Prospective evaluation of treatment of Hemophilus influenzae meningitis

Antibiotic regimens for early-onset neonatal sepsis

BACKGROUND

Neonatal sepsis is a major cause of morbidity and mortality. It is the third leading cause of neonatal mortality globally constituting 13% of overall neonatal mortality. Despite the high burden of neonatal sepsis, high-quality evidence in diagnosis and treatment is scarce. Possibly due to the diagnostic challenges of sepsis and the relative immunosuppression of the newborn, many neonates receive antibiotics for suspected sepsis. Antibiotics have become the most used therapeutics in neonatal intensive care units. The last Cochrane Review was updated in 2004. Given the clinical importance, an updated systematic review assessing the effects of different antibiotic regimens for early-onset neonatal sepsis is needed.

OBJECTIVES

To assess the beneficial and harmful effects of different antibiotic regimens for early-onset neonatal sepsis.

SEARCH METHODS

We searched the following electronic databases: CENTRAL (2020, Issue 8); Ovid MEDLINE; Embase Ovid; CINAHL; LILACS; Science Citation Index EXPANDED and Conference Proceedings Citation Index - Science on 12 March 2021. We searched clinical trials databases and the reference lists of retrieved articles for randomised controlled trials (RCTs) and quasi-RCTs.

SELECTION CRITERIA

We included RCTs comparing different antibiotic regimens for early-onset neonatal sepsis. We included participants from birth to 72 hours of life at randomisation.

DATA COLLECTION AND ANALYSIS

Three review authors independently assessed studies for inclusion, extracted data, and assessed risk of bias. We used the GRADE approach to assess the certainty of evidence. Our primary outcome was all-cause mortality, and our secondary outcomes were: serious adverse events, respiratory support, circulatory support, nephrotoxicity, neurological developmental impairment, necrotising enterocolitis, and ototoxicity. Our primary time point of interest was at maximum follow-up.

MAIN RESULTS

We included five RCTs (865 participants). All trials were at high risk of bias. The certainty of the evidence according to GRADE was very low. The included trials assessed five different comparisons of antibiotics. We did not conduct any meta-analyses due to lack of relevant data. Of the five included trials one trial compared ampicillin plus gentamicin with benzylpenicillin plus gentamicin; one trial compared piperacillin plus tazobactam with amikacin; one trial compared ticarcillin plus clavulanic acid with piperacillin plus gentamicin; one trial compared piperacillin with ampicillin plus amikacin; and one trial compared ceftazidime with benzylpenicillin plus gentamicin. None of the five comparisons found any evidence of a difference when assessing all-cause mortality, serious adverse events, circulatory support, nephrotoxicity, neurological developmental impairment, or necrotising enterocolitis; however, none of the trials were near an information size that could contribute significantly to the evidence of the comparative benefits and risks of any particular antibiotic regimen. None of the trials assessed respiratory support or ototoxicity. The benefits and harms of different antibiotic regimens remain unclear due to the lack of well-powered trials and the high risk of systematic errors.

AUTHORS' CONCLUSIONS

Current evidence is insufficient to support any antibiotic regimen being superior to another. Large RCTs assessing different antibiotic regimens in early-onset neonatal sepsis with low risk of bias are warranted.

Antibiotic regimens for late-onset neonatal sepsis

BACKGROUND

Neonatal sepsis is a major cause of morbidity and mortality. It is the third leading cause of neonatal mortality globally constituting 13% of overall neonatal mortality. Despite the high burden of neonatal sepsis, high-quality evidence in diagnosis and treatment is scarce. Due to the diagnostic challenges of sepsis and the relative immunosuppression of the newborn, many neonates receive antibiotics for suspected sepsis. Antibiotics have become the most used therapeutics in neonatal intensive care units, and observational studies in high-income countries suggest that 83% to 94% of newborns treated with antibiotics for suspected sepsis have negative blood cultures. The last Cochrane Review was updated in 2005. There is a need for an updated systematic review assessing the effects of different antibiotic regimens for late-onset neonatal sepsis.

OBJECTIVES

To assess the beneficial and harmful effects of different antibiotic regimens for late-onset neonatal sepsis.

SEARCH METHODS

We searched the following electronic databases: CENTRAL (2021, Issue 3); Ovid MEDLINE; Embase Ovid; CINAHL; LILACS; Science Citation Index EXPANDED and Conference Proceedings Citation Index - Science on 12 March 2021. We also searched clinical trials databases and the reference lists of retrieved articles for randomised controlled trials (RCTs) and quasi-RCTs.

SELECTION CRITERIA

We included RCTs comparing different antibiotic regimens for late-onset neonatal sepsis. We included participants older than 72 hours of life at randomisation, suspected or diagnosed with neonatal sepsis, meningitis, osteomyelitis, endocarditis, or necrotising enterocolitis. We excluded trials that assessed treatment of fungal infections.

DATA COLLECTION AND ANALYSIS

Three review authors independently assessed studies for inclusion, extracted data, and assessed risk of bias. We used the GRADE approach to assess the certainty of evidence. Our primary outcome was all-cause mortality, and our secondary outcomes were: serious adverse events, respiratory support, circulatory support, nephrotoxicity, neurological developmental impairment, necrotising enterocolitis, and ototoxicity. Our primary time point of interest was at maximum follow-up.

MAIN RESULTS

We included five RCTs (580 participants). All trials were at high risk of bias, and had very low-certainty evidence. The five included trials assessed five different comparisons of antibiotics. We did not conduct a meta-analysis due to lack of relevant data. Of the five included trials one trial compared cefazolin plus amikacin with vancomycin plus amikacin; one trial compared ticarcillin plus clavulanic acid with flucloxacillin plus gentamicin; one trial compared cloxacillin plus amikacin with cefotaxime plus gentamicin; one trial compared meropenem with standard care (ampicillin plus gentamicin or cefotaxime plus gentamicin); and one trial compared vancomycin plus gentamicin with vancomycin plus aztreonam. None of the five comparisons found any evidence of a difference when assessing all-cause mortality, serious adverse events, circulatory support, nephrotoxicity, neurological developmental impairment, or necrotising enterocolitis; however, none of the trials were near an information size that could contribute significantly to the evidence of the comparative benefits and risks of any particular antibiotic regimen. None of the trials assessed respiratory support or ototoxicity. The benefits and harms of different antibiotic regimens remain unclear due to the lack of well-powered trials and the high risk of systematic errors.

AUTHORS' CONCLUSIONS

Current evidence is insufficient to support any antibiotic regimen being superior to another. RCTs assessing different antibiotic regimens in late-onset neonatal sepsis with low risks of bias are warranted.

Scientific Basis of Hyponatremia and Its Clinical Presentations

Purpose

To describe causes, pathophysiologic mechanisms, and classifications of hyponatremia, and to describe clinical symptoms and underlying disease states associated with different levels of hyponatremia.

Summary

The key to comprehending hyponatremia is to understand body water content and plasma osmolality and accurately assess arterial volume. Hyponatremia results from sodium dilution because of retained water or sodium depletion because of electrolyte loss in excess of water loss. Body sodium, water, and extracellular fluid (ECF) volume are tightly regulated by mechanisms that act to maintain a closely controlled concentration of solutes in the ECF. These forces act to regulate water content and sodium excretion to maintain normal intravascular volume. The body closely defends normal plasma osmolality within a narrow range primarily by controlling the release of arginine vasopressin (AVP) and via the thirst mechanism. A number of factors can stimulate inappropriate AVP release and cause or worsen hyponatremia. Dysregulation of AVP plays an important role in heart failure and cirrhosis, common causes of hypervolemic hyponatremia.

Conclusion

Body water content and plasma osmolality are tightly regulated by the action of AVP. A variety of disease states are associated with hyponatremia related to inappropriate AVP release. The cause of the electrolyte disturbance must be determined, because it can have profound implications for treatment. Differential diagnosis can be guided by observation of the rapidity of onset as well as volume status changes. If untreated or treated inappropriately, hyponatremia can impact morbidity and mortality.

Global and regional risk of disabling sequelae from bacterial meningitis: a systematic review and meta-analysis

Few data sources are available to assess the global and regional risk of sequelae from bacterial meningitis. We aimed to estimate the risks of major and minor sequelae caused by bacterial meningitis, estimate the distribution of the different types of sequelae, and compare risk by region and income. We systematically reviewed published papers from 1980 to 2008. Standard global burden of disease categories (cognitive deficit, bilateral hearing loss, motor deficit, seizures, visual impairment, hydrocephalus) were labelled as major sequelae. Less severe, minor sequelae (behavioural problems, learning difficulties, unilateral hearing loss, hypotonia, diplopia), and multiple impairments were also included. 132 papers were selected for inclusion. The median (IQR) risk of at least one major or minor sequela after hospital discharge was 19.9% (12.3-35.3%). The risk of at least one major sequela was 12.8% (7.2-21.1%) and of at least one minor sequela was 8.6% (4.4-15.3%). The median (IQR) risk of at least one major sequela was 24.7% (16.2-35.3%) in pneumococcal meningitis; 9.5% (7.1-15.3%) in Haemophilus influenzae type b (Hib), and 7.2% (4.3-11.2%) in meningococcal meningitis. The most common major sequela was hearing loss (33.9%), and 19.7% had multiple impairments. In the random-effects meta-analysis, all-cause risk of a major sequela was twice as high in the African (pooled risk estimate 25.1% [95% CI 18.9-32.0%]) and southeast Asian regions (21.6% [95% CI 13.1-31.5%]) as in the European region (9.4% [95% CI 7.0-12.3%]; overall I(2)=89.5%, p<0.0001). Risks of long-term disabling sequelae were highest in low-income countries, where the burden of bacterial meningitis is greatest. Most reported sequelae could have been averted by vaccination with Hib, pneumococcal, and meningococcal vaccines.

Psychometric testing in bacterial meningitis: results of a long-term prospective study of infants and children treated between 1973 and 1977

Acute bacterial meningitis can result in structural damage to the nervous system with associated functional derangements. Neurologic abnormalities can be transient, although some sequelae, including lasting impairment in cognition and behavior, may be permanent. 1,2 In this brief report, we present the results of psychometric testing of patients conducted over a 5-year period in our prospective study of acute bacterial meningitis begun in 1973.

The syndrome of inappropriate secretion of antidiuretic hormone and fluid restriction in meningitis--how strong is the evidence?

In patients with meningitis, fluid restriction is recommended to counter the syndrome of inappropriate secretion of antidiuretic hormone (SIADH) and to reduce cerebral oedema. However, any effects of an increased plasma level of ADH upon cerebral oedema would be due not to fluid retention but to hypoosmolality. In a literature review of fluid and electrolyte disturbances and the effect of fluid therapy in bacterial/tuberculous meningitis, the prevalence of hyponatraemia, hypoosmolality and SIADH varied considerably; apparently, non-osmotic stimuli for the secretion of ADH, e.g. intracranial hypertension and hypovolaemia, were present in most patients. Neither clinical nor experimental studies have confirmed that fluid restriction reduces the cerebral oedema in meningitis. Furthermore, compared with maintenance therapy, fluid restriction did not improve outcome in a randomized controlled study. Thus, we find no evidence to support the use of fluid restriction in patients with meningitis. Fluid therapy in acute bacterial meningitis should aim at avoiding hypovolaemia and hypoosmolality based on the assumptions that (i) ADH is increased by non-osmotic stimuli; (ii) elevated ADH is less important for cerebral oedema than severe hypoosmolality, which may in itself induce or aggravate oedema; (iii) maintenance fluid therapy aiming at isoosmolality will not worsen neurological outcome; and (iv) hypovolaemia is difficult to detect, and detrimental for cerebral perfusion, in these patients.

[Hydration and meningitis]

For almost 20 years, fluid restriction has been applied in the management of bacterial meningitis. This recommendation was based upon the findings of elevated plasma levels of arginine vasopressin in children with bacterial meningitis and their interpretation as evidence for inappropriate secretion of antidiuretic hormone. Recent data indicate that this interpretation was erroneous and that elevated levels of arginine vasopressin is the consequence of hypovolemia in the majority of cases of bacterial meningitis. In addition, fluid restriction appears to worsen the prognosis. As a consequence, not only fluid restriction must not be systematically applied in the management of bacterial meningitis, but appropriate fluid and sodium intakes are necessary to compensate hypovolemia and dehydration. Only a small number of cases with evidence of inappropriate secretion of antidiuretic hormone will require fluid restriction.

Childhood bacterial meningitis in Saudi Arabia

This study analysed the bacterial aetiology and outcome of childhood meningitis observed over an 11-year period. Charts of 70 children with this diagnosis were reviewed. Three children were under 1 month of age, five were between 1 and 3 months and 60 were between 3 months and 5 years. The remaining two were over 5 years. There were 36 females and 34 males. The presenting symptoms in decreasing order of frequency were fever 86%, vomiting 29%, poor feeding 19%, seizure 14% and lethargy 14%. Aetiological organisms were as follows: Haemophilus influenzae 66%, Streptococcus pneumoniae 24%, Neisseria meningitidis 4%, Group B Streptococci 4%, and Staphylococcus aureus 2%. All H. influenzae isolates except one were sensitive to ampicillin. None of the S. pneumoniae isolates were resistant to penicillin. Complications occurred in 26% of the patients and included subdural effusion 23%, hearing loss 14%, seizure disorder 10%, developmental delay 9%, hydrocephalus 6% and motor deficit 30%. One patient died. Among H. influenzae cases, one of the 15 patients treated with steroids developed hearing loss. In contrast, four out of 31 who did not receive steroid therapy suffered from hearing loss. Haemophilus influenzae type b is the predominant cause of childhood bacterial meningitis in Saudi Arabia. Universal H. influenzae type b vaccination for children is highly recommended.

Acute-phase neurologic complications of Haemophilus influenzae type b meningitis: association with developmental problems at school age

The purposes of this study were to describe the incidence of acute-phase neurologic complications in a sample of 126 children with Haemophilus influenzae type b meningitis, and to determine if these complications were associated with higher rates of learning and behavior problems at school age. Risks were assessed by comparing rates of adverse psychoeducational outcomes in the 53 children in the sample with complications to corresponding outcome rates in the 67 children who were free of neurologic complications and who did not have abnormal electroencephalograms (EEGs) or computed tomographic (CT) scans. Comparisons were made by means of logistic regression analysis. Twenty-nine children (23% of the sample) had seizures, 16 (13%) were comatose or obtunded, 15 (12%) had sensorineural hearing loss, 8 (6%) had hemiparesis, and 7 (6%) had cranial nerve deficits other than hearing loss. Relative to children without complications, those with complications had higher rates of grade repetition and substandard performance on neuropsychological and achievement testing. Adverse outcomes, however, consisted primarily of more subtle cognitive and learning problems; only two of the children in the sample obtained prorated IQ scores below 70. Sequelae were associated with persistent neurologic deficits and bilateral hearing loss, as well as with transient symptoms including seizures, coma, and hemiparesis. While study findings argue against adverse consequences for the vast majority of children treated for this disease, the results clarify learning and behavior outcomes and indicate which children are at greatest risk.

Epilepsy after central nervous system infection: clinical characteristics and outcome after epilepsy surgery

Fifty-six (5.8%) patients with partial epilepsy secondary to central nervous system (CNS) infection (meningitis = 20 and encephalitis = 36) were identified from 963 patients studied with prolonged video-EEG monitoring. Twenty-seven (48.2%) patients had unilateral mesial temporal lobe epilepsy (UMTLE), 9 (16.1%) had bilateral mesial temporal lobe epilepsy (BMTLE), and 20 (35.7%) had neocortical epilepsy (NE). Younger age at infection and prolonged latency between the time of infection and development of epilepsy were predictive factors for UMTLE. Predictors for BMTLE were late age of infection and short latency between infection and epilepsy development. Development of NE was associated with short latency between infection and epilepsy, and younger age at infection. When outcome after temporal lobectomy was compared between the UMTLE group and a control group with UMTLE without history of CNS infection, no statistically significant differences were found. Central nervous system infection may lead to epilepsy, which in many cases, is generated by a single portion of the brain. In such cases, epilepsy surgery should be considered, as in patients without history of CNS infection.

Risk factors for adverse outcomes of bacterial meningitis

OBJECTIVE

To identify risk factors for adverse outcomes from bacterial meningitis.

METHODOLOGY

From a cohort of 166 children with bacterial meningitis who were studied prospectively, 130/158 (82%) survivors underwent neurological, neuropsychological, audiological and behaviour assessments 5-9 years following their illness.

RESULTS

Major adverse outcomes included B/166 (4.8%) deaths and severe neurological, intellectual or audiological sequelae in 11/130 (8.5%) children followed. Another 24 (18.5%) had cognitive, auditory or behaviour disorders. Bivariate analysis found age < or = 12 months, tertiary referral, symptoms > 24 h before diagnosis, seizures, focal neurological signs, deteriorating conscious state in hospital, Streptococcus pneumoniae infection and serum sodium concentration < 130 mmol/L were associated with adverse outcomes. Multivariate analysis showed age < or = 12 months, symptoms > 24 h, seizures after 72 h in hospital and focal neurological signs as independent risk factors. These were present in 18/19 (95%) children with major sequelae, but absent in 9/24 (37.5%) children with minor disabilities.

CONCLUSIONS

As minor disabilities following meningitis cannot be predicted, all survivors require assessment during their early school years.

Long-term sequelae of pneumococcal meningitis in children

The purpose of this study was to assess the long-term effects of pneumococcal meningitis in children. From 1967 to 1988, a total of 90 children were admitted to the Hospital for Infectious Diseases, Thessaloniki, Greece, with the diagnosis of pneumococcal meningitis. Sixteen patients died in the hospital as a direct result of meningitis. Eleven others were excluded from the study (neurologic deficits prior to onset of meningitis, two; death subsequent to hospitalization, two; recurrent meningitis, seven). Of the remaining 63 survivors, we were able to evaluate 47 patients (75%). Evaluation was performed 4 to 23 years (mean 12.3 +/- 5.8 years) after discharge. Forty patients returned to hospital for evaluation, and seven were evaluated by their primary physicians, who sent information by a standardized questionnaire. The following examinations were carried out: history, physical and neurologic examination, ophthalmologic and hearing evaluation, and psychometric testing. Fourteen patients (30%) had at least one neurologic handicap; nine (19%) had mental retardation, eight (17%) hearing loss, seven (15%) seizure disorder, five (11%) motor defects, and one each (2%) behavioral problems and visual impairment. The presence of coma was the strongest predictor of increased morbidity. The high frequency of long-term sequelae observed in our study supports the need of an effective vaccine.

Survival and functional outcome of children requiring mechanical ventilation during therapy for acute bacterial meningitis

OBJECTIVE

To determine predictors of survival and functional outcome of pediatric patients requiring mechanical ventilation during therapy for acute bacterial meningitis.

DESIGN

Retrospective case series.

SETTING

Pediatric intensive care unit (ICU) at a midwestern tertiary care children's hospital.

PATIENTS

Consecutive sample of 32 patients (median age 9.8 months; range 9 days to 12 yrs) from 1985 to 1990 with acute bacterial meningitis severe enough to require mechanical ventilation during therapy. Of these patients, 59% were female and 59% were white.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Data were analyzed to identify predictors of survival and functional status after hospital discharge. Variables included were vital signs, Pediatric Risk of Mortality (PRISM) score within the first 24 hrs of hospitalization, Glasgow Coma Score, and course of illness. Functional status was assessed at hospital discharge and at follow-up (median follow-up: 41.5 months, range 7 to 77) in the areas of locomotion, self-care, and communication. There were ten inhospital deaths. The 22 survivors formed three groups. At hospital discharge, seven children showed no functional disability. Seven patients were dependent in all three areas of function at discharge, with six still dependent at follow-up evaluation. Eight patients showed mild to moderate impairment in at least one area of function at hospital discharge. At follow-up, four of these eight patients demonstrated no functional disability, one had improved status, two were unchanged, and one was lost to follow-up. The best predictor of death and functional status at follow-up was the admission PRISM score. Hypotension and tachycardia within the first 24 hrs after pediatric ICU admission were strongly associated with poor outcome.

CONCLUSIONS

After bacterial meningitis in children whose care included mechanical ventilation, half of the patients died or survived with severe functional deficits. Patients with mild or moderate functional deficits at hospital discharge improved with time.

Inappropriate secretion of antidiuretic hormone in acute bacterial meningitis

Sixty children aged from 1 month to 12 years (mean (SD) 3.18 (3.49) years) with acute bacterial meningitis were studied for the incidence, clinical manifestations and outcome of the inappropriate secretion of antidiuretic hormone syndrome (SIADH). Serum sodium levels and osmolality of serum and urine were estimated on admission and on days 3 and 10. SIADH was diagnosed in 22 out of 60 cases (36.7%) on admission and in six of 48 cases (12.5%) on day 3. Hyponatraemia without SIADH, attributed to vomiting and fever, was detected in seven cases (11.7%). Serum sodium levels returned to normal within 48 hours in these cases. Serum osmolality and sodium levels took longer to return to normal values in patients with SIADH. However, none of the cases showed any evidence of SIADH on the 10th day. A significant correlation with SIADH was observed in cases with evidence of severe meningeal inflammation (p < 0.001). The incidence of SIADH was highest with Streptococcus pneumoniae (75%), followed by Haemophilus influenzae (57.1%). Overall mortality was 26.7%, and mortality was significantly higher (p < 0.001) in cases with SIADH, all of whom died during the 1st 72 hours. Ten out of 22 cases (45.4%) with SIADH who survived beyond the 1st 72 hours had an uneventful course even though all of them had biochemical evidence of SIADH on the 3rd day. Mortality was quite high also in children with severe malnutrition (75%) and in those with S. pneumoniae as the aetiological organism (75%).

Cost benefit analysis of Haemophilus influenzae type b vaccination programme in Israel

STUDY OBJECTIVE

The recent availability of Haemophilus influenzae type b (HIB) conjugate vaccines prompted an examination of the costs and benefits of four and three dose HIB prevention programmes targeting all newborns in Israel.

MEASUREMENTS AND MAIN RESULTS

A four dose programme would reduce the number of childhood (aged 0-13) HIB cases from 184.2 to 31.3 per year, yielding a benefit ($1.03 million) to cost ($3.55 million) ratio of just 0.29/l for health services only, based on a vaccine price of $7.74 per dose. When benefits resulting from a reduction in mild handicaps and severe neurological sequelae are included, the benefit ($4.48 million) to cost ratio rises to 1.26/l and it reaches 1.45/l when the $0.66 million indirect benefits of reduced work absences and mortality are also included. Break even vaccine costs are $2.24 when health service benefits only are considered and $11.21 when all the benefits are included.

CONCLUSION

In the absence of other projects with higher benefit to cost ratios, Israel should start to provide a nationwide HIB vaccination programme since the monetary benefits to society of such a programme will exceed the costs to society. A barrier to implementation may occur, however, because the costs of the programme exceed the benefits to the health services alone.

Plasma and cerebrospinal fluid arginine vasopressin in patients with and without fever

Hyponatraemia has been described in association with a number of acute infectious diseases, mainly bacterial and tuberculous meningitis and pneumonia, and has been attributed to inappropriate secretion of arginine vasopressin (AVP). The mechanism of inappropriate AVP production is uncertain, but there is experimental evidence to suggest that fever may stimulate secretion of AVP into plasma and cerebrospinal fluid. In this study, AVP concentrations in plasma and cerebrospinal fluid from 37 febrile children with infections have been compared with those from 27 afebrile control subjects. Ten of the febrile children had meningitis (eight bacterial, two viral) and the remainder a variety of other infectious diseases. Seventy four per cent of febrile infected children were hyponatraemic (serum sodium less than 135 mmol/l) compared with only 8% of the afebrile controls. Plasma AVP concentrations were significantly higher in the febrile patients (median 2.92 pmol/l, range 1.0-23.25, n = 28) than in controls (median 1.67 pmol/l, range 0.57-6.0, n = 14) but there was no significant difference in cerebrospinal fluid AVP concentrations. There was no difference in plasma AVP concentrations between patients with meningitis and those with infections not involving the central nervous system. Careful attention should be paid to fluid and electrolyte balance in all children with acute infections.

Effect of hydration status on cerebral blood flow and cerebrospinal fluid lactic acidosis in rabbits with experimental meningitis

The effects of hydration status on cerebral blood flow (CBF) and development of cerebrospinal fluid (CSF) lactic acidosis were evaluated in rabbits with experimental pneumococcal meningitis. As loss of cerebrovascular autoregulation has been previously demonstrated in this model, we reasoned that compromise of intravascular volume might severely affect cerebral perfusion. Furthermore, as acute exacerbation of the inflammatory response in the subarachnoid space has been observed after antibiotic therapy, animals were studied not only while meningitis evolved, but also 4-6 h after treatment with antibiotics to determine whether there would also be an effect on CBF. To produce different levels of hydration, animals were given either 50 ml/kg per 24 h of normal saline ("low fluid") or 150 ml/kg 24 h ("high fluid"). After 16 h of infection, rabbits that were given the lower fluid regimen had lower mean arterial blood pressure (MABP), lower CBF, and higher CSF lactate compared with animals that received the higher fluid regimen. In the first 4-6 h after antibiotic administration, low fluid rabbits had a significant decrease in MABP and CBF compared with, and a significantly greater increase in CSF lactate concentration than, high fluid rabbits. This study suggests that intravascular volume status may be a critical variable in determining CBF and therefore the degree of cerebral ischemia in meningitis.

Types of fluid disorder in children with bacterial meningitis

As part of a prospective study of children with bacterial meningitis we analyzed in 36 patients of our hospital the fluid balance on admission and during the first three days of treatment. On admission 10 of them (28%) had inappropriate antidiuretic hormone secretion SIADH, 10 (28%) hypo-osmolal and 10 (28%) iso-osmolal contraction. Six patients (17%) had no clear fluid disorder. The patients with SIADH had significantly lower mean serum NA+ (127 vs. 132 mEq/l, p less than 0.01) and higher mean urine Na+ (111 vs. 26 mEq/l, p less than 0.01) concentration as well as higher mean urinary Na+/K+ ratio (2.23 vs. 0.365, p less than 0.005) than the patients with hypo-osmolal contraction. They also tended to be younger and have a shorter history of fever. The patients with SIADH had a less strict fluid restriction than the patients with hypo-osmolal contraction, and their fluid balance normalized more slowly. Our findings support initial water restriction for all children with bacterial meningitis.

Epidemiology of Haemophilus influenzae type b invasive disease in Wales

OBJECTIVE

To investigate the epidemiology of invasive disease due to Haemophilus influenzae type b, the clones responsible, and the antibiotic resistance of the isolates.

DESIGN

Prospective population based analysis of clinical and epidemiological data collected for Gwynedd during 1980-90 and in the whole of Wales during 1988-90.

SETTING

19 hospitals in Wales; all medical microbiology laboratories in Wales participated.

PATIENTS

82 patients with confirmed invasive infections caused by H influenzae type b in Gwynedd during 1980-90 and 207 in Wales during 1988-90.

MAIN OUTCOME MEASURES

Clinical and epidemiological measures; analysis of the clonal types of the isolates based on the electrophoretic mobilities of 17 metabolic enzymes; and antibiotic resistance.

RESULTS

The annual incidence of H influenzae type b infections in Gwynedd was 3.2 cases/100,000 and in Wales was 2.5 cases/100,000. Most cases occurred in children aged under 5 years, the highest annual incidence being in those aged under 1 (84.6/100,000 and 56.9/100,000 in Wales). The cumulative risk of acquiring H influenzae type b disease by the fifth birthday was one in 456 in Gwynedd and one in 578 in Wales. Fifteen per cent of cases in Gwynedd and 7% of those in Wales occurred in adults. Predominant clinical conditions were meningitis in children and pneumonia in adults. In Gwynedd 2/70 (3%) children and 5/12 (42%) adults died. Long term neurological sequelae occurred in 8% (4/48) of children who survived haemophilus meningitis. Children presenting with infection were usually the youngest members of their family. No secondary household cases were identified. 100 of 128 (78%) strains were of a single clone, electrophoretic type 12.5, and 4/207 (1.9%) isolates from Wales were resistant to both ampicillin and chloramphenicol.

CONCLUSIONS

The annual rate of infection in children aged under 5 in four Welsh counties was 12-44% higher than that previously published for the United Kingdom. The study emphasises the potential value of a vaccine effective in early infancy and provides baseline data to assess its efficacy after its introduction. Alternatives to ampicillin and chloramphenicol should be used as first line, empirical treatment for severe infections that might be caused by H influenzae type b in Wales.

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.

Long term sequelae of childhood acute bacterial meningitis in a developing country. A study from the Sudan

35 survivors of acute bacterial meningitis (ABM) from a group of 44 Sudanese children--seen during 18 months (April 1985-November 1986)--were prospectively followed to ascertain the long-term sequelae of the disease. 30 (17 with Haemophilus influenzae, 8 Neisseria meningitidis, 4 Streptococcus pneumoniae and one child with Enterobacter cloacae meningitis) could be followed during the surveillance period (3-4 years). Three (10%), including 2 with hemiplegia, died after 11-12 months. The association between motor deficit on discharge from hospital and subsequent death was significant (p = 0.04). Of the remaining 27, neuropsychologic sequelae were recorded in 9 (33%). Sensorineural hearing loss was observed in 6 (22%) patients and improved in one during surveillance. Motor deficits were found to improve with time but were replaced by the development of epilepsy about 3 years later in 11% of the survivors. The mean IQ (+/- SD) score for a subgroup of 19 post-meningitic children (92.3 +/- 13.9) was found to be significantly lower than in their nearest-age sibling controls (100.7 +/- 10.2; p = less than 0.01). Younger age at admission and longer duration of ABM symptoms before treatment were significantly associated with poorer outcome (respectively, r = 0.63, p = less than 0.01, r = 0.67, p = less than 0.01). The potential impact of vaccination against the commonest organisms causing ABM in developing countries is discussed.

Management of infants at risk for occult bacteremia: a decision analysis

Because febrile infants with no obvious source of bacterial infection may have bacteremia, and because bacteremia is difficult to diagnose on clinical grounds, we used decision analysis to evaluate whether such infants should be treated with antibiotics, tested further, or sent home. Using a simple decision tree, we found that the decision to give empiric antibiotic treatment is the decision of choice. The difference in quality-adjusted life expectancy between the "best" and "worst" decisions was only 11 days. However, this difference translated to prevention of death or permanent disability in 60 cases per 100,000 febrile children. Further, empiric treatment remained the best management alternative unless the probability of bacteremia was less than 1.4% (less than any published prevalence), or the efficacy of treatment was less than 21%. Our analysis demonstrated that a test with far greater sensitivity than leukocyte count or other tests currently in use is needed to justify testing rather than treating empirically. Further, an enormous patient population would be needed to find a difference of both clinical and statistical significance between treated and untreated patients in a controlled trial. In the absence of such trials, we recommend blood culture and empiric antibiotic treatment of all infants at risk for occult bacteremia.

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.

The sequelae of Haemophilus influenzae meningitis in school-age children

BACKGROUND

Previous data on the consequences of Haemophilus influenzae type b meningitis for school-age children have been inconsistent, and much of the information on risk factors has been inconclusive. The present study was designed to evaluate the sequelae of this disease with a protocol for the comprehensive assessment of neuropsychological function.

METHODS

Ninety-seven school-age children (mean age, 9.6 years), each of whom had a school-age sibling, were recruited from a survey of the medical records of 519 children treated for H. influenzae type b meningitis between 1972 and 1984 (at a mean age of 17 months) at the children's hospitals of Toronto, Ottawa, and Montreal. Of the 97 children, 41 had had an acute neurologic complication. Sequelae were assessed by comparing the index children with their nearest siblings on the basis of standardized measures of cognitive, academic, and behavioral status.

RESULTS

Only 14 children (14 percent) had persisting neurologic sequelae: sensorineural hearing loss in 11 (unilateral in 6 and bilateral in 5), seizure disorder in 2, and hemiplegia and mental retardation in 1. Although the total sample of index children scored slightly below the siblings in reading ability, the 56 children without acute-phase neurologic complications (58 percent) were indistinguishable from their siblings on all measures. The differences between the groups were small even for the 41 pairs in which the index child had had an acute neurologic complication (mean full-scale IQ, 102 for the index children vs. 109 for the siblings). Sequelae were also associated with lower socioeconomic status and a lower ratio of glucose in cerebrospinal fluid to that in blood at the time of the meningitis. Behavioral problems were more prominent in index boys than index girls and in those who were older at the time of testing, but sex and age were not related to cognitive or academic sequelae.

CONCLUSIONS

We find a favorable prognosis for the majority of children who are treated for meningitis caused by H. influenzae type b.

Normalization of plasma arginine vasopressin concentrations when children with meningitis are given maintenance plus replacement fluid therapy

We hypothesized that plasma arginine vasopressin (AVP) concentrations in children with meningitis are appropriate for the children's degree of hypovolemia, even though the concentrations were higher than expected for the serum osmolality. A randomized study was conducted to compare the effect on plasma AVP concentrations of giving maintenance fluid requirements plus replacement of any deficit versus restricting fluids to two thirds of maintenance requirements for 24 hours. Plasma AVP concentrations and serum osmolality were measured before fluid therapy was begun and again after 24 hours. Nineteen children, 2 months to 17 years of age, were studied; 13 had bacterial meningitis (12 with Haemophilus influenzae type b). Ten children (seven with bacterial meningitis) received a mean of 1.42 times the calculated maintenance fluid requirements, and nine (six with bacterial meningitis) were restricted to a mean of 0.65 times maintenance. Children in the maintenance group also received significantly more sodium (mean = 6.3 mEq/kg/24 hr) than children in the fluid-restricted group (mean = 2.0 mEq/kg/24 hr). The two groups were comparable for plasma AVP concentration and serum osmolality before fluid therapy was begun. The plasma AVP concentration was significantly lower after 24 hours of maintenance plus replacement fluids than after fluid restriction (p = 0.005), and the change in AVP concentration correlated with the amount of sodium given (p less than 0.02). This study supports the hypothesis that serum AVP concentrations are elevated in patients with meningitis because of hypovolemia and become normal when sufficient sodium is given to facilitate reabsorption of water by the proximal tubule of the kidney. Patients with meningitis can be given maintenance plus replacement fluids but should be monitored for the development of the syndrome of inappropriate secretion of antidiuretic hormone.

Haemophilus influenzae meningitis with prolonged hospital course

A retrospective evaluation of Haemophilus influenzae type b meningitis observed over a 2-year period documented 86 cases. Eight of these patients demonstrated an unusual clinical course characterized by persistent fever (duration: greater than 10 days), cerebrospinal fluid pleocytosis, profound meningeal enhancement on computed tomography, significant morbidity, and a prolonged hospital course. The mean age of these 8 patients was 6 months, in contrast to a mean age of 14 months for the entire group. Two patients had clinical evidence of relapse. Four of the 8 patients tested for latex particle agglutination in the cerebrospinal fluid remained positive after 10 days. All patients received antimicrobial therapy until they were afebrile for a minimum of 5 days. Subsequent neurologic examination revealed a persistent seizure disorder in 5 patients (62.5%), moderate-to-profound hearing loss in 2 (25%), mild ataxia in 1 (12.5%), and developmental delay with hydrocephalus which required shunting in 1 (12.5%). One patient had no sequelae.

Pyogenic meningitis in hospitalized children in Kelantan, Malaysia

A 2.5-year retrospective study of pyogenic meningitis in hospitalized children in Kelantan was carried out with regard to aetiology, clinical features, investigation, treatment and outcome. There were 58 children with 43 cases (74.1%) occurring below the age of 1 year. Frequent presenting symptoms included fever (98.3%), fits (77.6%), anorexia (39.7%), vomiting (34.5%) and drowsiness (12.1%). On admission, 37 (63.7%) had neck stiffness, 10 (17.2%) had Kernig's sign and 32 (55.2%) had coma. CSF cultures were positive for Haemophilus influenzae in 29 (50%), Streptococcus pneumonia in 13 (22.4%) and Neisseria meningitidis in 3 (5.2%). The antibiotic sensitivity profiles showed that the three main organisms were 100% sensitive to Chloramphenicol, Streptococcus pneumoniae was 100% sensitive to penicillin, Neisseria meningitidis was 100% sensitive to penicillin and ampicillin, and Haemophilus influenzae was 90% sensitive to penicillin and ampicillin. The total hospital mortality was 18.9%. All but two of the eleven deaths occurred in children younger than 1 year. Nineteen of the 35 (54.3%) survivors attended for at least one follow-up after discharge from hospital. Of these 19 children, 47.4% had neurological sequelae.

Childhood acute bacterial meningitis in the Sudan: an epidemiological, clinical and laboratory study

The aims of the present study were to document the epidemiology, clinical features and complications of childhood acute bacterial meningitis (ABM) in The Sudan during both an inter-epidemic (endemic) period (1985-1986), and the 1988 serogroup A epidemic; and to examine the phenotypic and genetic similarities and differences of Neisseria meningitidis strains isolated in The Sudan and Sweden. A new enzyme immunoassay test (Pharmacia Meningitis EIA-Test) was evaluated as a potential rapid diagnostic method for the detection of Haemophilus influenzae (HI) type b, Neisseria meningitidis (MC) and Streptococcus pneumoniae (PNC). The test was found to have good sensitivity (0.86) and specificity (0.95) in the inter-epidemic period; and to be adaptable to the field work in The Sudan during the 1988 MC epidemic. During inter-epidemic (endemic) situations in The Sudan, greater than 90% of childhood ABM was caused by one of the three organisms, HI type b, MC and PNC. HI accounted for 57% of the cases. The peak incidence (76%) of HI cases was in infants (less than 12 months) similar to the situation in other African countries. The overall case fatality ratio was 18.6%. Prospective follow-up of survivors for 3-4 years revealed that an additional 43% either died or had permanent neurological complications, the most prevalent and persistent of which was sensorineural hearing loss recorded in 22% of long term survivors. Post-meningitic children were found to have significantly lower intelligence quotients (92.3 +/- 13.9) than their sibling controls (100.7 +/- 10.2, P = 0.029). Features of the large serogroup A sulphonamide resistant MC epidemic (February-August 1988) in Khartoum are described. An estimated annual incidence of 1,679/100,000 was recorded at the peak of the epidemic. The highest attack rate was in young children less than 5 years, as in many other African countries; nevertheless, a high morbidity was observed in adults (31% of the cases greater than or equal to 20 years). The clinical features, mortality (6.3%) and short term sequelae in Sudanese children were generally within the framework described for MC disease elsewhere. Detailed analysis of MC isolates from Sudan and Sweden by characterizing their electrophoretic enzyme types, DNA restriction endonuclease pattern and outer membrane proteins, revealed that serogroup A MC clone III-1 was responsible of The Sudan epidemic in 1988 and has been the dominant serogroup A organism in Sweden since 1973. The Sudanese strains isolated prior to the epidemic (1985) were clone IV-1.(ABSTRACT TRUNCATED AT 250 WORDS)

Haemophilus influenzae type b disease in the Oxford region

A prospective survey of children in the Oxford region identified 200 cases of systemic Haemophilus influenzae type b disease in the first three and a half years of the study. The annual incidence in children less than 5 years of age was 33.4/100,000. This represents a cumulative incidence of one systemic infection in 600 children before their 5th birthday. The mortality was 5.0%. The risk of H influenzae type b meningitis was one in 850 with a mortality of 5.6%, and substantial morbidity among survivors. From the total live birth rate, about 1300 cases of systemic H influenzae type b disease, over 900 cases of H influenzae type b meningitis, and 65 deaths would be predicted annually in children in the United Kingdom.

Follow-up of prospective randomized trial of ampicillin or chloramphenicol versus moxalactam treatment of Haemophilus influenzae type b meningitis

In a prospective randomized trial, moxalactam administered to 66 children was compared with ampicillin or chloramphenicol given to 68 children for the treatment of Haemophilus influenzae type b meningitis. Acute morbidity and mortality rates were equivalent between the two treatment groups. At 2 years after discharge, the results of psychologic tests (Bayley Scales of Infant Development or McCarthy Scales of Children's Abilities) were also equivalent between the two treatment groups for patients remaining in the study.

The predictive value of computed tomography and Haemophilus influenzae capsular antigen in subdural fluid collections

A study was made of 52 patients with Haemophilus influenzae type B meningitis complicated by subdural collections of fluid to determine which of these collections were sterile (effusions) and which infected (empyema). This differentiation is important for the treatment which differs in the two conditions. Cranial computed tomography (CT) alone was not as reliable as the combination of CT associated with detection of Haemophilus influenzae capsular antigen, in accurately predicting if a subdural fluid collection was infected, or had a high probability of becoming infected.

Prospective study of computed tomography in acute bacterial meningitis

We performed serial CT scans at the time of admission and discharge, and again after 6 to 18 months, in children older than 2 months of age with bacterial meningitis. During the 2-year study period, 60 patients with bacterial meningitis were admitted to British Columbia's Children's Hospital. Forty-one were included in the study, two of whom died soon after admission. The infecting organism was Haemophilus influenzae in 29, Neisseria meningitidis in six, and Streptococcus pneumoniae in six. Abnormalities on the first two CT scans included subdural effusion in eight patients, focal infarction in five, and pus in the basal cisterns in one. All patients with focal infarction or cisternal pus had hemiparesis. Marked cerebral edema was seen in the two patients who died. Transient mild dilation of the subarachnoid space was a common finding; the size of the ventricles or subarachnoid space was increased on the second scan in 29 of 36 patients, and decreased to normal on the third scan in 30 of 33 patients. Clinical management was not influenced by the CT findings, which failed to reveal any clinically significant abnormalities that were not suspected on neurologic examination.

Multivariate prognostication in bacterial meningitis of childhood

A multivariate method for prognosticating the outcome of bacterial meningitis was computerized on the basis of initial clinical and laboratory data in 123 patients. The model, based on likelihood ratios, is simple and rapid. At the time of diagnosis, it predicted the outcome correctly in 104/123 cases (85%) in the basic group and in 67/98 independent controls (68%). The sensitivity of the method in predicting death or mild to severe neurological sequelae was 83% in both groups. The predictive value of a calculated good prognosis was 94% in the basic group and 97% in the control group, and that of a calculated poor prognosis was 63% and 26%, respectively. The predictive system can be used for rapid assessment of prognosis in individual patients and for comparisons between groups.

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.

Thrombocytosis in children with Hemophilus influenzae meningitis

A retrospective study of thrombocytosis in children with Hemophilus influenzae meningitis was performed. Forty-five percent of patients had a platelet count greater than 500 X 10(9)/l during hospitalization. The mean platelet count was 284 X 10(9)/l on admission, and gradually increased to 648 X 10(9)/l on day 11 of hospitalization. These results document that thrombocytosis is common among children with H. influenzae meningitis and suggest that it is probably a recovery phenomenon.

Cefuroxime versus ampicillin plus chloramphenicol in childhood bacterial meningitis: a multicenter randomized controlled trial

In a multicenter randomized trial, 107 children with bacterial meningitis were initially given either cefuroxime or ampicillin plus chloramphenicol. Patients were alternately assigned to 7- or 10-day courses of the designated antimicrobial regimen. CSF isolates included Haemophilus influenzae type b (89, of which 25% were beta-lactamase positive), Streptococcus pneumoniae, and Neisseria meningitidis. Although mean CSF bactericidal titers against Haemophilus isolates were 1:6 in each treatment group, H. influenzae was cultured from CSF in four of 39 patients receiving cefuroxime, 24 to 48 hours after initiation of therapy, compared with none of 40 patients given ampicillin plus chloramphenicol (P = 0.11). Clinical cure rates were similar (95%); one death occurred in each group. One child given cefuroxime had persistent meningitis after 5 days of therapy, and mastoiditis with secondary bacteremia developed in one on day 10. Three patients had relapse or reinfection. One patient who received cefuroxime for 10 days had a relapse of epiglottitis 17 days later, and of the patients given ampicillin plus chloramphenicol, one had a relapse of meningitis 1 week after 7 days of therapy, and bacteremia developed in one 42 days after completion of 10 days of therapy. No increase in either in-hospital complications or relapses occurred with a 7-day treatment course. Proof of the equivalence of the antibiotic regimens and the efficacy of 7-day courses of treatment, as well as the consequences of delayed CSF sterilization, will require additional investigation.

Hyponatraemia associated with pneumonia or bacterial meningitis

Serum sodium concentrations were measured in 93 children with pneumonia or bacterial meningitis on their admission to hospital. Hyponatraemia (sodium value 134 mmol/l or less) was present in 33 (45%) of the 73 children with pneumonia, and in 10 (50%) of the 20 children with bacterial meningitis. Increased secretion of antidiuretic hormone is common in children with pneumonia, as well as in children with meningitis. The maintenance fluid requirement in these children is usually about 50 ml/kg/per day, and children with hyponatraemia caused by water overload need even lower fluid intakes. In developing countries, most children with pneumonia and meningitis should be managed without intravenous fluid treatment.

Cerebrospinal fluid parameters and auditory brainstem responses following meningitis

Auditory brainstem responses were measured in 94 children under 24 months of age immediately following treatment for bacterial meningitis. Evidence of peripheral hearing loss (thresholds of 30 dB HLn or greater) was found in 47% of the patients. In addition, 9% had prolonged interwave latencies, indicating the possible presence of retrocochlear pathology. Other clinical data were examined as well. CSF glucose concentration correlated with both the presence and magnitude of hearing loss (as measured by auditory brainstem responses). Magnitude of hearing loss also was associated with the presence of seizures. Although all children recovering from meningitis should be assessed for hearing loss, those who have had low CSF glucose concentrations and seizures appear to be at high risk.

Serum opsonic activity after immunization of adults with Haemophilus influenzae type b-diphtheria toxoid conjugate vaccine

We measured the uptake of radiolabeled Haemophilus influenzae type b by human polymorphonuclear leukocytes. Haemophilus influenzae type b strains were preopsonized in individual sera from six adults immunized with type b polysaccharide vaccine (PRP) or six adults immunized with PRP covalently coupled to diphtheria toxoid (PRP-D vaccine). Serum was heat inactivated before use, and exogenous human complement was added. Of the 12 subjects, 3 had high levels of opsonic activity (greater than 40% of immune control) in their preimmunization serum. This activity did not correlate with the concentrations of anti-PRP antibody and was unaffected by absorption of anti-PRP antibody. At 1 month after vaccination, the serum of PRP-D subjects had higher opsonic activity than that from subjects who received PRP (5% serum, mean PRP-D = 86%, mean PRP = 53%, P = 0.001). After 12 months, both groups had higher serum opsonic activity than before immunization (P less than 0.02), but there was no difference between the two groups (mean PRP-D = 48%, mean PRP = 51%). In postimmunization serum, opsonic activity induced by PRP-D or PRP vaccines correlated directly with anti-PRP antibody concentrations as measured by a radioantigen binding assay. We conclude that both vaccines induce opsonic activity, opsonic activity induced by immunization of adults correlates well with the concentration of anti-PRP antibody achieved, and in preimmune sera with low concentrations of anti-PRP antibody, factors other than anti-PRP antibody contribute to opsonic activity.

Prospective evaluation of hearing impairment as a sequela of acute bacterial meningitis

As part of a prospective study of acute bacterial meningitis in children, we studied for five years the hearing of 185 infants and children who had acute bacterial meningitis when they were more than one month of age. Nineteen (10.3 per cent) of the patients had persistent bilateral or unilateral sensorineural hearing loss. The incidence of hearing loss as determined by electric-response audiometry and conventional tests was 31 per cent with Streptococcus pneumoniae, 10.5 per cent with Neisseria meningitidis, and 6 per cent with Hemophilus influenzae infections. Transient conductive hearing impairment was found in 16 per cent of the sample, but in no case was there apparent improvement in a sensorineural deficit over time. The site of disease resulting in impaired hearing cannot be stated with certainty, but involvement of the inner ear or auditory nerve was suspected. The number of days of illness (symptoms) before hospitalization and institution of antibacterial treatment was not correlated with the development of sensorineural deafness.

Prospective comparative trial of moxalactam versus ampicillin or chloramphenicol for treatment of Haemophilus influenzae type b meningitis in children

In a prospective, randomized study, moxalactam in 44 children was compared with ampicillin or chloramphenicol in 47 children for the treatment of Haemophilus influenzae type b meningitis. Both groups were comparable in terms of clinical and laboratory findings at admission. The hospital course, neurologic sequelae including deafness, and number of deaths were the same for both groups. The incidence of adverse reactions also was the same except that diarrhea and thrombocytosis occurred significantly (P less than or equal to 0.04) more frequently in children given moxalactam. Moxalactam was equivalent to ampicillin or chloramphenicol in the treatment of H. influenzae type b meningitis in children.