reported greater use of blunting, but this difference was small and appeared unrelated to depression scores. Within the cancer group, repressive adaptation was unrelated to time elapsed since diagnosis. These findings are discussed with reference to the ongoing controversy regarding cancer–personality style associations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)