11meningits.pdf

MENINGITIS IN CHILDREN 2008 Sileshi Mulatu (BSC N, MSC N)

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OUTLINE OF PRESENTATION • • • • • • • • • • •

Anatomy and physiology Introduction Epidemiology Pathophysiology Types MOT Etiology CF Dx Rx DDX 2

Anatomy and Physiology • To understand bacterial meningitis, we should first understand the relatedanatomy and physiology of a healthy individual. • Meningitis, in general, is theinflammation of the protective membranes surrounding the brain and spinal cord. • In order to inflame these protective membranes, the bacteria mustsomehow enter the bloodstream and bypass the blood-brain barrier. 3

Blood-Brain Barrier/BBB • The BBB mainly consists of tight junctions, which seals the endothelial cells that line the brain capillaries. • Astrocytes,a type of neuroglia from the brain, closely attached to the endothelial cells and release chemicals to regulate the permeability of the tight junctions.

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PHYSIOLOGY • The intracranial compartment is protected by the skull, a rigid structure with a fixed internal volume.  Brain parenchyma — 80 %  CSF — 10 %  Blood — 10 %

• Because the overall volume of the cranial vault cannot change, an increase in the volume of one component, or the presence of pathologic components, necessitates the displacement of other structures, an increase in ICP, or both Ward JD 5

Bacterial Virulence Factors • Bacteria express or secrete virulence factors in order to achieve: Host colonization Cell entry and exit Immunosuppression, and Nutrition acquisition.

• Virulence factors are a pathogen's tools of invasion and a cause of disease.

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1. Fimbriae Fimbriae, also known as pili, are bacterial organelles that mediate adhesion of bacteria to host cell. Although fimbriaeoften play a role in initial adherence within the nasopharynx, their presence is not necessary for the organism to cause meningitis.

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2. Polysaccharide Capsule • The polysaccharide capsule acts as a virulence factor because it prevents phagocytosis. • Because the capsule surface is slippery, the bacterium slips away from the phagocyte during phagocytosis.

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3. IgA1 Proteases • IgA, a natural antibody type found in mucosal secretion, inhibits the adherence of microorganisms to mucosal surfaces. • Bacterial pathogens (e.g. Neisseria, Haemophilus, and Streptococcus species) produce IgA1 proteases which cleave IgA and facilitate bacterial adherence to mucosal surfaces . 9

4. Bacteriocins • Bacteriocinsare toxins produced by bacteria that inhibit the growth of other bacterial strains . • The pathogen expresses bacteriocinsto clear the area of any competitors for nutrients and space needed for colonization. • Hemocinis a bacteriocinproduced byH. influenzae . 10

Introduction • Infection of the central nervous system is the most common cause of fever associated with signs and symptoms of CNS disease in children. • Bacteria meningitis is one of the most potentially serious infections occurring in infants and older children. • This infection is associated with a high rate of acute complications and risk of long term morbidity. 11

Introduction… • Annual incidence in the developed countries is approximately 5-10 per 100,000. • 30000 infants and children develop bacterial meningitis in United States each year. • Approximately 90 per cent of cases occur in children during the first 5 years of life.

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Introd… • Despite the effectiveness of current antibiotics in clearing bacteria from the cerebrospinal fluid (CSF), bacterial meningitis continues to cause significant morbidity and mortality worldwide. Up to date

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Intro….

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Epidemiology • After the introduction of the Hib and pneumococcal conjugate vaccines to the infant immunization schedule, the incidence of bacterial meningitis declined in all age groups except children younger than two months. • The peak incidence continues to occur in children younger than two months. Thigpen MC, Whitney CG, MessonnierNE, et al 2011

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Epidemiology … • The highest incidence is among neonates, who are usually infected by bacteria found in the birth canal at the time of parturition. – 90% of cases occur before 5 yr. – Mortality 20-40% in neonates – Mortaility5-10% in infants and children.

? Group B streptococci account for the majority of cases (50%), followed by E. coli (25%) 16

Epi…

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Pathogenesis • Susceptibility of bacterial infection on CNS in the children – Immaturity of immune systems • Nonspecific immune – Insufficient barrier(Blood-brain barrier) – Insufficient complement activity – Insufficient chemotaxis of neutrophils – Insufficient function of monocyte-macrophage system – Blood levels of diminished interferon (INF) -γand interleukin -8 ( IL-8 )

Pathogenesis… • Susceptibility of bacterial infection on CNS in the children – Specific immune • Immaturity of both the cellular and humoralimmune systems – Insufficient antibody-mediated protection – Diminished immunologic response

– Bacterial virulence

Pathogenesis Offending bacterium from blood invades the meninges. • Bacterial toxins and Inflammatory mediators are released. – Bacterial toxics • Lipopolysaccharide, LPS • Teichoicacid • Peptidoglycan

Overview of How Meningitis Occurs • Pathophysiology

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Risk factors of meningitis • Extremes of age (< 5 or >60 years) • Immunosuppression, which increases the risk of opportunistic infections and acute bacterial meningitis • HIV infection, which predisposes to bacterial meningitis caused by encapsulated organisms, • Crowding (such as that experienced by military recruits and college dorm residents), which increases the risk of outbreaks of meningococcal meningitis 36

Risk factors • Recent exposure to others with meningitis, with or without prophylaxis • Contiguous infection (eg, sinusitis) • Dural defect (eg, traumatic, surgical, or congenital) • Bacterial endocarditis

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Types of meningitis 1.Bacterial meningitis bacterial infection. 2.Viral meningitis: caused by viruses (enterovirus) 3.Tuberculosis meningitis: Tuberculosis infection due to M. tuberculosis

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Types … 4. Cryptococcal meningitis: Infection from a Yeast called Cryptococcus. Often associated with AIDS. 5.Neoplastic meningitis: spread of solid tumors to the brain or spinal cord 6.Syphilitic meningitis: due to infection with the bacterium that causes syphilis.

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MODES OF TRANSMISSION:  Close contact with a person who is sick with the disease  Contact with carriers  Living in close quarters, such as college

dormitories  Being in crowded situations for prolonged periods of time  Sharing drinking glasses, water bottles, or eating utensils  Kissing, sharing a cigarette

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Etiology • Causative agent is age dependent Neonates and infants • Escherichia coli • B-haemolytic streptococci • Staphylococcus aurous • Staphylococcus epidermidis • Listeria monocytogenes

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Etiology I2mth-2yrs • Hib, • Strep pneumoniae & • Neisseria meningitis

2-21yrs • Neisseria meningitis /A, B, C, Y, and W 135, • Hiband • Strep pneumoniae, 42

Etiology… There are 3 main bacterial species that contribute to this disease:  Haemophilus influenzae type b  Neisseria meningitidis (Meningococcal)  Streptococcus pneumoniae (Pneumococcal)

 Generaly by Bacteria, viruses, fungi, parasites

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Clinical features • Regardless of etiology, most patients with CNS infection have similar clinical manifestations. • Common symptoms include headache, nausea, vomiting, anorexia, restlessness, altered state of consciousness, and irritability; most of these symptoms are nonspecific. Pong A, Bradley JS, 2010 44

Clinical features…  High grade fever  Feeding problems  Irritability  Seizures:is correlative with the inflammation of brain parenchyma, cerbral infarction and electrolyte disturbances.

 High-pitched crying  Bulging fontanels  Severe, persistent headache  Neck stiffness : Infants may not develop a stiff neck

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Clinical features…  Nausea and vomiting, sometimes along with diarrhea  Confusion and disorientation (acting "goofy") can progress to stupor, coma, and death  Drowsiness or sluggishness  Eye pain or sensitivity to bright light  Numbness and tingling Pong A, Bradley JS, 2010

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Clinical features… – Increased intracranial pressure • • • • • • •

Headache Projectile vomiting Hypertension Bulging fontanel Cranial sutures diastasis/separation Coma Cerebral hernia

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Clinical features… BRUDZINSKI SIGN is +ve

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Clinical features… • The Kernig sign is +ve

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Diagnosis (Investigations) • CM • INVESTIGATIONS  CSF analysis  Blood test  Chest X-ray  CT scan or MRI  Cultures of samples of CSF, blood, urine, mucus from the nose and throat, and pus from skin infections. 50

Dx… CSF ANALYSIS: LP -A thin needle is inserted between L4/L5 to withdraw a sample of CSF. – It will help to distinguish between the different type of meningitis.

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Laboratory Findings • Examination of cerebrospinal fluid (CSF) – – – – – –

Increased pressure of cerebrospinal fluid Cloudiness Evident Increased total WBC count (>1000×109 /L) Evident Increased neutrophils in leukocyte differential count Evident Decreased glucose (<1.1mmol/l) Evident Increased protein level

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Treatment Antibiotic Therapy • Therapeutic principle – Good permeability for Blood-brain barrier – Drug combination – Full dosage – Full course of treatment

Treatment of acute bacterial meningitis in children • Suspected bacterial meningitis is a medical emergency, and immediate diagnostic steps must be taken to establish the specific cause so that appropriate antimicrobial therapy can be initiated. • The mortality rate of untreated bacterial meningitis approaches 100 % and, even with optimal therapy, morbidity and mortality may occur. • Neurologic sequelae are common among survivors. 55

Cont… • Despite the effectiveness of current antibiotics in clearing bacteria from the CSF, bacterial meningitis continues to cause significant morbidity and mortality worldwide. • Empiric treatment should be begun as soon as the diagnosis is suspected using bactericidal agent(s) that achieve significant levels in the CSF

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Empiric treatment •Ceftriaxone 50-100 mg/kg/day IV/IM q12 hr •Vancomycin 60 mg/kg/day IV q6h.

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Convulsive management • Diazepam • Phenobarbital

• Treatment of increased intracranial pressure – Dehydration therapy • 20%Mannitol 5ml/kg iv q6h • Lasix1-2mg/kg iv

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General and Supportive Measures – Treatment of septic shock and DIC • • • • • •

Volume expansion Dopamine Corticosteroids Heparin Fresh frozen plasma Platelet transfusions

THERAPY FOR SPECIFIC PATHOGENS Microorganism

Recommended therapy

Streptococcus pneumoniae

Penicillin G or Ampicillin OR Vancomycin+ Thirdgeneration cephalosporin (eg, ceftriaxoneor cefotaxime) Penicillin G OR Third-generation cephalosporin (eg, eftriaxone or cefotaxime)

Neisseria meningitidis

Duration of treatment 2

weeks

7 days 60

Haemophilus influenzae

Third-generation cephalosporin (eg, ceftriaxoneor cefotaxime)

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3 weeks Listeria monocytogenes scherichia coli

Group B streptococci

Ampicillinor Penicillin G Third-generation cephalosporin (eg, ceftriaxone or cefotaxime)

21 days or 2 weeks

Ampicillinor Penicillin G

14-21 days

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Drug of choice according to the culture isolates r.

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B strep coccus

Organism

Monocytogenes .Influenzae

efotaxim Drug of choice eftriaxone and mpicillin

.Aureus

efotaxim eftriaxone and CAF enzile pens, Ceftriaxone ancomicin, Benzile pens, eftriaxone eftazidime, Vancomicin

seudomonas

eftazidime

.Meningitides .pneumoniae

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Differential Dx         

Cerebral malaria TBc meningitis Aseptic meningitis Brain abscess Brain tumer Bacterial infections Viral infections Trauma Malignancy

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COMPLICATIONS OF BACTERIAL MENINGITIS • Complications due to bacterial meningitis can be divided into systemic and neurologic. Systemic complications such as septic shock, disseminated intravascular coagulation, acute respiratory distress syndrome, and septic or reactive arthritis, are usually the consequence of the bacteremiathat frequently accompanies meningitis

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Complication • Subdural effusion

– Subdural effusions occur in about 10%-30% of children with bacterial meningitis. – Subdural effusions appear to be more frequent in the children under the age of 1 year and in haemophilus influenzae and pneumococalinfection. – Clinical manifestations are enlargement in head circumference, bulging fontanel, and cranial sutures

diastasis – Subdural effusions may be diagnosed by the examination of CT or MRI.

Prognosis • Appropriate antibiotic therapy reduces the mortality rate for bacterial meningitis in children, but mortality remain high. • Overall mortality in the developed countries ranges between 5% and 30%. • 50 percent of the survivors have some sequelae of the disease.

Prognosis • Prognosis depends upon many factors: – Age – Causative organism – Number of organisms and bacterial virulence – Duration of illness prior to effective antibiotic therapy – Presence of disorders that may compromise host response to infection

Read about ???? • • • • •

Role of corticosteroid Vaccine for prevention Nursing interventions Complications(acute and late) The Monro-Kellie hypothesis

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Complications Acute :          

Increased ICP Hydrocephalus Hypoglycemia Myocarditis Brain damage Severe diarrhea and vomiting Internal bleeding Low blood pressure Shock Death 71

Complications Late compications: • Development delay • Cerebral palsy • Microcephaly • Hemiparesis • Hearing loss • Blindness • Seizure disorder 72