BACTERIAL MENINGITIS--A REVIEW OF SELECTED ASPECTS. 1. GENERAL CLINICAL FEATURES, SPECIAL PROBLEMS AND UNUSUAL MENINGEAL REACTIONS MIMICKING BACTERIAL MENINGITIS

Bacterial meningitis post-PCV7: declining incidence and treatment

The epidemiology of bacterial meningitis in the United States has changed tremendously in the past 20 years. Since the introduction of the Haemophilus influenzae type b vaccine in 1988, the incidence of H. influenzae type b meningitis has declined by at least 97%, and Streptococcus pneumoniae has emerged as the most common etiologic agent. The PCV7 (7-valent pneumococcal conjugate vaccine [Prevnar]; Wyeth Pharmaceuticals) vaccine, which targets 7 pneumococcal serotypes, was introduced in 2000 and has had an enormous impact on both the incidence and epidemiology of bacterial meningitis. This article reviews the impact of the PCV7 vaccine and the most up-to-date evidence on diagnosis and empiric therapy of suspected bacterial meningitis in the current day.

Infections in alcoholic liver disease

Alcoholic individuals are at increased risk of infection in general, in part because of immune defects. In addition, associated situations, such as depressed mental status, increase risk to specific syndromes such as lung abscess related to depressed consciousness and aspiration. Social factors related to hygiene and living situations are also linked to specific microorganisms, such as Mycobacteria tuberculosis, Bartonella quintana, Vibrio vulnificus, and Capnocytophaga canimorus..

The role of cranial CT in the investigation of meningitis

Objective

To assess the usage of cranial computed tomography (CT) in patients admitted with meningitis.

Design

Retrospective study.

Setting

Heart of England NHS foundation trust, a teaching hospital in the West Midlands.

Participants

Two groups of adult patients admitted with meningitis between April 2001 and September 2004 and from September 2006 until September 2009.

Main outcome measures

The numbers of patients having cranial CT and lumbar puncture and whether any complications had arisen following lumbar puncture. The appropriateness of the CT request according to local criteria.

Results

A total of 111 patients were admitted in the initial time period and 47 patients in the second time period. In the first group, 67 patients underwent CT (61%), compared with 36 patients (80%) in the second group. There were eight abnormal scans (12%) in the initial group including three patients with radiological features of cerebral oedema. Of these patients, one underwent lumbar puncture and had no neurological sequelae. In the second group, there were five abnormal scans (14%) with one presenting a contraindication for lumbar puncture due to mild ventricular dilatation. A lumbar puncture was performed in this patient without complication. All patients with abnormal scans had clinical features to suggest raised intracranial pressure. CT scan requests were considered inappropriate in 26% of patients in the initial study period and 56% of patients in the second study period.

Conclusion

More patients with meningitis are undergoing CT and the number of inappropriate requests are increasing. There are few abnormal CT scans presenting a contraindication for lumbar puncture and the majority of these patients usually have clinical signs to suggest raised intracranial pressure.

Chapter 28: a history of bacterial meningitis

Thomas Willis (1621-1675) described patients with, "inflammation of the meninges with a continual fever" as well as an early (1661) epidemic of meningitis. Robert Whytt (1714-1766) provided a classic depiction of tuberculous meningitis and its stages, later extended by John Cheyne (1777-1836). Gaspard Vieusseux (1746-1814) and Andre Matthey (1778-1842) in Geneva, and Elisa North (1771-1843) in Massachusetts, described epidemic (meningococcal) meningitis. Heinrich Quincke (1842-1922) utilized his new technique of lumbar puncture (1891) to provide an early analysis of cerebrospinal fluid (CSF). William Mestrezat (1883-1929), and H. Houston Merritt (1902-1979) later compiled large series of CSF profiles in meningitis. Organisms causing meningitis were identified in the late 19th century including Streptococcus pneumoniae, Neisseria meningitidis and Haemophilus influenzae. Vladimir Kernig (1840-1917) and Josef Brudzinski (1874-1917) described their eponymous signs in 1882 and 1909. Successful treatment of meningitis began with the introduction of serum therapy for meningococcal meningitis by Georg Joachmann (1874-1915) in Germany and Simon Flexner (1863-1946) in America. Antibiotic therapy began in the 20th century with the use of sulfonamides by Francois Schwentker (1904-1954) and penicillin by Chester Keefer (1897-1972). Vaccination against meningitis debuted in the early 20th century, and progressed to the development of vaccines against Neisseria meningitidis and Haemophilus influenzae, which remain mainstays of modern medicine.

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.

Characterization of chemical meningitis after neurological surgery

We reviewed the records of 70 consecutive adult patients with meningitis after a neurosurgical procedure, to determine the characteristics that might help to distinguish a sterile postoperative chemical meningitis from bacterial infection. The spinal fluid profiles in bacterial and chemical meningitis are similar. The exceptions are that a spinal fluid white blood cell count > 7500/microL (7500 x 10(6)/L) and a glucose level of < 10 mg/dL were not found in any case of chemical meningitis. The clinical setting and clinical manifestations were distinct enough that no antibiotic was administered after lumbar puncture to 30 (43%) of the 70 patients with postoperative meningitis. Chemical meningitis was infrequent after surgery involving the spine and sinuses. Patients with chemical meningitis did not have purulent wound drainage or significant wound erythema or tenderness, coma, new focal neurological findings, or onset of a new seizure disorder. They rarely had temperatures > 39.4 degrees C or cerebrospinal fluid rhinorrhea or otorrhea.

[Details of meningitis in the elderly]

PURPOSE

Elderly patients being more at risk for infections than younger people, this study was aimed at defining the epidemiological and clinical features of meningitis in this population, with the objective of improving diagnosis and management.

METHODS

Over a period of 10 years, all cases admitted to an infectious diseases unit for acute meningitis were reviewed. Patients infected by human immunodeficiency virus (HIV), fungi meningitis, and who were younger than 15 years of age were excluded from the study. According to age, two groups were constituted (group A: < 65 years and group B: > or = 65 years) and compared.

RESULTS

One hundred fifty-two patients were included in the study: 110 (72.4%) in group A (29 with bacterial and 81 with viral meningitis) and 42 (26.7%) in group B (32 with bacterial and ten with viral meningitis); the mean age was, respectively, 32.7 +/- 12.9 years (range: 15-61 years) and 75.9 +/- 7.6 years (range: 65-94 years). Diagnosis was less frequently evoked in the elderly (n = 11; 26%) than in younger patients (n = 78; 71%) (P < 0.001). Streptococcus pneumoniae, Listeria monocytogenes, and herpes simplex virus were the three most common causal agents in group B. Confusion was the most common symptom among the elderly (88 vs. 17%; P < 0.001). The mortality rate was more important in group B than in group A (11.9 vs. 2.7%; P = 0.04).

CONCLUSIONS

Diagnosis of acute meningitis is difficult and must be evoked in the presence of any new neurologic sign. Cranial computerized tomography should not delay lumbar puncture, except in the presence of focal neurologic symptoms. Antimicrobial therapy takes into account the bacterial epidemiology.

Early management of meningococcal disease

Meningococcal disease is increasing in incidence in many countries, and effective vaccines for serogroup B strains will not be available for at least 5 to 10 years. In the interim, it is attention to principles of good clinical practice, particularly in the early management of the disease, that have the potential to reduce by half the current case fatality rate of approximately 10%. As discussed in this article, those principles include increased awareness, understanding of the disease and its early symptoms by parents and healthcare professionals, and careful attention to the patient before admission and during the hospital stay.

Microscopic examination and broth culture of cerebrospinal fluid in diagnosis of meningitis

We reviewed the results of microscopic Gram stain examination and routine culture for 2,635 cerebrospinal fluid (CSF) samples processed in an adult hospital microbiology laboratory during 55 months. There were 56 instances of bacterial or fungal meningitis (16 associated with central nervous system [CNS] shunt infection), four infections adjacent to the subarachnoid space, four cases of sepsis without meningitis, and an additional 220 CSF specimens with positive cultures in which the organism isolated was judged to be a contaminant. Because 121 of these contaminants were isolated in broth only, elimination of the broth culture would decrease unnecessary work. However, 25% of the meningitis associated with CNS shunts would have been missed by this practice. The most common cause of meningitis was Cryptococcus neoformans, followed by Streptococcus pneumoniae and Neisseria meningitidis. In 48 of 56 (88%) of cases, examination of the Gram-stained specimen revealed the causative organism. If patients who had received effective antimicrobial therapy prior to lumbar puncture are excluded, the CSF Gram stain is 92% sensitive. Microscopic examination incorrectly suggested the presence of organisms in only 3 of 2,635 (0.1%) CSF examinations. Thus, microscopic examination of Gram-stained, concentrated CSF is highly sensitive and specific in early diagnosis of bacterial or fungal meningitis.

Klebsiella ozaenae meningitis: report of two cases and review of the literature

Meningitis is rarely caused by Klebsiella ozaenae, a colonizer of the oral and nasopharyngeal mucosa. We describe two patients with K. ozaenae meningitis. Both patients suffered from a primary disease of the nasopharyngeal pathway; one had nasopharyngeal carcinoma and the other ozena. Review of the English-language literature from 1966 to the present revealed only two cases of K. ozaenae meningitis; pneumonia and hyperglycemia were noted in one patient and otitis media, sinusitis and diabetes mellitus in the other. All these four patients were over 50 years old. Of the four patients, two treated with third-generation cephalosporins recovered whereas one of the two treated with chloramphenicol died. One patient who died had a positive blood culture for K. ozaenae. Blood culture was positive in only one of the three survivors. Whether chloramphenicol should be replaced by a third-generation cephalosporin and whether blood culture indicates a poor prognosis in K. ozaenae meningitis remain to be determined.

Pyogenic meningitis in Ahmedabad

One hundred and thirty five cerebrospinal fluid (CSF) samples from children clinically diagnosed Pyogenic meningitis (in and around Ahmedabad) were subjected to physical, bacteriological, cytological and biochemical examinations. It was found that all CSF specimens were turbid, the culture positivity varied form 12.12 to 56%. The highest percentage was found in children of less than one year of age. The average percentage of culture positivity was 28.68%. The result of gram stain was more than that of cultural examination. Gram stain of CSF was specific, accurate and highly valuable in the diagnosis of pyogenic meningitis. Among gram positive organisms isolated, Staphylococcus aureus was highest (8.8%) followed by Diplococcus pneumoniae (3.7%), but Klebsiella was predominant (6.6%) among gram negative bacilli. Staph. aureus was 100% sensitive to erythromycin, gentamycin, kanamycin and ampicillin. The results of cytological and biochemical tests correlated (67.1%). There was increase in polymorphs and protein, sugar levels decreased.

Acute bacterial meningitis in adults. A review of 493 episodes

BACKGROUND AND METHODS

To characterize acute bacterial meningitis in adults, we reviewed the charts of all persons 16 years of age or older in whom acute bacterial meningitis was diagnosed at Massachusetts General Hospital from 1962 through 1988. We included patients who were admitted after initial treatment at other hospitals.

RESULTS

During the 27-year period, 445 adults were treated for 493 episodes of acute bacterial meningitis, of which 197 (40 percent) were nosocomial. Gram-negative bacilli (other than Haemophilus influenzae) caused 33 percent of the nosocomial episodes but only 3 percent of the community-acquired episodes. In the 296 episodes of community-acquired meningitis, the most common pathogens were Streptococcus pneumoniae (37 percent), Neisseria meningitidis (13 percent), and Listeria monocytogenes (10 percent); these organisms accounted for only 8 percent of the nosocomial episodes. Only 19 of the 493 episodes of meningitis (4 percent) were due to H. influenzae. Nine percent of all patients had recurrent meningitis; many had a cerebrospinal fluid leak. Seizures occurred in 23 percent of patients with community-acquired meningitis, and 28 percent had focal central nervous system findings. Risk factors for death among those with single episodes of community-acquired meningitis included older age (> or = 60 years), obtunded mental state on admission, and seizures within the first 24 hours. Among those with single episodes, the in-hospital mortality rate was 25 percent for community-acquired and 35 percent for nosocomial meningitis. The overall case fatality rate was 25 percent and did not vary significantly over the 27 years.

CONCLUSIONS

In our large urban hospital, a major proportion of cases of acute bacterial meningitis in adults were nosocomial. Recurrent episodes of meningitis were frequent. The overall mortality rate remained high.

Group D streptococcal bacteremia in children. A review of 72 cases in 12 years

A review was conducted of 72 cases of pediatric group D streptococcal (GDS) bacteremia treated at our institution during a 12-year period. These 72 cases represented 90% of all instances in which this organism was isolated by blood culture (in eight others, GDS was considered a contaminant); the rate of isolation of this organism relative to all positive blood cultures during this time period was 1.3%. Infection was nosocomially acquired in 25 cases; 18 occurred in an intensive care unit. At the time their positive blood culture was obtained, 25 patients were afebrile and 10 patients were receiving parenteral antibiotic therapy to which the isolate exhibited in vitro susceptibility. In 31 cases, GDS was isolated by blood culture in conjunction with another organism, most frequently Staphylococcus epidermidis. Underlying medical conditions or foci of infection associated with GDS bacteremia were identified in 65 patients; the most common were the presence of an indwelling central venous catheter (23), a variety of lesions of the gastrointestinal tract (21), and pulmonary infiltrate (15). Bacteremia was associated with GDS meningitis in three patients who had had no prior neurosurgical procedure. The overall mortality rate was 20%; nearly two thirds of all deaths occurred in patients younger than 1 year of age.

Adult meningitis. Rapid identification for prompt treatment

To be effective, treatment of meningitis should be based on the history and physical examination, careful examination of the cerebrospinal fluid, and good clinical judgment regarding the most likely pathogen. Meningitis in adults is usually caused by certain common viruses and bacteria, although atypical pathogens should be considered in immunocompromised patients. Supportive therapy measures are appropriate for viral disease, and intravenous acyclovir (Zovirax) may be given if infection with herpes simplex virus is suspected. In cases of presumed bacterial meningitis, antimicrobial agents should be selected that penetrate the blood-brain barrier and maintain activity against the most likely pathogens; antibiotic therapy should be instituted right away, along with supportive measures. Although corticosteroids have proven benefits in the treatment of pediatric populations with Haemophilus influenzae meningitis, their effectiveness in adults has not yet been established. Prophylaxis with vaccines or rifampin is sometimes useful.

Infections of the central nervous system

Infections of the central nervous system are common, serious medical conditions. One hundred consecutive adult cases with purulent meningitis of known etiology encountered by the Medical Service at Parkland Memorial Hospital were reviewed. Streptococcus pneumoniae was the most common pathogen (56 cases), followed by Neisseria meningitidis (16 cases) and Listeria monocytogenes (seven cases). Hemophilus influenzae, Staphylococcus aureus, and streptococci each accounted for five cases. An additional 15 patients had purulent meningitis with a pathogen being isolated. Twenty five purulent meningitis cases of known etiology after trauma or neurosurgery were reviewed. Staphylococcus aureus (five cases), Staphylococcus epidermidis (four cases), and gram negative bacilli (14 cases) were the most common pathogens. Review of intracranial suppurative infections demonstrated advances in microbiology, antibiotic therapy, and imaging, leading to improvements in therapy. Subdural empyema continues to be a difficult diagnosis to make and apparently is related to the anatomic pathology of the infectious process. To illustrate salient features about granulomatous meningitis and encephalitis, cases of tuberculous meningitis, herpes simplex encephalitis, St. Louis encephalitis, and encephalitis of undetermined etiology are presented and discussed.

Hearing loss and pneumococcal meningitis: an animal model

Clinical studies of predisposing factors in the development of hearing loss secondary to bacterial meningitis have produced conflicting results. An animal model of meningogenic labyrinthitis was developed for more precise study of these parameters. Rabbits were inoculated intrathecally with 10(5) pneumococci to induce meningitis. Hearing thresholds were measured using auditory-evoked responses to 1 kHz, 10 kHz, and click stimuli before infection and every 12 hours thereafter. Profound deafness occurred in all subjects at an average of 48 hours following infection. The incidence and severity of hearing loss was strongly correlated with the duration of meningitis. Temporal bone histology revealed acute inflammation of all perilymphatic spaces including the cochlear aqueduct. This model demonstrated that the risk and severity of hearing loss increase with the duration of meningitis and suggested that the cochlear aqueduct is an anatomic pathway for the extension of infection from the cerebrospinal fluid to the cochlea. The implications for therapy in humans is discussed.

Severity of childhood bacterial meningitis and duration of illness before diagnosis

Rapid diagnosis of childhood bacterial meningitis (BM) is generally believed to be essential to avoid poor outcome. To see whether duration of illness before admission to hospital was related to the severity of illness, data from children with BM diagnosed in 18 paediatric hospitals in Finland from 1984 to 1989 were collected prospectively. We divided 286 cases with culture-positive cerebrospinal fluid (CSF) into three groups: BM with a history of up to 24 h (short-history group, n = 141), of more than 24 h and up to 48 h (intermediate-history group, n = 75), and of more than 48 h (long-history group, n = 70). The longer the history, the better the clinical condition of the child. If symptoms or signs of BM lasted 48 h or less, the child did significantly worse, as judged by seven variables, than if the history was longer than 48 h (level of consciousness, p less than 0.001; seizures, p less than 0.01; CSF protein concentration, p less than 0.001; positive CSF gram-stain, p less than 0.01; positive blood culture, p less than 0.05 in Haemophilus influenzae meningitis; serum C-reactive protein, p less than 0.01 between intermediate-history and long-history groups; and urine sodium concentration, p less than 0.001). The differences were not affected by causative organism, sex, age, or preadmission oral antimicrobial agents. The findings show that if BM follows an insidious pattern of disease, diagnostic delay may be unavoidable, which may have medicolegal implications.

Seizures and other neurologic sequelae of bacterial meningitis in children

BACKGROUND

Although the mortality rate among children with bacterial meningitis has decreased dramatically in recent decades, some patients are left with neurologic sequelae. It has not been clearly established which features of the acute illness predict the chronic neurologic sequelae, including late seizures or epilepsy.

METHODS

We followed 185 infants and children prospectively during and after acute bacterial meningitis. The mean duration of follow-up was 8.9 years (range, 0.1 to 15.5). During the first six years standard neurologic examinations were performed; telephone interviews were conducted thereafter.

RESULTS

One month after meningitis, 69 children (37 percent) had neurologic abnormalities. Many of these signs resolved within a year, leaving only 26 children (14 percent) with persistent deficits: 18 (10 percent) had only sensorineural hearing loss, and 8 (4 percent) had multiple neurologic deficits. Thirteen children (7 percent) had one or more late seizures not associated with fever. The presence of persistent neurologic deficits indicative of cerebral injury was the only independent predictor of late afebrile seizures (P less than 0.001).

CONCLUSIONS

After bacterial meningitis only children with permanent neurologic deficits are at high risk for epilepsy. Those with normal examinations after the acute illness have an excellent change of escaping serious neurologic sequelae, including epilepsy.

Diseases that mimic meningitis. Analysis of 650 lumbar punctures

A retrospective review of charts for 650 children who had lumbar puncture for suspected meningitis was undertaken to determine the characteristics of patients with and without meningitis, identify other conditions suggesting meningitis, and evaluate the predictive value of signs and symptoms of meningitis. The incidence of positive lumbar punctures increased with patient age. Younger infants did not present with classical features of meningitis. Bulging fontanel, lethargy, and irritability were nonspecific symptoms. Vomiting and headache, although not specific, proved to be more sensitive indicators of meningeal infection. Most patients with meningitis (75%) had at least one sign of meningeal irritation, but so did 25% of patients without meningitis. Brudzinski's sign was not specific. In contrast, nuchal rigidity and Kernig's sign had high predictive value. Up to age five, the diseases most often suggesting meningitis were right-sided pneumonia, gastroenteritis, otitis, tonsillitis, exanthema subitum, and urinary tract infections. Of 171 patients with febrile convulsion, one (0.5%) had bacterial meningitis and four had aseptic meningitis.

Cranial nerve palsies in Streptococcus pneumoniae meningitis

Cranial nerve palsies are uncommon in nontuberculous bacterial meningitis. We report a patient with Streptococcus pneumoniae meningitis, multiple cranial nerve involvement, and cerebellar signs suggestive of basilar meningitis. Nontuberculous bacterial meningitis should be considered in the differential diagnosis of basilar meningitis.

Clinical evaluation of pneumococcal meningitis in adults over a twelve-year period

A retrospective study was performed to review the clinical features and outcome of 39 episodes of pneumococcal meningitis in 36 adult patients over a 12-year period. Overall mortality was 33.3%. Only a few of the deaths were directly related to the central nervous system disease and most of them were due to cardiorespiratory failure. Univariate analysis showed that death was more likely to occur in patients with advanced age, an absence of neck stiffness, a high pulse rate, an associated pneumonia, internal complications, or a long duration of the disease (greater than 7 days) before treatment was started. Patients who died had a higher erythrocyte sedimentation rate and serum bilirubin level and a lower serum sodium level than those who survived. Discriminant analysis showed the development of internal complications to be the strongest predictive factor of a poor outcome of illness. Two other important predictors of a poor outcome were the absence of neck stiffness and associated pneumonia. The history of a skull fracture or head surgery was significantly correlated with a better than average prognosis. The incidence of sequelae in survivors at the time of discharge amounted to 72%. None of the clinical features were significantly correlated with the development of sequelae, except a higher cerebrospinal fluid protein content.

Direct and indirect pathogenicity of beta-lactamase-producing bacteria in mixed infections in children

The recent emergence of numerous aerobic and anaerobic beta-lactamase-producing bacterial strains has been associated with an increase in the failure rate of penicillins in the therapy of infection caused by these organisms. These include respiratory tract, skin of soft tissue, female genital tract, intra-abdominal, and other miscellaneous infections. The important aerobic beta-lactamase-producing bacteria (BLPB) include Staphylococcus aureus, Branhamella catarrhalis, Haemophilus sp., Neisseria gonorrhoeae, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Legionella sp. The anaerobic BLPB are all Bacteroidiaceae and include Bacteroides fragilis group, B. melaninogenicus group, B. oralis, B. oris-buccae, and Fusobacterium sp. Laboratory, animal, and clinical studies that support the indirect pathogenicity of these organisms and the distribution of these BLPB in various infections are reviewed. BLPB may not only have a direct pathogenic role in causing the infection, but also an indirect pathogenic role. The indirect pathogenicity of these organisms is apparent through their ability not only to survive penicillin therapy, but also to protect penicillin-susceptible pathogens from that drug. These direct and indirect virulence characteristics of aerobic and anaerobic BLPB require the administration of appropriate antimicrobial therapy directed against all pathogens in mixed infections.

Haemophilus influenzae lipopolysaccharide-induced blood brain barrier permeability during experimental meningitis in the rat

The factors responsible for blood-brain barrier (BBB) injury during bacterial meningitis are incompletely defined. We evaluated the role of Haemophilus influenzae type b (Hib) lipopolysaccharide (LPS) in the alteration of blood-brain barrier permeability (BBBP) in an adult, normal and leukopenic, rat model of meningitis. Intracisternal inoculation of Hib LPS resulted in (a) dose-dependent increases in BBBP from 2 pg to 20 ng, with significant attenuation in the peak response after challenge with 500 ng and 1 microgram; (b) time-dependent increases in BBBP, with a delayed onset of at least 2 h, maximum alteration at 4 h, and complete reversal at 18 h; (c) greater BBBP than after challenge with the live parent strain; (d) and a close correlation (r = 0.86) between CSF pleocytosis and BBBP at 4 h. The LPS effect was significantly inhibited by preincubation with Polymyxin B and neutrophil acyloxyacyl hydrolase, however two different oligosaccharide-specific monoclonal antibodies did not inhibit activity. No change in BBBP after inoculation with Hib LPS occurred in leukopenic rats. Hib LPS, in the setting of an intact leukocyte response, exerts profound effects on BBBP.

Acute bacterial meningitis. Cerebrospinal fluid differential count

A retrospective analysis of 112 cases of pediatric bacterial meningitis over a 3-year period was performed to determine the rate of cerebrospinal fluid (CSF) lymphocytosis at initial evaluation. Of 14 neonates and 98 children older than 1 month of age not receiving preadmission antibiotic therapy, only one instance of CSF lymphocytosis occurred. This patient's CSF exhibited pleocytosis, hypoglycorrhachia, abnormally elevated protein content, and organisms visualized on gram stain smear. In children with bacterial meningitis not receiving antibiotic therapy at the time of evaluation, CSF differential cell count with relative lymphocytosis is rare.

Role of cerebrospinal fluid pleocytosis and Haemophilus influenzae type b capsule on blood brain barrier permeability during experimental meningitis in the rat

The influence of leukocytes and Haemophilus influenzae type b (Hib) capsule on blood brain barrier permeability (BBBP) to circulating 125I-albumin in normal and leukopenic rats was assessed after intracisternal inoculation of encapsulated (Rd-/b+/02) or unencapsulated (Rd-/b-/02) isogenic strains of Hib. Both normal and leukopenic animals had increased BBBP 18 h after inoculation, with normal rats demonstrating significantly increased BBBP after challenge with the encapsulated strain. Despite cerebrospinal fluid (CSF) pleocytosis in normal rats, CSF bacterial concentrations were not lower. Normal rats cleared unencapsulated Rd-/b-/02 more effectively than leukopenic rats, with BBBP correlating with CSF bacterial density and not leukocyte concentrations. Challenge with heat-killed Rd-/b+/02 resulted in increased BBBP in both normal and leukopenic rats, with greater BBBP at higher bacterial concentrations. The data suggest: (a) significant increases in BBBP occur in the near absence of CSF leukocytes; (b) CSF leukocytes can augment changes in BBBP; (c) type b capsule inhibits host clearance mechanisms within the CSF; and (d) BBBP appears to correlate with bacterial concentrations within the CSF.

Artificial ventilation and prognostic factors in bacterial meningitis

The use of artificial ventilation in patients with bacterial meningitis was increased from 8.0% of 176 patients admitted in 1966-1968 to 31.5% of 162 patients admitted in 1975-1976. The therapeutic regimen was otherwise unchanged. The fatality rate decreased from 14.2% in the first period to 8.6% in the second, whereas the rate of neurological sequelae increased from 11.3% to 16.9%. A linear logistic model analysis was applied to correct for the influence of factors of known prognostic importance in the two periods, e. g. age, level of consciousness at admission, mode of admission and etiology. The analysis showed a significant 50% reduction in fatality rate (p = 0.05), whereas the corrected rate of neurological sequelae appeared similar in the two periods. Our results suggest that an increased use of respirator treatment may improve the prognosis in bacterial meningitis.

Recurrent meningitis: a case report

Recurrent meningitis is an uncommon clinical problem. It is most likely to result from head trauma. Streptococcus pneumoniae is the most common infecting pathogen. Computed tomographic techniques are required to identify persistent bony defects in the skull that might predispose to this disorder. Because emergency physicians regularly care for victims of head trauma and meningitis, knowledge of this entity can be useful.

Systemic Hemophilus influenzae disease in children. A 10-year retrospective study of an urban hospital population

A 10-year retrospective study of age-frequency, sites of infection, and pre-existing conditions in 297 children with Hemophilus influenzae (HI) disease seen at Grady Memorial Hospital from 1974 through 1984 is described. The majority of the patients were black (73%) and of lower socioeconomic status and were less than 2 years of age. Manifestations of HI disease were similar to those described in reports from other centers, with meningitis being the most common (56.7%). Epiglottitis was much less common in the present study than is generally reported. The death rate of all patients was 1.8 percent. The results of this study indicate that HI disease continues to be a significant risk in children less than 2 years of age.

Acute neurologic infections

This article discusses acute bacterial, viral, toxin-mediated, and parasitic neurologic infections, emphasizing those infections that are potentially treatable, are rapidly fatal if untreated, or pose a significant risk of person-to-person transmission.

Antibiotic susceptibility of Haemophilus influenzae isolated from cerebrospinal fluid and blood

The emergence of ampicillin and chloramphenicol resistant Haemophilus influenzae type b in Denmark has created demands for alternative treatments of serious infections with H. influenzae. In this study 102 strains of H. influenzae recovered from cerebrospinal fluid (85) and blood (17) were tested for susceptibility to ampicillin, piperacillin, erythromycin, rifampicin, chloramphenicol, cefuroxime, cefotaxime, ceftazidime, ceftriaxone, moxalactam, aztreonam, and netilmicin by means of the agar dilution method. The majority (97%) was H. influenzae type b and of these strains 94% belonged to biotype I. Nine of the investigated strains were beta-lactamase producers. Ceftriaxone and cefotaxime were the most active agents (MIC90 less than or equal to 0.025 microliter/ml) followed by moxalactam and aztreonam (MIC90 = 0.1 microgram/ml). Except for ampicillin and piperacillin, the MIC was similar for beta-lactamase producers and non-producers. Several of the investigated antibiotics, especially some of the third generation cephalosporins, might constitute valid therapeutical alternatives to conventional drugs in the treatment of severe H. influenzae infections.