Inappropriate secretion of antidiuretic hormone in acute bacterial meningitis

Global Case Fatality of Bacterial Meningitis During an 80-Year Period: A Systematic Review and Meta-Analysis

Importance

The impact of vaccination, antibiotics, and anti-inflammatory treatment on pathogen distribution and outcome of bacterial meningitis over the past century is uncertain.

Objective

To describe worldwide pathogen distribution and case fatality ratios of community-acquired bacterial meningitis.

Data Sources

Google Scholar and MEDLINE were searched in January 2022 using the search terms bacterial meningitis and mortality.

Study Selection

Included studies reported at least 10 patients with bacterial meningitis and survival status. Studies that selected participants by a specific risk factor, had a mean observation period before 1940, or had more than 10% of patients with health care-associated meningitis, tuberculous meningitis, or missing outcome were excluded.

Data Extraction and Synthesis

Data were extracted by 1 author and verified by a second author. The study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Random-effects models stratified by age (ie, neonates, children, adults), Human Development Index (ie, low-income or high-income countries), and decade and meta-regression using the study period's year as an estimator variable were used.

Main Outcome and Measure

Case fatality ratios of bacterial meningitis.

Results

This review included 371 studies performed in 108 countries from January 1, 1935, to December 31, 2019, describing 157 656 episodes. Of the 33 295 episodes for which the patients' sex was reported, 13 452 (40%) occurred in females. Causative pathogens were reported in 104 598 episodes with Neisseria meningitidis in 26 344 (25%) episodes, Streptococcus pneumoniae in 26 035 (25%) episodes, Haemophilus influenzae in 22 722 (22%), other bacteria in 19 161 (18%) episodes, and unidentified pathogen in 10 336 (10%) episodes. The overall case fatality ratio was 18% (95% CI, 16%-19%), decreasing from 32% (95% CI, 24%-40%) before 1961 to 15% (95% CI, 12%-19%) after 2010. It was highest in meningitis caused by Listeria monocytogenes at 27% (95% CI, 24%-31%) and pneumococci at 24% (95% CI, 22%-26%), compared with meningitis caused by meningococci at 9% (95% CI, 8%-10%) or H influenzae at 11% (95% CI, 10%-13%). Meta-regression showed decreasing case fatality ratios overall and stratified by S pneumoniae, Escherichia coli, or Streptococcus agalactiae (P < .001).

Conclusions and Relevance

In this meta-analysis with meta-regression, declining case fatality ratios of community-acquired bacterial meningitis throughout the last century were observed, but a high burden of disease remained.

Meningitis in Children: Still a Can't-Miss Diagnosis

Although vaccination and antimicrobial treatment have significantly impacted the frequency and outcomes of meningitis in children, meningitis remains a critical can't-miss diagnosis for children, where early recognition and appropriate treatment can improve survival and neurologic outcomes. Signs and symptoms may be nonspecific, particularly in infants, and require a high index of suspicion to recognize potential meningitis and obtain the cerebrospinal fluid studies necessary for diagnosis. Understanding the pathogens associated with each age group and specific risk factors informs optimal empirical antimicrobial therapy. Early treatment and developmental support can significantly improve the survival rates and lifelong neurodevelopment of children with central nervous system infections.

Hyponatremia in tuberculous meningitis: A systematic review and meta-analysis

BACKGROUND

Tuberculous meningitis (TBM), manifests as the most severe involvement of the nervous system by Mycobacterium tuberculosis, it has a high mortality rate and a spectrum of systemic and neurological complications that can lead to debilitating or fatal sequelae, whereas hyponatremia is the commonly encountered life-threatening electrolyte disturbance. Thus, our study aimed to determine the prevalence, risk factors and differences in outcomes of hyponatremia in TBM.

METHODS

This systematic review was registered in PROSPERO (CRD42018088089). A comprehensive electronic search was conducted through ten databases to find relevant articles.

RESULTS

A total of 42 studies were included, 24 case reports and 18 retrospective studies. The prevalence rate of hyponatremia among TBM patients was 52% and the rate of death among those patients was 29%. The meta-regression analysis revealed that there was no significant effect of sodium level on the death rate in TBM patients (P-value = 0.9). Additionally, there was no significant difference in sodium level based on sex, and etiologies of hyponatremia.

CONCLUSIONS

Hyponatremia is commonly present in patient with TBM, but it is not significantly correlated to the rate of death. However, it is necessary to treat this potentially life-threatening condition appropriately according to its etiology, further research is needed on its pathophysiology in TBM, its risk factors, and the most appropriate treatment.

High Incidence of Hyponatremia in Patients Operated for Nonsellar/Suprasellar Supratentorial Tumors—A Prospective Observational Study

Background The incidence of hyponatremia is high in supratentorial tumors. However, most studies of supratentorial tumors have included patients with sellar/suprasellar tumors. It is common knowledge that sellar tumors have higher incidence and severity of hyponatremia. Incidence of hyponatremia is not known if we exclude sellar/suprasellar tumors. Therefore, this study was designed to evaluate the incidence of hyponatremia in supratentorial tumors after excluding sellar/suprasellar tumors.

Methods After institutional ethics committee approval and written informed consent, adult patients with supratentorial tumors (nonsellar/suprasellar) were recruited, and data were collected prospectively. In all patients, serum electrolytes were measured every 2 to 3 days. Hyponatremia was defined as serum sodium of <135 mEq/L. All the patients were followed up till death or discharge from the hospital.

Results A total of 61 patients’ data were analyzed. There were 31 male and 30 female patients with an average age of 44 years. There were 23 meningiomas, 36 gliomas, and 2 other tumors. Forty patients (66%) developed hyponatremia during hospital stay. There were 29 mild cases (serum sodium 131–134 mEq/L), 7 were moderate (serum sodium 126–130 mEq/L), and 4 were severe (serum sodium <126 mEq/L). Three hyponatremic meningioma patients died, of which two had mild hyponatremia and one had severe hyponatremia. Duration of hospital stay was longer in hyponatremic patients.

Conclusion The incidence of hyponatremia is high in supratentorial tumor patients after excluding sellar/suprasellar lesions. In the majority of patients, the disturbance is mild. Hyponatremic patients has a longer hospital stay and higher mortality.

Hyponatremia is associated with more severe biliary disease

BACKGROUND

Sodium level is an important clinical predictor of complex biliary disease. Hyponatremia has been observed in conjunction with biliary disease, however the nature of this association remains unclear.

AIM

To investigate the association between serum sodium and severe biliary disease.

METHODS

Of 920 patients with gallstone disease treated at the SFVA Hospital from 1989-2019 were studied. We conducted multivariate analyses of correlation between sodium level and biliary disease severity, the presence/location of biliary bacteria, and other factors. Minimum sodium level pre-intervention was collected. Gallstones, bile, and blood (as relevant) were cultured. Illness severity was characterized: (1) None (no infectious manifestations); (2) Systemic inflammatory response syndrome; (3) Severe illness (gangrenous cholecystitis, cholangitis, necrotizing pancreatitis); and (4) Multiple organ dysfunction syndrome (bacteremia, hypotension, organ failure). Comorbidity was defined using the Charlson Comorbidity Index (CCI).

RESULTS

Decreased sodium level significantly correlated with worsening illness severity, ascending bacterial infection, gangrenous changes, elevated CCI score, increasing age, male sex, and glucose. On multivariate analysis, all factors, except age, gender and glucose, independently correlated with sodium level and factors were additive.

CONCLUSION

This unique study is the first to explore, with such granularity, the relationship between biliary disease and sodium. No prior studies have examined specific culture and clinical data. It illustrates an inverse, independent correlation between illness severity and sodium. Culture data demonstrate that sodium decreases as infection ascends from gallstone colonization to bactibilia to bacteremia. Patient comorbidity and gangrenous changes also independently correlate with sodium on multivariate analysis. Sodium level is an important clinical indicator of disease severity for patients with biliary disease.

Hyponatremia in Children With Bacterial Meningitis

Background: Hyponatremia has frequently been described as a common complication associated with bacterial meningitis, though its frequency and clinical course in children with bacterial meningitis are unclear. The present study aimed to investigate the frequency, clinical characteristics, and prognosis associated with pediatric hyponatremia due to bacterial meningitis. Methods: We performed a retrospective review of children with bacterial meningitis provided with standard care. One hundred seventy-five children were included. We documented all participants' symptoms and signs, laboratory and microbiological data, radiological findings, and complications that occurred during their hospital admission. Disease severity was determined using the maximum Pediatric Cerebral Performance Category (PCPC) and minimum Glasgow Coma Scale (GCS). Residual deficits were assessed using PCPC at discharge. Results: Hyponatremia (<135 mmol/L) was seen in 116 (66.4%) of the patients assessed and was classified as mild (130-135 mmol/L) in 77, moderate (125-129 mmol/L) in 26, and severe (<125 mmol/L) in 13. Hyponatremia was associated with a shorter duration of symptoms before admission, higher CSF white cell counts, and a longer duration of hospitalization. Moderate and severe hyponatremia were associated with an increase in convulsions, impaired consciousness, altered CSF protein levels, higher maximum PCPC scores, and lower minimum GCS scores. Severe hyponatremia was further associated with the development of systemic complications including shock, multiple organ dysfunction syndrome, respiratory failure requiring mechanical ventilation, and an increase in poor outcome (PCPC ≥ 2). Hyponatremia was not associated with the development of neurologic complications. Logistic regression analyses revealed that convulsions (OR 12.09, 95% CI 2.63-56.84) and blood glucose levels > 6.1 mmol/L (OR 8.28, 95% CI 1.65-41.60) predicted severe hyponatremia. Conclusion: Hyponatremia occurred in 66.4% of the assessed pediatric bacterial meningitis patients. Moderate and severe hyponatremia affected the severity of pediatric bacterial meningitis. Only severe hyponatremia affected the short-term prognosis of patients with pediatric bacterial meningitis. We recommend that patients with pediatric bacterial meningitis who exhibit convulsions and increased blood glucose levels should be checked for severe hyponatremia. Further studies are needed to evaluate the effectiveness of treatment of hyponatremia.

Ticks and salt: an atypical case of neuroborreliosis

It is well documented that central nervous system (CNS) infections may lead to syndrome of inappropriate anti-diuretic hormone secretion (SIADH), but diagnosing these can prove difficult in patients with atypical presentations. We present a case of SIADH and muscle weakness in a patient without typical signs of CNS infection who was tested and diagnosed with neuroborreliosis based largely on her likelihood of exposure. This case indicates the need for Lyme testing in patients with unexplained SIADH who live in endemic areas. The patient was an 83-year-old female with a history of type 2 diabetes and hypertension, who presented from her primary care physician's office when her sodium was found to be 123 mEq/L. Her sole symptom was proximal muscle weakness. The diagnosis of SIADH was reached based on laboratory data. A trial of fluid restriction was initiated, but neither her sodium nor her muscle weakness improved. Lyme testing was performed as the patient lived in an endemic area and was positive. Lumbar puncture showed evidence of neurologic involvement. After realizing the appropriate treatment for hyponatremia in this case, intravenous ceftriaxone was started, and patient's sodium levels improved and muscle weakness resolved. Studies show that SIADH is associated with CNS infections, likely related to the inflammatory cascade. However, the atypical presentation of neuroborreliosis for our patient delayed the appropriate diagnosis and treatment. Our case demonstrates the need to screen for Lyme disease in endemic areas in patients presenting with neurologic symptoms and SIADH.

Hyponatraemia and neurological complications in children admitted with bronchiolitis

BACKGROUND

Hyponatraemia occurs during bronchiolitis, sometimes with neurological manifestations. The prevalence of the latter differs widely and little is known about the time of occurrence and associated factors. This study was undertaken to investigate these complications.

METHODS

This was a retrospective observational chart review of a cohort of 233 infants under 2 years of age admitted with bronchiolitis to a teaching hospital in the United Arab Emirates.

RESULTS

Hyponatraemia (serum sodium <135 mmol/L) occurred in 105 infants (45%, 95% CI 38-51). Hyponatraemia was present on admission in 84 infants (80%) with 90% of cases occurring within 6 days of the onset of illness. It was mild (130-135) in 100 infants (95%) and severe (<130) in five (5%). It was not significantly associated with age, duration of illness before admission, viral aetiology, white cell count or serum C-reactive protein concentrations, or the volume of administered intravenous fluid or use of 0.18% sodium chloride (NaCl). Neurological manifestations occurred in a 29-day-old child with a serum sodium level of 123 mmol/L while receiving two-thirds intravenous maintenance fluids (0.18% NaCl). His developmental milestones remained normal on follow-up to the age of 5 years.

CONCLUSION

Hyponatraemia is common in infants with bronchiolitis and occurs in the majority within 6 days of onset of symptoms. There was a significant association between the presence of fever (>38°C) on admission and the duration of hospitalisation.

A study of hyponatremia in tuberculous meningitis

SETTING

In view of paucity of studies on predictors of hyponatremia in tuberculous meningitis (TBM) and its influence on outcome, this study was undertaken.

OBJECTIVE

To study the frequency, predictors and prognosis of hyponatremia in TBM.

DESIGN

In this prospective hospital based study, 76 patients with TBM (definite 18 and probable 58) were enrolled. The severity of meningitis was graded as I-III and hyponatremia as severe (<120mEq/L), moderate (120-129mEq/L) or mild (130-134mEq/L). Hospital death was noted and functional outcome was assessed by modified Rankin Scale (mRS) on discharge.

RESULTS

34 (44.7%) TBM patients had hyponatremia (mild 3, moderate 23 and severe 8). Hyponatremia was due to cerebral salt wasting in 17, syndrome of inappropriate secretion of antidiuretic hormone in 3 and miscellaneous causes in 14 patients. Hyponatremia was related to GCS score and basal exudates. Outcome of TBM was related to duration of hospitalization, GCS score, focal deficit, mechanical ventilation, severity of TBM, age and comorbidities. Cerebral salt wasting was related to severity of TBM.

CONCLUSION

Hyponatremia occurred in 44.7% of TBM patients. Cerebral salt wasting was the commonest cause of hyponatremia and was related to the severity of TBM.

Intravenous maintenance fluid therapy in children

Intravenous fluids are frequently used in paediatrics but have been associated with significant adverse outcomes. Understanding the composition of fluid prescribed and administering an appropriate rate is essential for safe fluid administration, along with regular monitoring. Recent evidence has shown that using an isotonic fluid with a sodium concentration similar to plasma can decrease the risk of hyponatraemia without an increase in adverse effects. This should lead to a change in guidelines: isotonic fluid should now be used as the primary maintenance intravenous fluid given to the majority of children.

Hyponatremia in children with tuberculous meningitis: A hospital-based cohort study

Background:

Hyponatremia has long been recognized as a potentially serious metabolic consequence of tuberculous meningitis (TBM) occurring in 35–65% of children with the disease. The syndrome of inappropriate antidiuretic hormone (SIADH) secretion has for long been believed to be responsible for the majority of cases of hyponatremia in TBM. Cerebral salt wasting syndrome (CSWS) is being increasingly reported as a cause of hyponatremia in some of these children.

Aim:

This study was done to determine the frequency and causes of hyponatremia in children with TBM.

Methods:

Children with newly diagnosed TBM admitted over a 2-year period (January 2009 to December 2010) were included. All patients received anti-tubercular therapy, mannitol for cerebral edema, and steroids. Patients were monitored for body weight, urine output, signs of dehydration, serum electrolytes, blood urea nitrogen, serum creatinine, and urinary sodium. Hyponatremia was diagnosed if the serum sodium was <135 mEq/L. CSWS was diagnosed if there was evidence of excessive urine output, volume depletion, and natriuresis in the presence of hyponatremia. The outcome in terms of survival or death was recorded.

Results:

Twenty-nine of 75 children (38.7%) with TBM developed hyponatremia during their hospital stay. In 19 patients, hyponatremia subsided after the discontinuation of mannitol. Ten patients with persistent hyponatremia had CSWS. There were no patients with SIADH.

Conclusions:

CSWS is an important cause of hyponatremia in children with newly diagnosed TBM. In our patients, it was more commonly seen than SIADH.

140 mmol/L of sodium versus 77 mmol/L of sodium in maintenance intravenous fluid therapy for children in hospital (PIMS): a randomised controlled double-blind trial

BACKGROUND

Use of hypotonic intravenous fluid to maintain hydration in children in hospital has been associated with hyponatraemia, leading to neurological morbidity and mortality. We aimed to assess whether use of fluid solutions with a higher sodium concentration reduced the risk of hyponatraemia compared with use of hypotonic solutions.

METHODS

We did a randomised controlled double-blind trial of children admitted to The Royal Children's Hospital (Melbourne, VIC, Australia) who needed intravenous maintenance hydration for 6 h or longer. With an online randomisation system that used unequal block sizes, we randomly assigned patients (1:1) to receive either isotonic intravenous fluid containing 140 mmol/L of sodium (Na140) or hypotonic fluid containing 77 mmol/L of sodium (Na77) for 72 h or until their intravenous fluid rate decreased to lower than 50% of the standard maintenance rate. We stratified assignment by baseline sodium concentrations. Study investigators, treating clinicians, nurses, and patients were masked to treatment assignment. The primary outcome was occurrence of hyponatraemia (serum sodium concentration <135 mmol/L with a decrease of at least 3 mmol/L from baseline) during the treatment period, analysed by intention to treat. The trial was registered with the Australian New Zealand Clinical Trials Registry, number ACTRN1260900924257.

FINDINGS

Between Feb 2, 2010, and Jan 29, 2013, we randomly assigned 690 patients. Of these patients, primary outcome data were available for 319 who received Na140 and 322 who received Na77. Fewer patients given Na140 than those given Na77 developed hyponatraemia (12 patients [4%] vs 35 [11%]; odds ratio [OR] 0·31, 95% CI 0·16-0·61; p=0·001). No clinically apparent cerebral oedema occurred in either group. Eight patients in the Na140 group (two potentially related to intravenous fluid) and four in the Na77 group (none related to intravenous fluid) developed serious adverse events during the treatment period. One patient in the Na140 had seizures during the treatment period compared with seven who received Na77.

INTERPRETATION

Use of isotonic intravenous fluid with a sodium concentration of 140 mmol/L had a lower risk of hyponatraemia without an increase in adverse effects than did fluid containing 77 mmol/L of sodium. An isotonic fluid should be used as intravenous fluid for maintenance hydration in children.

FUNDING

National Health and Medical Research Council, Murdoch Childrens Research Institute, The Royal Children's Hospital, and the Australian and New Zealand College of Anaesthetists.

Incidence, Etiology and Outcomes of Hyponatremia after Transsphenoidal Surgery: Experience with 344 Consecutive Patients at a Single Tertiary Center

Hyponatremia is often seen after transsphenoidal surgery and is a source of considerable economic burden and patient-related morbidity and mortality. We performed a retrospective review of 344 patients who underwent transsphenoidal surgery at our institution between 2006 and 2012. Postoperative hyponatremia was seen in 18.0% of patients at a mean of 3.9 days postoperatively. Hyponatremia was most commonly mild (51.6%) and clinically asymptomatic (93.8%). SIADH was the primary cause of hyponatremia in the majority of cases (n = 44, 71.0%), followed by cerebral salt wasting (n = 15, 24.2%) and desmopressin over-administration (n = 3, 4.8%). The incidence of postoperative hyponatremia was significantly higher in patients with cardiac, renal and/or thyroid disease (p = 0.0034, Objective Risk (OR) = 2.60) and in female patients (p = 0.011, OR = 2.18) or patients undergoing post-operative cerebrospinal fluid drainage (p = 0.0006). Treatment with hypertonic saline (OR = −2.4, p = 0.10) and sodium chloride tablets (OR = −1.57, p = 0.45) was associated with a non-significant trend toward faster resolution of hyponatremia. The use of fluid restriction and diuretics should be de-emphasized in the treatment of post-transsphenoidal hyponatremia, as they have not been shown to significantly alter the time-course to the restoration of sodium balance.

Inflammation and hyponatremia: an underrecognized condition?

Timely diagnosis of hyponatremia is important for preventing potential morbidity and mortality as it is often an indicator of underlying disease. The most common cause of eurvolemic hyponatremia is the syndrome of inappropriate antidiuretic hormone (SIADH) secretion. Recent studies have demonstrated that proinflammatory cytokines such as interleukin (IL) 1β and IL-6 are involved in the development of hyponatremia, a condition that is associated with severe inflammation and is related to antidiuretic hormone (ADH) secretion. Serum sodium levels in hyponatremia are inversely correlated with the percentage of neutrophils, C-reactive protein, and N-terminal-pro brain type natriuretic peptide. Additionally, elevated levels of serum IL-6 and IL-1β are found in inflammatory diseases, and their levels are higher in patients with hyponatremia. Because it is significantly correlated with the degree of inflammation in children, hyponatremia could be used as a diagnostic marker of pediatric inflammatory diseases. Based on available evidence, we hypothesize that hyponatremia may be associated with inflammatory diseases in general. Understanding the mechanisms responsible for augmented ADH secretion during inflammation, monitoring patient sodium levels, and selecting the appropriate intravenous fluid treatment are important components that may lower the morbidity and mortality of patients in a critical condition.

Hyponatremia in patients with infectious diseases

Hyponatremia is a common electrolyte disturbance associated with considerable morbidity and mortality. Hyponatremia may not infrequently be present during the course of an infection, does not cause specific symptoms and may be overlooked by clinicians. Nonetheless, it may reflect the severity of the underlying process. This review focuses on the clinical and pathophysiological aspects of hyponatremia associated with infectious diseases. In the majority of cases, the fall in serum sodium concentration is of multifactorial origin owing to increased secretion of the anti-diuretic hormone either appropriately or inappropriately. Inadvertent administration of fluids may worsen hyponatremia and prolong morbidity.

Neurobrucellosis associated with syndrome of inappropriate antidiuretic hormone with resultant diabetes insipidus and hypothyroidism

Neurological involvement of the central nervous system in brucellosis is uncommon. We describe a rare case of meningoencephalitis due to Brucella melitensis infection, associated with the syndrome of inappropriate antidiuretic hormone secretion and leading to diabetes insipidus and hypothyroidism. Neurobrucellosis, although rare, should be considered in cases of neurological disease of unknown etiology.

Hyponatremia in the neurosurgical patient: epidemiology, pathophysiology, diagnosis, and management

OBJECTIVE

Hyponatremia is an important and common electrolyte disorder in critically ill neurosurgical patients that has been reported in association with a number of different primary diagnoses. The correct diagnosis of the pathophysiological cause is vital because it dramatically alters the treatment approach.

METHODS

We review the epidemiology and presentation of patients with hyponatremia, the pathophysiology of the disorder with respect to sodium and fluid balance, and the diagnostic procedures for determining the correct cause.

RESULTS

We then present the various treatment options, including discussion of one of the newest groups of agents, the arginine vasopressin receptor antagonists, currently under study for the treatment of hyponatremia in neurosurgical patients.

CONCLUSION

Hyponatremia is a serious comorbidity in neurosurgical patients that requires particular attention as its treatment varies by cause and its consequences can affect neurological outcome.

Hypotonic vs isotonic saline solutions for intravenous fluid management of acute infections

BACKGROUND

Hypotonic saline is commonly used as maintenance fluid in the management of acute infections. In recent years use of a hypotonic saline has been associated with adverse outcomes. To reduce the rates of adverse outcomes, use of isotonic saline as maintenance fluid has been suggested.

OBJECTIVES

To asses adverse events and benefits associated with infusion of hypotonic saline compared to isotonic saline solutions in the management of acute infections.

SEARCH STRATEGY

We searched MEDLINE, EMBASE, The Cochrane Controlled Trials Register, current controlled trials and the Specialised register of the Injuries Group.

SELECTION CRITERIA

Randomised trials comparing hypotonic saline to isotonic saline in the management of acute infections.

DATA COLLECTION AND ANALYSIS

Three reviewers independently evaluated all potentially relevant articles, examined each study for possible inclusion and assessed the methodology quality using the Cochrane guidelines.

MAIN RESULTS

No trials met our inclusion criteria.

REVIEWERS' CONCLUSIONS

We found no randomised controlled evidence to show that use of isotonic saline as a maintenance fluid instead of a hypotonic saline will lead to an improvement in outcomes. Randomised trials with adequate design and sample sizes are needed to evaluate the possible advantages and risks of using isotonic saline as maintenance fluid.

Are Haemophilus influenzae infections a significant problem in India? A prospective study and review

It has been suggested Haemophilus influenzae serotype b (Hib) disease is uncommon in Asia. During 1993--1997, we conducted prospective surveillance of acute infections caused by H. influenzae in 6 academic referral Indian hospitals. The study included 5798 patients aged 1 month to 50 years who had diseases likely to be caused by H. influenzae; 75% of the patients were aged <5 years. A total of 125 H. influenzae infections were detected, 97% of which were caused by Hib. Of 125 isolates, 108 (86%) were from children aged <5 years, and 11 (9%) were from adults aged >18 years. Sixty-two percent of the patients had meningitis. The case-fatality rate was 11% overall and 20% in infants with Hib meningitis. Up to 60% of all isolates were resistant to chloramphenicol, ampicillin, trimethoprim-sulfamethoxazole, or erythromycin; 32% were resistant to >/= 3 antimicrobial drugs, but none were resistant to third-generation cephalosporins. These data suggest that available Hib vaccines will benefit Indian children.

La Crosse encephalitis in children

BACKGROUND

La Crosse encephalitis is a mosquito-borne disease that can be mistaken for herpes simplex encephalitis. It has been reported in 28 states but may be underrecognized.

METHODS

We investigated the manifestations and clinical course of La Crosse encephalitis in 127 patients hospitalized from 1987 through 1996. The diagnosis was established by serologic testing for IgM and IgG antibodies to La Crosse virus. Data were collected by chart review.

RESULTS

Most of the patients were school-aged children (mean [+/-SD] age, 7.8+/-3.5 years; range, 0.5 to 15.0). Symptoms included headache, fever, and vomiting (each in 70 percent or more of the patients), seizures (in 46 percent), and disorientation (in 42 percent). Thirteen percent had aseptic meningitis. Hyponatremia developed in 21 percent, and there were signs of increased intracranial pressure in 13 percent. Six patients, including three with cerebral herniation, underwent intracranial-pressure monitoring. The 13 patients (11 percent) whose condition deteriorated in the hospital had decreases in serum sodium levels (P=0.007), and increases in body temperature (P=0.003) at the time of deterioration. At admission, these patients more often had a history of vomiting (P=0.047) and a score of 12 or lower on the Glasgow Coma Scale (P=0.02) than the others; a trend toward a greater prevalence of seizures at admission was also evident in this group (P=0.07). All the patients survived, but 15 of them (12 percent) had neurologic deficits at discharge. Follow-up assessments, performed in 28 children, suggested an increase in cognitive and behavioral deficits 10 to 18 months after the episode of encephalitis.

CONCLUSIONS

La Crosse virus infection should be considered in children who present with aseptic meningitis or encephalitis. Hyponatremia and increasing body temperature may be related to clinical deterioration.

Haemophilus influenzae disease in children in India: a hospital perspective

We review and summarize published information on diseases caused by Haemophilus influenzae in India and unpublished data from our center covering more than three decades. Since the mid-1950s H. influenzae has been the most common cause of pyogenic meningitis in children admitted to our hospital, accounting for one-third to one-half of cases. Information from other centers in India has been scanty; the lower frequency of isolation of Haemophilus in studies in some centers may be caused by unsatisfactory media and culture methods. The annual numbers of admissions for pyogenic meningitis in our hospital have been quite similar to the numbers of cases of poliomyelitis. Assuming that the similar numbers of children hospitalized with these two diseases indicate similar incidence rates in the community and taking into account the frequency of Haemophilus isolations in pyogenic meningitis, we estimate that there may be as many as 75 to 100 cases of meningitis caused by this organism per year per 100000 children <5 years of age. Although pneumonia caused by H. influenzae has been recognized in a few studies, information is too scanty to attempt the estimation of incidence. Pus-producing infections caused by Haemophilus are rare. Epiglottitis caused by Haemophilus does not seem to occur in India. In recent years we have found that most invasive Haemophilus infections are caused by H. influenzae type b (Hib); other types or untypable strains are infrequent. An increasing prevalence of resistance to chloramphenicol and ampicillin has been recognized in our center and elsewhere. Thus from a hospital perspective, primary prevention by using Hib vaccine seems to be a rational and beneficial intervention. Community-based studies to measure the disease burden of Hib are urgently needed for a more satisfactory assessment of the need for, and cost benefit of, Hib immunization of all infants.