Meningitis
Study guide:
Definition:
Inflammation of the leptomeninges and CSF.
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Acute meningitis (bacterial and viral)"hours to days.
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Chronic meningitis (TB or cryptococcal)"weeks to months
Types:

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Pregnant patient: L.monocytogenes.
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Alcoholic patient: S.pneumoniae, and L. monocytogenes
Immunocomprimised patient:
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S.Pneumoniae
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L. monocytogenes
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Pseudomona aeruginosa
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Mycobacterium tuberculosis
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Mycobacterium avium.
Pathophysiology:
Acute Bacterial Meningitis:
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Transmission:
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Direct inoculation from neighboring structures
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Congenital defect (NTD)
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Hematogenous
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Crossing the BBB attracting the Polymorphs WBCs.
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Bacteria use glucose for survival so glucose will be decreased.
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Pus formation and adhesions.
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Edema increasing the ICP.
Acute Viral Meningitis
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Transmission is mainly through fecal-oral route then to the blood → crossing the BBB → lymphocytic infiltrates.
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No pus formation.
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Little or no cerebral edema.
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Self-limited.
Risk factors (Can Induce Severe Attacks Of Head PAINS):
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Cancer
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Immunocompromised o! Sinusitis
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Age extremes
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Otitis
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Head trauma
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Parameningeal infection (osteomyelitis of the skull)
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Alcoholism
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Infections (systemic)
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Neurosurgical procedures
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Splenectomy
Clinical Presentation:
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Classic triad.
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Elderly and neonates present with no specific symptoms:
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Poor feeding
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Irritability and agitationx
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III CN palsy in cases of ICP.
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Positive Brudzisnki/Kerning signs.
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Any bacterial meningitis may develop acute septic shock.
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Viral: less prominent meningitic signs stiffness
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Headache is the most severe feature.
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Special considerations:
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Petechial rash → meningococcal infection (It’s an emergency).
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Investigation:
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CBC
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Blood Cultures (for bacterial meningitis)
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PCR (for viral meningitis)
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CT or MRI (to exclude any masses)
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CSF analysis:
Fever
Neck
stiffness
Mental
status change
Never do CSF before checking for space occupying lesion on CT!
Management:
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Antibiotics for bacterial meningitis should start even before identifying the organism:
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Adjust the antibiotic spectrum after the microbiology report:
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For TB meningitis:
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Rifampicin, isoniazid and pyrazinamide.
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Ethambutol is avoided (eye complication).
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Steroids are given in the first 4 days to decrease the edema and ICP.
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Viral meningitis:
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No specific treatment
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Acyclovir is used for HSV or severe EBV.
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Complications:
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Hearing loss (most common complication in children).
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Cerebral abscess.
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Hydrocephalus.
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Increased ICP.
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Focal seizures and epilepsy.
Prophylaxis:
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ACWY pneumococcus vaccine in Hajj
References:
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Sattar, Husain A. Fundamentals Of Pathology. Chicago: Pathoma.com, 2011. Print.
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Le, Tao, Vikas Bhushan, and Herman Singh Bagga. First Aid For The USMLE Step 2 CK. New York: McGraw-
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Hill Medical, 2010. Print.
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Agabegi, Steven S, Elizabeth D Agabegi, and Adam C Ring. Step-Up To Medicine. Philadelphia: Wolters
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Kluwer/Lippincott Williams & Wilkins, 2013. Print.
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Lissauer, Tom, Graham Clayden, and Alan Craft. Illustrated Textbook Of Paediatrics. Edinburgh: Mosby, 2012. Print.
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Meningitis, Overview. 'Overview Of Meningitis - Neurologic Disorders'. Merck Manuals Professional Edition. N.p.,
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2015. Web. 25 Sept. 2015.
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Uptodate.com,. 'Neurologic Complications Of Bacterial Meningitis In Adults'. N.p., 2015. Web. 25 Sept. 2015.
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Yogarajah, Mahinda. Neurology. Edinburgh: Mosby/Elsevier, 2014. Print.
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Goljan, Edward F. Rapid Review Pathology. Philadelphia, PA: Saunders/Elsevier, 2014. Print.
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Hauser, Stephen, and Scott Josephson. Harrison's Neurology In Clinical Medicine. 3rd ed. McGraw Hill. Print.
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Le, Tao et al. First Aid For The® USMLE. Print.
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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