Meningitis

Meningitis, signs,symptoms, treatment, drugs.

1. Meningitis By: Darya Osman Hussein Daoud

2. Introduction Meningitis is an acute inflammation of the meninges (i.e. the protective membranes covering the brain and spinal cord) Can be bacterial, viral or fungal The causative organism depends on the age of the individual May also be caused by some drugs

3. Bacterial meningitis – causative organisms Birth – 4 wks : Streptococci group B, E. coli, Listeria 4 – 12 wks : Streptococci group B, Pneumococcus Salmonella, Listeria, H. influenza type B 3 mths – 3 yrs : Pneumococcus, Neisseria meningitidis , H. influenza 3yrs – adult: Pneumococcus, Meningococcus

4. Viral meningitis Most common infection of CNS especially in <1yr Causative organisms: Herpes, influenza, rubella, echo, coxsackie , EBV, adenovirus Tretatment is sympromatic Complcations associated with envephalitis and ICP

5. TB Meningitis Usually insidious: difficult to diagnose in early stages (fever 30%, URTI 20%) Rare in children in developed countries If untreated is usally fatal Meningitis usually occurs 3-6 mnths after primary infection 1 st stage: lasts 1-2 weeks, fever malaise, headache 2 nd stage: +/- suddenly, menigal signs 3 rd stage: worsening neurological condition, death

6. Meningitis – Pathogenesis Begins with infection of upper respiratory tract by bacteria, viral of fungal infection Infection progresses and invasion of the blood streem occurs Microbe enters the subarachnoid space in places where the BBB isvulnerable (e.g. choroid plexus) The presence of invador is detected by immune cells of the brain (astrocytes and microglia) which react by releasing large amounts of cytokines stimulating the inflammatory response of the immunesystem

7. The BBB becomes more permeable leading to vasogenic cerebral edema Large numbers of WBCs enter the CSF causing inflammation and interstitial edema Cerebral vasculitis occurs which leads to decreased blood flow and cytotoxic edema The three forms of edema all lead to increased intracranial pressure leading to decreased blood entering the brain and hypoxia induced apoptosis Meningitis – Pathogenesis cont.

8. Clinical features – Infants Non specific in newborns and infants Fever Irritability Lethargy Poor feeding High pitched cry Convulsions

9. Clinical features – Older children Severe headache Stiff neck Photophobia Fever and vomiting Drowsy and less responsive/vacant Rash

10. Clinical features - Adults Headache, fever and vomiting Neck rigidity and photophobia Pain in posterior thigh or lumbar region Rash on skin and joint pain Lethargy, seizures, confusion, coma, focal deficits and cranial nerve palsies(if not treated immediately)

11. Physical exam – Kernig’s sign Patient in supine position with leg flexed at hip and knee Extension of leg while hip still flexed Patient will experience pain and hamstring muscle spasm if meningeal irritiation /inflammation is present

12. Physical exam – Brudzinski’s neck sign Patient is in supine position Head is raised towards the chest slowly If hips and knees flex in response to the passive neck flexion (as shown) there is menengial irritiation /inflammation

13. Physical exam – Glass test When a rash is present if it does not fade when a glass is pressed to it A sign of meningococcal infection and septicaemia

14. Diagnostic tests – Lumbar Puncture CSF from lumbar puncture is used to culture cells, glucose level, protein, cell count and differential and gram test

15. Diagnostic tests – LP findings Bacterial Viral Fungal TB Malignant Cell number 10 – 100,000 <2000 <2000 250 – 500 --- Cell type Polys Lymphocytes --- Lymphocytes Lymphocytes Glucose Low Normal Low Very Low Low Protein High Normal or high High High High G-Stain G + ve G – ve G – ve G + ve Zn ---

16. Management and Treatment Medical emergency Early diagnosis essential I mmediate pharmacological treatement / intervension Intensive supportive treatment Prophylaxis for family Notification to GP and Public health autority

17. Management/Treatment cont. Mechanical ventilation may beneeded if lowlevelof consciousness orevidence of respiratory failure Monitoring intracranial pressure andcerebral perfusion Hydrocephalus ( obstuctedflow of CSF) may require insertion of temporary or long-term drainage device(e.g. cerebral shunt)

18. Pharmacological Intervention – Antibiotics Empiric antibiotics should be started immediately even before LP results Recommended to administer benzylpenicillin before transfter to hospital Treatment starts with a 3 rd generation Cefalosporin ( eg . Cefotaxime ) with possible addition of Vancomycin Can also use Chloramphenicol as monotherapy or in combination with Ampicillin

19. Pharmacological Intervention – Antibiotic treatment The drug used depends on susceptibility of causative organism as well as the age of the patient Organism Age Group Antibiotic Unknown Infants <1mths Ampicillin, Cefotaxime , Gentamicin Unknown Children >1mths and Adults Ampicillin, Cefotaxime , Vancomycin Gram-positive organisms (unidentified) Children and Adults Ceftriaxone, Vancomycin , Ampicillin Gram-negative bacilli (unidentified) Children and Adults Cefazidime , Gentamicin Haemophilus influenza type b Children and Adults Ceftriaxone Meningococci Children and Adults Penicillin G plus ceftriaxone Streptococci Children and Adults Vancomcin , Nafcillin (with or without rifampin) Listeria sp Children and Adults Ampicillin, Gentamicin, Trimethoprim- sulfamethoxaxzole Enteric gram-negative bacteria(Escherichia coli, Proteus sp, Klebsiella sp) Children and Adults Ceftriaxone, Gentamicin Pseudomonas Children and Adults Ceftazidime , Cefepime (may be used with the addition of aminoglycoside) Staphyococci Children and Adults Vancomycin , Nafcillin (with or without rifampin)

20. Pharmacological Intervension – Other drugs Other medication may be used to control/relieve symptoms Steroids: Used to control alterations of CSF flow Dexamethasone – decreased subarachnoids space inflammation Antiepileptic agents Used to control seizure activity Mannitol Used to decease intracranial pressure Antivirals Used for viral meningitis Antifungals E.g amphotericin B and Flucytosine Used for fungal meningitis

21. Pharmacological Intervention- Prophylaxis Rifampicin Children: 5mg/Kg bd x 2/7 Adults: 600mg bd x 2/7 Pregnant contact Cefuroxime IM x 1 dose Vaccine Available against H. influenza, Pneumococcal conjugate, and meningicoccus ,

22. Paritally treated meningitis 50% of cases have prior antibiotic use which can alter findings Acture history is vital CSF mainly lyphocytic (not usually polys) Can have normal glucose + ve cultures reduced by 30% Gram stain reduced by 20%

23. Complications Septic shock Verebral oedema Seizure Arteritis/venous thrombosis Subdural effusions Hyrocephalus Abscess Brain damange deafness

24. Mortality/Morbidity Bacterial: overall mortality 5-10% Neonatal meningitis: 15-20% Older children: 3-10% S. pneumonia: 26-30% H.influenza type B: 7-10% N. meningitides: 3.5 – 10% 30% neurological complications 4% profound b/l hearing loss

25. Mortality/Morbidity cont. Viral meningoencephalitis : Enteroviral fewer complications Tuberculous meningitis: related to stage of disease Stage I - 30% Stage II - 56 % Stage III - 94%