CNS infections Flashcards Preview

MD4001 Pathology > CNS infections > Flashcards

Flashcards in CNS infections Deck (22):
1

what are the symptoms of meningitis

headache, sore throat, drowsiness, fever, photophobia, neck stiffness, petechial or pupuric rash, vomiting, shivering


babies: tense/bulging soft spot on head, not feeding, irritable, stiff body with jerky movements, floppy and lifeless

2

what are the clinical features of meningitis

intravascular coagulation, endotoxaemia, shock, organ failure, raised intracranial pressure

3

what are the endothelial cells supported by in the BBB

thin basement membrane

4

what cells make up the BBB

tightly packed endothelial cells lining the blood vessels
breach by infective agent causes encephalitis

5

what is the blood- CSF barrier

barrier at arachnoid membrane and in ventricles

breach causes meningitis

6

what are the most common bacterial causes of meningitis

•Neisseriameningitidis
•Haemophilusinfluenzae
•Streptococcus pneumoniae
•Mycobacterium tuberculosis

7

what are the most common viral causes of meningitis

Enteroviruses:
•Echovirus
•Coxsackie virusesA & B
•poliovirus
Herpes viruses:
•Herpes simplex 1 & 2
Paramyxovirus:
•Complication of mumps

8

what is a common fungal cause of meningitis

cryptococcus neoformans

9

what protozoa can cause meningitis

•Amoebae
•Naegleria
•Acanthamoeba

10

what are the features of neisseria meningitidis

•Meningococcal disease
•Gram negative
•Intracellular diplococus
•Only infects humans
•Exists as normal flora in nasopharynx
•Distinct pathogenic serogroups
•Transmission by droplet spread or direct contact from carriers
•5 strains –A, B, C, W135, Y

11

what are the features of haemophilus influenza

•Gram-negative
•Coccobacilli
•Six capsular serotypes (a-f) known to cause disease
•Most virulent strain is H. influenzaetype b (Hib)

12

what are the features of Streptococcus pneumoniae

•Pneumococcal disease
•Chains of cocci
•Gram positive
•Exists as normal flora in nasopharynx
•Also causes pneumonia, otitis media

13

what are the virulence factors of bacterial meningits

•Anti-phagocytic polysaccharide capsule
•Endotoxin
•IgA protease
•Outer membrane proteins (OMPs)
•Pili(fimbriae)

14

what is the most at risk age group for meningitis

2-5 months

15

what are complications of bacterial meningits

•Sepsis
•Intellectual deficit
•Deafness
•Arthritis
•Skin necrosis

16

what vaccines can prevent bacterial meningitis

•MenC(meningococcal group C)
•Hib(Haemophilusinfluenzaetype B)
•BCG (Mycobacterium tuberculosis)
•Strep. Pneumoniae (pneumonococcal)
•MenB(meningococcal group B)
•Men ACWY (quadrivalent)

17

what are the features of viral meningitis

•Milder disease than bacterial but more common
•NAAT is a valuable diagnostic tool
•Identify in faeces, urine, CSF, serology
•No specific treatment
•Aciclovir(herpes)
•Use of vaccination (polio)

18

what are the features of tuberculous meningitis

•Frequently associated with miliaryTB
•Usually develops when Rich focus discharges contents in sub-arachnoid space
•Acid-fast bacilli in CSF smear
•NAAT and culture from CSF
•Treated with rifampicin, isonazid, pyrazinamide, ethambutol
•Vaccination with BCG

19

what are the features of encephalitis

usually viral in origin
•Viruses gain access to CNS via blood or neurons
•Primary encephalitis
–First exposure to virus results in virus directly affecting brain / spinal cord
•Secondary encephalitis
–Virus first infects another part of body, then affects CNS when reactivated

20

what are brain abscesses

•Begin as diffuse inflammation of brain matter progressing to focal lesion
•Arise from pia mater suppuration
•Visualised by MRI or CT scans
•Diagnosed by culture from aspirated pus

21

what are the possible causes of brain abscesses

•Predisposing factors
–Otitismedia
–Mastoiditis
–Sinusitis
•Oral-nasopharyngeal flora
–Aerobic (S. aureus, Strep. milleri)
–Anaerobic (Bacteroidessp., Fusobacteriumsp.)
•Immunocompromised(eg. HIV, transplantation)
–Protozoa (Toxoplasmagondii)
–Fungi (Candida sp., Nocardiasp., Aspergillussp.)

22

what are Transmissible Spongiform Encephalopathies(TSEs)

•Prion diseases
•Affects humans...
–Creutzfeldt-Jakob disease (CJD)
–New variant Creutzfeldt-Jakob disease (nvCJD)
•...and animals
–Bovine Spongiform Encephalopathy (BSE)
–Kuru
–Scrapie