Sequelae of epidemic meningococcal meningitis in Africa

Multiplex detection of meningitis and encephalitis pathogens: A study from laboratory to clinic

Introduction

Infectious meningitis and encephalitis (ME) are life-threatening conditions are caused by various pathogens. Conventional laboratory tests with low sensitivity and specificity cannot help with early diagnosis.

Methods

A prospective study using the novel multiplex PCR detection for 18 pathogens of ME (MME-18) was conducted to investigate the clinical utilization and the epidemiology characteristics of ME in southwestern China. Patients with suspected intracranial infection were recruited between May and October 2019 at West China Hospital of Sichuan University. The MME-18 was used to detect cerebrospinal fluid, and conventional experiments including cryptococcal capsular antigen detection, GeneXpert, real-time PCR, and clinical feedback were used to verify the result of MME-18.

Results

Among 581 tested patients, 139 eligible individuals were enrolled in the study. Among them, Mycobacterium tuberculosis was the most common pathogen in mono-infection. Viruses and Cryptococcus neoformans were also frequently detected. Of 139 infected patients, 12 cases were diagnosed by MME-18 only, 57 patients by conventional testing only, and 70 cases by both comparator tests and MME-18. There were 96.3% (79/82) diagnoses made by MME-18 had a favorable outcome, and two of twelve diagnoses, made solely by MME-18, had a likely unclear clinical significance.

Discussion

The MME-18 showed satisfactory consistency with expert clinical consensus for patients presenting with ME. Combined with conventional testing and clinical suspicion, MME-18 may help clinicians with the early identification of pathogens.

Bacterial Meningitis in Children: Neurological Complications, Associated Risk Factors, and Prevention

Bacterial meningitis is a devastating infection, with a case fatality rate of up to 30% and 50% of survivors developing neurological complications. These include short-term complications such as focal neurological deficit and subdural effusion, and long-term complications such as hearing loss, seizures, cognitive impairment and hydrocephalus. Complications develop due to bacterial toxin release and the host immune response, which lead to neuronal damage. Factors associated with increased risk of developing neurological complications include young age, delayed presentation and Streptococcus pneumoniae as an etiologic agent. Vaccination is the primary method of preventing bacterial meningitis and therefore its complications. There are three vaccine preventable causes: Haemophilus influenzae type b (Hib), S. pneumoniae, and Neisseria meningitidis. Starting antibiotics without delay is also critical to reduce the risk of neurological complications. Additionally, early adjuvant corticosteroid use in Hib meningitis reduces the risk of hearing loss and severe neurological complications.

Histopathological changes to the peripheral vestibular system following meningitic labyrinthitis

OBJECTIVE

While cochlear ossification is a common sequalae of meningitic labyrinthitis, less is known about the effects of meningitis on peripheral vestibular end organs. Herein, we investigate histopathologic changes in the peripheral vestibular system and cochlea in patients with a history of meningitic labyrinthitis.

METHODS

Temporal bone (TB) specimens from patients with a history of meningitis were evaluated and compared to age-matched controls. Specimens were evaluated by light microscopy and assessed for qualitative changes, including the presence of vestibular and/or cochlear endolymphatic hydrops, presence and location of inflammatory cells, new bone formation, and labyrinthitis ossificans; and quantitative changes, including Scarpa's ganglion neuron (ScGN) and spiral ganglion neuron (SGN) counts.

RESULTS

Fifteen TB from 10 individuals met inclusion and exclusion criteria. Presence of inflammatory cells and fibrous tissue was found in 5 TB. Of these, evidence of labyrinthitis ossificans was found in 2 TB. In the peripheral vestibular system, mild to severe degeneration of the vestibular membranous labyrinth was identified in 60% of cases (n = 9 TBs). There was a 21.2% decrease (range, 3%-64%) in the mean total count of ScGN in patients with meningitis, compared to age-matched controls. In the cochlea, there was a 45% decrease (range, 25.3%-80.9%) in the mean total count of SGN compared to age-matched controls (n = 14 TBs).

CONCLUSIONS

Otopathologic analysis of TB from patients with a history of meningitic labyrinthitis demonstrated distinct peripheral vestibular changes. Future research may help to delineate potential mechanisms for the observed otopathologic changes following meningitis.

LEVEL OF EVIDENCE

N/A.

Neurological Sequelae of Adult Meningitis in Africa: A Systematic Literature Review

The high human immunodeficiency virus (HIV) prevalence in sub-Saharan Africa has markedly changed the epidemiology and presentation of adult meningitis. We conducted a systematic review using PubMed, Embase, Ovid, CENTRAL, and African Index Medicus to identify studies in Africa with data on neurological outcomes in adults after meningitis. We found 22 articles meeting inclusion criteria. From 4 studies with predominately pneumococcal meningitis, a median of 19% of survivors experienced hearing loss up to 40 days. Two studies of cryptococcal meningitis evaluated 6- to 12-month outcomes; in one, 41% of survivors had global neurocognitive impairment and 20% severe impairment at 1 year, and in a second 30% of survivors had intermediate disability and 10% severe disability at 6 months. A single small study of patients with tuberculosis/HIV found marked disability in 20% (6 of 30) at 9 months. Despite the high burden of meningitis in sub-Saharan Africa, little is known about neurological outcomes of patients with HIV-associated meningitides.

Towards understanding the epidemiology of Neisseria meningitidis in the African meningitis belt: a multi-disciplinary overview

OBJECTIVES

Neisseria meningitidis is the major cause of seasonal meningitis epidemics in the African meningitis belt. In the changing context of a reduction in incidence of serogroup A and an increase in incidence of serogroups W and C and of Streptococcus pneumoniae, a better understanding of the determinants driving the disease transmission dynamics remains crucial to improving bacterial meningitis control.

METHODS

The literature was searched to provide a multi-disciplinary overview of the determinants of meningitis transmission dynamics in the African meningitis belt.

RESULTS

Seasonal hyperendemicity is likely predominantly caused by increased invasion rates, sporadic localized epidemics by increased transmission rates, and larger pluri-annual epidemic waves by changing population immunity. Carriage likely involves competition for colonization and cross-immunity. The duration of immunity likely depends on the acquisition type. Major risk factors include dust and low humidity, and presumably human contact rates and co-infections; social studies highlighted environmental and dietary factors, with supernatural explanations.

CONCLUSIONS

Efforts should focus on implementing multi-country, longitudinal seroprevalence and epidemiological studies, validating immune markers of protection, and improving surveillance, including more systematic molecular characterizations of the bacteria. Integrating climate and social factors into disease control strategies represents a high priority for optimizing the public health response and anticipating the geographic evolution of the African meningitis belt.

Neurological sequelae of bacterial meningitis

OBJECTIVES

We reported on occurrence and impact of neurological sequelae after bacterial meningitis.

METHODS

We reviewed occurrence of neurological sequelae in children and adults after pneumococcal and meningococcal meningitis.

RESULTS

Most frequently reported sequelae are focal neurological deficits, hearing loss, cognitive impairment and epilepsy. Adults with pneumococcal meningitis have the highest risk of developing focal neurological deficits, which are most commonly caused by cerebral infarction, but can also be due to cerebritis, subdural empyema, cerebral abscess or intracerebral bleeding. Focal deficits may improve during clinical course and even after discharge, but a proportion of patients will have persisting focal neurological deficits that often interfere in patient's daily life. Hearing loss occurs in a high proportion of patients with pneumococcal meningitis and has been associated with co-existing otitis. Children and adults recovering from bacterial meningitis without apparent neurological deficits are at risk for long-term cognitive deficits. Early identification of neurological sequelae is important for children to prevent additional developmental delay, and for adults to achieve successful return in society after the disease.

CONCLUSIONS

Neurological sequelae occur in a substantial amount of patients following bacterial meningitis. Most frequently reported sequelae are focal neurological deficits, hearing loss, cognitive impairment and epilepsy.

Timely detection of bacterial meningitis epidemics at district level: a study in three countries of the African Meningitis Belt

BACKGROUND

Bacterial meningitis is a major public health problem in the African 'Meningitis Belt', where recurrent unpredictable epidemics occur. Despite the introduction in 2010 of the conjugate A vaccine, the reactive strategy remains important for responding to epidemics caused by other bacteria and in areas not yet vaccinated. Review of weekly numbers of suspected cases in Niger, Mali and Burkina Faso identified spatial disparities in the annual patterns of meningitis, which suggested a more local way of defining epidemics and initiating a timely vaccination campaign.

METHOD

We defined an epidemic district-year as an excess of cases compared to the incidence previously experienced in the given district. Groups of similar districts in terms of seasonal patterns were identified by cluster analysis. We investigated a cluster-specific criterion of early epidemic onset to anticipate epidemic district-years.

RESULTS

These were encouraging, as epidemic district-years were fairly efficiently captured, with an average time gained of 2.5 weeks over the current strategy.

CONCLUSION

This early-onset criterion could help ensure timely implementation of vaccination campaigns without the need to modify the implemented surveillance system. The next step is to extend this study to other countries of the Meningitis Belt, and to explain the differences in seasonal patterns in the different clusters.

Seasonality of meningitis in Africa and climate forcing: aerosols stand out

Bacterial meningitis is an ongoing threat for the population of the African Meningitis Belt, a region characterized by the highest incidence rates worldwide. The determinants of the disease dynamics are still poorly understood; nevertheless, it is often advocated that climate and mineral dust have a large impact. Over the last decade, several studies have investigated this relationship at a large scale. In this analysis, we scaled down to the district-level weekly scale (which is used for in-year response to emerging epidemics), and used wavelet and phase analysis methods to define and compare the time-varying periodicities of meningitis, climate and dust in Niger. We mostly focused on detecting time-lags between the signals that were consistent across districts. Results highlighted the special case of dust in comparison to wind, humidity or temperature: a strong similarity between districts is noticed in the evolution of the time-lags between the seasonal component of dust and meningitis. This result, together with the assumption of dust damaging the pharyngeal mucosa and easing bacterial invasion, reinforces our confidence in dust forcing on meningitis seasonality. Dust data should now be integrated in epidemiological and forecasting models to make them more realistic and usable in a public health perspective.

A multi-state spatio-temporal Markov model for categorized incidence of meningitis in sub-Saharan Africa

Meningococcal meningitis is a major public health problem in the African Belt. Despite the obvious seasonality of epidemics, the factors driving them are still poorly understood. Here, we provide a first attempt to predict epidemics at the spatio-temporal scale required for in-year response, using a purely empirical approach. District-level weekly incidence rates for Niger (1986-2007) were discretized into latent, alert and epidemic states according to pre-specified epidemiological thresholds. We modelled the probabilities of transition between states, accounting for seasonality and spatio-temporal dependence. One-week-ahead predictions for entering the epidemic state were generated with specificity and negative predictive value >99%, sensitivity and positive predictive value >72%. On the annual scale, we predict the first entry of a district into the epidemic state with sensitivity 65∙0%, positive predictive value 49∙0%, and an average time gained of 4∙6 weeks. These results could inform decisions on preparatory actions.

Modeling the cost-effectiveness of the integrated disease surveillance and response (IDSR) system: meningitis in Burkina Faso

Background

Effective surveillance for infectious diseases is an essential component of public health. There are few studies estimating the cost-effectiveness of starting or improving disease surveillance. We present a cost-effectiveness analysis the Integrated Disease Surveillance and Response (IDSR) strategy in Africa.

Methodology/Principal Findings

To assess the impact of the IDSR in Africa, we used pre- and post- IDSR meningococcal meningitis surveillance data from Burkina Faso (1996–2002 and 2003–2007). IDSR implementation was correlated with a median reduction of 2 weeks to peak of outbreaks (25^th percentile 1 week; 75^th percentile 4 weeks). IDSR was also correlated with a reduction of 43 meningitis cases per 100,000 (25^th–40: 75^th-129). Assuming the correlations between reductions in time to peak of outbreaks and cases are related, the cost-effectiveness of IDSR was $23 per case averted (25^th-$30; 75^th - cost saving), and $98 per meningitis-related death averted (25^th-$140: 75^th – cost saving).

Conclusions/Significance

We cannot absolutely claim that the measured differences were due to IDSR. We believe, however, that it is reasonable to claim that IDSR can improve the cost-effectiveness of public health surveillance.

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.

Deafness--the neglected and hidden disability

The problem of deafness or hearing loss is increasing world-wide. In countries rich and poor, people are living longer, and presbyacusis, the deafness of old age, is becoming more frequent. Hearing loss is a chronic and often life-long disability that, depending on the severity and the frequencies affected, can cause profound damage to the development of speech, language, and cognitive skills in children, especially if commencing prelingually. That damage, in turn, affects the child's progress in school and, later, his or her ability to obtain, keep, and perform an occupation. For all ages and for both sexes, hearing loss causes difficulties with interpersonal communication and leads to significant individual social problems, especially isolation and stigmatization. All of these difficulties are much magnified in developing countries, where there are generally limited services for the hard of hearing, few people trained to help those with hearing loss, and little awareness about how to deal with the difficulties associated with such loss. Although deafness and hearing impairment are likely to have huge economic effects in such countries, in most areas these effects remain to be quantified.

Vaccines against bacterial meningitis

Meningitis remains an important cause of morbidity and mortality among children >5 years of age and is especially prevalent in developing countries. Effective routine immunization against Hib, pneumococcus and serogroupC meningococcus has had a significant impact on both invasive disease and carriage caused by these encapsulated bacteria. The major challenge in prevention of meningitis remains the delivery of vaccines worldwide, especially to resource-poor regions with the greatest disease burden.

The future of meningitis vaccines

Without effective vaccines meningitis remains a substantial worldwide threat with major health-care implications. A number of advances have been made in vaccine design and implementation over the last decade, with new vaccine initiatives providing substantial promise for the future reduction of global disease burden.

Development of vaccines against meningococcal disease

Neisseria meningitidis is a major cause of bacterial meningitis and sepsis. Polysaccharide-protein conjugate vaccines for prevention of group C disease have been licensed in Europe. Such vaccines for prevention of disease caused by groups A (which is associated with the greatest disease burden worldwide), Y, and W135 are being developed. However, conventional approaches to develop a vaccine for group B strains, which are responsible for most cases in Europe and the USA, have been largely unsuccessful. Capsular polysaccharide-based vaccines can elicit autoantibodies to host polysialic acid, whereas the ability of most non-capsular antigens to elicit broad-based immunity is limited by their antigenic diversity. Many new membrane proteins have been discovered during analyses of genomic sequencing data. These antigens are highly conserved and, in mice, elicit serum bactericidal antibodies, which are the serological hallmark of protective immunity in man. Therefore, there are many promising new vaccine candidates, and improved prospects for development of a broadly protective vaccine for group B disease, and for control of all meningococcal disease.

Survival and sequelae of meningococcal meningitis in Ghana

BACKGROUND

Meningococcal meningitis epidemics are frequent in the Sahel zone of Africa but there is little information on the frequency of long-term sequelae. We analysed excess mortality in the two years following the 1997 epidemic in northern Ghana and carried out a case-control study to assess sequelae in the survivors.

METHODS

Two-year survival of 696 meningitis cases recorded at the War Memorial Hospital, Navrongo, was analysed using data from a demographic surveillance system. A structured questionnaire on disability and on psychiatric, neuropsychological and behavioural problems was administered to 505 of the survivors and 505 age- sex- and location-matched controls as well as to their respective relatives. Cases and controls underwent full neurological and neuropsychological examination and were evaluated for hearing impairment by audiometry.

RESULTS

Survival rates after the first month following the attack were similar in cases and controls. Hearing impairment was the major sequela, and was reported in 6 per cent of cases and 2 per cent of controls (odds ratio [OR] = 3.10; 95% CI : 1.48-7.09). Audiometry detected severe and profound hearing loss in the worse affected ear (> or =70 db) in 8/496 (1.6%) survivors but in only one control. Survivors of meningitis were more likely to suffer from feelings of tiredness (OR = 1.47; 95% CI : 1.03-2.11) and were more often reported by relatives to have insomnia (OR = 2.31; 95% CI : 1.17-4.82) and daily alcohol consumption.

INTERPRETATION

Meningococcal meningitis annually causes approximately 10 000 cases of deafness in sub-Saharan Africa; there is a need for early detection of affected survivors and promotion of simple hearing devices. There is a sizeable burden of depressive disorders secondary to meningitis which should be identified and looked after appropriately.

Comparison of cost-effectiveness of preventive and reactive mass immunization campaigns against meningococcal meningitis in West Africa: a theoretical modeling analysis

For epidemic meningitis control in sub-Saharan Africa, the World Health Organization recommends a strategy of emergency vaccination with meningococcal A + C polysaccharide vaccine when epidemic thresholds are exceeded. An alternative strategy for areas without effective surveillance systems is mass preventive campaigns before outbreaks occur. A model was formulated to simulate epidemics and to compare the cost-effectiveness of these two strategies for the district of Matam, Senegal, where an actual preventive campaign was performed during 1997. The preventive strategy prevented 59% of the cases compared to 49% for the emergency strategy. The cost per case prevented was US$59 for the preventive strategy and US$133 for the reactive strategy, and the preventive strategy saved US$0.20 per habitant. Preventive meningococcal vaccination through mass campaigns prevented more outcomes at a lower cost, provided that the occurrence of an epidemic could be predicted within 3 years and that the vaccination coverage rates for the preventive and standard strategies were > 70% and < 94%, respectively. Sub-Saharan African countries without effective surveillance systems should consider mass preventive campaigns while awaiting an affordable conjugate vaccine.

Meningitis seasonal pattern in Africa and detection of epidemics: a retrospective study in Niger, 1990-98

Control of epidemic meningitis is still an unresolved problem in Africa. WHO has promoted the use of surveillance and response following alerts based on weekly threshold levels. In order to avoid any waste of resources related to false-positive alerts, it was decided not to choose too sensitive thresholds. This policy, however, leads to delayed response. The seasonal pattern of epidemics provides a solution to this dilemma. We carried out a retrospective survey of district-level surveillance data in Niger from June 1990 to June 1998. We identified an early and late meningitis season. Following this pattern, we studied the performance of the WHO-recommended threshold as compared to alternative thresholds for identifying early, late and non-epidemic district-years (DYs). (ADY was defined as a 52-week period starting in the last week of June, at the district level). We studied 296 DYs, comprising 50 early epidemic, 38 late epidemic, and 208 non-epidemic DYs. Early epidemics were more often large and accounted for almost 75% of total cases. When applied no later than the first week of March, a highly sensitive alternative threshold resulted in initiation of an alert, with a median of 3 weeks earlier than the standard threshold, with no false-positive alerts, i.e., a specificity of 1.

Emergency vaccination against epidemic meningitis in Ghana: implications for the control of meningococcal disease in West Africa

BACKGROUND

Recurrent epidemics of meningococcal disease have been reported throughout the African meningitis belt since description of the disease in 1912. Meningooccal polysaccharide vaccines can effectively prevent disease but the optimum strategy for their use in this setting has been controversial. We used data from an outbreak of meningococcal disease in northern Ghana in 1997 to assess the potential effect of different vaccination strategies.

METHODS

We identified all reported cases of meningococcal meningitis and estimated the number of cases and deaths that could have been prevented by vaccination through use of a simple mathematical model. We then assessed the potential effect of different vaccination strategies and the burden of these strategies on the public-health system.

FINDINGS

In the three affected regions in northern Ghana there were 18703 cases and 1356 deaths reported between November, 1996, and May, 1997. Vaccination began in the third week of February and continued to April, reaching 72% of the at-risk population and preventing an estimated 23% of cases and 18% of deaths. A strategy of routine childhood and adult immunisation would have prevented 61% of cases had this same rate of vaccine coverage been achieved and maintained before the epidemic. If vaccination had started after the onset of the epidemic in January, as currently advocated by WHO guidelines, a similar proportion (61%) of cases could have been prevented.

INTERPRETATION

Prevention of epidemics of meningococal disease in west Africa will be difficult until long-lasting conjugate vaccines capable of interrupting transmission of Neisseria meningitidis can be incorporated into routine infant-immunisation schedules. Until then, the strategy of surveillance and response advocated by WHO is as effective and more practical than a strategy of routine childhood and adult vaccination with currently available polysaccharide vaccines.

Manson Lecture. Meningococcal meningitis in Africa

This review covers the history of meningococcal meningitis in Africa since epidemics of the infection were first described around 100 years ago. It is possible that an epidemic strain of the meningococcus was introduced into West Africa from the Sudan by pilgrims returning from the Haj around the turn of the century. Since 1905 major epidemics of meningococcal meningitis have occurred in countries of the Sahel and sub-Sahel every few years, culminating in a massive epidemic in which nearly 200,000 cases were reported in 1996. Attempts to control epidemic meningococcal meningitis in Africa by vaccination with meningococcal polysaccharide vaccines have met with only modest success because epidemics can progress with great rapidity and vaccination is often started too late. This situation should be improved as a result of a recent initiative, the International Coordinating Group (ICG), which is contributing to better surveillance in countries at risk and ensuring that vaccine is available when needed. However, in the medium term, the best prospect for the control of meningococcal meningitis in Africa lies in the recent development of polysaccharide-protein conjugate vaccines which, unlike polysaccharide vaccines, are immunogenic in the very young, induce immunological memory and are likely to give long-lasting protection.

A cost-effectiveness analysis of vaccination strategies against N. meningitidis meningitis in sub-Saharan African countries

This analysis evaluates the cost-effectiveness (C/E) of routine vaccination against Neisseria meningitidis. Three different preventive strategies are analyzed: mass vaccination during epidemics (the current standard of care), routine preventive vaccination and a combination strategy of routine vaccination with mass vaccination during epidemics. A Markov model is used to simulate the epidemics of meningitis in a cohort of 5-year old children and compare these different strategies. The results show that mass vaccination strategy is dominated by the two other strategies. The incremental C/E ratios are US$50/QALY for the routine vaccination, and US$199/QALY for the combination strategy. The costs per fatal case averted are US$1161 for the routine vaccination, and US$2397 for the combination strategy. The C/E ratios are sensitive to: the incidence of meningococcal meningitis, the costs of treating cases, the costs of routine vaccination and the costs and effectiveness of mass immunization campaign. However the rank ordering of the strategies is almost never altered. In conclusion, the results of this analysis suggest that mass vaccination in sub-Saharan Africa in case of epidemics should be reconsidered. Routine vaccination against meningococcal meningitis at an early age, with or without mass vaccination during epidemics is more effective, with a C/E ratio within the range of other vaccination strategies currently in place in Africa.

[Hearing findings in subjects after meningitis]

INTRODUCTION

It was proposed to ascertain the occurrence of individuals who present hearing loss, due to contracting meningitis, as well as to characterize the diagnosed loss as far as the type, degree and the audiometric configuration are concerned.

MATERIAL AND METHOD

The methodology used comprised a survey of 949 references of patients attended at the Hearing Disturbance Center of the HPRLLP/USP, in order to select those who presented hearing loss after meningitis and, from the analysis of the hearing evaluation to which they were submitted, achieve the proposed goal.

RESULTS AND CONCLUSION

The results indicated a 6.2 percent occurrence as regards hearing loss due to meningitis in relation to other causes and the characteristic of this hearing loss was predominantly sensorineural, symmetrical, al linear and to a profound degree.

Childhood hearing loss in sub-Saharan Africa: a review and recommendations

Nearly 10% of the world's population lives in sub-Saharan Africa, a region comprised of many countries with least developed nation status. The region has a predominantly young population and many children in the region are at risk of pathologies associated with hearing loss. Despite the constraints associated with low socioeconomic levels, a number of valuable studies have been carried out into the prevalence and etiology of childhood hearing loss in the sub-Saharan region. A review of the published literature related to childhood hearing loss in sub-Saharan Africa is presented and recommendations made on possible future research directions that could assist hearing loss prevention and management.

Dexamethasone adjunctive therapy for bacterial meningitis in children: a retrospective study in Brazil

The clinical records of 87 children with bacterial meningitis treated with antibiotics (group 1) and of 92 treated with antibiotics plus dexamethasone (group 2), admitted to the Instituto Materno Infantil de Pernambuco, Recife, Brazil over 2 consecutive years (1991 and 1992), were analysed. There were no significant differences between treatment groups regarding characteristics on admission except that group 1 were younger. The overall case fatality rate was 19%, with 14% in group 2 and 24% in group 1 (p = 0.09). Rate of discharge without sequelae was 70% in the steroid-treated children and 56% in children treated with antibiotics alone (p = 0.07). Among children aged 6-59 months, those treated with dexamethasone compared with those treated with antibiotics alone had a better case fatality rate (11% vs 25%; p = 0.05) and a better rate of discharge without sequelae (73% vs 52%; p = 0.02). Among the cases with a CSF culture positive for Haemophilus influenzae, 77% were discharged without sequelae in group 2 compared with 51% in group 1 (p = 0.03). The addition of dexamethasone to standard antibiotic treatment improves the outcome of children between 6 and 59 months of age admitted to hospital with a diagnosis of bacterial meningitis.

Sequelae one year after meningococcal disease

Of 99 consecutive patients with meningococcal disease, 6 died during the acute stage. The 93 survivors were examined one year after hospitalization. 21 (40%) of the adults and 6 (15%) of the children had definite sequelae, and an additional 27% and 11% possible sequelae. 6 adults (12%) and 1 child (2%) had definite neurological sequelae. Electroencephalography (EEG) abnormalities were observed in 7 adults (14%) and 2 children (5%). Epileptogenic activity was present in 3 of these, but none had experienced seizures. 8 adults (19%) and 5 children (14%) had sensorineural hearing loss or impaired vestibular function. Cerebral computerized tomography (CT) scan showed definite and possible abnormalities in 1 (3%) and 6 (18%), respectively, of the 34 patients tested. Neuropsychological tests were performed in 9 patients, 2 of these showed definite impairment. The frequency of neurological abnormalities was higher than in many previous studies, probably reflecting the more comprehensive examinations performed in the present study. However, only 3 patients had serious sequelae. The results suggest that the occurrence of sequelae after meningococcal disease is related to the severity of the acute disease. This may explain the higher rate of sequelae in adults, who have a higher proportion of seriously ill patients. The presence of meningitis is not required for the occurrence of neurological sequelae.

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.

Clinical features and complications of epidemic group A meningococcal disease in Sudanese children

The clinical presentation and laboratory features in relation to short-term outcome in 118 prospectively studied Sudanese children who were admitted with meningococcal (MC) meningitis and/or septicaemia during the 1988 group A MC epidemic in Greater Khartoum are described. Their ages ranged from 25 days to 15 years (mean: 78 months) and 42% were less than 5 years old. The male:female ratio was 1.6:1. Forty (34%) came from one of the peri-urban shanty towns encircling Greater Khartoum. A history of MC immunization (A and C vaccine) was obtained in 22%, but only five children (4.8%) had the vaccine between 4 weeks and 1 year before their illness. The commonest symptoms on admission were vomiting, neck rigidity and diarrhoea. Convulsions were significantly more frequent in children under 5 years old (p = 0.0005). Fifty-six (47%) had evidence of malnutrition. In descending order, fever, neck stiffness and Kernig's sign were the most commonly observed signs, the latter two being significantly more often detected in children older than 1 year. Twenty-four patients 20%) had disturbed consciousness. The case fatality rate was 6.3% and this was significantly higher in those presenting with meningococcal septicaemia (p = 0.0006). Other significant associations with mortality were short duration (less than 1 day) of symptoms (p = 0.0006) and clinical shock detected on admission p = 0.003). Transient complications were infrequent and permanent neurological sequelae were confined to bilateral profound sensorineural hearing loss in three children (2.9%) and hemiplegia in two 1.9%.(ABSTRACT TRUNCATED AT 250 WORDS)

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)