Infectious Diseases of the Brain Flashcards Preview

Neurology Module > Infectious Diseases of the Brain > Flashcards

Flashcards in Infectious Diseases of the Brain Deck (59):
0

What is most commonly affected in bacterial meningitis?

Subarachnoid space.

1

How does bacterial meningitis spread?

Typically hematogenous spread:
-25% Otitis media, sinusitis
-12% Pneumonia
-16% immunocompromised

2

Causative Organisms of Bacterial Meningitis in Neonates

Group B beta-hemolytic strep and enteric gram neg bacilli

3

Causative Organism of Bacterial Meningitis in Children

Haemophilus influenzae (40-60%)
Neisseria meningitidis
Streptococcus pneumoniae

4

Most common causative organisms of bacterial meningitis in adults

S.pneumoniae (30-50%)
N. Meningitidis (10-35%)

Other: Staphylococcus, H.Influenzae, Gram neg bacilli, Listeria)

5

Bacterial Meningitis causative organisms in the elderly:

S pneumoniae
E coli
Klebsiella
Listeria

6

Bacterial Meningitis presentation:

Fulminant illness <24 hours
Respiratory illness may precede by 7 days (25%)

Classic:
-Headache
-Stiff Neck
-Fever
-Photophobia

7

What are less common presentations of bacterial meningitis?

Mental status changes.
Nausea/Vomiting
Seizures
Lethargy
Confusion

8

Presentation of bacterial meningitis in infants:

High pitched crying
Refusal to eat
Bulging fontanelles

9

PE tests for bacterial meningitis:

Nucchal Rigidity
Kernig's Sign
Brudzinski's sign
Skin Rash - Neisseria Meningococcal (65%)

10

What is notable about PE for bacterial meningitis?

Poor sensitivity! Do not rely on negative exams!

11

How is bacterial meningitis diagnosed?

Lumbar puncture - cloudy

12

Other labs for bacterial meningitis:

Blood cultures
CBC - NL does not r/o bacterial meningitis

13

Imaging for bacterial meningitis

CT to rule out mass or abscess

14

Bacterial Meningitis Treatment 1 m - 50 y

Vancomycin 1 g IV q 6 hours
+
Ceftriaxone 2 g IV q 12 h OR Cefotaxine 2 g IV q 6h

15

Bacterial Meningitis Treatment over 50

Vancomycin 1g IV q 8 h
+
Ceftriaxone (2 g IV q 12 h) OR Cefotaxine (2g IV q 6h)
+
Ampicillin (Listeria)

16

How long do you treat Bacterial Meningitis?

S Peumoniae - 10-14 days
Neisseria - 7 days

17

Complications of Bacterial Meningitis

Cerebral edema
Vasculitis (arteritis- stroke; venous sinus thrombosis)
Increased ICP
Hydrocephalus
Seizures
DIC

18

What is the prognosis for bacterial meningitis?

N meningitis
-meningoccemia 30% mortality rate
-meningitis alone 4-5%
Pneumococcal meningitis - 30% mortality rate

19

What vaccines are available for bacterial meningitis prevention?

Pneumococcal
Meningococcal

20

Post exposure prophylaxis for bacterial meningitis:

Contagious 7 days prior to illness - 24 hours after antibiotics.

Rifampin x 2 days
Cipro x one oral dose
Ceftriaxone IM x1

For anyone who has been in high contact with the infected persons or healthcare workers.

21

Who gets the pneumococcal vaccine?

> 65
Other: asthma, smokers >50, HIV, nursing home patients
Reduces risk by 50%

22

Who gets the meningococcal vaccine?

Ages 11-55 yo
Before age 16 - 2 doses
Reduces risk by 50%

23

Viral Meningitis AKA

Aseptic Meningitis

24

Incidence of Viral Meningitis

7.6 cases / 100,000 adults vs 1.5 cases/ 100,00 adults (bacterial)

25

Causative organisms of viral meningitis in children

Enterovirus
Arbovirus
HSV
Borrelia Burgdoferi (Lyme)
Coxsackie Virus

26

Causative Organisms of Viral Meningitis in adults:

Enterovirus
HSV
Varicella-Zoster

27

Viral Meningitis Signs and Symptoms

Flue like symptoms
Headache
Fever
Malaise
Photophobia
Meningeal irritation

28

Can bacterial meningitis be easily differentiated from viral from an H&P?

NO!!! Must treat as bacterial until proven otherwise!! Bacterial more severe!

29

Treatment of Viral Meningitis

Asymptomatic

30

Prognosis of viral meningitis

good, very low mortality rate

31

Who gets Tuberculous meningitis?

Debilitated
Immunocompetent patients

32

How is tuberculous meningitis spread?

primary focus - lungs

33

Symptoms of Tuberculous meningitis?

Headache
Malaise
Fever
Weight loss
Nucchal rigidity

34

What does a lumbar puncture show in Tuberculous meningitis?

AFP

35

Treatment of Tuberculous meningitis?

INH
Streptomycin
Rifampin
Pyrazinamide x 6-9 months

36

Who is at risk for cryptococcal meningitis?

Debilitated
Immunocompetent patients
DM

37

What is encephalitis?

Inflammation of the brain
+/- meningeal involvement
Brain dysfunction predominant

38

Signs and Symptoms of encephalitis

Headache
Fever
Mental status changes

39

Most common cause of encephalitis:

Herpes Simplex Encephalitis
-HSV1 often lies dormant in the trigeminal ganglian
-Frontal/orbital
- Anteromedial/temporal

40

What symptoms does HSVI cause in encephalitis?

Presence of virus causes severe inflammation, edema, necrosis, hemorrhage.

If lymbic system is involved may cause personality changes, change in olfactory function/olfactory hallucinations.

If asymmetric involvement - may include hemiparesis and appear as stroke.

41

How is HSV encephalitis diagnosed?

CSF PCR for HCV GOLD STANDARD - false negatives may occur in first 12 hours and after 10 days

42

What will a lumbar puncture show with HSV encephalitis?

CSF leukocytes - 10-200 cells
CSF protein ~ 100 mg/dL
CSF glucose normal to low

43

What imaging is used for HSV Encephalitis?

MRI preferred (CT normal for first 5 days) - diffuse edema
T1 - hypointensity
T2 - hyperintensity

44

Treatment of HSV Encephalitis

Acyclovir IV 12.5 mg/kg IV q 8 h x 14 days
+/- steroids

45

HSV Encephalitis prognosis

Poor :-(

Mortality 10-40%

HIGH risk for neuro deficits

46

What neuro deficits can develop due to HSV encephalitis?

Personality disorders/changes
Dementia
Aphasia
Memory - inability o form new memories (hippocampal destruction)

47

What is the leading cause of epidemic encephalitis?

Arbovirus

48

When is Arbovirus prevalent?

Summer - early autumn

49

Incubation period for Arbovirus

2-18 days after mosquito bite

50

Range of arbovirus

Mild to severe

51

Types of Arbovirus

Eastern equine encephalitis
Western equine encephalitis
St. Louis encephalitis
Californian encephalitis
Venezuelan equine
West Nile Virus
Mumps

52

What are the natural hosts of West Nile Virus (WNV)?

Animals (most commonly horses)
Humans are only incidental

53

Prevalence of WNV

99% of cases are asymptomatic or self-limiting

1% results in severe illness

54

What increases risk of severity for WNV?

Age over 50 yo increases risk of severe course 20-fold

55

Signs and Symptoms of NSV

Abrupt Onset!
Fever
Malaise
Profound fatigue
Weakness
+/- headache, eye pain, nausea and vomiting

56

PE findings for WNV

Occipital LAN (generalized LAN)
+/- maculopapular rash
Conjunctivitis
Flushing

57

Diagnosis of WNV

CBC- leukopenia

Lumbar Puncture
-Lymphocytosis
-Normal glucose
+/- elevated protein
- IgM ELISA (positive 8-21 days after onset)

58

Treatment of WNV

Supportive
Research trials: ribavirin, interferon
Fatigue may last for WEEKS
Poliomyelitis-like syndrome