Clinical findings and management of patients with meningitis with an emphasis on Haemophilus influenzae meningitis in rural Tanzania

INTRODUCTION

The spectrum of meningitis pathogens differs depending on the age of patients and the geographic region, amongst other. Although meningitis vaccination programs have led to the reduction of incidence rates, an imbalance between low- and high-income countries still exists.

METHODS

In a hospital-based study in rural northern Tanzania, we consecutively recruited patients with confirmed meningitis and described their clinical and laboratory characteristics.

RESULTS

A total of 136 patients with meningitis were included. Fever (85%), meningism (63%) and impairment of consciousness (33%) were the most frequent clinical symptoms/signs. Nearly 10% of all patients tested were positive for malaria. The majority of the patients with bacterial meningitis (39%), especially those under 5years of age, were confirmed to be infected with Haemophilus influenzae (26%), Streptococcus pneumoniae (19%) and Neisseria meningitidis (15%). Haemophilus influenzae represented the dominant causative organism in children under 2years of age.

CONCLUSION

Our study emphasizes the importance of recognizing warning symptoms like fever, meningism and impairment of consciousness, implementing laboratory tests to determine responsible pathogens and evaluating differential diagnoses in patients with meningitis in sub-Saharan Africa. It also shows that Haemophilus influenza meningitis is still an important cause for meningitis in the young, most probabaly due to lack of appropriate vaccination coverage.

Educational achievement and economic self-sufficiency in adults after childhood bacterial meningitis

IMPORTANCE

To our knowledge, no previous study has examined functioning in adult life among persons who had bacterial meningitis in childhood.

OBJECTIVE

To study educational achievement and economic self-sufficiency in adults diagnosed as having bacterial meningitis in childhood.

DESIGN, SETTING, AND PARTICIPANTS

Nationwide population-based cohort study using national registries of Danish-born children diagnosed as having meningococcal, pneumococcal, or Haemophilus influenzae meningitis in the period 1977-2007 (n=2784 patients). Comparison cohorts from the same population individually matched on age and sex were identified, as were siblings of all study participants. End of study period was 2010.

MAIN OUTCOMES AND MEASURES

Cumulative incidences of completed vocational education, high school education, higher education, time to first full year of economic self-sufficiency, and receipt of disability pension and differences in these outcomes at age 35 years among meningitis patients, comparison cohorts, and siblings.

RESULTS

By age 35 years, among persons who had a history of childhood meningococcal (n=1338), pneumococcal (n=455), and H. influenzae (n=991) meningitis, an estimated 11.0% (41.5% vs 52.5%; 95% CI, 7.3%-14.7%), 10.2% (42.6% vs 52.8%; 95% CI, 3.8%-16.6%), and 5.5% (47.7% vs 53.2%; 95% CI, 1.9%-9.1%) fewer persons, respectively, had completed high school and 7.9% (29.3% vs 37.2%; 95% CI, 1.6%-14.2%), 8.9% (28.1% vs 37.0%; 95% CI, 0.6%-17.2%), and 6.5% (33.5% vs 40.0%; 95% CI, 1.4%-11.6%) fewer had attained a higher education compared with individuals from the comparison cohort. Siblings of meningococcal meningitis patients also had lower educational achievements, while educational achievements of siblings of pneumococcal and H. influenzae meningitis patients did not differ substantially from those in the general population. At end of follow-up, 3.8% (90.3% vs 94.1%; 95% CI, 1.1%-6.5%), 10.6% (84.0% vs 94.6%; 95% CI, 5.1%-16.1%), and 4.3% (90.6% vs 94.9%; 95% CI, 2.0%-6.6%) fewer meningococcal, pneumococcal, and H. influenzae meningitis patients were economically self-sufficient and 1.5% (3.7% vs 2.3%; 95% CI, -0.2% to 3.2%), 8.7% (10.0% vs 1.3%; 95% CI, 5.0%-12.4%), and 3.7% (6.2% vs 2.5%; 95% CI, 1.6%-5.8%) more received disability pension compared with individuals from the comparison cohort.

CONCLUSIONS AND RELEVANCE

In a Danish population, bacterial meningitis in childhood was associated with lower educational achievement and economic self-sufficiency in adult life. This association may apply particularly to pneumococcal and H. influenzae meningitis, whereas for meningococcal meningitis the lower educational achievement may be family-related.

Acute bacterial meningitis as the cause of a traffic accident

This is a report about a traffic accident without an apparent external cause. The driver responsible for the accident was diagnosed with acute bacterial meningitis. From a forensic aspect the meningitis was determined as the underlying reason for the accident, but it could not be assumed that the driver should have recognized the danger in time.

Bacterial profile and clinical outcome of childhood meningitis in rural Yemen: A 2-year hospital-based study

BACKGROUND

Childhood acute bacterial meningitis (ABM) is an important cause of death and long-term neurological disability in Yemen, the only low income-high mortality country in the Arabian Peninsula. The objective of this study was to document the microbial characteristics, the antibacterial sensitivity pattern, and the outcome for children hospitalized with ABM, prior to the introduction of Haemophilus influenzae type b (Hib) vaccine in Yemen.

PATIENTS AND METHODS

The study was retrospective, conducted at a rural district hospital, serving the rural population of the northern parts of Yemen. All patients aged 1 month-15 years admitted between May 1999 and June 2001, with clinical evidence of meningitis and cerebrospinal fluid (CSF) cultured, were included in the study. Clinical information from case notes, including CSF result and the outcome on discharge, were obtained. Analysis of extracted data was performed using Epi Info software.

RESULTS

During the 2-year study period, 160 study patients met the inclusion criteria, and 7 (4.4%) were negative for bacterial growth. In the 153 positive cultures there were 46 (30.1%) Streptococcus pneumoniae (SP), 23 (15%) H. influenzae (HI), 81 (52.9) Neisseria meningitidis (NM), 2 (1.3%) Staphylococcus aureus (S. aureus), and 1 (0.7%) Escherichia coli. Sixteen study patients died (overall case fatality rate (CFR) 10%), 7 aged under 12 months, 6 aged 12-60 months, and 3 more than 60 months. Ten deaths were due to SP meningitis, 2 HI meningitis, 3 NM meningitis, and 1 had S. aureus. Of the 144 survivors, 28 (19.4%) developed permanent neurological complications, 17 aged less than 12 months, 6 aged 12-60 months, and 5 more than 60 months. SP meningitis accounted for 57.1% (16/28), and 6 (21.4%) had HI meningitis. Among the 89 aged 1-60 months, 13 died (CFR 14.6%), and 23 (30.3%) of the 76 survivors developed permanent complications. Of those tested 20% and 35% of the 20 HI tested isolates and 9.5% and 14.3% of the 42 SP isolates, were resistant to ampicillin and penicillin G, respectively, and the majority of the 81 NM isolates were sensitive to both. The 3 pathogens were largely resistant to gentamicin, and almost all were susceptible to chloramphenicol and cefotaxime.

CONCLUSION

In contrast to the studies from the low-mortality countries of the region, our study showed that the predominant pathogens of childhood ABM were SP and NM. SP meningitis was associated with increased mortality and permanent disability.

Identification of a haem-utilization protein (Hup) in Haemophilus influenzae

Haemophilus influenzae has an absolute growth requirement for a porphyrin source. This growth requirement can be satisfied in vitro by haem, haemoglobin or the haemoglobin-haptoglobin, haem-haemopexin and haem-albumin complexes. A family of proteins, termed the Hgp proteins, which are essential for utilization of the haemoglobin-haptoglobin complex, has previously been identified. A strain lacking the Hgp proteins also has a residual ability to utilize haemoglobin, indicating that additional moieties contribute to haemoglobin utilization. Using a haemoglobin affinity method an approximately 105 kDa protein was isolated. Mutation of the identified gene in an Hgp null background reduced the ability of the mutant strain to utilize haemoglobin in vitro. The mutation also resulted in a reduced ability to utilize haem, haem-haemopexin, haem-albumin and haemoglobin-haptoglobin, thus identifying a general haem-utilization protein (Hup) in Haemophilus influenzae.

Audiovestibular and neuropsychological outcome of adults who had recovered from childhood bacterial meningitis

A sample of 22 subjects was studied from a population of adults who had suffered from bacterial meningitis in childhood. Audiovestibular, oculomotor and neuropsychological investigations were performed and quality of life was assessed. An age-matched control group of 20 subjects was recruited. In the meningitis group, nine subjects had abnormal pure tone audiograms. One was previously undiagnosed and a progression was found in four. There was an overrepresentation of subclinical vestibular pathology (6 out of 9 (67%)) in this group. Audiovestibular test results showed a peripheral pattern and oculomotor tests were normal. The quality of life scores of those with hearing loss were significantly higher than those in the control group. Neuropsychological tests of brain dysfunction were abnormal in six out of 22 (27%) who had recovered from meningitis. The prevalence of such dysfunctions was not related to audiovestibular disorder. The quality of life scores of those with brain dysfunctions were similar to those of the control group. The findings of reduced auditory memory and tone level perception in four out of 22 (18%), suggest that lesions of central auditory pathways may follow from bacterial meningitis. The results support the idea that inner ear damage is the major cause of hearing loss after bacterial meningitis. Despite the absence of brainstem involvement, central nervous system lesions with disturbed auditory processing and language functions can be of significance. The high frequency of discrete brain dysfunctions indicate that a thorough neuropsychological investigation is required after bacterial meningitis.

Role of leukocytes in cerebral autoregulation and hyperemia in bacterial meningitis in rabbits

The effect of leukocytes on regional cerebral blood flow (rCBF) and cerebrovascular autoregulation in experimental meningitis was determined in rabbits. Four groups of animals were studied. Cerebrospinal fluid (CSF) leukocyte migration was prevented in two groups by pretreatment with 1.5 mg/kg of IB4, a monoclonal antibody directed against CD11/18 leukocyte adhesion receptors. Intracisternal inoculation was performed with saline (control and control-IB4 groups) or Haemophilus influenzae type b (Hib and Hib-IB4 groups). Eighteen hours later, rCBF was determined with radiolabeled microspheres. Autoregulation was assessed by graded hemorrhagic hypotension. Compared with untreated meningitis (Hib group), IB4-pretreated meningitis (Hib-IB4 group) was associated with a reduced CSF leukocyte count (1,980 +/- 880 vs. 200 +/- 110 cells/microliter; P < 0.05) and an elevated CSF colony count (2.87 +/- 0.08 vs. 5.63 +/- 0.72 log10colony-forming units/ml; P < 0.05). Compared with control, baseline CBF was elevated in both untreated and IB4-pretreated meningitis (51 +/- 2, 54 +/- 2, 66 +/- 5, and 102 +/- 17 ml.100 g-1.min-1 in control, control-IB4, Hib, and Hib-IB4 groups, respectively). The degree of hyperemia in meningitis was related to the CSF colony count, with a high CBF occurring in animals with high colony counts. During hypotension, CBF remained at or above baseline in the Hib group and both control groups, indicating preservation of cerebrovascular autoregulation in untreated Hib meningitis. In the Hib-IB4 group, the elevated baseline CBF was not maintained during hypotension, falling to 51% of baseline at a cerebral perfusion pressure of 30 mmHg and indicating impairment of cerebrovascular autoregulation. These results suggest that CSF leukocytes are not primarily responsible for the hyperemic response in Hib meningitis. Cerebral hyperemia may be induced either directly by bacterial components or indirectly by components of the inflammatory cascade that precede CSF leukocyte migration.

Hemophilus influenzae type b meningitis: pediatric overview

The authors valued the incidence and clinical therapeutic aspects of Haemophilus influenzae type b (Hib) meningitis in children. They report a retrospective study, in children, with diagnosis of acute purulent meningitis, from January 1982 to December 1994, aged between 1 month and 14 years. Particular attention was direct to Haemophilus influenzae type b meningitis (20 cases). The incidence rate of Hib meningitis in the overall cases (89) was 22.47% (20), while among children younger than 5 years Hib was the most frequently pathogen isolated (20/58-34.47%). In 1/4 of cases, particularly in children younger than 1 years, exordium was aspecific and unclear. At admission culture and examination of Cerebrospinal Fluid (CFS) have been done. CFS was cultured on blood agar and chocolate plates. A latex agglutination test was used for rapid detection of the bacterial antigens. In some cases we looked for bacterial antigens in urine. 20% of children had complications and 10% had sequelae (1 years of follow-up). We didn't have any dead. Antibiotic treatment was principally with Ampicillin, Cephalosporin and Chloramphenicol. The results of this study confirm the Hib gravity and suggest that the administration of conjugate vaccine against Hib to all living in Italy is justified.

Long-term outcome of Haemophilus influenzae meningitis in Navajo Indian children

OBJECTIVES

To determine the long-term neurologic, cognitive, and educational outcomes of Navajo children who survived Haemophilus influenzae type b meningitis.

DESIGN

Retrospective cohort study, with 3.6- to 15.0-year follow-up.

SETTING

Navajo Indian reservation.

PARTICIPANTS

Population-based cohort of 76 Navajo children with Haemophilus meningitis at less than 5 years of age between 1975 and 1986, with 41 (54%) consenting to undergo follow-up in 1990. Each case was matched to one nearest-age sibling and one unrelated age-matched control.

MAIN OUTCOME MEASURES

Standard intelligence test scores, neurologic abnormalities, and school performance.

RESULTS

The mean IQ for cases was lower than that for siblings (79 vs 87, P = .006) or age-matched controls (79 vs 95, P < .001). Twenty-nine percent of cases had severe neurologic sequelae, including mental retardation (24%), severe hearing loss (5%), cerebral palsy (7%), and seizure disorder (12%). Eight percent of siblings (relative risk for cases vs siblings, 8.0; P = .05) and 2% of age-matched controls (relative risk vs cases, 10.0; P = .01) had mental retardation. No siblings or age-matched controls had any other severe neurologic sequela. Twenty-nine percent of cases, 23% of siblings (relative risk, 2.5; P = .45), and 0% of age-matched controls (P = .001) required special education services, while 42% of cases, 23% of siblings (relative risk, 3.3; P = .10), and 11% of age-matched controls (relative risk, 4.0; P = .005) had been retained in a grade in school.

CONCLUSIONS

Navajo survivors of Haemophilus meningitis suffer more long-term neurologic, cognitive, and school-related disability than siblings or age-matched controls. They may also suffer higher morbidity than Haemophilus meningitis survivors in the general population.

Cerebrovascular responsiveness to CO2 in Haemophilus influenzae type b meningitis in rabbits

The effect of experimental meningitis on regional cerebral blood flow (rCBF), cerebral metabolic rate for oxygen (CMRO2), and cerebrovascular responsiveness to CO2 was determined in pentobarbital-anesthetized rabbits. The animals were inoculated intracisternally with saline (control) or log-phase Haemophilus influenzae type b (Hib). Eighteen hours later rCBF was determined with radiolabeled microspheres at normocapnia, hypocapnia, and hypercapnia. Cerebrovascular responses to hypocapnia and hypercapnia were assessed by calculating the change in cerebrovascular resistance per millimeter mercury change in PaCO2. At all CO2 levels, meningitis (M) was associated with elevated CBF compared with control (C: 47.5 +/- 3.0, M: 60.9 +/- 4.5 ml.100 g-1.min-1 at normocapnia, P < 0.01). Regional differences were present. In forebrain, the hyperemia in meningitis was confined to the superficial cortical grey matter. When compared with control, meningitis was not associated with altered vasoreactivity during hypocapnia (C: -0.026 +/- 0.006, M: -0.026 +/- 0.008 mmHg.ml-1 x 100 g-1.min-1.mmHg PaCO2(-1)) or hypercapnia (C: -0.037 +/- 0.004, M: -0.026 +/- 0.008 mmHg.ml-1 x 100 g.min.mmHg PaCO2(-1)). CMRO2 in meningitis was not significantly different from control (C: 3.53 +/- 0.29, M: 3.51 +/- 0.22 ml O2.100 g-1.min-1). These findings indicate that cerebrovascular responsiveness to CO2 is preserved in experimental Hib meningitis. Furthermore, enhanced CBF together with unchanged CMRO2 indicates that "luxury" cerebral perfusion is present in this model of bacterial meningitis.

Brainstem auditory evoked potentials following meningitis in children

The report concerns findings for brainstem auditory evoked potentials (BAEPs) recorded in 116 children, aged between a few days and 7 years, having suffered from bacterial meningitis. 26% of cases occurred between birth and 6 months, 55% between 6 months and 2 years, and 19% after 2 years of age. Hemophilus was the most common bacteria (49%), followed by Pneumococcus (22%) and Meningococcus (15%). Neurological complications were found in 30% of the meningitis cases and accounted for 85% of all complications found. 29% of BAEPs were abnormal, of which 47% revealed transmission, 32% endocochlear and 21% retrocochlear impairment. Transmission impairment mainly occurred before the age of 2 years (88%), most frequently in meningococcus meningitis cases (44%), and independently of neurological complications. Retrocochlear impairment was found in association with neurological complications in 71% of cases. Endocochlear BAEP damage was found in 9.5% of cases, half of which were bilateral and total, representing cophosis: it was found at all ages, and without any particular associated neurological complication. Hemophilus was the commonest bacterial agent in endocochlear cases overall, with Pneumococcus underlying 50% of cophosis cases. The study shows BAEP recording in association with a clinical ear examination is useful following childhood bacterial meningitis, screening for definitive endocochlear and deafness, distinguishing total from partial hearing-loss and indicating suitable treatment.

[Value of dexamethasone therapy in bacterial meningitis]

Due to growing understanding of pathophysiological mechanisms in acute inflammation new strategies for treatment of bacterial meningitis have been developed. The use of dexamethasone as adjunctive therapy for bacterial meningitis during the first 4 days (0.15 mg per kilogram body weight every six hours 30 min before antibiotic treatment for four days) showed a significantly reduce of neurologic sequelae in four clinical studies. A reduction of case fatality rate in more severe cases down to 50% was observed. In regard of these results the American academy of infectious diseases recommends since 1991 for children from the age of 3 month with Haemophilus influenzae meningitis a therapy regime as above.

Haemophilus influenzae type B impairment of pial vessel autoregulation in rats

To examine the mechanisms of autoregulatory impairment in meningitis, we studied the effects of Haemophilus influenzae type b (Hib) on pial vessels during hemorrhagic hypotension in rats, using a cranial window technique. We prepared cranial windows in barbiturate-anesthetized, mechanically ventilated rats. Artificial cerebrospinal fluid or 10(5) Hib in cerebrospinal fluid (n = 7 each group) was suffused over the pial surface. Pial arteriolar diameter was measured hourly for 4 h. Autoregulation was assessed as the ability of pial arterioles to dilate in response to graded hemorrhagic hypotension at 2 and 4 h. Pial arterioles exposed to Hib dilated progressively to 149 +/- 27% of baseline at 4 h. Vessel diameter in the Hib group was significantly greater than in the control group beginning at 2 h. Autoregulation was progressively impaired in Hib-exposed rats compared with control rats [-5.85 +/- 1.38 versus -8.02 +/- 2.02 and -3.82 +/- 1.57 versus -8.53 +/- 1.72% dilation/kPa fall in mean arterial blood pressure at 2 and 4 h, respectively (p < 0.05)]. These data suggest that autoregulation is impaired in pial arterioles exposed to Hib because involved vessels have a finite dilatory capacity and are close to maximal dilation before hypotensive challenge.

Modulation of blood-brain barrier permeability by tumor necrosis factor and antibody to tumor necrosis factor in the rat

In an attempt to understand the role of TNF in the central nervous system (CNS) pathophysiologic events associated with bacterial meningitis, we examined the effect of intravenous vs. intracisternal administration of TNF alpha on penetration of circulating 125I-labeled albumin into cerebrospinal fluid (CSF) and CSF white blood cell (WBC) counts in rats. Intracisternal administration of tumor necrosis factor alpha (TNF-alpha) resulted in dose- and time-dependent alterations of the CSF penetration and CSF WBCs, while intravenous administration of TNF-alpha did not induce any changes. These changes by intracisternal TNF were abolished by heat treatment of TNF or coadministration of MAb to TNF-alpha. Mab to TNF-alpha also significantly reduced the CSF penetration of circulating albumin in experimental hematogenous Haemophilus influenzae type b meningitis in infant rats but this salutary effect required both intravenous and intracisternal administration. However, MAb to TNF-alpha failed to affect CSF pleocytosis in experimental hematogenous meningitis. These findings suggest that some of CNS pathophysiologic changes in bacterial meningitis may be a result of the local production of TNF but other host inflammatory responses may also participate in CNS inflammation in hematogenous bacterial meningitis.

Evaluation of the patient with neck complaints following tonsillectomy or adenoidectomy

The emergency physician should be cognizant of the potential postoperative complications of tonsillectomy or adenoidectomy. Two unusual cases are presented to illustrate the differential diagnosis of the postoperative complaint of neck stiffness.

[Value of corticosteroids in bacterial meningitis]

Bacterial meningitis mortality largely results from the intense host inflammation response to infection. Lysis of bacteria releases bacterial components that stimulate production of cytokines. Cerebrospinal fluid concentrations of these cytokines have been shown to correlate with the severity of the meningitis in both experimental and clinical situations. Dexamethasone has an antiinflammatory effect superior to methylprednisolone. It is the only agent with which significant clinical studies have yet been performed. A recent study recommends the routine use of dexamethasone with Haemophilus influenzae meningitis. The immediate and long-term clinical profiles indicate significantly better outcomes for the dexamethasone group. It is prudent to administer dexamethasone before the first parenteral dose of antibiotic to prevent the release of bacterial components induced by bacterial lysis. The search for agents that down modulate inflammation more strongly continues. Some monoclonal antibodies are superior to dexamethasone in experimental meningitis without modification of antibiotic pharmacokinetics.

Precise quantification of fever in childhood bacterial meningitis

Precise quantity of fever was determined in 191 cases of childhood bacterial meningitis by calculating the areas between the line indicating 37.8 degrees C or 39.5 degrees C temperature and the line connecting all individual temperature values. Temperature measurements were performed rectally one to four times a day throughout the hospitalization. The obtained areas under the curves (AUC), expressed as degree-hours, proved to be a sensitive index for delineating each individual fever pattern and reflected the magnitude of fever more precisely than the traditional fever curves. Children under five had significantly (p less than 0.05) greater AUC than those at five to 15 years; similarly, patients with Haemophilus influenzae meningitis showed greater AUC (i.e., had more fever) than those with meningococcal disease (p less than 0.05). The overall rates of secondary (14%), persistent (16%), and prolonged fever (8%) were virtually identical to previous reports; no drug fever was reported in this study. In cases with prolonged fever, a significantly higher rate (40%) of neurological complications was found compared to those who became afebrile earlier. This method is potentially utilizable in other diseases and conditions where precise measurement of fever is of clinical or scientific relevance.

Blood-brain barrier alterations in bacterial meningitis: development of an in vitro model and observations on the effects of lipopolysaccharide

To further examine the effects of purified Haemophilus influenzae type b lipopolysaccharide (LPS) on blood-brain barrier permeability, we have developed an in vitro model of the BBB. Microvascular endothelial cells were isolated from rat cerebral cortices by enzymatic digestion, dextran centrifugation, and separation on percoll gradients. The cells were determined to be endothelial in origin by positive fluorescent staining for Factor VIII-related antigen and the ability to take up acetylated low density lipoproteins, and their cerebral origin by the formation of junctional complexes in vitro. Cells were seeded onto semipermeable polycarbonate filters and permeability assessed by measuring traversal of radioactive albumin across the monolayer. Treatment of the cells with LPS at concentrations of 1.0 microgram/ml and 0.1 microgram/ml for 4 h led to statistically significant increases in albumin permeability of 4.6% (P = 0.001) and 5.6% (P less than 0.001), respectively, without evidence of cell death as assessed by release of lactate dehydrogenase into the media. These results indicate that LPS significantly increases albumin permeability across a monolayer of cerebral microvascular endothelial cells in the absence of host inflammatory cells. Future studies on the effects of LPS on intracellular regulation will determine the mechanisms responsible for these alterations.

Modulation of inflammation and cachectin activity in relation to treatment of experimental Hemophilus influenzae type b meningitis

By use of an experimental lapin model, the effect of ceftriaxone therapy on inflammation during Hemophilus influenzae type b (Hib) meningitis was evaluated. Meningitis was induced by intracisternal inoculation of 2 x 10(4) to 2 x 10(5) colony-forming units of Hib. Administration of ceftriaxone 6 h after infection provoked rapid bacterial lysis associated with greatly increased concentrations of bacteria-free endotoxin (lipooligosaccharide) and tumor necrosis factor alpha (TNF) in the cerebrospinal fluid (CSF). CSF TNF activity peaked 2 h after initiation of antibiotic therapy (24.4 +/- 2 ng/ml), was significantly higher than that in untreated controls (1.4 +/- 1.1 ng/ml; P less than .05), and was associated with a substantially increased inflammatory response as reflected by higher CSF white blood cell count (24,500 +/- 8,151 vs. 1,920 +/- 644 in untreated controls; P less than .05), lower glucose, and higher protein and lactate concentrations. Simultaneous administration of dexamethasone with antibiotic therapy resulted in a significant reduction in CSF TNF activity that was associated with a substantial reduction in CSF white blood cell count. These data suggest that initiation of ceftriaxone therapy in experimental Hib meningitis exacerbates the meningeal inflammatory response, which can be modulated by concurrent dexamethasone administration.

Haemophilus influenzae outer membrane vesicle-induced blood-brain barrier permeability during experimental meningitis

Haemophilus influenzae type b (Hib) lipopolysaccharide (LPS) may be present in the cerebrospinal fluid largely as part of outer membrane vesicles (OMV), which could possibly alter its activity. Similar to inoculation of purified Hib LPS, intracisternal inoculation of Hib OMV into adult rats resulted in dose- and time-dependent increases in blood-brain barrier permeability. Polymyxin B, but not an oligosaccharide-specific monoclonal antibody, significantly inhibited the activity of Hib OMV. No change in blood-brain barrier permeability occurred in leukopenic rats inoculated with Hib OMV. Hib OMV was as active as purified Hib LPS on a weight basis and therefore appears to be a relevant vehicle for the delivery of LPS during meningitis.

Brain edema and increased intracranial pressure in the pathophysiology of bacterial meningitis

A number of advances in our understanding of the pathophysiology of bacterial meningitis have been made in recent years. In vivo studies have shown that bacterial cell wall fragments and endotoxins are highly active components, independent of the presence of viable bacteria in the subarachnoid space. Their presence in the cerebrospinal fluid is associated with the induction of inflammation and with the development of brain edema and increased intracranial pressure. Antimicrobial therapy may cause an additional increase of harmful bacterial products in the cerebrospinal fluid and thereby potentiate these pathophysiological alterations. These changes may contribute to the development of brain damage during meningitis. Some promising experimental work has been directed toward counteracting the above phenomena with non-steroidal or steroidal anti-inflammatory agents as well as with monoclonal antibodies. Although considerable advances have been made, further research needs to be done in these areas to improve the prognosis of bacterial meningitis.

The use of CSF pressure recordings in acute purulent meningitis

Non-fluid displacing pressure transducers can be applied to a spinal needle at LP and direct CSF pressure recordings obtained routinely. The method is particularly applicable to children with suspected meningitis and is both a safer and a more accurate estimate of CSF pressure. Children with acute purulent meningitis frequently have raised intracranial pressure on presentation and Mannitol infusion during the LP recording is useful in returning the pressure to normal.

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.

The management of fulminant meningitis in the intensive care unit

Fulminant meningitis requires aggressive management in an intensive care unit setting. The pathophysiology of the various factors that damage the central nervous system in this disease have been reviewed, as well as the management of the many complications of this serious, often devastating, infection. The etiologic agents according to age group have been discussed, and recommendations for empiric therapy have been made.

Hemophilus influenzae meningitis in the rat: behavioral, electrophysiological, and biochemical consequences

Hemophilus influenzae is the most common cause of bacterial meningitis in children, and a high percentage of survivors are at risk for long-term sequelae. To explore the mechanisms responsible for these sequelae, a neonatal rat model was used to define the behavioral, electrophysiological, and biochemical changes following meningitis. Three days after inoculation of 6-day-old rats with a minimum of 1 X 10(7) colony-forming units of a virulent Hemophilus influenzae, type b, cerebrospinal fluid and blood were cultured to confirm the presence of meningitis and bacteremia, respectively. At this time, forebrain norepinephrine and dopamine levels were significantly elevated in meningitic rats when standardized on a wet-weight basis. No changes in brain serotonin or heart norepinephrine levels could be found in the 9-day-old rats. No residual changes were found in steady-state concentrations of norepinephrine or dopamine in surviving adult rats. However, survivors that had had meningitis as neonates showed significant impairment in active and passive avoidance learning tasks and demonstrated a significantly higher level of activity during a habituation period in circular photocell activity cages. No change in the flinch-jump threshold was detected. Brainstem auditory evoked potentials showed delays of various waves in 3 of 10 Hemophilus influenzae type b-treated adult rats tested. These rats also exhibited markedly augmented locomotory responses to d-amphetamine (1 mg/kg), suggesting a long-lasting perturbation of central monoamine neuronal transmission.

Adult meningitis caused by Hemophilus influenzae serotype f, biotype I

Meningitis and septicemia developed in an adult patient as a complication of otitis media. The rare etiologic agent responsible for the infection was identified as Hemophilus influenzae serotype f, biotype I. With appropriate therapy, complete recovery was achieved without complications or relapse.

Cerebral infarction in Hemophilus influenzae type B meningitis

Over a 5-year period, 8 (4.7%) of the 170 children diagnosed at Milwaukee Children's Hospital as having Hemophilus influenzae type b (HITB) meningitis developed cerebral infarction. Compared with children who did not develop infarcts or with children who developed other neurologic complications, such as subdural effusion, empyema, or meningoencephalitis, these children had significantly higher cerebrospinal fluid (CSF) leukocyte counts on initial lumbar puncture and had a greater likelihood of seizure activity. In seven of eight patients with cerebral infarction, a focal or generalized seizure heralded neurologic findings associated with abnormal radiographic studies. Two of the eight patients died, and two were permanently severely damaged. In the other four patients, there was eventual recovery from gross neurologic deficits. The mortality in patients with HITB meningitis complicated by cerebral infarction (25%) was significantly greater than that in other patients with HITB meningitis (0.6%). The pathophysiology of infarction in patients with bacterial meningitis is uncertain but may in part relate to arteriospasm. Cerebral infarction is a serious, and in the present experience, not uncommon complication of H. influenzae meningitis.

Haemophilus influenzae meningitis: a 5-year study in Ibadan, Nigeria

A total of 131 children with Haemophilus influenzae meningitis was studied over a period of 5 years. Of these, 92% and of those who died from this disease, 94% were 2 years old or less. Mortality was 26% and morbidity among the survivors was 36%. Most of the children studied were marasmic. The seasonal incidence is discussed since incidence peaked mainly in the dry season with a secondary peak in the rainy season. Haemoglobin (H6) electrophoresis, done in respect of a few children, showed a significantly higher incidence of Hb SS among patients than in the general population. This relationship is being studied further. The prognosis did not appear to be significantly affected by the choice between a combination of penicillin and chloramphenicol on the one hand and ampicillin alone on the other. A combination of penicillin and chloramphenicol is preferred to chloramphenicol alone in initiating therapy because 100% of strains of H. influenzae isolated in our laboratory are susceptible to chloramphenicol but only 75% of strains of Streptococcus pneumoniae are susceptible to this drug.

Hemophilus aphrophilus meningitis followed by vertebral osteomyelitis and suppurative psoas abscess

Hemophilus aphrophilus is an uncommon pathogen in man. It has rarely been reported as a cause of meningitis, exclusively in boys three years or younger. Osteomyelitis due to this organism is also rare. H. aphrophilus was responsible for meningitis, probable thoracic empyema, and ultimately vertebral osteomyelitis and suppurative psoas abscess formation in a woman following metrizamide myelography. The patient responded well to antibiotic treatment and surgical drainage. The organism was sensitive not only to chloramphenicol but also to newer cephalosporin antibiotics.

Bacterial meningitis in infancy: effects on intracranial pressure and cerebral blood flow velocity

The effects of acute bacterial meningitis on intracranial pressure (ICP) and cerebral blood flow velocity (CBFV) were studied in four older infants (mean age, 5.75 months) and in four newborns. ICP and CBFV were affected in the older infants, but not in the newborns. In the older infants, ICP was markedly elevated in the first 2 days of illness (mean peak ICP, 240 mm H2O). With resolution of intracranial hypertension in the next few days, CBFV increased approximately 80%. In the newborns, there was no marked elevation of ICP or change in CBFV. Impaired cerebral perfusion, due to intracranial hypertension, is a potential cause of brain injury in older infants. Other mechanisms of brain injury may be more important in newborns.

Fulminating haemophilus influenzae b meningitis

Haemophilus influenzae type b (HIb) is the most common cause of bacterial meningitis in children with a mortality rate ranging from 1.6% to 14%. Most patients have a 2-3 day history of symptoms prior to admission. A few have fulminating disease with rapid neurological deterioration. Review of 191 cases of HIb meningitis revealed a mortality rate of 2.1% but all who died had fulminating meningitis (FM). Four of six patients with FM died. FM patients had symptoms for less than 24 hours before rapid neurological deterioration with increased ICP, seizures, coma and/or respiratory arrest. Review of 10 FM cases revealed that on admission, 5 had hypotension, 3 had thrombocytopenia, and 8 had coma. Typical CSF changes were seen in only 7. All fatal cases died within 24 hours. Brain swelling and tonsillar herniation were found at autopsy. SDS-PAGE outer membrane protein subtyping did not show one "killer strain". Animal and autopsy data suggest that diminished CSF outflow and cerebral edema contribute to increased ICP. To improve survival of FM patients, initial treatment must (1) decrease ICP below levels impairing cerebral perfusion, (2) maintain adequate ventilation and blood pressure, and include (3) LP when stable, (4) antibiotics, and (5) close monitoring. Utilizing these principles, two FM patients survived without major sequelae.

Prolonged course of meningitis due to an arachnoid cyst

An infected arachnoid cyst was found in a child with bacterial meningitis and prolonged fever. Surgical drainage of the cyst resulted in rapid improvement.

Auditory evoked potentials in bacterial meningitis

Auditory evoked potentials obtained on infants and children recovering from bacterial meningitis are effective in early and reliable detection of sensorineural deafness, particularly in those who demonstrate absence of wave I.

Spinal cord involvement in acute bacterial meningitis

A 25-month-old boy had the development of respiratory arrest and quadriplegia with a T-10 sensory level during the acute phase of Haemophilus influenzae meningitis. The sequelae of spinal cord involvement of bacterial meningitis are reviewed. A possible mechanism of the spinal cord involvement in this case is discussed with reference to known pathology of H influenzae meningitis.

Haemophilus influenzae b infection in rats: effect of splenectomy on bloodstream and meningeal invasion after intravenous and intranasal inoculations

We investigated the effect of splenectomy on the susceptibility of rats to intravenous or intranasal inoculation of Haemophilus influenzae, type b. The 50% lethal dose for asplenic rats inoculated either by intravenous (i.v.) (10(4.7)) or intranasal (i.n.) (10(4.6)) injection was similar, but significantly lower than the 50% lethal dose value in sham-operated rats (10(8.6) i.v. and 10(9.0) i.n.). Mean survival time was significantly longer for asplenic rats inoculated i.n. (49.3 h) compared to asplenic rats inoculated i.v. (24.4h). Similarly, sham-operated rats inoculated i.n. survived significantly longer after i.n. challenge (mean survival time, 171.4 h) than after i.v. challenge (34.7 h). Bacteremia was detected in 100% of asplenic rats and in 80% of sham-operated rats. The geometric mean number of bacteria in the blood of asplenic rats (10(4.90) per ml) was significantly greater than in sham-operated rats (10(3.29) per ml). Meningitis was detected in 7 of 15 randomly sacrificed asplenic rats, whereas none of 15 sham-operated rats had evidence of meningeal invasion. Thus, the asplenic rat was more susceptible to experimentally induced H. influenzae bacteremia, meningitis, and fatal sepsis and offers a biologically relevant experimental model for investigating the role of the spleen in defense against infection with encapsulated bacteria.

Haemophilus influenzae meningitis in adults

Haemophilus influenzae meningitis though common in childhood is rarely seen in the adult. During the past four years eight cases of H. influenzae meningitis have been seen in St. Thomas's Hospital and four of these were in patients over 20 years old. There was a possible predisposing condition in two patients. In each case there was difficulty in identification of the organism in the Gram-stained film of the cerebrospinal fluid deposit.