Comparing clinical outcomes in HIV-infected and uninfected older men hospitalized with community-acquired pneumonia

OBJECTIVES

Outcomes of community-acquired pneumonia (CAP) among HIV-infected older adults are unclear.

METHODS

Associations between HIV infection and three CAP outcomes (30-day mortality, readmission within 30 days post-discharge, and hospital length of stay [LOS]) were examined in the Veterans Aging Cohort Study (VACS) of male Veterans, age ≥ 50 years, hospitalized for CAP from 10/1/2002 through 08/31/2010. Associations between the VACS Index and CAP outcomes were assessed in multivariable models.

RESULTS

Among 117 557 Veterans (36 922 HIV-infected and 80 635 uninfected), 1203 met our eligibility criteria. The 30-day mortality rate was 5.3%, the mean LOS was 7.3 days, and 13.2% were readmitted within 30 days of discharge. In unadjusted analyses, there were no significant differences between HIV-infected and uninfected participants regarding the three CAP outcomes (P > 0.2). A higher VACS Index was associated with increased 30-day mortality, readmission, and LOS in both HIV-infected and uninfected groups. Generic organ system components of the VACS Index were associated with adverse CAP outcomes; HIV-specific components were not. Among HIV-infected participants, those not on antiretroviral therapy (ART) had a higher 30-day mortality (HR 2.94 [95% CI 1.51, 5.72]; P = 0.002) and a longer LOS (slope 2.69 days [95% CI 0.65, 4.73]; P = 0.008), after accounting for VACS Index. Readmission was not associated with ART use (OR 1.12 [95% CI 0.62, 2.00] P = 0.714).

CONCLUSION

Among HIV-infected and uninfected older adults hospitalized for CAP, organ system components of the VACS Index were associated with adverse CAP outcomes. Among HIV-infected individuals, ART was associated with decreased 30-day mortality and LOS.

The microbiota and microbiome in aging: potential implications in health and age-related diseases

Advances in bacterial deoxyribonucleic acid sequencing allow for characterization of the human commensal bacterial community (microbiota) and its corresponding genome (microbiome). Surveys of healthy adults reveal that a signature composite of bacteria characterizes each unique body habitat (e.g., gut, skin, oral cavity, vagina). A myriad of clinical changes, including a basal proinflammatory state (inflamm-aging), that directly interface with the microbiota of older adults and enhance susceptibility to disease accompany aging. Studies in older adults demonstrate that the gut microbiota correlates with diet, location of residence (e.g., community dwelling, long-term care settings), and basal level of inflammation. Links exist between the microbiota and a variety of clinical problems plaguing older adults, including physical frailty, Clostridium difficile colitis, vulvovaginal atrophy, colorectal carcinoma, and atherosclerotic disease. Manipulation of the microbiota and microbiome of older adults holds promise as an innovative strategy to influence the development of comorbidities associated with aging.

A cluster-randomized controlled trial of a multicomponent intervention protocol for pneumonia prevention among nursing home elders

BACKGROUND

Pneumonia remains an important public health problem among elderly nursing home residents. This clinical trial sought to determine if a multicomponent intervention protocol, including manual tooth/gum brushing plus 0.12% chlorhexidine oral rinse, twice per day, plus upright positioning during feeding, could reduce the incidence of radiographically documented pneumonia among nursing home residents, compared with usual care.

METHODS

This cluster-randomized clinical trial was conducted in 36 nursing homes in Connecticut. Eligible residents >65 years with at least 1 of 2 modifiable risk factors for pneumonia (ie, impaired oral hygiene, swallowing difficulty) were enrolled. Nursing homes were randomized to the multicomponent intervention protocol or usual care. Participants were followed for up to 2.5 years for development of the primary outcome, a radiographically documented pneumonia, and secondary outcome, a lower respiratory tract infection (LRTI) without radiographic documentation.

RESULTS

A total of 834 participants were enrolled: 434 to intervention and 400 to usual care. The trial was terminated for futility. The number of participants in the intervention vs control arms with first pneumonia was 119 (27.4%) vs 94 (23.5%), respectively, and with first LRTI, 125 (28.8%) vs 100 (25.0%), respectively. In a multivariable Cox regression model, the hazard ratio in the intervention vs control arms, respectively, was 1.12 (95% confidence interval [CI], .84-1.50; P = .44) for first pneumonia and 1.07 (95% CI, .79-1.46, P = .65) for first LRTI.

CONCLUSIONS

The multicomponent intervention protocol did not significantly reduce the incidence of first radiographically confirmed pneumonia or LRTI compared with usual care in nursing home residents.

CLINICAL TRIALS REGISTRATION

NCT00975780.

Outcomes among older adult liver transplantation recipients in the model of end stage liver disease (MELD) era

BACKGROUND

Since 2002, the Model of End Stage Liver Disease (MELD) score has been the basis of the liver transplant (LT) allocation system. Among older adult LT recipients, short-term outcomes in the MELD era were comparable to the pre-MELD era, but long-term outcomes remain unclear.

MATERIAL AND METHODS

This is a retrospective cohort study using the UNOS data on patients age ≥ 50 years who underwent primary LT from February 27, 2002 until October 31, 2011.

RESULTS

A total of 35,686 recipients met inclusion criteria. The cohort was divided into 5-year interval age groups. Five-year over-all survival rates for ages 50-54, 55-59, 60-64, 65-69, and 70+ were 72.2%, 71.6%, 69.5%, 65.0%, and 57.5%, respectively. Five-year graft survival rates after adjusting for death as competing risk for ages 50-54, 55-59,60-64, 65-69 and 70+ were 85.8%, 87.3%, 89.6%, 89.1% and 88.9%, respectively. By Cox proportional hazard modeling, age ≥ 60, increasing MELD, donor age ≥ 60, hepatitis C, hepatocellular carcinoma (HCC), dialysis and impaired pre-transplant functional status (FS) were associated with increased 5-year mortality. Using Fine and Gray sub-proportional hazard modeling adjusted for death as competing risk, 5-year graft failure was associated with donor age ≥ 60, increasing MELD, hepatitis C, HCC, and impaired pre-transplant FS.

CONCLUSIONS

Among older LT recipients in the MELD era, long-term graft survival after adjusting for death as competing risk was improved with increasing age, while over-all survival was worse. Donor age, hepatitis C, and pre-transplant FS represent potentially modifiable risk factors that could influence long-term graft and patient survival.

The ability of virulence factor expression by Pseudomonas aeruginosa to predict clinical disease in hospitalized patients

BACKGROUND

Pseudomonas aeruginosa is an opportunistic pathogen that frequently causes hospital acquired colonization and infection. Accurate identification of host and bacterial factors associated with infection could aid treatment decisions for patients with P. aeruginosa cultured from clinical sites.

METHODS

We identified a prospective cohort of 248 hospitalized patients with positive P. aeruginosa cultures. Clinical data were analyzed to determine whether an individual met predefined criteria for infection versus colonization. P. aeruginosa isolates were tested for the expression of multiple phenotypes previously associated with virulence in animal models and humans. Logistic regression models were constructed to determine the degree of association between host and bacterial factors with P. aeruginosa infection of the bloodstream, lung, soft tissue and urinary tract.

RESULTS

One host factor (i.e. diabetes mellitus), and one bacterial factor, a Type 3 secretion system positive phenotype, were significantly associated with P. aeruginosa infection in our cohort. Subgroup analysis of patients with P. aeruginosa isolated from the urinary tract revealed that the presence of a urinary tract catheter or stent was an additional factor for P. aeruginosa infection.

CONCLUSIONS

Among hospitalized patients with culture-documented P. aeruginosa, infection is more likely to be present in those with diabetes mellitus and those harboring a Type 3 secretion positive bacterial strain.

Infectious diseases in the nursing home setting: challenges and opportunities for clinical investigation

The global population is aging. With the high prevalence of dementia and functional decline in older Americans, many aging adults with disabilities reside in nursing homes in their final stage of life. Immunosenescence, multiple comorbid diseases, and grouped quarter living all coalesce in nursing home residents to increase the risk for infectious disease. The unique issues involved with diagnosis, prognosis, and management of infectious diseases in nursing home residents make research based in the nursing home setting both necessary and exciting for the physician investigator. This review discusses the opportunities and challenges involved with research of the evolving public health problem of infections among nursing home residents.

Pandemic influenza H1N1 2009, innate immunity, and the impact of immunosenescence on influenza vaccine

Seasonal and pandemic strains of influenza have widespread implications for the global economy and global health. This has been highlighted recently as the epidemiologic characteristics for hospitalization and mortality for pandemic influenza H1N1 2009 are now emerging. While treatment with neuraminidase inhibitors are effective for seasonal and pandemic influenza, prevention of morbidity and mortality through effective vaccines requires a rigorous process of research and development. Vulnerable populations such as older adults (i.e., > age 65 years) suffer the greatest impact from seasonal influenza yet do not have a consistent seroprotective response to seasonal influenza vaccines due to a combination of factors. This short narrative review will highlight the emerging epidemiologic characteristics of pandemic H1N1 2009 and focus on immunosenescence, innate immune system responses to influenza virus infection and vaccination, and influenza vaccine responsiveness as it relates to seasonal and H1N1 pandemic influenza vaccines.

Clinical practice guideline for the evaluation of fever and infection in older adult residents of long-term care facilities: 2008 update by the Infectious Diseases Society of America

Residents of long‐term care facilities (LTCFs) are at great risk for infection. Most residents are older and have multiple comorbidities that complicate recognition of infection; for example, typically defined fever is absent in more than one‐half of LTCF residents with serious infection. Furthermore, LTCFs often do not have the on‐site equipment or personnel to evaluate suspected infection in the fashion typically performed in acute care hospitals. In recognition of the differences between LTCFs and hospitals with regard to hosts and resources present, the Infectious Diseases Society of America first provided guidelines for evaluation of fever and infection in LTCF residents in 2000. The guideline presented here represents the second edition, updated by data generated over the intervening 8 years. It focuses on the typical elderly person institutionalized with multiple chronic comorbidities and functional disabilities (e.g., a nursing home resident). Specific topic reviews and recommendations are provided with regard to what resources are typically available to evaluate suspected infection, what symptoms and signs suggest infection in a resident of an LTCF, who should initially evaluate the resident with suspected infection, what clinical evaluation should be performed, how LTCF staff can effectively communicate about possible infection with clinicians, and what laboratory tests should be ordered. Finally, a general outline of how a suspected outbreak of a specific infectious disease should be investigated in an LTCF is provided.

Clinical practice guideline for the evaluation of fever and infection in older adult residents of long-term care facilities: 2008 update by the Infectious Diseases Society of America

Residents of long-term care facilities (LTCFs) are at great risk for infection. Most residents are older and have multiple comorbidities that complicate recognition of infection; for example, typically defined fever is absent in more than one-half of LTCF residents with serious infection. Furthermore, LTCFs often do not have the on-site equipment or personnel to evaluate suspected infection in the fashion typically performed in acute care hospitals. In recognition of the differences between LTCFs and hospitals with regard to hosts and resources present, the Infectious Diseases Society of America first provided guidelines for evaluation of fever and infection in LTCF residents in 2000. The guideline presented here represents the second edition, updated by data generated over the intervening 8 years. It focuses on the typical elderly person institutionalized with multiple chronic comorbidities and functional disabilities (e.g., a nursing home resident). Specific topic reviews and recommendations are provided with regard to what resources are typically available to evaluate suspected infection, what symptoms and signs suggest infection in a resident of an LTCF, who should initially evaluate the resident with suspected infection, what clinical evaluation should be performed, how LTCF staff can effectively communicate about possible infection with clinicians, and what laboratory tests should be ordered. Finally, a general outline of how a suspected outbreak of a specific infectious disease should be investigated in an LTCF is provided.

Clinical practice guideline for the evaluation of fever and infection in older adult residents of long-term care facilities: 2008 update by the Infectious Diseases Society of America

Residents of long-term care facilities (LTCFs) are at great risk for infection. Most residents are older and have multiple comorbidities that complicate recognition of infection; for example, typically defined fever is absent in more than one-half of LTCF residents with serious infection. Furthermore, LTCFs often do not have the on-site equipment or personnel to evaluate suspected infection in the fashion typically performed in acute care hospitals. In recognition of the differences between LTCFs and hospitals with regard to hosts and resources present, the Infectious Diseases Society of America first provided guidelines for evaluation of fever and infection in LTCF residents in 2000. The guideline presented here represents the second edition, updated by data generated over the intervening 8 years. It focuses on the typical elderly person institutionalized with multiple chronic comorbidities and functional disabilities (e.g., a nursing home resident). Specific topic reviews and recommendations are provided with regard to what resources are typically available to evaluate suspected infection, what symptoms and signs suggest infection in a resident of an LTCF, who should initially evaluate the resident with suspected infection, what clinical evaluation should be performed, how LTCF staff can effectively communicate about possible infection with clinicians, and what laboratory tests should be ordered. Finally, a general outline of how a suspected outbreak of a specific infectious disease should be investigated in an LTCF is provided.

Nursing home practitioner survey of diagnostic criteria for urinary tract infections

OBJECTIVES

To identify clinical and laboratory criteria used by nursing home practitioners for diagnosis and treatment of urinary tract infections (UTIs) in nursing home residents. To determine practitioner knowledge of the most commonly used consensus criteria (i.e., McGeer criteria) for UTIs.

DESIGN

Self-administered survey.

SETTING

Three New Haven-area nursing homes.

PARTICIPANTS

Physicians (n=25), physician assistants (PAs, n=3), directors/assistant directors of nursing (n=8), charge nurses (n=37), and infection control practitioners (n=3).

MEASUREMENTS

Open- and closed-ended questions.

RESULTS

Nineteen physicians, three PAs, and 41 nurses completed 63 of 76 (83%) surveys. The five most commonly reported triggers for suspecting UTI in noncatheterized residents were change in mental status (57/63, 90%), fever (48/63, 76%), change in voiding pattern (44/63, 70%), dysuria (41/63, 65%), and change in character of urine (37/63, 59%). Asked to identify their first diagnostic step in the evaluation of UTIs, 48% (30/63) said urinary dipstick analysis, and 40% (25/63) said urinalysis and urine culture. Fourteen of 22 (64%) physicians and PAs versus 40 of 40 (100%) nurses were aware of the McGeer criteria for noncatheterized patients (P<.001); 12 of 22 (55%) physicians and PAs versus 38 of 39 (97%) nurses used them in clinical practice (P<.001).

CONCLUSION

Although surveillance and treatment consensus criteria have been developed, there are no universally accepted diagnostic criteria. This survey demonstrated a distinction between surveillance criteria and criteria practitioners used in clinical practice. Prospective data are needed to develop evidence-based clinical and laboratory criteria of UTIs in nursing home residents that can be used to identify prospectively tested treatment and prevention strategies.

Prognostic Scoring Systems for Infectious Diseases: Their Applicability to the Care of Older Adults

Physicians often make clinical predictions about individual patients. For many infectious diseases, published prognostic scoring systems (PSSs) can help predict relevant outcomes. Validated PSSs exist for the general adult population for diseases such as pneumonia, endocarditis, meningitis, and bloodstream infection. Although these PSSs have been rigorously derived and validated, they have limited value in the care of older adults, because most studies have involved a heterogeneous adult population with mortality as the primary end point. In the United States, the number of patients who are > or =65 years old is growing, and their health care costs are increasing. Assessment of clinical outcomes other than merely survival (i.e., physical functional ability, cognitive ability, need for nursing home care, and overall quality of life) is required for this population. Some pioneering work has been done to develop PSSs that specifically address the health care needs of older adults. This review will describe existing PSSs and explore areas of further investigation.

Impact of valve surgery on 6-month mortality in adults with complicated, left-sided native valve endocarditis: a propensity analysis

CONTEXT

Complicated, left-sided native valve endocarditis causes significant morbidity and mortality in adults. The presumed benefits of valve surgery remain unproven due to lack of randomized controlled trials.

OBJECTIVE

To determine whether valve surgery is associated with reduced mortality in adults with complicated, left-sided native valve endocarditis.

DESIGN AND SETTING

Retrospective, observational cohort study conducted from January 1990 to January 2000 at 7 Connecticut hospitals. Propensity analyses were used to control for bias in treatment assignment and prognostic imbalances.

PATIENTS

Of the 513 adults with complicated, left-sided native valve endocarditis, 230 (45%) underwent valve surgery and 283 (55%) received medical therapy alone.

MAIN OUTCOME MEASURE

All-cause mortality at 6 months after baseline.

RESULTS

In the 6-month period after baseline, 131 patients (26%) died. In unadjusted analyses, valve surgery was associated with reduced mortality (16% vs 33%; hazard ratio [HR], 0.43; 95% confidence interval [CI], 0.29-0.63; P<.001). After adjustment for baseline variables associated with mortality (including hospital site, comorbidity, congestive heart failure, microbial etiology, immunocompromised state, abnormal mental status, and refractory infection), valve surgery remained associated with reduced mortality (adjusted HR, 0.35; 95% CI, 0.23-0.54; P<.02). In further analyses of 218 patients matched by propensity scores, valve surgery remained associated with reduced mortality (15% vs 28%; HR, 0.45; 95% CI, 0.23-0.86; P =.01). After additional adjustment for variables that contribute to heterogeneity and confounding within the propensity-matched group, surgical therapy remained significantly associated with a lower mortality (HR, 0.40; 95% CI, 0.18-0.91; P =.03). In this propensity-matched group, patients with moderate to severe congestive heart failure showed the greatest reduction in mortality with valve surgery (14% vs 51%; HR, 0.22; 95% CI, 0.09-0.53; P =.001).

CONCLUSIONS

Valve surgery for patients with complicated, left-sided native valve endocarditis was independently associated with reduced 6-month mortality after adjustment for both baseline variables associated with the propensity to undergo valve surgery and baseline variables associated with mortality. The reduced mortality was particularly evident among patients with moderate to severe congestive heart failure.

Complicated left-sided native valve endocarditis in adults: risk classification for mortality

CONTEXT

Complicated left-sided native valve endocarditis causes significant morbidity and mortality in adults. Lack of valid data regarding estimation of prognosis makes management of this condition difficult.

OBJECTIVE

To derive and externally validate a prognostic classification system for adults with complicated left-sided native valve endocarditis.

DESIGN, SETTING, AND PATIENTS

Retrospective observational cohort study conducted from January 1990 to January 2000 at 7 Connecticut hospitals among 513 patients older than 16 years who experienced complicated left-sided native valve endocarditis and who were divided into derivation (n = 259) and validation (n = 254) cohorts.

MAIN OUTCOME MEASURE

All-cause mortality at 6 months after baseline.

RESULTS

In the derivation and validation cohorts, the 6-month mortality rates were 25% and 26%, respectively. Five baseline features were independently associated with 6-month mortality (comorbidity [P =.03], abnormal mental status [P =.02], moderate to severe congestive heart failure [P =.01], bacterial etiology other than viridans streptococci [P<.001 except Staphylococcus aureus, P =.004], and medical therapy without valve surgery [P =.002]) and were used to create a prognostic classification system. In the derivation cohort, patients were classified into 4 groups with increasing risk for 6-month mortality: 5%, 15%, 31%, and 59% (P<.001). In the validation cohort, a similar risk among the 4 groups was observed: 7%, 19%, 32%, and 69% (P<.001).

CONCLUSIONS

Adults with complicated left-sided native valve endocarditis can be accurately risk stratified using baseline features into 4 groups of prognostic severity. This prognostic classification system might be useful for facilitating management decisions.

The diagnostic accuracy of Kernig's sign, Brudzinski's sign, and nuchal rigidity in adults with suspected meningitis

To determine the diagnostic accuracy of Kernig's sign, Brudzinski's sign, and nuchal rigidity for meningitis, 297 adults with suspected meningitis were prospectively evaluated for the presence of these meningeal signs before lumbar puncture was done. Kernig's sign (sensitivity, 5%; likelihood ratio for a positive test result [LR(+)], 0.97), Brudzinski's sign (sensitivity, 5%; LR(+), 0.97), and nuchal rigidity (sensitivity, 30%; LR(+), 0.94) did not accurately discriminate between patients with meningitis (>/=6 white blood cells [WBCs]/mL of cerebrospinal fluid [CSF]) and patients without meningitis. The diagnostic accuracy of these signs was not significantly better in the subsets of patients with moderate meningeal inflammation (>/=100 WBCs/mL of CSF) or microbiological evidence of CSF infection. Only for 4 patients with severe meningeal inflammation (>/=1000 WBCs/mL of CSF) did nuchal rigidity show diagnostic value (sensitivity, 100%; negative predictive value, 100%). In the broad spectrum of adults with suspected meningitis, 3 classic meningeal signs did not have diagnostic value; better bedside diagnostic signs are needed.

Computed tomography of the head before lumbar puncture in adults with suspected meningitis

BACKGROUND

In adults with suspected meningitis clinicians routinely order computed tomography (CT) of the head before performing a lumbar puncture.

METHODS

We prospectively studied 301 adults with suspected meningitis to determine whether clinical characteristics that were present before CT of the head was performed could be used to identify patients who were unlikely to have abnormalities on CT. The Modified National Institutes of Health Stroke Scale was used to identify neurologic abnormalities.

RESULTS

Of the 301 patients with suspected meningitis, 235 (78 percent) underwent CT of the head before undergoing lumbar puncture. In 56 of the 235 patients (24 percent), the results of CT were abnormal; 11 patients (5 percent) had evidence of a mass effect. The clinical features at base line that were associated with an abnormal finding on CT of the head were an age of at least 60 years, immunocompromise, a history of central nervous system disease, and a history of seizure within one week before presentation, as well as the following neurologic abnormalities: an abnormal level of consciousness, an inability to answer two consecutive questions correctly or to follow two consecutive commands, gaze palsy, abnormal visual fields, facial palsy, arm drift, leg drift, and abnormal language (e.g., aphasia). None of these features were present at base line in 96 of the 235 patients who underwent CT scanning of the head (41 percent). The CT scan was normal in 93 of these 96 patients, yielding a negative predictive value of 97 percent. Of the three misclassified patients, only one had a mild mass effect on CT, and all three subsequently underwent lumbar puncture, with no evidence of brain herniation one week later.

CONCLUSIONS

In adults with suspected meningitis, clinical features can be used to identify those who are unlikely to have abnormal findings on CT of the head.

Community-acquired bacterial meningitis in adults: categorization of causes and timing of death

The relationship between cause and timing of death in 294 adults who had been hospitalized with community-acquired bacterial meningitis was investigated. For 74 patients with community-acquired bacterial meningitis who died during hospitalization, the underlying and immediate causes of death were identified according to the criteria of the World Health Organization and National Center for Health Statistics. Patients were classified into 3 groups: category I, in which meningitis was the underlying and immediate cause of death (59% of patients; median duration of survival, 5 days); category II, in which meningitis was the underlying but not immediate cause of death (18%; median duration of survival, 10 days); and category III, in which meningitis was neither the underlying nor immediate cause of death (23%; median duration of survival, 32 days). In a substantial proportion of adults hospitalized with community-acquired bacterial meningitis, meningitis was neither the immediate nor the underlying cause of death. A 14-day survival end point discriminated between deaths attributable to meningitis and those with another cause.

Utility of prognostic stratification in adults with community-acquired bacterial meningitis

Prognostic stratification uses baseline clinical features to subdivide patients into subgroups with different risks for a particular outcome. We review the importance of prognostic stratification in internal medicine, in infectious diseases, and in adults with community-acquired bacterial meningitis.

Treatment of bacterial meningitis

Major epidemiological changes have altered the empiric therapy of patients with bacterial meningitis, a disease with significant morbidity and mortality. We offer recommendations for empiric management decisions and specific antibiotic choices for patients with bacterial meningitis.

A prognostic rule for elderly patients admitted with community-acquired pneumonia

PURPOSE

We sought to identify admission characteristics predicting mortality in elderly patients hospitalized with community-acquired pneumonia and to develop a prognostic staging system and discriminant rule.

PATIENTS AND METHODS

We retrospectively analyzed data from 2,356 patients aged > or = 65 years admitted with community-acquired pneumonia. Multivariable analyses of a derivation cohort (n = 1,000) identified characteristics associated with hospital mortality. A staging system and discriminant rule based on these characteristics were tested in a validation cohort (n = 1,356). Our discriminant rule was compared with a rule formulated from a heterogeneous adult population with community-acquired pneumonia.

RESULTS

Hospital mortality rates were 9% (derivation cohort) and 12% (validation cohort). We identified five independent predictors of mortality: age > or = 85 years [odds ratio 1.8 (95% confidence interval 1.1-3.1)], comorbid disease [odds ratio 4.1 (2.1-8.1)], impaired motor response [odds ratio 2.3 (1.4-3.7)], vital sign abnormality [odds ratio 3.4 (2.1-5.4)], and creatinine level > or = 1.5 mg/dL [odds ratio 2.5 (1.5-4.2)]. These variables stratified patients into four distinct stages with increasing mortality in the derivation cohort (Stage 1, 2%; Stage 2, 7%; Stage 3, 22%; Stage 4, 45%; P = 0.001) as well as in the validation cohort (Stage 1, 4%; Stage 2, 11%; Stage 3, 23%; Stage 4, 41%; P = 0.001). The discriminant rule developed from the derivation cohort had greater overall accuracy (77.1%) in the validation cohort than a rule formulated from a heterogeneous adult population (68.0%, P = 0.001).

CONCLUSION

Elderly patients with community-acquired pneumonia have characteristics at admission that can predict mortality. Our staging system and discriminant rule improve prognostic stratification of these patients.

Community-acquired bacterial meningitis: risk stratification for adverse clinical outcome and effect of antibiotic timing

BACKGROUND

Community-acquired bacterial meningitis causes substantial morbidity and mortality in adults.

OBJECTIVE

To create and test a prognostic model for persons with community-acquired bacterial meningitis and to determine whether antibiotic timing influences clinical outcome.

DESIGN

Retrospective cohort study; patients were divided into derivation and validation samples.

SETTING

Four hospitals in Connecticut.

PATIENTS

269 persons who, between 1970 and 1995, had community-acquired bacterial meningitis microbiologically proven by a lumbar puncture done within 24 hours of presentation in the emergency department.

MEASUREMENTS

Baseline clinical and laboratory features and times of arrival in the emergency department, performance of lumbar puncture, and administration of antibiotics. The target end point was the development of an adverse clinical outcome (death or neurologic deficit at discharge).

RESULTS

For the total group, the hospital mortality rate was 27%. Fifty-six of 269 patients (21 %) developed a neurologic deficit, and in 9% the neurologic deficit persisted at discharge. Three baseline clinical features (hypotension, altered mental status, and seizures) were independently associated with adverse clinical outcome and were used to create a prognostic model from the derivation sample. The prediction accuracy of the model was determined by using the concordance index (c-index). For both the derivation sample (c-index, 0.73 [95% CI, 0.65 to 0.81]) and the validation sample (c-index, 0.81 [CI, 0.71 to 0.92]), the model predicted adverse clinical outcome significantly better than chance. For the total group, the model stratified patients into three prognostic stages: low risk for adverse clinical outcome (9%; stage I), intermediate risk (33%; stage II), and high risk (56%; stage III) (P=0.001). Adverse clinical outcome was more common for patients in whom the prognostic stage advanced from low risk (P=0.008) or intermediate risk (P=0.003) at arrival in the emergency department to high risk before administration of antibiotics.

CONCLUSIONS

In persons with community-acquired bacterial meningitis, three baseline clinical features of disease severity predicted adverse clinical outcome and stratified patients into three stages of prognostic severity. Delay in therapy after arrival in the emergency department was associated with adverse clinical outcome when the patient's condition advanced to the highest stage of prognostic severity before the initial antibiotic dose was given.

Acute meningitis with a negative Gram's stain: clinical and management outcomes in 171 episodes

PURPOSE

To characterize the diagnostic spectrum and physician management decisions of patients presenting to an emergency department with an acute, community-acquired illness, cerebrospinal fluid (CSF) white blood cell count > 5/mm3, and a negative Gram's stain for bacteria.

PATIENTS AND METHODS

In this retrospective cohort study over a 2-year period, symptoms, examination findings, paraclinical data, physician management, and clinical outcomes were assessed for each patient.

RESULTS

One hundred sixty-eight patients (171 patient episodes) were evaluated. Almost half of the cohort presented in nonsummer months (48%); 20% of concurrent comorbid disease, and 15% had identified immunocompromising conditions. The reported examination findings were diverse, with diverse, with fever [49%] and neck stiffness [39%] being the most frequent findings. The majority were hospitalized (70%), with a median stay of 4 days. Approximately one half underwent computed tomography or magnetic resonance imaging (49%), and received empiric treatment with antibiotics (52%). A diagnostic cause was established in 23%, with the majority being inherently treatable diseases (including syphilis, bacteremia, Lyme disease). Variables significantly associated with a subsequent proven diagnostic cause included: age > 60 years; presence of comorbid disease (especially immunodeficiency); and presentation in winter months.

CONCLUSIONS

A large proportion of patients presenting with acute meningitis and a negative CSF Gram's stain undergo hospitalization, noninvasive cranial imaging, and receive empiric antibiotic therapy. Better clinical guidelines are needed to identify the diagnostic and management decisions that benefit patient outcome.

Primary prevention of cryptococcal meningitis by fluconazole in HIV-infected patients

To evaluate whether oral fluconazole reduces the risk of a first episode of cryptococcal meningitis in HIV-infected patients, we conducted a case-control study of patients cared for in a university teaching hospital and two urban HIV-outpatient clinics. Cases consisted of HIV-infected patients with CD4 cell counts less than 250/microL who developed a first episode of cryptococcal meningitis between July 1, 1990, and June 30, 1993. For each case (n = 18), 4 control subjects were chosen from HIV-infected patients (CD4 count < 250/microL) whose cerebrospinal fluid was negative for cryptococcal antigen and culture, and who were matched by age, sex, and time of lumbar puncture. There were no significant differences between cases and controls in age, sex, insurance status, mean CD4 count, history of oral candidosis, presence of a previous AIDS-defining illness, the number of visits to the HIV-outpatient clinic, or use of antiretroviral therapy. In the 6 months before lumbar puncture, 2 of 18 cases (11%) and 26 of 72 controls (36%) were exposed to fluconazole, a finding that gives a matched odds ratio (adjusted for race, route of HIV infection, and CD4 count) of 0.08 (95% CI 0.01-0.84; p = 0.035) and indicates a 92% protective efficacy. We conclude that fluconazole reduces the risk of a first episode of cryptococcal meningitis in HIV-infected patients with a CD4 count less than 250/microL. Although the optimum dose and duration of fluconazole could not be determined, our results suggest that less than daily use was effective in the prevention of cryptococcal meningitis.

Yeast perinephric abscess: report of a case and review

We report a case of yeast perinephric abscess and review 11 other published cases. This rare entity occurs primarily in patients who have diabetes mellitus, who have recently undergone surgery, or who have urinary tract obstruction. The clinical illness is often subacute or chronic with nonspecific symptoms. Candida and Torulopsis species are the reported etiologic agents. Successful therapy usually consists of percutaneous or surgical drainage of the abscess. Overall mortality is 25%; however, no patient in this series died as a direct result of perinephric infection.

Ultrastructural localization of albumin transport across the cerebral microvasculature during experimental meningitis in the rat

Injury to the blood brain barrier (BBB) is a fundamental sequela of bacterial meningitis, yet the precise mechanism facilitating exudation of albumin across the endothelium of the cerebral microvasculature remains conjectural. After intracisternal inoculation of Escherichia coli (0111:B4) lipopolysaccharide in rats to elicit a reversible meningitis and BBB injury, we utilized in situ tracer perfusion and immunolabeling procedures to identify by transmission electron microscopy the precise topography and microvascular exit pathway(s) of bovine serum albumin (BSA). Results revealed that during meningitis there was: (a) an inducible increase in immunodetectable monomeric BSA binding to the luminal membrane of all microvascular segments in the pia-arachnoid and superficial brain cortex; (b) similar uptake of both colloidal Au-BSA (as well as monomeric BSA) by plasmalemmal vesicles but no detectable transcytosis to the abluminal side; and (c) predominant exit of both perfused Au-BSA and immunodetectable monomeric BSA through open intercellular junctions of venules in the pia-arachnoid. This was corroborated in separate experiments documenting focal pial venular leaks of in situ perfused 0.01% colloidal carbon black during experimental meningitis. These results provide precise localization of BBB injury in meningitis to meningeal venules, confirm a paracellular exit pathway of albumin via open intercellular junctions, and suggest an injury mechanism amenable to specific therapeutic intervention.

Recombinant human interleukin-1 induces meningitis and blood-brain barrier injury in the rat. Characterization and comparison with tumor necrosis factor

The diversity of infectious agents capable of inducing meningitis and blood-brain barrier (BBB) injury suggests the potential for a common host mediator. The inflammatory polypeptides, IL-1 and TNF, were tested in an experimental rat model as candidate mediators for induction of meningitis and BBB injury. Intracisternal challenge of rIL-1 beta into rats induced neutrophil emigration into cerebrospinal fluid (CSF) and significantly increased BBB permeability to systemically administered 125I-BSA as early as 3 h later (P less than 0.05). This injury was reversible, dose dependent and significantly inhibited by prior induction of systemic neutropenia (via intraperitoneal cyclophosphamide) or preincubation of the rIL-1 beta inoculum (50 U) with an IgG monoclonal antibody to rIL-1 beta. Similar kinetics and reversibility of CSF inflammation and BSA permeability were observed using equivalent dose inocula of rIL-1 alpha. rTNF-alpha was less effective as an independent inducer of meningitis or BBB injury over an inoculum range of 10(1) U (0.0016 micrograms/kg)-10(6) U (160 micrograms/kg) when injected intracisternally, but inoculum combinations of low concentrations of rTNF alpha (10(3) U) and rIL-1 beta (0.0005-5.0 U) were synergistic in inducing both meningitis and BBB permeability to systemic 125I-BSA. These data suggest that in situ generation of interleukin-1 within CSF (with or without TNF) is capable of mediating both meningeal inflammation and BBB injury seen in various central nervous system infections.

Recent advances in the pathogenesis and pathophysiology of bacterial meningitis

Bacterial meningitis continues to account for worldwide morbidity and mortality despite the advent of effective bactericidal antibiotic therapy. Recent advances over the past 10 years in the development of experimental animal models as well as basic investigation into critical bacterial surface virulence factors have begun to clarify a conceptual framework for understanding the mechanism of meningitis development in humans. Basic observations regarding competing host defenses and bacterial virulence factors have supported a pathogenetic sequence of mucosal colonization with a meningeal pathogen; systemic host invasion with intravascular replication; blood brain barrier penetration and unimpeded CSF proliferation amid the impaired host defenses in the CSF milieu; and pathophysiologic sequelae including vasogenic, cytotoxic, and interstitial brain edema (and other processes) accounting for irreversible neuronal injury and death. Only through continued basic investigation into each of these pathogenetic steps will significant reductions in morbidity and mortality ensue.

Morphologic alterations of the blood-brain barrier with experimental meningitis in the rat. Temporal sequence and role of encapsulation

The cerebral capillary endothelium is unique and functions as an effective blood-brain barrier (BBB) owing to its intercellular tight junctions and rare pinocytotic vesicles. To assess how bacterial meningitis alters the BBB, rats were inoculated intracisternally with three encapsulated meningeal pathogens (Escherichia coli K1+, Streptococcus pneumoniae type III, Haemophilus influenzae type b) and an unencapsulated mutant strain (H. influenzae Rd). After defined infection durations, the morphologic alterations of the cerebral capillary endothelium were quantitatively assessed by transmission electron microscopy. Results revealed a significant increase in pinocytotic vesicle formation (P less than 0.001) early after meningitis induction (4 h) that was sustained with longer infection durations (10 h, 18 h) for all encapsulated strains tested. In addition, there was a progressive increase in completely separated intercellular junctions with increasing infection duration, (P less than 0.05). 4 h after induction of meningitis with H. influenzae Rd, cerebrospinal fluid (CSF) bacterial concentrations, cerebral capillary morphologic changes, and functional BBB permeability to circulating 125I-albumin were similar to those observed with H. influenzae type b. However, prolonging the H. influenzae Rd infection to 18 h allowed for CSF clearance of the organism, thereby precluding the significant increase in separated junctions or progression of functional BBB permeability seen with the encapsulated H. influenzae type b. These data suggest a uniform morphologic explanation for altered BBB permeability in meningitis with a reproducible temporal sequence. Encapsulation does not appear essential for BBB injury, but may facilitate its progression by allowing the organism to evade host clearance.