Meningitis

Question 1

Meningitis

Answer 1

Infection and inflammation of meninges

Question 2

How does meningitis occur

Answer 2

Blood brain barrier usually controls access of potentially toxic metabolites into CSF and tissues.
Failure of this mechanism results in meningitis.

Question 3

Encephalitis

Answer 3

Infection of the brain parenchyma

Question 4

Meningo encephalitis

Answer 4

Inflammation of brain + meninges.

Question 5

Aseptic meningitis

Answer 5

Inflammation of meninges with sterile CSF –caused by viruses

Question 6

Classification of Meningitis - Duration

Answer 6

Acute: Symptoms present in 24 hrs
Sub acute: Symptoms lasting 1-7 days
Chronic: Symptoms lasting over 7 days

Question 7

Classification of Meningitis - Etiology

Answer 7

Bacterial meningitis
Fungal meningitis
Viral (aseptic) meningitis

Question 8

Acute meningitis - Bacteria

Answer 8

Pneumococcus , Meningococcus
Hemophilus influenzae , Group B Streptococcus , Enteric GNB -E.coli
Listeria monocytogenes , Staph. aureus

Question 9

Acute meningitis - Parasites

Answer 9

Naegleria Fowleri
Angiostrongylus , Acanthamoeba spp.
Strongyloides stercoralis , Entamoeba histolytica .

Question 10

Chronic meningitis - Bacteria

Answer 10

Mycobacterium tuberculosis

Cryptococcus neoformans

Question 11

Chronic meningitis - Fungi

Answer 11

Histoplasma , Coccidiodes, Candida, Blastomyces

Question 12

Chronic meningitis - Others

Answer 12

Toxoplasma , Lyme disease , Syphilis , Cysticerosis.

Question 13

Transmission - Acute meningitis

Answer 13

Spread via bloodstream
Spread from Para meningeal structures – e.g. Sinusitis
Direct infection to subarachnoid space via fracture
Direct infection

Question 14

Pathogenesis - meningitis

Answer 14

1) Nasopharyngeal colonization
2) Invasion of epithelium
3) Invasion of blood
4) Further dissemination
5) Cerebrospinal fluid tissues

Question 15

Symptoms - infant

Answer 15

• Fever
• Not feeding; possible vomiting
• Blank stare
• Lethargic
• Pale, blotchy

Question 16

Symptoms - adult

Answer 16

• Stiff neck
• Headache
• Fever
• Vomiting
• Light sensitivity
• Drowsiness/confusion
• Joint pain
  (Small irregular spots on trunk/ Petechiae if meningococcal)

Question 17

Medical emergency

Answer 17

Need antibiotic therapy asap; life threatening

Question 18

Specimen

Answer 18

Blood, CSF

Question 19

High intercranial pressure

Answer 19

Can result from bleeding in the brain, a tumor, stroke, aneurysm, high blood pressure, or brain infection

Question 20

CSF profile

Answer 20

Glucose: <40 mg/dL.
Protein: > 150 mg/dL.
WBCs: >500 cells/µL (usually > 1000).
Early: May be < 100.
Cell differential: Predominance of Neutrophils (PMNs)
Culture: Positive

Question 21

Microscope

Answer 21

Centrifuge
Examine sediment
Gram stain
India ink – Capsules of cryptococcus neoformans

Question 22

Cultures

Answer 22

Blood Agar Plate
Chocolate Agar Plate
Mac Conkey’s agar

Question 23

Latex agglutination

Answer 23

Negative reaction:
The suspension remains slightly milky in appearance.

Positive reaction:
agglutination (or visible clumping) and slight clearing of the suspension occurs within 2-10 minutes .

Detects - Meningococci, Pneumococci, H. influenzae

Question 24

H. influenzae

Answer 24

Gram –ve short rods (long filamentous form in meningitis-CSF) ,non motile, chocolate agar.

Colonies - smooth moist grey-require factor X & factor V

Staph aureus Factor V Satellitism.

Question 25

Listeria monocytogenes

Answer 25

Small pleomorphic, Gram +, coccoid bacilli , motile. Catalase positive. Blood agar; produces β haemolysis Lab identification: Catalase positive. Tumbling motility

Question 26

Escherichia coli

Answer 26

Gram: Gram-negative rods/bacilli (pink) BA (Blood Agar): Large, white, colonies. MAC (MacConkey): Lactose fermenting, pink colonies ,moist ,smooth Commercial kits for Enterobacteriacae

Question 27

Strepto. agalactiae | (Gr B Strep.) - lab ID

Answer 27

Gram : Gram Positive cocci in pairs and short chains polysaccharide capsule - virulence factor, BA: Off-White β-haemolytic colonies CAMP positive reaction – arrowhead shaped area of enhanced haemolysis.

Question 28

Strepto. pneumoniae

Answer 28

Gram: Gram Positive cocci in pairs (diplococci) (purple) BA: Alpha haemolytic colonies (Green tinged) Lab. I.D. : Catalase negative. Optochin susceptible, Bile soluble. Quellung reaction. Most common cause of meningitis

Question 29

Quellung reaction

Answer 29

a biochemical reaction in which antibodies bind to the bacterial capsule of Streptococcus pneumoniae etc.

Question 30

Neisseria meningitidis

Answer 30

Gram: Gram negative diplococci (pink) CHOC: Clear, moist colonies. Capnophilic

Question 31

Pseudomonas aeruginosa

Answer 31

``` Gram: Gram negative rods/bacilli (pink) BA: Colonies may show haemolysis, metallic sheen. MAC: Non-fermenter, non-pink colonies Oxidase positive ,-Motility +ve ```

Question 32

Complications

Answer 32

Acute cerebral edema DIC (disseminated intravascular coagulation of blood) Brain abscess Hemorrhagic necrosis of adrenal glands (Waterhouse Friderichsen Syndrome with meningitis)