Presentation is loading. Please wait.

Presentation is loading. Please wait.

Infectious diseases… meningitis PHCP 402 By L.K.Sarki.

Similar presentations


Presentation on theme: "Infectious diseases… meningitis PHCP 402 By L.K.Sarki."— Presentation transcript:

1 Infectious diseases… meningitis PHCP 402 By L.K.Sarki

2 What is it? Infectious meningitis is an inflammation of the meninges arachnoid and pia mater (subarachnoid space) associated with the presence of bacteria, viruses, fungi or protozoa in the CSF (cerebrospinal fluid)

3 What is it? It is associated with significant mortality and risk of serious sequelae in survivors meningitis can also be caused by physical injury cancer chemical irritation subarachnoid haemorrhage and other conditions or certain drugs

4 Why is it important? Every year, bacterial meningitis epidemics affect more than 400 million people living in the 21 countries of the "African meningitis belt" (from Senegal to Ethiopia). In this area over cases were reported between 1996–2010. Of these cases, 10% resulted in deaths, with another 10–20% developing neurological sequelae.

5 Why is it important? During the 2010 epidemic season (weeks 1–26) 22 831 cases were recorded in 14 countries under enhanced surveillance. Among these cases there were 2415 deaths, giving a case-fatality ratio (CFR) of 10.6%. The highest number of cases were reported by Burkina Faso (6145 including 863 deaths) followed by Nigeria (4699 cases including 322 deaths) and Chad (3058 cases including 231 deaths).

6

7

8 epidemics In the 2009 epidemic season, a large-scale outbreak affected the countries of the African Belt, in particular Nigeria This year, 217 districts crossed the epidemic threshold 175 of them from Nigeria alone In 2010, African countries were less affected by meningitis epidemics Still, 46 districts from Burkina Faso, Chad, Cameroon, Democratic Republic of Congo, Ghana, Niger and Nigeria crossed the epidemic threshold

9 Why is it important? Neurologic sequelae frequently associated with meningitis include seizures, sensorineural hearing loss, and hydrocephalus Generally, 30% – 50% of patient who survive meningitis may develop neurologic disabilities

10 Why is it important? The risk of the development of neurologic sequelae depends on the infecting organism At risk Both passive and active exposures to cigarette smoke where shown to be risk factors for bacterial meningitis, especially meningococcal disease

11 Why is it important? Although bacterial meningitis occurs in all age groups, it is predominantly a disease of the young children, with 40 – 50% of all cases occurring in the first 4 years of life Also it is a disease of the very old

12 What causes it? Streptococcus pneumoniae (pneumococcal meningitis)
Responsible for about 75% of meningitis cases The most common cause of bacterial meningitis in adults aged over 45 years, but almost half of all cases of pneumococcal meningitis occur in children aged under 5 years

13 What causes it? Neisseria meningitidis (meningococcal meningitis)
The most common cause of bacterial meningitis from infancy through to middle age There are several serogroups of N. meningitidis Serogroup A and W135 predominate in Africa Haemophilus influenzae Group B Streptococcus (GBS) Listeria monocytogenes

14 What causes it? Age group Most likely organism
Neonates (< 2 months) Group B streptococcus (S. agalactiae) E. coli, and other G-ve bacilli (Klebsiella, Serratia species), L. monocytogenes Infants and children (2 mo – 10 yrs) S. pneumoniae, N. meningitidis, H. influenzae (children not vaccinated with Hib only) Children and adults ( >10 – 30 yrs) N. meningitidis, S. pneumoniae Adults (30 – 60 yrs) S. pneumoniae, N. meningitidis Elderly ( > 60 yrs) S. pneumoniae, N. meningitidis, E. coli, Klebsiella species, and other G-ve bacilli, L. monocytogenes

15 transmission Contagious
close or long contact with a sick person in the same household or daycare center direct contact with a patient's oral secretions kissing (e.g., saliva or mucus) Listeria monocytogenes by eating contaminated food not spread by casual contact or by simply breathing the air where a person with meningitis has been

16 Pathogenesis/pathophysiology
Meningitis develop either from Haematogenous spread of the pathogen The most common mechanism Contigous spread from a parameningeal focus E.g., sinusitis or otitis media Or Direct inoculation as occurs with head trauma or postneurosurgery

17 Colonisation & invasion of the oropharyngeal/nasopharyngeal mucosa by the meningeal pathogens
Penetration of the Blood Brain Barrier (BBB) Release of cell wall substances (e.g., lipopolysaccharide/endotoxin/teichoic acid Release of inflammatory mediators (IL-1, IL-6, PGE2, TNF) by the endothelial cells and monocytes Increased permeability of the BBB leads to influx of albumin into the subarachnoid space Brain oedema, increased intracranial pressure, altered cerebral blood flow Cranial nerve injury, seizures, hypoxic-ischemia brain damage, herniation

18 Clinical manifestation
Acute bacterial meningitis Typical symptoms present abruptly (sudden-onset) and evolve quickly over a period of several hours The ‘triad’ clinical features are the most common symptoms Fever Stiff neck (nuchal rigidity) Altered mental status When all these three features are present meningitis should be strongly suspected (may differ in infants) Acute bacterial meningitis usually presents sudden onset of headache, neck stiffness, photophobia, fever and vomiting. On examination kernig’s sign may be positive. This is resistance to the extension of the leg when the hip is flexed, due to meningeal irritation in the lumbar area. Untreated patients with bacterial meningitis deteriorate rapidly, with development of seizures, focal cerebral signs and cranial nerve palsies. Finally obtundation and loss of conciouness heraLD DEATH

19 Clinical manifestation
Headache Photophobia unusual intolerance to light A positive Brudzinski’s sign Reflex flexion of the hip and knees produced upon flexion of the neck when lying in the recumbent position Kernig’s sign pain upon extension of the hamstrings when lying supine with the thighs perpendicular to the trunk

20 Clinical manifestation
Seizures Anorexia Nausea and vomiting Irritability (crying) In infants – early physical signs are usually non specific and include fever, diarrhoea, lethargy, feeding difficulties and respiratory distress

21 CSF analysis Helpful in determining the type of organism causing the meningitis (bacterial, fungal or viral) Lumbar puncture It should be a clear colorless fluid which in the lumbar region of the spinal cord is at a Pressure = 50 – 150mmH20, there may be up to 5 cells/ml, the protein concentration is up to 0.4g/L, and the glucose concentration is usually 2.2 – 4.4mmol/L (at least 60% of the blood glucose) Gram-stained smears CT scan PCR

22 CSF analysis In acute bacterial meningitis the CSF is purulent, containing numerous WBC (>500 cells/mm3 with a predominance of PMNs and often is turbid in appearance. Protein nearly always is elevated and glucose concentration is low

23 treatment Antimicrobial therapy of meningitis requires attainment of adequate levels of bactericidal agents within the CSF Passage of antibiotics into CSF is dependent on the degree of meningeal inflammation and integrity of the BBB and properties of the antibiotic Lipid solubility Protein binding Ionic blood pH Molecular size Conc. of the drug in the serum

24 CSF penetration Vs antibiotics
Very good penetrators Penetrate even when the meninges are not inflamed CPC, metronidazole Good penetrators Achieve adequate penetration only when the meninges are inflamed, and given in high doses Beta-lactams, quinolones

25 CSF penetration Vs antibiotics
Poor penetrators Penetrate poorly under all circumstances Aminoglycosides, erythromycin, vancomycin

26 What to give? empirical treatment Urgent – Transfer patient to hospital If unable to transfer urgently to hospital Give broad-spectrum antibiotic Single injection – either Benzylpenicillin IV or IM 1.2g for adults and child > 10 years 600mg for Child 1 – 9 years 300mg for Infant < 1year Initially to cover all the likely pathogens. For the purpose of selecting empiric antimicrobial therapy, patients with acute bacterial meningitis can be categorised into 4 broad groups – neonates and infants aged below 3 months; immunocompetent older infants, children and adults; immunocompromised patients and those with ventricular shunts

27 What to give? Alternatively 3rd-generation cephalosporin Or Cefotaxime
CPC

28 What to give? Consider adjunctive treatment with dexamethasone – starting before or with first dose of antibacterial treatment Adult - 10mg Child – 125mcg Usually given every 6 hours for 4 days only Significantly reduces the rates of unfavourable outcomes, mortality, severe hearing loss and neurological sequelae May reduce CSF penetration of antibiotics

29 Age group 1st choice alternative Neonates aged <8 days Ampicillin 50mg/kg bd OR amoxicillin 25mg/kg bd AND cefotaxime 50mg/kg bd OR ceftazidime 50mg/kg bd Benzylpenicillin 50mg bd AND ampicillin 50mg bd OR amoxicillin 25mg/kg bd AND gentamicin 2.5mg/kg bd Neonates aged 8-28 days Ampicillin 50mg/kg 4x/d OR amoxicillin 25mg/kg tds AND cefotaxime 50mg/kg tds OR ceftazidime 50mg/kg tds Benzylpenicillin 50mg 3-4x/d AND ampicillin 50mg 3-4x/d OR amoxicillin 25mg/kg 3x/d AND gentamicin 2.5mg/kg 3x/d Infants aged 1-3months Ampicillin 50mg/kg 4x/d OR amoxicillin 25mg/kg tds AND cefotaxime 50mg/kg tds OR ceftriaxone mg/kg once daily

30 Age group 1st choice alternative
Infants and children aged >3 monthsن Cefotaxime 50mg/kg 3x daily OR ceftriaxoneﮫ mg/kg once dailya Ampicillin 50mg/kg 4x daily OR amoxicillin 25mg/kg 3x/d OR benzylpenicillinﻋ 30mg/kg 4-hourly and chloramphenicolﺿ mg/kg 4x daily adults Cefotaximeﺷ 2g 3x daily OR ceftriaxoneﮫ,ﺷ 2-4g once daily Benzylpenicillin 2.4g 4-hourly OR ampicillin 2-3g 4x daily OR amoxicillin 2g 3x or 4x daily AND chloramphenicol mg/kg 4x daily ن calculated doses for children should not exceed maximum recommended doses for adults ﮫ ceftriaxone should not be administered to neonates within 24h of completion of infusions of calcium-containing solutions, causion should be exercised in older age groups ﻋ benzylpenicillin is inactive against H. influenzae and should therefore not be used in children aged <5years ﺿ monitoring of serum chloramphenicol level is recommended, especially in children aged ≤4years ﺷ add ampicillin or amoxicillin to cover L. monocytogens in elderly patients or where Gram-positive bacilli seen CSF

31 epidemics The epidemic threshold is an operational threshold established in order to differentiate the seasonal case recrudescence from epidemics. Once the weekly attack rate reaches this pre-defined threshold within a given district, and meningococcal meningitis is confirmed, a reactive vaccination campaign should be implemented.

32 vaccination Meningococcal vaccine
Meningococcal polysaccharide A, C, W135 and Y conjugate vaccine ACWY Vax® Capsular polysaccharide antigens of Neisseria meningitidis

33 vaccination Pneumococcal vaccine Pneumococcal polysaccharide vaccine
pneumovax® II Polysaccharide from each of 23 capsular types of pneumococcus Pneumococcal polysaccharide conjugate vaccine Prevenar 13® Polysaccharide from each of 13 capsular types of pneumococcus

34 Prophylaxis People who qualify as close contacts of a person with meningococcal or Haemophilus influenzae type b (Hib) meningitis are at higher risk of getting disease and may need preventive antibiotics Close contacts of a person with meningitis caused by other bacteria, such as Streptococcus pneumoniae, do not need antibiotics

35 Chemoprophylaxis in contacts of cases of infection with N
Chemoprophylaxis in contacts of cases of infection with N. meningitidis or Hib Persons who have slept in the same house as the patient at any time during the 7 days before the onset of symptoms Friends of the patient Unless treated with ceftriaxone (which reliably eliminates nasopharyngeal carriage), the index patient should also receive antibiotic prophylaxis as soon as he or she is able to take oral medication

36 Chemoprophylaxis in contacts of cases of infection with N
Chemoprophylaxis in contacts of cases of infection with N. meningitidis or Hib Healthcare workers: Individuals who have administered mouth-to-mouth resuscitation or had some other form of prolonged close face-to-face contact with the patient Universities, schools, nurseries and other closed communities where two or more linked cases have occurred Before initiating prophylaxis - Consult Hospital infection team OR Public health doctor

37 Chemoprophylaxis in contacts of cases of infection with N
Chemoprophylaxis in contacts of cases of infection with N. meningitidis or Hib Meningococcal infection Ciprofloxacin (oral) Adults mg single dose Child 5 – 12 yrs 250mg “ Child 1mo – 4 yrs 125mg “ Rifampicin (oral)

38 Invasive Hib Rifampicin (oral)- given once daily for 4 days Adults 600mg (for pregnant women obtain expert advice) Child 1-3 months 10mg/kg Child >3 months 20mg/kg (max. 600mg)

39 Patient care Risk of serious toxicity when CPC is used, especially in neonates Advice AVOID if possible Poor CSF penetration with gentamicin in neonates, especially ‘preterms’ Advice SUBSTITUTE with, or ADD cefotaxime (better CSF penetration)- close monitoring of serum levels

40 Patient care Treatment failures in meningitis due to penicillin resistant strains Advice CONSIDERING one of the newer antibiotics with good activity against multiresistant G +ve bacteria Prolonged therapy is usually required for meningitis cases due to L. monocytogens – usally 3 – 4 weeks Up to 10% relapse rate after short courses of therapy


Download ppt "Infectious diseases… meningitis PHCP 402 By L.K.Sarki."

Similar presentations


Ads by Google