Meningitis 

Study guide:

Definition:

Inflammation of the leptomeninges and CSF.

  • Acute meningitis (bacterial and viral)"hours to days.

  • Chronic meningitis (TB or cryptococcal)"weeks to months  


Types:

  • Pregnant patient: L.monocytogenes.

  • Alcoholic patient: S.pneumoniae, and L. monocytogenes

Immunocomprimised patient:

  • S.Pneumoniae

  • L. monocytogenes

  • Pseudomona aeruginosa

  • Mycobacterium tuberculosis

  • Mycobacterium avium.

Pathophysiology:

Acute Bacterial Meningitis: 

  • Transmission:

    • Direct inoculation from neighboring structures

    • Congenital defect (NTD)

    • Hematogenous

  • Crossing the BBB attracting the Polymorphs WBCs.

  • Bacteria use glucose for survival so glucose will be decreased.

  • Pus formation and adhesions.

  • Edema increasing the ICP.

Acute Viral Meningitis

  • Transmission is mainly through fecal-oral route then to the blood → crossing the BBB → lymphocytic infiltrates.

  • No pus formation.

  • Little or no cerebral edema.

  • Self-limited.

Risk factors (Can Induce Severe Attacks Of Head PAINS):

  • Cancer

  • Immunocompromised o! Sinusitis

  • Age extremes

  • Otitis

  • Head trauma

  • Parameningeal infection (osteomyelitis of the skull)

  • Alcoholism

  • Infections (systemic)

  • Neurosurgical procedures

  • Splenectomy

Clinical Presentation:

  • Classic triad.

  • Elderly and neonates present with no specific symptoms:

    1. Poor feeding

    2. Irritability and agitationx

  • III CN palsy in cases of ICP.

  • Positive Brudzisnki/Kerning signs.

  • Any bacterial meningitis may develop acute septic shock. 􏰁

  • Viral: less prominent meningitic signs stiffness  

    • Headache is the most severe feature.

  •  Special considerations:

    • Petechial rash  meningococcal infection (It’s an emergency).

Investigation:

  • CBC

  • Blood Cultures (for bacterial meningitis)

  • PCR (for viral meningitis)

  • CT or MRI (to exclude any masses)

  • CSF analysis:

Fever

Neck
stiffness

Mental

status change

Never do CSF before checking for space occupying lesion on CT!

Management:

  • Antibiotics for bacterial meningitis should start even before identifying the organism:

  • Adjust the antibiotic spectrum after the microbiology report:

  • For TB meningitis:

    • Rifampicin, isoniazid and pyrazinamide.

    • Ethambutol is avoided (eye complication).

  • Steroids are given in the first 4 days to decrease the edema and ICP.

  • Viral meningitis:

    • No specific treatment

    • Acyclovir is used for HSV or severe EBV. 

​​

Complications:

  • Hearing loss (most common complication in children).

  • Cerebral abscess.

  • Hydrocephalus.

  • Increased ICP.

  • Focal seizures and epilepsy.

Prophylaxis:

  • ACWY pneumococcus vaccine in Hajj

References:

  1. Sattar, Husain A. Fundamentals Of Pathology. Chicago: Pathoma.com, 2011. Print.

  2. Le, Tao, Vikas Bhushan, and Herman Singh Bagga. First Aid For The USMLE Step 2 CK. New York: McGraw-

  3. Hill Medical, 2010. Print.

  4.  Agabegi, Steven S, Elizabeth D Agabegi, and Adam C Ring. Step-Up To Medicine. Philadelphia: Wolters

  5. Kluwer/Lippincott Williams & Wilkins, 2013. Print.

  6.  Lissauer, Tom, Graham Clayden, and Alan Craft. Illustrated Textbook Of Paediatrics. Edinburgh: Mosby, 2012. Print.

  7. Meningitis, Overview. 'Overview Of Meningitis - Neurologic Disorders'. Merck Manuals Professional Edition. N.p.,

  8. 2015. Web. 25 Sept. 2015.

  9.  Uptodate.com,. 'Neurologic Complications Of Bacterial Meningitis In Adults'. N.p., 2015. Web. 25 Sept. 2015.

  10. Yogarajah, Mahinda. Neurology. Edinburgh: Mosby/Elsevier, 2014. Print.

  11. Goljan, Edward F. Rapid Review Pathology. Philadelphia, PA: Saunders/Elsevier, 2014. Print.

  12. Hauser, Stephen, and Scott Josephson. Harrison's Neurology In Clinical Medicine. 3rd ed. McGraw Hill. Print.

  13. Le, Tao et al. First Aid For The® USMLE. Print.

  14. Meningitis.ca,. 'Meningococcal Disease'. N.p., 2015. Web. 25 Sept. 2015. (Figure 1).

First author:        Roaa Amer

Second author:   Abdullah AlAsaad

                           Lama AlLuhaidan 

Reviewed:           Bayan AlZomaili

Format Editor:    Adel Yasky