2. Meningitis

Question 1

what is meningitis?

Answer 1

inflammation of meningeal lining of brain and spine

Question 2

where is CSF found?

Answer 2

within the subarachnoid space, beneath the arachnoid membrane, on top of the pia mater. It also surrounds the spinal cord and fills open spaces (ventricles) inside the brain

Question 3

function of CSF?

Answer 3

CSF helps to maintain a constant pressure inside the skull, known as intracranial pressure (ICP).

Question 4

common bacterial causes of meningitis in adults?

Answer 4

Neisseria meningitidis
Haemophilus influenzae
Streptococcus pneumoniae

Question 5

common viral causes of meningitis in adults?

Answer 5

Enteroviruses:
Echoviruses
Coxsackie viruses A and B poliovirus
Herpes viruses:
Herpes simplex virus 1 and 2

Question 6

typical CSF in bacterial infection?

Answer 6

cloudy
white cell count increased
cell type = neutrophils
proteins = increased
glucose = low

Question 7

typical CSF in viral infection?

Answer 7

clear
white cell count increased
cell type = lymphocytes
proteins = moderate increased
glucose = normal or slightly decreased

Question 8

describe gram stain of neisseria meningitides

Answer 8

gram negative

diplococci

Question 9

characteristics of neisseria meningitides?

Answer 9

• Normal flora of nasopharynx

* Spread via Inhalation of respiratory droplets

Question 10

clinical significance of neisseria meningitides?

Answer 10

• Gram-negative Sepsis, meningitis, meningococcal sepsis

Question 11

virulence factors of neisseria meningitides?

Answer 11

• LPS capsule = Antiphagocytic

* Pili – attaches to nasopharyngeal mucosa

Question 12

investigations of neisseria meningitides?

Answer 12

• Gram stain of CSF from lumbar puncture
• Throat swab
• Tumbler test

Question 13

treatment/ prevention of neisseria meningitides?

Answer 13

• Ceftriaxone (Passes through BBB)
• Cefotaxime – In new-born children
• ABCWY Vaccine

Question 14

what type of antibiotic is ceftriaxone?

Answer 14

beta lactam - cephalosporin - inhibits cell wall synthesis

Question 15

clinical features of meningitis?

Answer 15

• classic triad
- fever
- headache
- neck stiffness
• photophobia
• phonophobia
• vomiting
• non-blanching rash

Question 16

investigations of meningitis

Answer 16

FBC, U&E, lactate, CRP
blood culture
lumbar puncture
PCR
Tumbler test

Question 17

what are two diagnostic tests for meningitis?

Answer 17

kernig’s sign - positive when the thigh is flexed at the hip and knee at 90 degree angles, and subsequent extension in the knee is painful
brudzinski’s sign - if flexing neck causes automatic flexion of knees

Question 18

how are pathogens of meningitis spread?

Answer 18

direct spread - through skull fracture, up through nose

haemotogenous spread - blood

Question 19

what is the tumbler test

Answer 19

placing tumbler glass over rash to see if it blanching or not

Question 20

what is the rash found in meningitis?

Answer 20

petechial rash - tiny bleed into the skin - low platelet count

Question 21

what is DIC?

Answer 21

The main mechanisms of DIC are inflammatory cytokine-initiated activation of tissue factor-dependent coagulation and insufficient control of anticoagulation pathways. At a simplistic level the coagulation process goes out of control. Lots of small clots form. These use up many of the anticoagulation factors. The consequence is that there is bleeding occurring at the same time as the small clots are being formed. As an example platelets (which are important in forming clots) are used up in making the clots and the platelet count becomes low. This allows for the small bleeds into the skin (petechiae).

Question 22

what is seen in patients with severe DIC?

Answer 22

Ecchymoses: The petechial lesions can coalesce and form larger lesions that appear ecchymotic. Ecchymoses (diameter >10 mm) are mainly noted in patients with severe DIC. These lesions are secondary to subcutaneous hemorrhage.