This document provides an overview of meningitis, including: - Meningitis is an acute bacterial infection of the membranes surrounding the brain and spinal cord (meninges). - Common causes include bacteria like Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae. - Risk factors include young age, male sex, poverty, and conditions affecting immunity. Prompt diagnosis via lumbar puncture and CSF analysis is important. Treatment involves antibiotics and supportive care, while complications can include neurological deficits. Vaccination and prophylaxis are effective prevention methods.

1. HO 3rd year lecture
Meningitis
Prepared by: Dr Elbet

2. Content
Introduction
Epidemiology
Etiology
Clinical feature
Diagnosis
Complication
Management

3. • DEFINITION
-Acute &diffuse bacterial infection of the
CNS with primary involvement of the
meninges .

4. Introduction
• Infection of the CNS may be diffuse or focal.
– diffuse infection
– Meningitis, encephalitis ,or both
– Focal infection of the CNS
– Brain abscess

5. Etiology
• Viral infections > bacterial > fungal &
parasitic
• Factors affecting etiologic agent
– Age of the host
– Immune status of the host
– Vaccination status
– Predisposing factors/anatomic factors

6. Cont….
 Birth-2 months
 GBS (Streptococcus agalactiae)
 E.coli, klebsella
 L.Monocytogens
 Group D streptococus
 2months-12years
 H.influenza
 S.Pneumonia
 N.Meninigitis
 Others: s.aureus, pseudomonas, CONS,
salmonella

7. Epidemiology
Transmission
• Person-to-person contact through respiratory tract
secretions or droplets.
Risk factors
• Young age
• Male gender
• Black race
• Poverty
• Over crowding
• Recent colonization with pathogenic bacteria
• Bacterima and/or close contact with N.meningitids or
H.inflenza meninigitis

8. Cont…..
 Anatomic defects
 Lumbosacral dremal sinus
 Ruptured meningomylocele
 Ventriculo peritoneal shunts
 Otitis media
 Cochlear transplants(30x)
 Midline cranial or facial defects
 Basal skull fracture
 Complement deficiency(C5-8)
 T cell lymphocyte defect or chemotherapy
 Anatomic or functional asplenia

9. invasive pneumococcal infections
• Peaks incidence 6 months-2 yrs
• Risks
– anatomic or functional asplenia
– HIV
– otitis media, sinusitis, pneumonia, CSF otorrhea
or rhinorrhea,
– cochlear implant
– chronic graft versus host disease

10. NEISSERIA MENINGITIDIS
• Five serogroups : A, B, C, Y, and W-135
• sporadic or epidemic.
• Epidemic disease in developing countries is
caused by serogroup A.
• More common in winter and spring
• Risk of infection in close Contact is 1%
(1000x)

11. HAEMOPHILUS INFLUENZAE TYPE B
• 70% of meningitis in U5 children is caused by
H. inf. type b(prior to vaccination)
• Age predilected:2 mo–2 yr of age
• peak incidence 6–9 mo of age
• Risks
– Contacts with H. influenzae type b disease.
– Incompletely vaccinated
– not vaccinated
– HIV infection.

12. Pathogenesis
1)Hematogneous spread
Nasopharyngeal colonization with pathogenic
organisms (H.inf , n.meningitids, s.pneumoniae)
2)from a contiguous focus of infection.

13. Pathology
• Direct damage to CNS by the inflammatory
process
– neutrophilic infiltration,
– increased vascular permeability,
– alterations of the blood-brain barrier, and
– vascular thrombosis.
• Immune mediated damage induced by
bacterial components.

14. Damages caused by meningitis
• Extensive exudates in the CSF circulation path
ways
• Communicating hydrocephalus
• Subdural effusion/ empyema
• Ventriculitis
• Necrotizing arteritis subarachinoid hemmorage
• Cranial neuropathies
• Cerebral infarction
• Increased intracranial pressure
• Cerebral herniation

15. Mechanism of cerebral injury
 Damage to the cerebral cortex may be due to the
focal or diffuse effects of
 vascular occlusion (infarction, necrosis, lactic
acidosis),
 hypoxia,
 bacterial invasion (cerebritis),
 toxic encephalopathy (bacterial toxins),
 elevated ICP,
 ventriculitis, and
 transudation (subdural effusions).

16. Effects of cerebral injury
• Impaired consciousness/comma
• Seizures
• Cranial nerve deficits
• Motor and sensory deficits
• later psychomotor retardation.

17. Clinical feature
• Clinical manifestations of bacterial meningitis are
variable and nonspecific.
• Non specific s & s
– Preceding history of URTI.
– Fever , nausea, vomiting, irritability, anorexia,
headache
– Petechiae, purpura, DIC
• Meningeal irritation signs
– back pain, nuchal rigidity
– Confusion ,Convulsion(33%)

18. Cont….
• Kerning and Brudzinski signs are inconsistently
found in younger children less than 12–18
mo.
• Meningeal irritation signs are present in 60 to
80 percent of children with bacterial
meningitis and in approximately 25 percent of
children with normal CSF findings.

19. DIAGNOSIS.
• The diagnosis of acute pyogenic meningitis is
confirmed by analysis of the CSF, which
typically reveals microorganisms on Gram
stain and culture, a neutrophilic pleocytosis,
elevated protein, and reduced glucose
concentrations.

20. Contraindications for LP
• (1) evidence of increased ICP (other than a
bulging fontanel)
• (2) severe cardiopulmonary compromise
• (3) infection at the site of the LP.
• Thrombocytopenia is a relative
contraindication.

21. Lumbar Puncture
• Normal CSF WBC finding
– Neonates up to 30 leukocytes/mm3
– older children <5 leukocytes/mm3.
• Turbid CSF is present when the CSF leukocyte count
exceeds 200–400/mm3.
• In Most bacterial meningitis
• CSF leukocyte count >1,000/mm3 with neutrophilic
predominance (75–95%).
• Pleocytosis may be absent in patients with severe
overwhelming sepsis and meningitis.
• Gram stain is positive in 70–90% of patients with
untreated bacterial meningitis.

22. Differential diagnosis
• Viral meningoencephalities
• Tuberculous meningitis
• Para meningeal infections
• Brain tumor
• Tuberculoma
• Fungal meningitis

23. Tratment
• Emperic therapy
– Crystaline pencillin loading dose 250,000IU/kg stat
followed by 500,000 IU/kg divided in 8 doses
– Chlorapmpheniclo 50 mg/kg loading followed by
100mg/kg qid
– Dexamethasone 0.6 mg/kg qid for 48 hours
– Modify antibiotic based on culture and sensitivity result.
• Suportive therapy : maintainace fluid 2/3 of daily
requirment.
• Manage complications like increased ICP and seizure

24. Duration of therapy
• N. meningitidis meningitis 5–7 days .
• H. influenzae type b meningitis 7–10 days.
• Partialy treated meningitis treat with
ceftriazone or cefotaxime for 7–10 days.
• Gram-negative bacillary meningitis for 3 wks
or for at least 2 wk after CSF sterilization.

25. Complications
• seizures,
• increased ICP,
• cerebral edema,
• ischemia,
• subdural effusion/ empyema
• disseminated illness (septic arthritis, pericarditis,
etc.).
• DIC
• SIADH

26. Neurologic Sequelae
• Sensory neural hearing loss,
• mental retardation,
• recurrent seizures,
• delay in acquisition of language,
• visual impairment,
• behavioral problems

27. Poor Prognostic factors
• Age less than 6 mo.
• high concentrations of bacteria/bacterial
products in their CSF.
• seizures lasting more than 4 days into
therapy.
• coma or focal neurologic signs at
presentation.
• Pneumococcal meningitis

28. Prevention
• Vaccination
• antibiotic prophylaxis for susceptible at-risk
contacts