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Flashcards in CP Central Nervous systems Deck (69):
1

Define = Meningitis

Inflammation of meninges

2

Define = Encephalitis

inflammation of brain

3

Define = Meningo-encephalitis

inflammation of brain and meninges

4

Aseptic Meningitis
- provide clinical picture
- what is most common cause
- other causes x7

White cell count >5x106/L (5/mm3) in cerebrospinal fluid (CSF)
Negative bacterial culture of the CSF
Viruses are the commonest cause, others include:
Partially treated bacterial meningitis
Listeria
TB
Syphilis
Malignancy,
Autoimmune conditions,
Drugs

5

What is the basic infectious particle of a virus

viron

6

what do viral proteins form

capsid, membrane projections

7

what do viral enzymes do

used for replicating genetic material, influencing transcription and protein modification

8

Epidemiology of viral meningitis

COMMON - children neonates
5-15 cases per 100,000

9

Aetiology of viral meningitis

Enterovirus - commonest cause
Echoviruses
Coxsackie viruses
Parecho viruses
Enteroviruses 70 and 71
Poliovirus
Herpes viruses
Herpes Simplex Virus 2 (HSV 2) >> HSV 1
Varicella Zoster Virus (VZV)
Cytomegalovirus (CMV), Epstein Barr Virus (EBV)
HHV6, HHV7
Arboviruses (e.g. Japanese Encephalitis virus)
Mumps Virus
HIV
Adenovirus
Measles
Influenza
Parainfluenza type 3
Lymphocytic choriomeningitis virus (LCMV)

10

What must you always check if you think the patient has viral meningitis

travel history, sexual history, and
IMMUNOCOMPROMISED

11

Pathogenesis of viral meningitis

colonization of mucosal surfaces
invades epithelial surface
replicated in cells
desseminates and invades CNS - via cerebral micro vascular endothelial cells, choroid plexus epithelium, olfactory nerve

12

How does the enterovirus enter the CNS

blood stream (haematogenous spread)

13

How does HSV or VZV enter CNS in viral meningitis

traveling up peripheral nerves (neurotropically)

14

clinical presentation of viral meningitis

Fever,
Meningism (headache, stiffneck, photophobia)
Children = bulging anterior fontanelle

15

What is Kernig's Sign

With hip and knee flexed to 90o, the knee cannot be extended due to pain/stiffness in the hamstrings

16

What is Brudzinski's sign

Flexing the neck causes the hips and knees to flex

17

What is nuchal rigidity

Resistance to flexion of the neck

18

What investigations for viral meningitis

Bloods - FBC, U&E, clotting, culture
CT head (do 1st)
Lumbar puncture - ASAP
Viral PCR - gold standard

19

CSF findings viral meningitis

White cell count
Pleocytosis = white cells in CSF
Lymphocytic, usually

20

CSF findings Bacterial meningitis

High opening pressure
WBC - 100-20,000 v high
high protien
high glucose
gram stain 60-90% +ve

21

Treatment

IV antibiotics
cefotaxime if bacterial
HSV and VZV = aciclovir
supportive therapy
NOTIFY PUBLIC HEATH

22

Enteroviral Meningitis

COMMONEST UK
fever, vom, anorexia, rash, URT symptoms,
No specific treatment
Full recovery

23

HSV - Herpes Simplex Virus 1
causes/

Cold Sores and viral encephalitis

24

HSV2 - Herpes simplex virus 2 causes

genital herpes, meningitis
2nd common cause
Mollarets meningitis - recurrent aseptic meningitis

25

VZV - varicella zoster virus
causes

Chickenpox, shingles
Meningitis RARE but possible
Aciclovir may be useful
normal recovery expected

26

Mumps meningitis

10-30% mumps cases
CNS symptoms 5 days post parotisis
No specific treatment
preventable with vaccination

27

HIV and meningitis

can occur as part of primary infection
fever, lymphadenopathy, pharyngitis, rash
IMPORTANT TO DIAGNOSE

28

Viral Encephalitis
Main causes
others

90% Herpes Simplex Virus1
Other viruses causes:
VZV, EBV, CMV
Adenovirus
Measles
Mumps
Enteroviruses (including polio)
Arboviruses (e.g. West Nile, Japanese B, St Louis, Eastern and Western Equine Encephalitis)
Influenza
Rubella
HIV
Rabies
Other causes:
Bacteria (e.g. Strep pneumoniae, Neisseria meningitidis, TB)
Malignancy (paraneoplastic)
Autoimmune
Acute disseminated encephalomyopathy (ADEM)
Other immune-mediated

29

what percentage of viral encephalitis are unknown aetiology

37%

30

clinical presentation of viral encephalitis

Altered mental state
confusion --> coma
fever, headache, meningism
Focal neurology
seizures
weakness, dysphasia, cranial nerve palsy, ataxia

31

What should patient be started ON for viral encephalitis

IV aciclovir
if ANY change in mental state even if not 100% sure encephalitis

32

Viral encephalitis investigations

Bloods - FBC, U&E, CRP, clotting, serology
CT
LP - microscopy, culture and sensitivity, protien and glucose, viral PCR
MRI - looking for HSV
EEG - 75% in HSV encephalitis have abnormal temporal lobe activity

33

Treatment for Viral encephalitis

HIGH dose IV aciclovir
14-21 days

34

HSE epidemiology

rare
high risk 50 yo

35

HSE pathogenesis

Direct transmission of virus via neural or olfactory pathway
OR
Reactivation in trigeminal
ganglia
acute focal necrotising encephalitis
inflammation of brain

36

outcome HSE

untreated - 70% dead
survivors - paralysis, speech lose, personality change
BEST - aciclovir within 4 days of symptoms

37

Acute disseminated encephalomyelopathy (ADEM

immune mediated CNS demyelination,
clinical findings = encephalitis
CSF findings - Viral meningitis
Treatment - steriods

38

What are the different types of primary bacterial infections of the CNS

Meningitis
Encephalitis
Ventriculitis
Brain Abscess
Ventriculoperitoneal shunt and external ventricular drain infection
subdural empyema
eye infections

39

What is a brain abscess

focal suppurative process within the brain parenchyma (pus in the substance of the brain

40

What causes brain abscesses

often polymicrobial
60-70% Streptococci "milleri"
10-15% Staph aureus common post trauma
Anaerobes
Gram -ve enteric bacteria
fungi, TB, toxoplasma gondii, nocardia, actinomyces

41

4 clinical settings of brain abscess pathogenesis

-Direct Spread from contiguous suppurative focus
- haematogenous spread from distant focus
- trauma
- cryptogenic - no focus

42

Clinical presentation of brain abscess

headache - COMMON
focal neurological deficit 30-50%
confusion
fever

43

Management of brain abscess

Drainage = gold standard

44

why should brain abscesses be drained

1 - reduce intercranial pressure
2 confirm diagnosis
3 obtain pus for microbiological investigation
4 enhance efficacy of antibiotics
5 avoid infection spread to ventricles

45

Antibiotics treatment for brain abscess?

ampicillin
penicillin
cefuroxime
cefotaxina
ceftazidime
metronidazole
Challenge penetration of drugs into CSF blood barrier and blood brain barrier

46

What empirical treatment for a
ODONTOGENIC abscess

IV cefotaxime 2g 6hourly
IV metronidazole 500mg 8hourly

47

Empirical treatment plan for OTOGENIC abscess

IV benzyl penicillin 2.4g 6 hourly
IV ceftazidime 2g 8hourly
IV metronidazole 500g 8hourly

48

possible complications for brain abscess

rained intracranial pressure
mass effect
cloning
rupture into ventricles causing ventriculitis

49

Subdural empyema
- define
- causes
- pathogenesis

1) Infection between dura and arachnoid mata
2) causes often polymicrobial
anaerobes, streptococci, gram -ve, strep pneumoniae, haemophilus influenzae, staph aureus
3) spread infection from sinuses 50-80%, middle ear and mastoid 10-20%, distant site 5%, can be post trauma or surgery

50

Subdural empyema
- presentation
- management

1) headache, fever, focal neurological deficit, confusion, seizure, coma
2) urgent drainage of pus, antimicrobial agents

51

Ventriculoperitoneal VP shunt
External ventricular drain EVD infection
- what
- how
- diagnosis
- treatment

1) device to monitor inter cranial pressure or drain excess CSF
2) colonised by organisms that cause ventriculitis
3) CSF microscopy and culture (usually coagluase -ve staph)
4) device removal, intraventricular antibiotics

52

What is Neisseria Meningitidis

-gram -ve diplococci
-require blood for growth
-13 capsular types: A,B,C W135 -and Y are most common
-Can be detected by PCR
- natural Habitat = NASOPHARYNX
- 5-20% people are carriers
- crosses blood brain barrier and multiplies in subarachnoid space

53

What can be causes be Neisseria Meningitidis

1 ) Fulminant septicaemia
2) septicaemia with purpuric rash
3) Septicaemia with meningitis
4) Pyogenic (purulent) meningitis with no rash
5) Chronic meningococcal bacteraemia with arthralgia
6) Focal sepsis
7) Conjunctivitis, endophthalmitis

54

Treatment for Neisseria Meningitidis

-Ceftriaxone, cefotaxime
-Penicillin
-Intensive Care
-Chemo prophylaxis of contacts = Rifampicin, ciprofloxacin
- Vaccination - group A,C, W135

55

What is Haemophilius Influenzae

- must be grown in blood
- small pleopmorphic Gram -ve cocci-bacilli
- six antigenic types a-f
- type b causes most invasive disease

56

Carriage of Haemophilus influenzae
- normal carriage
- passage to blood stream
- virulence factors

Normal
- restricted to humans
- 25-80% carry non-capsulated strain
- 5-10% carry capsulated stains

Throat - invade submucosa - blood

Virulence factors
- type b capsule
- Fimbrae, IgA proteases, outer membrane proteins, liposaccahrides

57

Treatment for Haemophilus influenzae

Treatment
Ceftriaxone, cefotaxime
Ampicillin
β-lactamase producing strains common

Chemoprohylaxis of contacts of invasive disease
Rifampicin

H.influenzae Type b conjugate vaccines
Dramatic reduction in the incidence of invasive disease

58

What is Streptococcus Pneumoniae

- gram +ve cocci - cells grow in pairs
- needs blood or serum from growth
- polysaccahride capsule: 95 capsular types
- normal habitat - human respiratory tract
- transmission - droplet spread

59

Treatment Streptococcus pneumoniae

Ceftriaxone, cefotaxime
- Penicillin resistant common in some parts of the world

- No Chemoprohylaxis of contacts of invasive disease

- Conjugate vaccine available against common serotypes
- reduction in the incidence of invasive disease in children introduced US

60

When should steroids be used in meningitis in adults

- given shortly before 1st dose of antibiotics
- S. pneumoniae = give steroids
- no benefit - meningococcal meningitis

61

Neonatal meningitis?

Group B beta-haemolytic Streptococci
Escherichia coli
Listeria monocytogenes

Neonatal
Neonatal infection. Variable onset
Early ( 5 days). Usually meningitis.

Cefotaxime
Ampicillin and gentamicin

62

Complications for meningitis

Death
overwhelming sepsis, raised intracranial pressure
Deafness, delayed development, seizures, stroke, hydrocephalus

63

Lymphocytic meningitis

Viral meningitis
Most common form of meningitis
Enteroviruses
Herpes simplex

Benign outcome
Symptomatic treatment

Spirochete
Treponemal
Borrelia

Note Polio virus can cause meningitis that may lead to paralysis
Prevented by vaccination

64

Tb meningitis

-insidious onset
-diagnosis - hard - AFB not seen on microsopy
-12 months standard Tb treatment
-steroids beneficial

65

Cryptococcal Meningitis

cryptococcus = yeast
common problem patients with late stage HIV
lymphocytic meningits
prolonged course of treatment
- amphotericin, flucytosine, fluconazole

66

Clostridium tetani

- Gram +ve spore forming bacillus
- terminal round spore
- strict anaerobe

67

Spread of clostridium tetani

organism widespread in soil
organism - non invasive but produces tetanospasmin
- toxin genes plasmid encoded
- toxin spreads via blood stream and retrograde transport
- binds to ganglioside receptors, blocks release of inhibitory interneurones
- convulsive contractions of voluntary muscles

68

What does clostridium tetani

Tetanus (lockjaw)
Tonic muscle spasms
Trismus
Opisthotonus

Respiratory difficulties

Cardiovascular instability
(sympathetic nervous system)

69

Treatment of Clostridium tetani

Treatment
Antitoxin (horse or human)
Penicillin or metronidazole

Drugs for spasms
Muscle relaxants
Respiratory support

Prevention
Toxoid