Infectious Diseases of the Brain

Question 0

How does bacterial meningitis spread?

Answer 0

Typically hematogenous spread:

• 25% Otitis media, sinusitis
• 12% Pneumonia
• 16% immunocompromised

Question 1

What is most commonly affected in bacterial meningitis?

Answer 1

Subarachnoid space.

Question 2

Causative Organisms of Bacterial Meningitis in Neonates

Answer 2

Group B beta-hemolytic strep and enteric gram neg bacilli

Question 3

Causative Organism of Bacterial Meningitis in Children

Answer 3

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

Question 4

Most common causative organisms of bacterial meningitis in adults

Answer 4

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

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

Question 5

Bacterial Meningitis causative organisms in the elderly:

Answer 5

S pneumoniae
E coli
Klebsiella
Listeria

Question 6

Bacterial Meningitis presentation:

Answer 6

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

Classic:

- Headache
- Stiff Neck
- Fever
- Photophobia

Question 7

What are less common presentations of bacterial meningitis?

Answer 7

Mental status changes.
Nausea/Vomiting
Seizures
Lethargy
Confusion

Question 8

Presentation of bacterial meningitis in infants:

Answer 8

High pitched crying
Refusal to eat
Bulging fontanelles

Question 9

PE tests for bacterial meningitis:

Answer 9

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

Question 10

What is notable about PE for bacterial meningitis?

Answer 10

Poor sensitivity! Do not rely on negative exams!

Question 11

How is bacterial meningitis diagnosed?

Answer 11

Lumbar puncture - cloudy

Question 12

Other labs for bacterial meningitis:

Answer 12

Blood cultures

CBC - NL does not r/o bacterial meningitis

Question 13

Imaging for bacterial meningitis

Answer 13

CT to rule out mass or abscess

Question 14

Bacterial Meningitis Treatment 1 m - 50 y

Answer 14

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

Question 15

Bacterial Meningitis Treatment over 50

Answer 15

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

Question 16

How long do you treat Bacterial Meningitis?

Answer 16

S Peumoniae - 10-14 days

Neisseria - 7 days

Question 17

Complications of Bacterial Meningitis

Answer 17

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

Question 18

What is the prognosis for bacterial meningitis?

Answer 18

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

Question 19

What vaccines are available for bacterial meningitis prevention?

Answer 19

Pneumococcal

Meningococcal

Question 20

Post exposure prophylaxis for bacterial meningitis:

Answer 20

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.

Question 21

Who gets the pneumococcal vaccine?

Answer 21

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

Question 22

Who gets the meningococcal vaccine?

Answer 22

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

Question 23

Viral Meningitis AKA

Answer 23

Aseptic Meningitis

Question 24

Incidence of Viral Meningitis

Answer 24

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

Question 25

Causative organisms of viral meningitis in children

Answer 25

``` Enterovirus Arbovirus HSV Borrelia Burgdoferi (Lyme) Coxsackie Virus ```

Question 26

Causative Organisms of Viral Meningitis in adults:

Answer 26

Enterovirus HSV Varicella-Zoster

Question 27

Viral Meningitis Signs and Symptoms

Answer 27

``` Flue like symptoms Headache Fever Malaise Photophobia Meningeal irritation ```

Question 28

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

Answer 28

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

Question 29

Treatment of Viral Meningitis

Answer 29

Asymptomatic

Question 30

Prognosis of viral meningitis

Answer 30

good, very low mortality rate

Question 31

Who gets Tuberculous meningitis?

Answer 31

Debilitated | Immunocompetent patients

Question 32

How is tuberculous meningitis spread?

Answer 32

primary focus - lungs

Question 33

Symptoms of Tuberculous meningitis?

Answer 33

``` Headache Malaise Fever Weight loss Nucchal rigidity ```

Question 34

What does a lumbar puncture show in Tuberculous meningitis?

Answer 34

AFP

Question 35

Treatment of Tuberculous meningitis?

Answer 35

INH Streptomycin Rifampin Pyrazinamide x 6-9 months

Question 36

Who is at risk for cryptococcal meningitis?

Answer 36

Debilitated Immunocompetent patients DM

Question 37

What is encephalitis?

Answer 37

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

Question 38

Signs and Symptoms of encephalitis

Answer 38

Headache Fever Mental status changes

Question 39

Most common cause of encephalitis:

Answer 39

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

Question 40

What symptoms does HSVI cause in encephalitis?

Answer 40

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.

Question 41

How is HSV encephalitis diagnosed?

Answer 41

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

Question 42

What will a lumbar puncture show with HSV encephalitis?

Answer 42

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

Question 43

What imaging is used for HSV Encephalitis?

Answer 43

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

Question 44

Treatment of HSV Encephalitis

Answer 44

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

Question 45

HSV Encephalitis prognosis

Answer 45

Poor :-( Mortality 10-40% HIGH risk for neuro deficits

Question 46

What neuro deficits can develop due to HSV encephalitis?

Answer 46

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

Question 47

What is the leading cause of epidemic encephalitis?

Answer 47

Arbovirus

Question 48

When is Arbovirus prevalent?

Answer 48

Summer - early autumn

Question 49

Incubation period for Arbovirus

Answer 49

2-18 days after mosquito bite

Question 50

Range of arbovirus

Answer 50

Mild to severe

Question 51

Types of Arbovirus

Answer 51

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

Question 52

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

Answer 52

Animals (most commonly horses) | Humans are only incidental

Question 53

Prevalence of WNV

Answer 53

99% of cases are asymptomatic or self-limiting 1% results in severe illness

Question 54

What increases risk of severity for WNV?

Answer 54

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

Question 55

Signs and Symptoms of NSV

Answer 55

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

Question 56

PE findings for WNV

Answer 56

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

Question 57

Diagnosis of WNV

Answer 57

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

Question 58

Treatment of WNV

Answer 58

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