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Biomedical subjects

Allan R Tunkel

Publications and source records attributed to Allan R Tunkel.

10 recordsLinked to original sources
PubMed2006

Drug Insight: adjunctive therapies in adults with bacterial meningitis.

Despite the availability of effective antibiotics, mortality and morbidity rates associated with bacterial meningitis are high. Studies in animals have shown that bacterial lysis, induced by treatment with antibiotics, leads to inflammation in the subarachnoid space, which might contribute to an unfavorable outcome. The management of adults with bacterial meningitis can be complex, and common complications include meningoencephalitis, systemic compromise, stroke and raised intracranial pressure. Various adjunctive therapies have been described to improve outcome in such patients, including anti-inflammatory agents, anticoagulant therapies, and strategies to reduce intracranial pressure. Although a recent randomized trial provided evidence in favor of dexamethasone treatment, few randomized clinical studies are available for other adjunctive therapies in adults with bacterial meningitis. This review briefly summarizes the pathogenesis and pathophysiology of bacterial meningitis, and focuses on the evidence for and against use of the available adjunctive therapies in clinical practice.

Adult↗
PubMed2004

Antimicrobial agents in the treatment of bacterial meningitis.

The use of antimicrobial agents in the treatment of acute bacterial meningitis has undergone significant changes in recent years. There is a wealth of in vitro and animal model data that support the use of the specific antimicrobial agents in the treatment of bacterial meningitis, although not all regimens have been evaluated in clinical trials. Recent investigations have focused on expanding the potential antimicrobial formulary to manage patients with bacterial meningitis effectively in this era of increasing antimicrobial resistance. Despite these advances, the morbidity and mortality of acute bacterial meningitis remain unacceptably high. The use of adjunctive dexamethasone has been shown to improve morbidity and mortality in patients with bacterial meningitis, although concerns have been raised that dexamethasone may reduce penetration of certain antimicrobial agents into cerebrospinal fluid.

Anti-Bacterial Agents↗
PubMed2002

Infections caused by viridans streptococci in patients with neutropenia.

The frequency of isolation of viridans streptococci from the blood of neutropenic patients with cancer has significantly increased over the course of the last 10-15 years. Risk factors in this patient population include severe neutropenia, oral mucositis, administration of high-dose cytosine arabinoside, and antimicrobial prophylaxis with either trimethoprim-sulfamethoxazole or a fluoroquinolone. In some patients with cancer and neutropenia who develop viridans streptococcal bacteremia, a toxic shock-like syndrome has been described; Streptococcus mitis has been the causative species in most cases. Because resistance of viridans streptococci to a variety of antimicrobial agents is increasingly recognized, penicillin susceptibility cannot be assumed, and empirical vancomycin therapy should be used to treat neutropenic patients with cancer who have shock or are developing acute respiratory distress syndrome. Given the seriousness of septicemia caused by viridans streptococci and the potential for selection of other resistant microorganisms, the routine practice of antimicrobial prophylaxis for neutropenic patients with cancer should be reconsidered.

Anti-Bacterial Agents↗
PubMed2002

Central nervous system infections in injection drug users.

Central nervous system infections in injection drug users are often devastating in terms of excess morbidity and mortality. In injection drug users with infective endocarditis, embolization from infected valvular vegetations may cause cerebral infarction, intracranial hemorrhage, and the formation of brain abscess. Focal intracranial infections (i.e., brain abscess and spinal epidural abscess) may occur in the absence of infective endocarditis, resulting from bacteremia that seeds the brain or epidural space. Antimicrobial therapy, combined with surgical intervention, may be essential to improve outcome from these neurologic complications. Toxin-mediated diseases (especially tetanus and wound botulism) are also seen in injection drug users. Inoculation of Clostridium spp at injection sites may lead to toxin generation and disease. Clinicians must maintain a high level of suspicion for these diagnoses in injection drug users.

Brain Abscess↗
PubMed2002

Meningococcal vaccines: a progress report.

Neisseria meningitidis causes a wide range of human disease and remains a common cause of septicaemia and meningitis. Meningococcal serogroups A, B, C and Y cause the majority of cases of invasive disease in the US and throughout the world, with epidemics usually caused by serogroups A and C. Most patients with meningococcaemia, with or without meningitis, respond to standard antimicrobial therapy with either penicillin or ampicillin, but the recent emergence of meningococcal strains that are intermediately resistant to penicillin may alter these recommendations in the future. Given the devastating nature of meningococcal disease and emergence of these resistant strains, prevention (specifically through vaccination) remains the best approach to control this serious infection. A polysaccharide meningococcal vaccine is efficacious against disease caused by serogroups A, C, Y and W135, but is not effective in infants and children aged <2 years, and the duration of efficacy decreases markedly during the first 3 years after a single dose of the vaccine. Conjugate meningococcal vaccines have been developed to address these concerns. Initial studies with the meningococcal C conjugate vaccine have shown that the vaccine is safe and immunogenic and provides a T cell-dependent antigen that can be boosted by further doses of vaccine, or following exposure to the homologous organism or cross-reacting antigens. The UK recently implemented routine vaccination with the meningococcal C conjugate vaccine to all infants, and to all persons aged >1 year in a catch-up programme to immunise all school-aged children and young adults up to 20 years of age. Early postlicensure data indicate that this vaccine has shown significant efficacy in reduction of invasive meningococcal disease in these age groups. The full impact of vaccination will be determined once all age groups are immunised.

Animals↗