1,218 research outputs found
Charge order suppression and antiferromagnetic to ferromagnetic switch over in Pr_0.5Ca_0.5MnO_3 nanowires
We have prepared crystalline nanowires (diameter ~ 50 nm, length ~ a few
microns) of the charge ordering manganite Pr_0.5Ca_0.5Mn_O3 using a low
reaction temperature hydrothermal method and characterized them using X-ray
diffraction, transmission electron microscopy, SQUID magnetometry and electron
magnetic resonance measurements. While the bulk sample shows a charge ordering
transition at 245 K and an antiferromagnetic transition at 175 K, SQUID
magnetometry and electron magnetic resonance experiments reveal that in the
nanowires phase, a ferromagnetic transition occurs at ~ 105 K. Further, the
antiferromagnetic transition disappears and the charge ordering transition is
suppressed. This result is particularly significant since the charge order in
Pr_0.5Ca_0.5MnO_3 is known to be very robust, magnetic fields as high as 27 T
being needed to melt it.Comment: 12 pages including 4 figures. submitted to Applied Physics Letter
Ethambutol induced optic neuritis: a case series
Ethambutol is one of the first line chemotherapeutic agents used in the treatment of tuberculosis used both in the intensive and continuation phase according to the new Revised National Tuberculosis Control Program guidelines. Patient acceptability is rather good with this drug as it produces comparatively lesser adverse effects. The most important and serious side effect reported is optic neuritis, resulting in loss of visual acuity, color vision and field defects. The incidence of optic neuritis is generally directly proportional to the dose and duration of ethambutol therapy. Here we report four cases of ethambutol induced optic neuritis in patients on fixed dose combinations (FDC) of ethambutol, isoniazid, pyrazinamide and rifampicin who presented in Ophthalmology OPD in a span of 2 months, between June and July 2019. Contradictory to the rare occurrence of ethambutol induced optic neuritis this comparatively higher incidence of optic neuritis is alarming. We observed that the presentation of ethambutol induced optic neuritis can vary and dose of ethambutol along with other factors can also contribute to it. So proper pre-treatment evaluation, dosage adjustment, periodic monitoring and early detection have a significant role in prevention and treatment of ethambutol induced optic neuritis
Gender inequality in hands-only cardiopulmonary resuscitation videos on YouTube
Background: Bystander cardiopulmonary resuscitation (CPR) is performed at a significantly lower rate in women than in men. YouTube has a significant role in influencing the publicās perceptions about CPR due to its popularity. The aim of the study was to compare the availability, quality, and scientific accuracy of YouTube videos demonstrating hands-only CPR performed on men and woman recipient.Methods: Using three search terms similar to hands-only CPR, YouTube was searched for videos in English. This study included the first 60 videos for each search term. All the videos meeting the inclusion criteria were viewed and classified according to gender of recipient of CPR. Views per day were calculated. Videos were scored for quality and scientific accuracy, using Global Quality Scale (GQS) score and comprehensiveness analysis respectively. Mean, standard deviation was calculated for all the variables. Independent t-tests were done to compare the mean values. A p value<0.05 was considered significant.Results: Only 12 (1.7%) videos demonstrated hands-only CPR performed on women as compared to 43 videos (6%) demonstrated in men. There was a statistically significant difference in GQS score, whereas, there was no statistically significant difference in viewer rate and comprehensiveness analysis score based upon the gender of recipient of CPR.Conclusions: The availability and quality of YouTube videos demonstrating hands-only CPR performed on men and women recipients differ significantly. There are limited numbers of videos available for demonstrations of CPR performed on women, and the majority of them are of poor quality and lack scientific accuracy
Digital Twin Technology in Internet of Things (IOT)
Developments in virtual technology and data acquisition technology put way to digital twin (DT) technology. Digital twin is a virtual entity that is linked to a real-world entity. Both the link and the virtual representation can be realized in several different ways. Digital Technology plays a very much key role in different areas like in production management, manufacturing, health care, smart cities and so on. Mainly Digital Twin Technology is developed to improve manufacturing processes. With the development of new-generation information and digitalization technologies, more data can be collected, and it is time to find a way for the deep application of all these data. As a result, the concept of digital twin has aroused much concern and is developing rapidly. Digital twins facilitate to monitor, understand, and optimize the functions of all physical entities and for humans and also provide continuous feedback to improve quality of life and well-being. Digital Twin is best described as the effortless integration of data between a physical and virtual machine in either direction. This paper provides an overview of the Digital Twin technology used in different work spaces and also how it will be effective in the Internet of Things network
Host range of Phellinus sensu lato in India: An overview
Phellinus Quel. is a member of family Hymenochaetaceae of the order Hymenochaetales. This genus comprises wood-inhabiting, saprophytic and parasitic species. Species of Phellinus sensu lato are known to have large host range and cause white rot of various types to live standing or dead trees from all over the world. The current study is based on a thorough study of literature to document the host range of Phellinus species from India. The study indicated that one hundred and seventy four plant species from 51 families are found to be infected by Phellinus species. The families found to be the most affected are Fabaceae, Combretaceae, Meliaceae, Dipterocarpaceae, Anacardiaceae, Myrtaceae, Meliaceae, Lauraceae, Fagaceae, Rosaceae.Ā Many plant (tree) species are affected by Phellinus; this establishes it as a potential pathogen and wood decay fungi. The present study also reports Phellinus from almost all over India and every climatic zones. This indicated the high tolerance and acclimatization of Phellinus towards diverse climatic conditions. The most affected host is Artocarpus followed by Terminalia and Acacia. Although the study reports Phellinus from diverse climatic zones of India, the most affected families and genera are from moist tropical conditions. This indicates that Phellinus has vigorous activity in warm and moist areas and affects diverse plant/tree species in these areas like Maharashtra and Kerala. The states like Uttar Pradesh, Bihar, Jharkhand, Odisha, Rajasthan, Karnataka, Andhra Pradesh, Telengana, Union Territories, Manipur, Mizoram and Nagaland are still left to be explored. The present study has key significance in biodiversity, medicinal as well as the pathogenic study of Phellinus. It provides an overall host range of genus Phellinus, confirming its vast host diversity. The information could further be used in disease, biodiversity and plant pathological assessments
Lysis of vibrio cholerae cells: direct isolation of the outer membrane from whole cells by treatment with urea
Cells of Vibrio cholerae underwent rapid autolysis when suspended in media of low osmolarity under non-growing conditions. Chaotropes like urea and guanidine. HCl which are potent protein denaturants caused complete and immediate lysis of whole cells. This unique sensitivity of V. cholerae to protein denaturants led to the development of a rapid method for the selective isolation of the outer membrane upon treatment of whole cells with urea. The composition of the outer membrane isolated from both whole cells and crude envelopes by treatment with urea was comparable with that of the outer membrane isolated by other conventional methods
Congestion Aware WSN-IoT-Application Layer Protocols for Healthcare Services
In the healthcare industry, WSN-IoT networks can be used to gather patient data for statistical purposes. IoT-based application-level protocols do not take into account these facts while forwarding the data to the gateway or server, which may degrade the network performance if the data was collected from a patient with ordinary/critical health issues and the route was busy or congested. In this paper, we'll look at the performance of two application layer protocols (i.e. CoAP and MQTT) within the constraints of a scalable network by integrating a congestion-aware scheme with them
Comparison of LMA Fastrach and I-GEL as a conduit for Blind Tracheal Intubation
INTRODUCTION:
The major responsibility of the anaesthesiologist is to provide adequate ventilation to the patient. The most vital element in providing functional respiration is the airway.
Management of the airway has come a long way since the
development of endotracheal intubation by Macewen in 1880 to present day use of modern and sophisticated airway devices.
Using an endotracheal tube to secure a patient's airway is still the gold standard. Most routine orotracheal or nasotracheal intubations are performed with the help of a laryngoscope that has a curved or straight blade.
Difficulties encountered during intubation can be due to a number of factors and may be difficult to predict. It is important to have a strategy prepared and to be familiar with the equipment. This will help to avoid potential morbidity or mortality from the sequelae of hypoxia and/or cardiovascular catastrophe that may result from a failed intubation.
The anaesthesiologist must be familiar with the major decision making components of the difficult airway algorithm. Over the years many attempts have been made to address various factors responsible for difficult intubations and this has resulted in a number of different techniques. It is best to use affordable, safe and useful adjuncts that are best suited to our particular anaesthetic set up.
Insertion of a supraglottic device in these situations is a
recognised alternative and may be a life-saving procedure. Some supraglottic devices allow for subsequent tracheal intubation using a blind or a fibreoptic technique. Tracheal intubation through a classical laryngeal mask airway had been extensively studied and is more time consuming.
One device commonly used as a conduit for intubation is the
intubating laryngeal mask airway (ILMA). The ILMA has been the āgold standardā among the supraglottic airway devices since 1997. It has showed a high success rate for blind or fibreoptic-guided tracheal intubation in patients with both expected and unexpected difficult airways.
I-GEL supraglottic airway (Intersurgical Ltd., Wokingham, UK) is a relatively new device for airway management. It is made from Styrene Ethylene Butadiene Styrene and is anatomically preformed to mirror the peri-laryngeal structures. It can be described as an uncuffed peri-laryngeal sealer according to Millerās classification.
We chose the I-GEL airway in comparison with the ILMA mainly
because both devices allow direct tracheal intubation. I-GEL airway has some potential benefits over the ILMA: it is disposable, cheap and has an additional channel for drainage of gastric contents. Moreover, insertion of the I-GEL is usually easy and quick.
Furthermore, its wide bore facilitates direct passage of a standard size tracheal tube. It can be a useful adjunct to tracheal intubation in patients with difficult airway as documented in several case reports.
Data for the I-GEL airway as a conduit for blind endotracheal intubation is not available as only case reports have been published.
Hence a prospective randomized single blind study was designed to compare the new supraglottic airway device, I-GEL, to ILMA as a conduit for blind endotracheal intubation in patients undergoing elective surgery under general anaesthesia.
AIM OF THE STUDY:
The aim of the study is to compare two supraglottic airway
devices: I-GEL and Intubating LMA as a conduit for blind endotracheal intubation in patients undergoing elective surgery under general anaesthesia. We compare the two devices on the following metrics:
1. First attempt success rate for blind endotracheal intubation through the supraglottic airway device.
2. Total time required for the successful blind endotracheal intubation through the supraglottic airway device.
3. Ease of placement of supraglottic airway device
a) Number of attempts required for the placement of the supraglottic airway device.
b) Time required for the placement of the supraglottic airway device.
MATERIALS AND METHODS:
Study Design:
This study was a single blind, randomized, prospective
comparative study conducted in Government Stanley Medical College and Hospital, Chennai.
Study Setting and Population:
The Institutional Ethical committee approval was obtained before commencement of the study. Written informed consent was obtained from all the patients. Eighty adult patients of ASA Physical status 1 & 2 of either sex undergoing elective surgical procedures under general anaesthesia were enrolled in the study.
The study was conducted at the General Surgery theatre complex, Stanley Medical College and Hospital, Chennai. The study was conducted from January 2010 to October 2010. The supraglottic airway device insertion and blind tracheal intubation was done by the author.
PATIENT SELECTION:
Inclusion criteria:
1. Age 20 to 50 years,
2. Both sexes,
3. Weight 40-70 kg.,
4. Mallampatti 1 & 2,
5. ASA physical status 1-2,
6. Patients undergoing elective surgery under general anaesthesia,
requiring endotracheal intubation.
Exclusion Criteria:
1. Patients with limited mouth opening (less than 2 cm).
2. Anticipated difficult airway.
3. Patients at increased risk of aspiration, or having a history of symptomatic gastro-esophageal reflux or hiatus hernia.
4. Symptoms related to laryngo-pharyngeal anomaly.
5. Musculoskeletal abnormalities affecting the cervical vertebrae.
MATERIALS:
1. Intubating Laryngeal mask airway (ILMA),
2. I-GEL,
3. Endo-tracheal tube,
4. IV cannulae,
5. Monitors,
6. Drugs for general anaesthesia.
STUDY METHOD:
After obtaining ethical committee approval, the patients were randomized into one of the two groups using a closed envelope method with predetermined group numbers and then single-blinded.
1. Group A: I-GEL for airway management,
2. Group B: ILMA for airway management.
Patients were advised for preoperative overnight fasting for 8 hours. They were given aspiration prophylaxis with Tab Ranitidine 150 mg and Tab Metoclopramide 10 mg on the night before surgery and Inj. Glycopyrrolate 5mcg/kg im, one hour before induction.
SUMMARY:
Insertion of supraglottic airway and tracheal intubation through it may be indicated where conventional laryngoscopy fails. The ILMA was specially designed for this purpose. IGEL, a relatively new device has some benefits: disposable, cheap & its wide bore facilitate direct passage of a standard size tracheal tube. It can be a useful adjunct to tracheal intubation in patients with difficult airway as documented in several case reports.
A prospective randomized single blind study was designed to
compare the supraglottic airway devices I-GEL and ILMA as a conduit for blind endotracheal intubation in patients undergoing elective surgery under general anaesthesia.
After obtaining the Institutional Ethical committee approval, eighty adult patients of ASA Physical status 1 & 2 of either sex undergoing elective surgical procedures under general anaesthesia wererandomly allocated into two groups, Group A: IGEL(n=40) and Group B: ILMA (n=40). Ease of tracheal intubation was assessed by the first attempt success rate, the total time required for the intubation. Ease of supraglottic device insertion was also assessed by the number of attempts and the time required for the device placement. Any complication during intubation was noted.
The study showed no significant difference between the two
groups based on the demographic variables. The mean insertion time for I-GEL was significantly less than ILMA (p<0.05). There was no statistical difference between the two groups in number of attempts required for the placement of the supraglottic airway device.
The overall success rate, as well as the first attempt success rate for blind endotracheal intubation was high in the ILMA and were 95% and 87.5% respectively. The failure rate for blind endotracheal intubation through the supraglottic device was significantly high in the I-GEL (27.5%) with high incidence of esophageal intubation when compared to ILMA (p<0.05). The mean time for tracheal intubation was equal in both the groups.
The time required for supraglottic device removal was
significantly less for I-GEL (p<0.05). There was no statistically significant difference in the total time required for successful endotracheal intubation (including the time for airway insertion, tracheal intubation, device removal) between both the groups. Complications like oesophageal intubation and mucosal trauma were high with the IGEL.
CONCLUSION:
We conclude that, based on the results of our study, I-GEL aids easy and rapid insertion as a supraglottic airway device, but when it is used as a conduit for blind endotracheal intubation, the failure rate is high as there is more incidence of oesophageal intubation. In contrary, ILMA being a gold standard device meant for intubation guide, has a high first attempt success rate for blind endotracheal intubation
Prevalence and Diagnosis of Acute Bacterial Meningitis in a Tertiary Care Centre.
INTRODUCTION:
Definition
Bacterial meningitis is an acute purulent infection within the subarachnoid
Space or throughout the leptomeninges. It is associated with the cns
Inflammatory reaction that may result in decreased consciousness, seizures, raised
Intracranial pressure (icp) and stroke. The meninges, the subarachnoid space, and
The brain parenchyma are all frequently involved in the inflammatory reaction.
Epidemiology
Bacterial meningitis, an infection of the membranes (meninges) and
Cerebrospinal fluid (csf) surrounding the brain and spinal cord, is a major cause
Of death and disability worldwide. Beyond the perinatal period, three organisms
Transmitted from person to person through the exchange of respiratory secretions
Are responsible for most cases of bacterial meningitis: neisseria meningitidis,
Haemophilus influenzae and streptococcus pneumoniae. The etiology of bacterial
Meningitis varies with age and region of the world. Worldwide, without epidemics
One million cases of bacterial meningitis are estimated to occur and 200,000 of
These die annually. Case-fatality rates vary with age at the time of illness and the
Species of bacterium causing infection, but typically range from 3 to 19% in
Developed countries. Higher case-fatality rates (37-60%) have been reported in
Developing countries. Up to 54% of survivors are left with disability due to
Bacterial meningitis, including deafness, mental retardation, and neurological
Sequelae.
The epidemiology of bacterial meningitis has changed significantly in
Recent years, reflecting a dramatic decline in the incidence of meningitis due to
Haemophilus influenzae, and a smaller decline in that due to neisseria
Meningitidis, following the introduction and increasingly widespread use of
Vaccines for both these organisms.
Currently, the organisms most commonly responsible for community
Acquired bacterial meningitis are streptococcus pneumoniae (50%), n.
Meningitidis (25%), group b streptococci (15%) and listeria monocytogenes
(10%). H. Influenzae now accounts for <10% of cases of bacterial meningitis in
Most series. Many other microbes and organisms, including mycobacterium
Tuberculosis, bacteria, fungi, protozoa and worms, may also cause meningitis or
Meningeal inflammation. In economically advanced countries, the mortality of
Bacterial meningitis is less than 10 percent but it may be 30 percent or more in
Developing countries (greenwood 1987; bryan et al. 1990; bijlmer 1991).
The epidemiology is changing swiftly following the development of
Conjugated polysaccharide vaccines for invasive hib disease, for meningococcal
Meningitis caused by serogroups a, c, y, and w-135 and for pneumococcal
Meningitis caused by a range of common serotypes. Bacterial meningitis carries a
High mortality and morbidity if untreated or treated late. The success of parenteral
Antibiotic therapy depends on early diagnosis.
Bacterial profile of meningitis
S. Pneumoniae is the most common cause of meningitis in adults >20 years
Of age, accounting for nearly half the reported cases (1.1 per 100,000 persons per
Year). S. Pneumoniae is acquired through the respiratory route. There are a number
Of predisposing conditions that increase the risk of pneumococcal meningitis, the
Most important of which is pneumococcal pneumonia. Additional risk factors
Include coexisting acute or chronic pneumococcal sinusitis or otitis media,
Alcoholism, diabetes, splenectomy, hypogammaglobulinemia, complement
Deficiency, and head trauma with basilar skull fracture and csf rhinorrhea.
Mortality remains ~20% despite antibiotic therapy.
N. Meningitidis accounts for 25% of all cases of bacterial meningitis (0.6
Cases per 100,000 persons per year) and for up to 60% of cases in children and
Young adults between the ages of 2 and 20. N. Meningitidis is classified into
Serogroups based on the immunological reactivity of the capsular polysaccharide.
Although 12 serogroups have been identified, the three serogroups a, b and c
Account for over 90% of meningococcal disease. Meningococcal disease differs
From other leading causes of bacterial meningitis because of its potential to cause
Large-scale epidemics. A region of sub-saharan africa extending from ethiopia in
The east to the gambia in the west and containing fifteen countries and over 260
Million people is known as the āmeningitis beltā because of its high endemic rate
Of disease with superimposed, periodic, large epidemics caused by serogroup a,
And to a lesser extent, serogroup c.
During epidemics, children and young adults are most commonly affected,
With attack rates as high as 1,000/100,000 population, or 100 times the rate of
Sporadic disease. The highest rates of endemic or sporadic disease occur in
Children less than 2 years of age. In developed countries, endemic disease is
Generally caused by serogroups b and c. Epidemics in developed countries are
Typically caused by serogroup c although epidemics due to serogroup b have also
Occurred in brazil, chile, cuba, norway and more recently in new zealand.
The presence of petechial or purpuric skin lesions can provide an important
Clue to the diagnosis of meningococcal infection. In some patients the disease is
Fulminant, progressing to death within hours of symptom onset. Infection may be
Initiated by nasopharyngeal colonization, which can result in either an
Asymptomatic carrier state or invasive meningococcal disease. The risk of invasive
Disease following nasopharyngeal colonization depends on both bacterial virulence
Factors and host immune defense mechanisms, including the host's capacity to
Produce antimeningococcal antibodies and to lyse meningococci by both classic
And alternative complement pathways. Individuals with deficiencies of any of the
Complement components, including properdin, are highly susceptible to
Meningococcal infections.
H. Influenzae causes meningitis in unvaccinated children and adults.
Meningitis caused by h. Influenzae occurs mostly in children under the age of 5
Years and most cases are caused by organisms with the type b polysaccharide
Capsule (h. Influenzae type b, hib).the frequency of h. Influenzae type b
Meningitis in children has declined dramatically since the introduction of the hib
Conjugate vaccine, although rare cases of hib meningitis in vaccinated children
Have been reported. While most children are colonized with a species of h.
Influenzae, only 2-15% harbour hib. H. Influenzae is acquired through the
Respiratory route. An essential virulence factor which plays a major role in
Determining the invasive potential of an organism is the polysaccharide capsule of
Hib. Meningitis is the most severe form of hib disease. In most countries,
However more cases and deaths are due to pneumonia than to meningitis.
Escherichia coli k1 are an increasingly common cause of meningitis in
Individuals with chronic and debilitating diseases such as diabetes, cirrhosis, or
Alcoholism and in those with chronic urinary tract infections. Gram-negative
Meningitis can also complicate neurosurgical procedures, particularly craniotomy.
Group b streptococcus or s.agalactiae was previously responsible for
Meningitis predominantly in neonates, but it has been reported with increasing
Frequency in individuals >50 years of age, particularly those with underlying
Diseases.
Neonatal bacterial meningitis (bacterial meningitis in the first month of life)
Is rare but serious, with a mortality up to 30ā40 percent and permanent sequelae in
Up to 30 percent of survivors. The causative organisms are different from those of
Bacterial meningitis at other ages, since most bacterial meningitis in this age group
Is due to organisms derived from ascending infection in utero or from the birth
Canal during delivery (de louvois 1994). Occasionally outbreaks occur in hospital
Nurseries. Neonatal bacterial meningitis is almost always preceded by bacteremia.
In uk, the principal causative organisms are gram negative enteric bacilli and
Group b streptococci. The latter can cause early onset or late onset disease as long
As 3ā4 months after birth. Other bacteria, including pneumococci, listeria
Monocytogenes, meningococci, other streptococci, and staphylococcus aureus,
Can also cause neonatal meningitis.
L. Monocytogenes has become an increasingly important cause of
Meningitis in neonates (60 years,
And immunocompromised individuals of all ages. Infection is acquired by
Ingesting foods contaminated by listeria. Foodborne human listerial infection
Has been reported from contaminated milk, soft cheeses, and several types of
"ready-to-eat" foods, including delicatessen meat and uncooked hotdogs.
Staphylococcus aureus and coagulase negative staphylococci are
Important causes of meningitis that occurs following invasive neurosurgical
Procedures, particularly shunting procedures for hydrocephalus, or as a
Complication of the use of subcutaneous ommaya reservoirs for administration of
Intrathecal chemotherapy.
Pathophysiology
The most common bacteria that cause meningitis, s. Pneumoniae and n.
Meningitidis, initially colonize the nasopharynx by attaching to nasopharyngeal
Epithelial cells. Bacteria are transported across epithelial cells in membrane bound
Vacuoles to the intravascular space or invade the intravascular space by creating
Separations in the apical tight junctions of columnar epithelial cells. Once in the
Bloodstream, bacteria are able to avoid phagocytosis by neutrophils and classic
Complementāmediated bactericidal activity because of the presence of a
Polysaccharide capsule. Bloodborne bacteria can reach the intraventricular choroid
Plexus, directly infect choroid plexus epithelial cells, and gain access to the csf.
Some bacteria such as s. Pneumoniae can adhere to cerebral capillary endothelial
Cells and subsequently migrate through or between these cells to reach the csf.
Bacteria are able to multiply rapidly within csf because of the absence of
Effective host immune defenses.
Normal csf contains few white blood cells (wbcs) and relatively small
Amounts of complement proteins and immunoglobulins. The paucity of the latter
Two prevents effective opsonization of bacteria, an essential prerequisite for
Bacterial phagocytosis by neutrophils. Phagocytosis of bacteria is further impaired
By the fluid nature of csf, which is less conducive to phagocytosis than a solid
Tissue substrate. A critical event in the pathogenesis of bacterial meningitis is the
Inflammatory reaction induced by the invading bacteria. Many of the neurologic
Manifestations and complications of bacterial meningitis result from the immune
Response to the invading pathogen rather than from direct bacteria induced tissue
Injury. As a result, neurologic injury can progress even after the csf has been
Sterilized by antibiotic therapy.
The lysis of bacteria with the subsequent release of cell-wall components
Into the subarachnoid space is the initial step in the induction of the inflammatory
Response and the formation of a purulent exudate in the subarachnoid space.
Bacterial cell-wall components, such as the lipopolysaccharide (lps)
Molecules of gram negative bacteria and teichoic acid and peptidoglycans of s.
Pneumoniae, induce meningeal inflammation by stimulating the production of
Inflammatory cytokines and chemokines by microglia, astrocytes, monocytes,
Microvascular endothelial cells, and csf leukocytes.
In experimental models of meningitis, cytokines including tumor necrosis
Factor (tnf) and interleukin 1 (il-1) are present in csf within 1ā2 h of
Intracisternal inoculation of lps. This cytokine response is quickly followed by an
Increase in csf protein concentration and leukocytosis. Chemokines (cytokines
That induce chemotactic migration in leukocytes) and a variety of other
Proinflammatory cytokines are also produced and secreted by leukocytes and
Tissue cells that are stimulated by il-1 and tnf. In addition, bacteremia and the
Inflammatory cytokines induce the production of excitatory amino acids, reactive
Oxygen and nitrogen species (free oxygen radicals, nitric oxide, and peroxynitrite),
And other mediators that can induce death of brain cells.
Diagnosis
Examination of csf still offers the best chance of observing, isolating, and
Identifying the causative organism in bacterial meningitis (kaplan et al. 1986b;
British society for the study of infection research committee 1995). Lumbar
Puncture is particularly valuable if a dose of a parenteral antibiotic has not been
Given either before or on hospital admission.
The clearance of organisms in csf after antibiotic use was estimated as 2
Hrs for meningococci and 4 hrs for pneumococci (kanegaye et al. 2001). Even if
Bacteria cannot be recovered on culture, microscopy is likely to confirm the
Diagnosis of bacterial meningitis and may indicate the likely causative organism.
Lumbar puncture should never be used as a reason to defer commencing antibiotic
Treatment and other resuscitation measures. The ādoor-to-needleā time for patients
Hospitalized for suspected bacterial meningitis should be less than 1 h.
Direct microscopy
Direct microscopy of uncentrifuged or centrifuged csf may reveal the
Presence of bacteria or fungi and can provide immediate confirmation of the
Diagnosis. Staining with acridine orange is more sensitive than the gram stain
(kleinman et al. 1984). The organisms seen on microscopy in antibiotic-treated
Patients may fail to grow on culture, but the morphology and gram reaction of the
Organism, the age of the patient, and the clinical features often permit an educated
Guess at the identity of the causative organism.
Bacterial antigen detection test
Tests for bacterial antigen in csf can provide a quick diagnosis, but they
Are less sensitive than the gram stain and do not often alter clinical management
(maxson et al. 1994). Many tests are based on the agglutination of antibody-coated
Latex particles and work quite well for pneumococci, meningococci of serogroups
And for group b streptococci. They are less successful for the detection of
Serogroup b meningococci.
The limulus lysate test is a sensitive test for endotoxin from gram negative
Organisms but has not found wide acceptance till date. Rapid identification of the
Offending organism by gram's stain characteristics or bacterial antigen detection
Testing (badt) allows chemoprophylaxis of contacts whenever indicated
Csf culture
Csf should be inoculated on to good-quality culture media, always
Including at least columbia blood agar and a heated blood agar. Plates should be
Incubated in five percent co2 for a minimum of 48 h. If a ruptured cerebral
Abscess is suspected, or if meningitis has followed neurosurgery or a history of
Previous meningeal trauma, a second blood agar plate should be incubated
Anaerobically for 5ā7 days. If delay in processing of specimens was anticipated,
Csf can be inoculated in trans isolate medium. T-i medium is a biphasic medium
That is useful for the primary culture of etiological agents of bacterial meningitis
From csf samples. It was used as a growth medium as well as a holding and
Transport medium.
The possibility of parameningeal infection especially subdural empyema
And brain abscess must be considered and pursued actively, if csf shows an
Inflammatory response, but no bacteria is seen or cultured or detected by pcr
Tests and the patientās condition is not improving. Ct scans may sometimes fail to
Detect intracranial collections of pus. Subdural empyema (or brain abscess) should
Be suspected if āmeningitisā is diagnosed in a child or young adult in whom there
Is a recent history of sinusitis or middle ear infection. The importance of not
Missing these conditions lies in the need for urgent neurosurgical and ear, nose,
And throat (ent) assessment as part of the management protocol. Most cases of
Subdural empyema are initially misdiagnosed as bacterial meningitis.
Blood culture
For the diagnosis of bacterial meningitis, blood should be collected when a
Spinal tap is contraindicated or cannot be performed for technical reasons. Blood
Should be cultured in trypticase soy broth (tsb) or brain heart infusion with a
Growth supplement and chemical inhibitors such as 0.025% sodium polyanethol
Sulfonate(sps).
Polymerase chain reaction
Pcr tests for the detection of meningococcal and pneumococcal
Dna in csf are now used routinely in the uk. Meningococcal pcr is specific
And sensitive for the diagnosis of meningococcal meningitis (borrow et al. 1997)
And provides serogroup information in the majority of cases. Amplification of
Sections of 16s ribosomal rna, common to most species of pathogenic bacteria,
May also prove to be of value (greisen et al. 1994).
Treatment
Bacterial meningitis is a medical emergency. The goal is to begin antibiotic
Therapy within 60 min of a patient's arrival in the emergency room. Empirical
Antimicrobial therapy is initiated in patients with suspected bacterial meningitis
Before the results of csf gram's stain and culture are known. S. Pneumoniae and
N. Meningitidis are the most common etiologic organisms of community-acquired
Bacterial meningitis. Due to the emergence of penicillin and cephalosporin
Resistant s. Pneumoniae, empirical therapy of community acquired suspected
Bacterial meningitis in children and adults should include a combination of
Dexamethasone, a third-generation cephalosporin (e.g., ceftriaxone or cefotaxime)
And vancomycin plus acyclovir, as hsv encephalitis is the leading disease in the
Differential diagnosis. Ceftriaxone or cefotaxime provide good coverage for
Susceptible s. Pneumoniae, group b streptococci, and h. Influenzae and adequate
Coverage for n. Meningitidis. Cefepime is a broad spectrum fourth generation
Cephalosporin with in vitro activity similar to that of cefotaxime or ceftriaxone
Against s. Pneumoniae and n. Meningitidis.
Ampicillin should be added to the empirical regimen for coverage of l.
Monocytogenes in individuals 55 or those with suspected
Impaired cell-mediated immunity because of chronic illness, organ transplantation,
Pregnancy, malignancy or immunosuppressive therapy. In hospital acquired
Meningitis, and particularly meningitis following neurosurgical procedures,
Staphylococci and gram negative organisms including p. Aeruginosa are the most
Common etiologic organisms. In these patients, empirical therapy should include a
Combination of vancomycin, ceftazidime, cefepime or meropenem. Ceftazidime,
Cefepime or meropenem should be substituted for ceftriaxone or cefotaxime in
Neurosurgical patients and in neutropenic patients, as ceftriaxone and cefotaxime
Do not provide adequate activity against cns infection with p. Aeruginosa.
Meropenem is a carbapenem antibiotic that is highly active in vitro against l.
Monocytogenes, has been demonstrated to be effective in cases of meningitis
Caused by p. Aeruginosa, and shows good activity against penicillin-resistant
Pneumococci.
Prevention
The risk of secondary cases of meningococcal disease among close contacts
(i.e. Household members, day-care centre contacts, or anyone directly exposed to
The patientās oral secretions) is high. Antimicrobial chemoprophylaxis with a short
Course of oral rifampin or a single oral dose of ciprofloxacin, or a single injection
Of ceftriaxone is effective in eradicating nasopharyngeal carriage of n.
Meningitidis. Although very effective in preventing secondary cases, antimicrobial
Chemoprophylaxis is not an effective intervention for altering the course of an
Outbreak. In epidemics, mass chemoprophylaxis is not recommended.
Vaccines have an important role in the control and prevention of bacterial
Meningitis. Vaccines against n. Meningitidis, h. Influenzae, and s. Pneumoniae
Are currently available, but the protection afforded by each vaccine is specific to
Each bacterium and restricted to some of the serogroups or serotypes of each
Bacterium.
In industrialized countries, routine use of polysaccharide-protein hib
Conjugate vaccines for immunization of infants has almost eliminated hib
Meningitis and other forms of severe hib disease. Pneumococcal polysaccharide
Vaccines have been used to prevent disease in the elderly and in persons with
Chronic illnesses that may impair their natural immunity to pneumococcal disease.
Meningococcal polysaccharide vaccines are generally used in response to
Epidemics and for the prevention of disease in travellers although other uses are
Currently under investigation.
In addition to the existing armamentarium of vaccines, new generation
Vaccines against meningococcal and pneumococcal disease are under development
And evaluation. These vaccines may provide a high degree of protection and broad
Coverage in all age groups. Until these vaccines become widely available, the
Current vaccines should be used appropriately and efficiently. Use of any of these
Vaccines will require laboratory identification of the agents causing disease in
Addition to epidemiological information about the age and risk groups that are
Most affected.
Though various indian studies on epidemiology and comparison of various
Diagnostic techniques for acute bacterial meningitis are available, no such study
Has been carried out in madurai. Since government rajaji hospital, madurai
(grh) is the largest tertiary care hospital attached to madurai medical college
Catering the needs of lakhs of people from southern districts of tamilnadu, the
Present study was carried out among patients admitted at medicine & paediatric
Wards
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