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Biomedical subjects

M W Weber

Publications and source records attributed to M W Weber.

At least 19 recordsLinked to original sources
PubMed2000

Outcome of meningitis caused by Streptococcus pneumoniae and Haemophilus influenzae type b in children in The Gambia.

In developing countries, endemic childhood meningitis is a severe disease caused most commonly by Streptococcus pneumoniae or Haemophilus influenzae type b (Hib). Although many studies have shown that fatality rates associated with meningitis caused by these organisms are high in developing countries, little is known about the long-term outcome of survivors. The purpose of this study was to assess the importance of disabilities following pneumococcal and Hib meningitis in The Gambia. 257 children aged 0-12 years hospitalized between 1990 and 1995 with culture-proven S. pneumoniae (n = 134) or Hib (n = 123) meningitis were included retrospectively in the study. 48% of children with pneumococcal meningitis and 27% of children with Hib meningitis died whilst in hospital. Of the 160 survivors, 89 (55%) were followed up between September 1996 and October 1997. Of the children with pneumococcal meningitis that were traced, 58% had clinical sequelae; half of them had major disabilities preventing normal adaptation to social life. 38% of survivors of Hib meningitis had clinical sequelae, a quarter of whom had major disabilities. Major handicaps found were hearing loss, mental retardation, motor abnormalities and seizures. These data show that despite treatment with effective antibiotics, pneumococcal and Hib meningitis kill many Gambian children and leave many survivors with severe sequelae. Hib vaccination is now given routinely in The Gambia; an effective pneumococcal vaccine is needed.

Child↗
PubMed2000

Evaluation of clinical pallor in the identification and treatment of children with moderate and severe anaemia.

BACKGROUND: Anaemia from malaria is a common problem in developing countries. Blood transfusion in developing countries is available in few hospitals. Children who are severely anaemic and may require urgent blood transfusion usually present to peripheral first-level health facilities from where they must be referred to hospitals. Since most peripheral facilities do not determine haemoglobin levels, the decision on referral has to be made on clinical grounds. OBJECTIVES: To evaluate the sensitivity and specificity of clinical pallor of the palms, nailbeds, conjunctivae, buccal mucosa or tongue against haemoglobin values and their reproducibility among health workers. METHODS: A total of 2540 children 2 months to 5 years of age presenting to a rural health centre in Ethiopia were enrolled. Clinically detected pallor was compared with measured blood haemoglobin concentrations. RESULTS: Any anaemia (haemoglobin < 11 g/dl) was found in 61% of the children. Severe anaemia (haemoglobin < 5 g/dl) was found in 4%. The presence of any pallor clinically correlated with moderate anaemia (haemoglobin level < 8 g/dl) could be detected with a sensitivity of 95% and a specificity of 64-68% when the palm and nailbeds were used and a sensitivity of 84% and a specificity of 81% when the conjunctivae were used. Severe anaemia was detected clinically as severe pallor in 50-56% of cases (with a specificity of 95-96%). Agreement between physicians was highest for conjunctivae and nailbed pallor (87%) and lowest for palm pallor (73%). Using multivariate analysis, identification of a systolic ejection murmur or altered sensorium, the presence of splenomegaly or malarial parasitaemia were independently predictive of severe and moderately severe anaemia. CONCLUSIONS: Moderate and severe anaemia can be identified clinically in most cases for treatment and referral purposes. A systolic ejection murmur, altered sensorium, the presence of splenomegaly or malarial parasitaemia may be used as additional tools in considering urgent referral for blood transfusion.

Anemia, Iron-Deficiency↗
PubMed1999

Respiratory illness after severe respiratory syncytial virus disease in infancy in The Gambia.

OBJECTIVE: To determine the frequency of later respiratory tract morbidity after respiratory syncytial virus (RSV) disease in infancy. DESIGN: Cohort study with passive, clinic-based surveillance. SETTING: Outpatient department in The Gambia. SUBJECTS: One hundred five children admitted to the hospital with severe RSV disease (case cohort), 105 control children matched for age not admitted to the hospital during the previous RSV season (control cohort 1), and 102 control children born after the RSV season (control cohort 2). MAIN OUTCOME MEASURES: Frequencies of pneumonia, wheezing, and hospital admission with acute lower respiratory tract infection. RESULTS: Pneumonia was more common in case children than in both control groups (adjusted incidence rate ratio [IRR, 95% CI]: 3.80 [2.73, 6. 10]), as was wheezing (IRR 7.33 [3.10,17.54]), pneumonia or wheezing (IRR 3.96 [2.60, 6.04]), and admission with pneumonia or wheezing (IRR 3.40 [1.87, 6.15]). The incidence rate per 100 child-years for pneumonia in the dry season for 12-month-old children was 27 for case patients, 8.1 for control cohort 1, and 6.51 for control cohort 2. By 3 years of age, the rates had fallen to low levels in all groups. CONCLUSIONS: Pneumonia and wheezing are significantly more common in children after RSV-associated lower respiratory tract disease than in control subjects, but the incidence declines rapidly with increasing age.

Acute Disease↗
PubMed1999

Renal involvement in Gambian children with cerebral or mild malaria.

Kidney function was studied in 80 Gambian children with cerebral malaria, 73 children with mild malaria, and in 19 children with other febrile illnesses. Serum creatinine was measured, and the excretion in urine of immunoglobulin G, transferrin, albumin and alpha 1 microglobulin was determined. Twenty-five percent of children with cerebral malaria, and 4% of children with mild malaria had an elevated serum creatinine above 62 mumol/l. Increased urinary protein excretion was frequent: 53% of children with cerebral malaria had a glomerulo-tubular pattern of protein excretion, and 46% a tubular pattern. Median albuminuria was 68 mg/l in children with cerebral malaria, 18 mg/l in children with mild malaria, and 9 mg/l in febrile children with other diseases (P < 0.0001). There was no significant association between the proteinuria and height of fever or the degree of parasitaemia, and there was no significant association between death and signs of renal impairment. Renal involvement is common in children with malaria in The Gambia, with prerenal, glomerular, and tubulo-interstitial factors contributing. It is more pronounced in children with cerebral malaria than in those with mild malaria. However, renal dysfunction is relatively mild and does not indicate a worse prognosis.

Alpha-Globulins↗
PubMed1999

Biochemical and haematological variables in Gambian children with cerebral malaria.

Biochemical and haematological measurements were made in Gambian children who satisfied the criteria for the diagnosis of cerebral malaria over a 3-year period. Biochemical and haematological values were available for 388 and 624 children, respectively. Biochemical signs of renal and hepatic dysfunction were found and these may have contributed in a cumulative way to the high mortality seen in the study children. Cerebral involvement in children with cerebral malaria is only one, though the most important, manifestation of a multi-organ disease.

Blood Cell Count↗
PubMed1999

Risk factors for severe respiratory syncytial virus infection leading to hospital admission in children in the Western Region of The Gambia.

BACKGROUND: Acute lower respiratory tract infections (ALRI) are the major cause of mortality and morbidity in young children worldwide. Respiratory syncytial virus (RSV) infection is the most important viral cause of severe ALRI but only a small proportion of children infected with this virus develop severe disease. To identify possible risk factors for severe RSV infection leading to hospital admission we have carried out a case-control study of Gambian children with RSV infection admitted to hospital. METHODS: In all, 277 children admitted to three hospitals in the Western Region of The Gambia with lower respiratory tract infection due to RSV were compared with 364 control children matched for age and location of residence who had not been admitted to hospital with an ALRI during the RSV season. A detailed questionnaire covering a wide range of potential social, environmental and nutritional risk factors was administered to the child's guardian. RESULTS: Cases came from larger or more crowded compounds than controls; increased risk was particularly associated with greater numbers of children in the age group 3-5 years living in the compound (odds ratio [OR] for > or =2 children in the age group 3-5 years = 9.1, 95% CI: 3.7-28). Cases were more likely to have a sibling who had died (OR = 3.4, 95% CI: 1.7-7). Controls were more likely to have been exposed to smoke from cooking fires (OR for the mother of cases cooking at least once daily = 0.31, 95% CI: 0.14-0.7). Other protective factors were father's nationality and some professions. Vegetables were included in the diet of controls more frequently than in that of cases (OR = 0.16, 95% CI: 0.06-0.46). Mothers of cases complained of asthma more frequently than mothers of controls, but the number of asthmatic mothers was small (4.2 versus 0.5%, P = 0.05). CONCLUSIONS: Risk factors for severe RSV infection identified in this study are not amenable to public health interventions. Prevention of severe infection is likely to require the development of an effective vaccine.

Case-Control Studies↗
PubMed1999

Chloramphenicol pharmacokinetics in infants less than three months of age in the Philippines and The Gambia.

BACKGROUND: The broad antimicrobial spectrum and affordable price of chloramphenicol make it an attractive first line treatment option for children with severe illnesses in developing countries. Little is known, however, about its pharmacokinetics in young infants in these settings. METHODS: We studied infants younger than 3 months of age hospitalized in Manila, Philippines and The Gambia with possible severe bacterial infections likely to benefit from treatment with chloramphenicol. Infants in the first week of life received intramuscular doses of 25 mg/kg chloramphenicol once daily, twice daily in the second through fourth week of life and three times daily from 5 to 12 weeks of age. Blood samples were taken at 0.5, 1, 2 and 3 h after the first dose, 1 h before the second dose and before the repetition doses on subsequent days. In the Philippines a second group of infants was treated with oral chloramphenicol according to the same dosage schedule. RESULTS: Thirty-eight infants received intramuscular chloramphenicol, and 20 received oral drug. Intramuscular administration resulted in therapeutic concentrations (10 to 25 microg/ml) in 73 to 86% of children in each of the three age groups in the first 6 h and in 50 to 80% on Days 2 and 3. Between 33 and 38% of children had potentially toxic values on Days 2 and 3. In contrast, after oral administration, only about one-half of the children reached therapeutic values in serum at any time up to Day 3 after start of treatment. CONCLUSIONS: Intramuscular chloramphenicol can be used as a second line drug for the treatment of severe infections in infants younger than 90 days of age, where third generation cephalosporins are not available. It quickly achieves therapeutic values in a high proportion of children. However, severe infections should not be treated with oral chloramphenicol in this age group, because therapeutic serum concentrations were inconsistently achieved.

Administration, Oral↗
PubMed1999

Clinical algorithm for malaria during low and high transmission seasons.

OBJECTIVES: To assess the proportion of children with febrile disease who suffer from malaria and to identify clinical signs and symptoms that predict malaria during low and high transmission seasons. STUDY DESIGN: 2490 children aged 2 to 59 months presenting to a health centre in rural Ethiopia with fever had their history documented and the following investigations: clinical examination, diagnosis, haemoglobin measurement, and a blood smear for malaria parasites. Clinical findings were related to the presence of malaria parasitaemia. RESULTS: Malaria contributed to 5.9% of all febrile cases from January to April and to 30.3% during the rest of the year. Prediction of malaria was improved by simple combinations of a few signs and symptoms. Fever with a history of previous malarial attack or absence of cough or a finding of pallor gave a sensitivity of 83% in the high risk season and 75% in the low risk season, with corresponding specificities of 51% and 60%; fever with a previous malaria attack or pallor or splenomegaly had sensitivities of 80% and 69% and specificities of 65% and 81% in high and low risk settings, respectively. CONCLUSION: Better clinical definitions are possible for low malaria settings when microscopic examination cannot be done. Health workers should be trained to detect pallor and splenomegaly because these two signs improve the specificity for malaria.

Algorithms↗
PubMed1999

Long-term morbidity and mortality following hypoxaemic lower respiratory tract infection in Gambian children.

Acute lower respiratory infections (ALRI) are the main cause of death in young children worldwide. We report here the results of a study to determine the long-term survival of children admitted to hospital with severe pneumonia. The study was conducted on 190 Gambian children admitted to hospital in 1992-94 for ALRI who survived to discharge. Of these, 83 children were hypoxaemic and were treated with oxygen, and 107 were not. On follow-up in 1996-97, 62% were traced. Of the children with hypoxaemia, 8 had died, compared with 4 of those without. The mortality rates were 4.8 and, 2.2 deaths per 100 child-years of follow-up for hypoxaemic and non-hypoxaemic children, respectively (P = 0.2). Mortality was higher for children who had been malnourished (Z-score < -2) when seen in hospital (rate ratio = 3.2; 95% confidence interval (CI) = 1.03-10.29; P = 0.045). Children with younger siblings experienced less frequent subsequent respiratory infections (rate ratio for further hospitalization with respiratory illness = 0.15; 95% CI = 0.04-0.50; P = 0.002). Children in Gambia who survive hospital admission with hypoxaemic pneumonia have a good prognosis. Survival depends more on nutritional status than on having been hypoxaemic. Investment in oxygen therapy appears justified, and efforts should be made to improve nutrition in malnourished children with pneumonia.

Acute Disease↗
PubMed1998

Respiratory syncytial virus infection in tropical and developing countries.

Little is known about the epidemiology of respiratory syncytial virus (RSV) infection in tropical and developing countries; the data currently available have been reviewed. In most studies, RSV was found to be the predominant viral cause of acute lower respiratory tract infections (ALRI) in childhood, being responsible for 27-96% of hospitalised cases (mean 65%) in which a virus was found. RSV infection is seasonal in most countries; outbreaks occur most frequently in the cold season in areas with temperate and Mediterranean climates and in the wet season in tropical countries with seasonal rainfall. The situation on islands and in areas of the inner tropics with perennial high rainfall is less clear-cut. The age group mainly affected by RSV in developing countries is children under 6 months of age (mean 39% of hospital patients with RSV). RSV-ALRI is slightly more common in boys than in girls. Very little information is available about the mortality of children infected with RSV, the frequency of bacterial co-infection, or the incidence of further wheezing after RSV. Further studies on RSV should address these questions in more detail. RSV is an important pathogen ill young children in tropical and developing countries and a frequent cause of hospital admission. Prevention of RSV infection by vaccination would have a significant impact on the incidence of ALRI in children in developing countries.

Age Distribution↗
PubMed1998

The clinical spectrum of respiratory syncytial virus disease in The Gambia.

BACKGROUND: Respiratory syncytial virus (RSV) is a well-recognized cause of lower respiratory tract infections in early childhood in industrialized countries, but less is known about RSV infection in developing countries. METHODS: Four outbreaks of RSV infection that occurred between 1993 and 1996 in The Gambia, West Africa, were studied. RSV was sought by immunofluorescent staining of nasopharyngeal aspirate samples among young children who presented with respiratory infections at three hospitals in the Western Region of the country. RESULTS: Five hundred seventy-four children with RSV infection were identified. The median ages of children seen in 1993 through 1996 were 3, 7, 8 and 5 months, respectively. Sixty-two percent of children <6 months old were boys. Thirteen children (2.4%) had conditions considered to increase the risk of severe RSV infection. On physical examination crepitations were heard in 80% of the children admitted to hospital, whereas wheezes were heard in only 39%. Eighty (16%) children received oxygen because of hypoxemia. Nine of 255 blood cultures (3.5%) were positive: 4 Streptococcus pneumoniae; 2 Haemophilus influenzae type b; 2 Staphylococcus aureus; and 1 Enterobacter agglomerans. Thirteen children died (2.4%). During the 4 study years 90, 25, 75 and 95% of isolates typed were RSV Subgroup A, respectively. CONCLUSIONS: RSV is a significant cause of lower respiratory tract infection in young children in The Gambia, causing epidemics of bronchiolitis. It poses a significant burden on the health system, especially through the demand for supplementary oxygen. The clinical spectrum of RSV disease in The Gambia is similar to that seen in developed countries; concomitant bacterial infections are uncommon.

Developing Countries↗
PubMed1997

Relation between severe malaria morbidity in children and level of Plasmodium falciparum transmission in Africa.

BACKGROUND: Malaria remains a major cause of mortality and morbidity in Africa. Many approaches to malaria control involve reducing the chances of infection but little is known of the relations between parasite exposure and the development of effective clinical immunity so the long-term effect of such approaches to control on the pattern and frequency of malaria cannot be predicted. METHODS: We have prospectively recorded paediatric admissions with severe malaria over three to five years from five discrete communities in The Gambia and Kenya. Demographic analysis of the communities exposed to disease risk allowed the estimation of age-specific rates for severe malaria. Within each community the exposure to Plasmodium falciparum infection was determined through repeated parasitological and serological surveys among children and infants. We used acute respiratory-tract infections (ARI) as a comparison. FINDINGS: 3556 malaria admissions were recorded for the five sites. Marked differences were observed in age, clinical spectrum and rates of severe malaria between the five sites. Paradoxically, the risks of severe disease in childhood were lowest among populations with the highest transmission intensities, and the highest disease risks were observed among populations exposed to low-to-moderate intensities of transmission. For severe malaria, for example, admission rates (per 1000 per year) for children up to their 10th birthday were estimated as 3.9, 25.8, 25.9, 16.7, and 18.0 in the five communities; the forces of infection estimated for those communities (new infections per infant per month) were 0.001, 0.034, 0.050, 0.093, and 0.176, respectively. Similar trends were noted for cerebral malaria and for severe malaria anaemia but not for ARI. Mean age of disease decreased with increasing transmission intensity. INTERPRETATION: We propose that a critical determinant of life-time disease risk is the ability to develop clinical immunity early in life during a period when other protective mechanisms may operate. In highly endemic areas measures which reduce parasite transmission, and thus immunity, may lead to a change in both the clinical spectrum of severe disease and the overall burden of severe malaria morbidity.

Anemia↗
PubMed1997

Predictors of hypoxaemia in hospital admissions with acute lower respiratory tract infection in a developing country.

Since oxygen has to be given to most children in developing countries on the basis of clinical signs without performing blood gas analyses, possible clinical predictors of hypoxaemia were studied. Sixty nine children between the ages of 2 months and 5 years admitted to hospital with acute lower respiratory tract infection and an oxygen saturation (Sao2) < 90% were compared with 67 children matched for age and diagnosis from the same referral hospital with an Sao2 of 90% or above (control group 1), and 44 unreferred children admitted to a secondary care hospital with acute lower respiratory infection (control group 2). Using multiple logistic regression analysis, sleepiness, arousal, quality of cry, cyanosis, head nodding, decreased air entry, nasal flaring, and upper arm circumference were found to be independent predictors of hypoxaemia on comparison of the cases with control group 1. Using a simple model of cyanosis or head nodding or not crying, the sensitivity to predict hypoxaemia was 59%, and the specificity 94% and 93% compared to control groups 1 and 2, respectively; 80% of the children with an Sao2 < 80% were identified by the combination of these signs. Over half of the children with hypoxaemia could be identified with a combination of three signs: extreme respiratory distress, cyanosis, and severely compromised general status. Further prospective validation of this model with other datasets is warranted. No other signs improved the sensitivity without compromising specificity. If a higher sensitivity is required, pulse oximetry has to be used.

Acute Disease↗
PubMed1997

Evaluation of an algorithm for the integrated management of childhood illness in an area with seasonal malaria in the Gambia.

Most of the 12.4 million deaths occurring every year among under-5-year-olds in developing countries could be prevented by the application of simple treatment strategies. So that health professionals who have had limited training can identify and classify the common childhood diseases, WHO developed a treatment algorithm (the Integrated Management of Childhood Illness (IMCI) or Sick Child algorithm), a prototype of which was tested in 440 Gambian children aged between 2 months and 5 years. The children were first assessed by a trained field worker using the algorithm, and then by a paediatrician whose clinical diagnosis was supported by laboratory investigations and, when indicated, a chest X-ray. Compared with the paediatrician's diagnosis, the sensitivity and specificity of the draft IMCI algorithm were, respectively, 81% and 89% for the detection of pneumonia, 67% and 96% for dehydration, 87% and 8% for malaria parasitaemia (any level), 100% and 9% for malaria parasitaemia (above 5000 parasites/microliter), 100% and 99% for measles, 31% and 97% for otitis media, and 89% and 90% for malnutrition. Among the children admitted by the physician, 45% had been recommended for admission by the algorithm. Intermittent fever, chills and sweats did not help in discriminating between malaria and non-malarious fevers; shivering or shaking of the body had a sensitivity of only 35%. While the algorithm dealt with the majority of presenting complaints, the most common problems not addressed by the chart were skin rashes (21%), mouth problems (8%), and eye problems (6%). The draft IMCI algorithm proved to be effective in the diagnosis of pneumonia, gastroenteritis, measles and malnutrition, but not malaria where its use without microscopy would result in considerable over-treatment, especially in a low transmission area or during a low transmission season in countries with seasonal malaria. The current algorithm would benefit from expansion to cover management of localized infections as well as skin, mouth and eye problems.

Algorithms↗
PubMed1997

Pallor as a clinical sign of severe anaemia in children: an investigation in the Gambia.

Anaemia associated with malaria is a major public health problem in African countries. Since most primary health facilities have to rely on physical signs and not laboratory tests to detect anaemic patients who need referral for blood transfusion, we have assessed the reliability of simple clinical signs to predict severe anaemia. A trained field assistant examined 368 children admitted to a tertiary care hospital, assessing the pallor of their eyelids (conjunctiva), palms and nailbeds, counting the respiratory rate, and looking for signs of respiratory distress. After the children's admission, their packed cell volume (PCV) was measured, and the need for transfusion and the outcomes were noted. A second observer examined 173 of these children so that interobserver variability in the detection of clinical signs could be assessed. A total of 27% of the 368 children had a PCV of < 15%. In a multiple regression analysis, definite pallor of the conjunctiva, definite pallor of the palms, and a "sick" appearance of the child were identified as independent significant predictors of a PCV of < 15%. The best predictor was a combination of definite pallor of the conjunctiva and pallor of the palms, with a sensitivity of 80% and a specificity of 85%. Inclusion of signs of respiratory distress did not improve the prediction. Pallor was a reproducible sign (weighted kappa statistic for the comparison between two observers: kappa = 0.6 for conjunctival pallor). We conclude that pallor can be used as a sign for referring children who may require blood transfusion.

Anemia↗
PubMed1996

Humidification of oxygen with unheated humidifiers in tropical climates.

In developing countries, oxygen therapy in hospitals is frequently humidified with unheated bubble-through humidifiers. We assessed the efficacy of humidification under such circumstances. The water temperature in the humidifier and the ambient air temperature were measured and compared to the oxygen flow rate. It was calculated that oxygen was cooled in the humidifier by 6.12 degrees C (95% CI: 5.88; 6.35) per liter of flow for flow rates up to 2 l/min. Using the average temperatures on the hospital ward in January and August, and the WHO-recommended flow rates of 0.5 l/min and 1 l/min, the relative humidity of the oxygen delivered to a child was estimated to be between 34% and 56%. We conclude that unheated bubble-through humidifiers achieve low humidity in oxygen in tropical climates. Some of the complications associated with the use of nasopharyngeal catheters for the delivery of oxygen might be explained by this, as oxygen of low humidity and temperature is delivered directly into the posterior nasopharynx.

Acute Disease↗