Meningitis

Meningitis

1. Anatomy of the scalp, meninges and the BBB

   • SCALP
     • Skin
     • Connective tissue
     • Epicranial Aponeurosis
     • Loose areolar tissue
     • Pericranium
     • Nerve and Arterial Supply of the Scalp
   • meninges
     • Dural Folds
       • The outer layer of the dura forms the endocranium
       • The inner layer of the dura is folded to form
         • Falx cerebri
           • Lies in the mid-sagittal plane and separates the two cerebral hemispheres
         • Tentorium cerebelli
           • Forms the roof of the posterior cranial fossa, and separates the cerebral hemispheres from the cerebellum
     • Arachnoid Mater
       • It consists of layers of connective tissue, is avascular, and does not receive any innervation.
       • arachnoid granulations allow CSF to re-enter the circulation via the dural venous sinuses.
     • Pia Mater
       • It is the only covering to follow the contours of the brain (the gyri and fissures.
       • it is highly vascularized, with blood vessels perforating through the membrane to supply the underlying neural tissue.
   • Blood Brain Barrier

2. Fever

   • Pathophysiology
     • pyrogens
       • macrophages and immune cells are activated
         • cytokines
           • Pyretic cytokines: IL-1, IL-6, IL-8 macrophage inflammatory protein 1b, interferon gamma.
           • activate phospholipase
             • will induce the production of PE2
               • change the temperature set point
   • Differential Diagnosis

3. Differential Diagnosis of Stiff Neck

4. Epidemiology of Neisseria Meningitides

   • Meningitis due to Neisseria Meningitides has the highest incidence worldwide in Africa, exactly in a region of Sub-Saharan Africa (Meningitis belt).
   • This region is hyper-endemic and extends from Senegal to Ethiopia.
   • In the meningitis belt, 350 million people at least are at risk of getting meningitis in the annual epidemics.

5. Meningitis Definition

   • is an inflammation (infection) of the meninges also involves the fluid (CSF) surrounding the brain and spinal cord

6. Meningitis Clinical Picture

7. Pathophysiology of meningitis

   • Bacteria
     • Penetrates BBB; endotoxin and inflammatory mediators initiate a CSF inflammatory response
       • Causing leakage of protein and fluid out of the cerebral vasculature
         • Causing cerebral edema and cerebral vascular thrombosis
           • Edema and increased intracranial pressure
             • Reduction in cerebral perfusion and cerebral infarction
               • Brain death

8. Kernig’s sign

   • • Positive Kernig’s sign happens when the patient experiences back pain or when he can’t extend his knee.

9. Brudzinski’s sign

   • • Positive brudzinski’s sign happens when involuntary flexion of knee and hip happens.

10. CSF

11. Management of Meningitis

    • Aim of Management
      • Eradicate Infection
      • Alleviate sings &symptoms
      • Prevent complications

12. Prevention & Chemoprophylaxis

    • For Anyone who has been in close contact with a meningitis patient within seven days before the onset of the disease is at increased risk of contracting it themselves. With meningococcal and Hib infections, preventative antibiotics are usually offered to close contacts. These reduce, but cannot eliminate, the risk of family members or other close contacts becoming ill.
      • Vaccine – pre-exposure prophylaxis
      • Rifampin and ciprofloxacin - ideally within 24 hours after the case is identified
    • The most effective way to protect against certain types of bacterial meningitis is to complete the recommended vaccine schedule.
    • There are vaccines for three types of bacteria that can cause meningitis:
      • Streptococcus pneumoniae (pneumococcus)
      • Neisseria meningitidis (meningococcus)
        • Meningococcal conjugate vaccines (Menactra)- Covers Serogroups A, C, Y and W-135
        • Serogroup B meningococcal vaccines (Bexsero) recommended dose of vaccine is a single 0.5-mL subcutaneous injection
      • Haemophilus influenzae type b (Hib).

13. Complications of meningitis

    • Hydrocephalus
    • Hearing loss
    • Seizures
    • Thrombophlebitis
    • Septicemia (Waterhouse-Friderichsen Syndrome)
    • Death

14. Prognosis of meningitis

    • Bacterial Meningitis
      • 48 – 72 hours following initial treatment
      • More likely to experience complications
    • Viral Meningitis
      • Recovery without neurologic sequelae

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