CNS Infections

Question 1

What are some clinical consequences of untreated infections of the CNS?

Answer 1

Brain herniation and death Cord compression and necrosis with subsequent permanent paralysis

Question 2

List infections of the CNS

Answer 2

Encephalitis Meningitis Meningoencephalitis Encephalomyelitis Epidural abscess Neuritis Sepsis syndrome due to infection elsewhere

Question 3

Name different classifications of meningitis

Answer 3

Acute pyogenic (bacterial) meningitis Acute aseptic (viral) meningitis Acute focal suppurative infection (brain abscess, subdural and extradural empyema) Chronic bacterial infection (tuberculosis) Acute encephalitis

Question 4

What is acute encephalitis?

Answer 4

An infection of the brain parenchyma

Question 5

What does the brain look like when infected by pyogenic meningitis?

Answer 5

Thick layer of suppurative exudate covering the leptomeninges

Question 6

What is seen microscopically in pyogenic meningitis?

Answer 6

Neutrophils in the subarachnoid space

Question 7

What pathogens cause bacterial meningitis?

Answer 7

Pneumococcus Meningococcus Haemophilus influenza

Question 8

What other pathogen can cause bacterial meningitis in patients >60 or immunocompromised?

Answer 8

Listeria spp

Question 9

What antibiotics are used to treat bacterial meningitis?

Answer 9

Ceftriazone IV + Dexamethasone IV If P allergy: chloramphenicol IV

Question 10

What antibiotic can be added to cover listeria infection?

Answer 10

Amoxicillin IV P allergy: co-trimoxazole

Question 11

Why does H. influenza rarely cause meningitis?

Answer 11

Vaccination

Question 12

Which bacteria is diplococcus, gram positive and stains purple?

Answer 12

Strep pneumonia

Question 13

Which bacteria is gram-negative (stains pink) and is intracellular?

Answer 13

Neisseria meningitidis

Question 14

Which bacteria is gram positive, bacillus (rod-shaped) and occurs in over 60s and alcoholics?

Answer 14

Listeria monocytogenes

Question 15

Which bacteria is gram negative and bacillus?

Answer 15

H. influenzae

Question 16

Which pathogen causes viral meningitis?

Answer 16

Enteroviruses e.g. ECHO virus

Question 17

How is viral meningitis diagnosed?

Answer 17

Viral stool culture Throat swab CSF PCR

Question 18

What is the treatment for viral meningitis?

Answer 18

Supportive Self-limiting

Question 19

What questions should you ask when taking a history from a patient with suspected encephalitis?

Answer 19

Current or recent febrile, flu-like illness? Altered behaviour, personality change or altered consciousness? New onset seizures? Focal neurological symptoms? Rash? Family/neighbours affected? Travel history? Recent vaccinations? Animals (rabies)? Fresh water (leptospirosis)? Mosquito/tick bites? Immunocompromised? HIV?

Question 20

What are the clinical features of encephalitis?

Answer 20

Insidious onset Stiffness in head/neck Stupor, coma Seizures, partial paralysis Confusion, psychosis Speech, memory symptoms

Question 21

Which disease is coma more likely to present in, encephalitis or meningitis?

Answer 21

Encephalitis

Question 22

What are the investigations for encephalitis?

Answer 22

Lumbar puncture EEG MRI

Question 23

Should acyclovir be given pre-emptively if there is a delay in treating encephalitis?

Answer 23

Yes- prompt therapy improves outcomes

Question 24

What are the common signs and symptoms of meningitis?

Answer 24

Fever, cold hands + feet Drowsy Severe muscle pain Severe headache Dislike bright lights Vomiting Confusion + irritability Pale, blotchy skin Spots/rash Stiff neck Convulsions/seizures

Question 25

Which bacteria commonly infects neonates with community acquired bacterial meningitis?

Answer 25

Listeria Group B Streptococci E.coli

Question 26

Which bacteria commonly infects children with community acquired bacterial meningitis?

Answer 26

H. influenza

Question 27

Which bacteria commonly infects children aged 10-21yrs with community acquired bacterial meningitis?

Answer 27

Neisseria menigitidis

Question 28

Which bacteria commonly infects \>21yrs with community acquired bacterial meningitis?

Answer 28

Streptococcus pneumonias \> Neisseria meningitidis

Question 29

Which bacteria commonly infects \>65yrs with community acquired bacterial meningitis?

Answer 29

Streptococcus pneumonia \> Listeria

Question 30

Which bacteria commonly infects patients with decreased cell mediated immunity with community acquired bacterial meningitis?

Answer 30

Listeria monocytogenes

Question 31

Which bacteria commonly infects neurosurgery/head trauma patients with community acquired bacterial meningitis?

Answer 31

Staph aureus Staph epidermis Aerobic GNR

Question 32

Which bacteria commonly infects fracture of cribriform patients with community acquired bacterial meningitis?

Answer 32

Streptococcus pneumoniae

Question 33

Which bacteria commonly infects CSF shunt patients with community acquired bacterial meningitis?

Answer 33

Staph epidermidis Staph aureus Aerobic GNR Propionibacterium acnes

Question 34

What percentage of those who survive meningitis with have life-altering after effects. Give examples

Answer 34

25% Limb loss Blindness Deadness Cerebral palsy Quadriplegia Severe mental impairement

Question 35

What is the pathogenesis of bacterial meningitis?

Answer 35

Nasopharyngeal colonisation Direct extension of bacteria- parameningeal foci (sinusitis, mastoiditis or brain abscess) or across skull defects/fractures From remote foci of infection (endocarditis, pneumonia, UTI)

Question 36

Which bacteria causes meningococcal meningitis?

Answer 36

Neisseria meningitidis Found in throats of healthy carriers

Question 37

What indicates the presence of n. meningitidis in CSF?

Answer 37

Bacteria found in leukocytes

Question 38

Which type of H. influenza meningitis is most common in children under 4?

Answer 38

Type B

Question 39

How does the vaccine for H. influenza work?

Answer 39

Conjugated vaccine directed against capsular polysaccharide antigen

Question 40

Which groups of people are most susceptible to s. pneumoniae meningitis?

Answer 40

Hospitalised patients Patients with CSF skull fractures Diabetics Alcoholics Young children

Question 41

Which vaccine is given to children to protect against pneumococcal meningitis?

Answer 41

Pneumococcal pneumonia vaccine

Question 42

What is a gram positive bacilli (+blood cultures)?

Answer 42

Listeria monocytogenes

Question 43

What is the antibiotic of choice for listeria monocytogenes?

Answer 43

IV ampicillin/amoxicillin Ceftriaxone has no value

Question 44

Who is affected most by TB meningitis?

Answer 44

Reactivation Elderly

Question 45

How is TB meningitis treated?

Answer 45

Isoniazid + rifampicin (add pyrazinamide + ethambutol)

Question 46

What are features of cryptococcal meningitis?

Answer 46

Fungal Mainly in HIV disease CD4 \<100 Disseminated infection

Question 47

What is found on investigation of a patient with cryptococcal meningitis?

Answer 47

Subtle neurological presentation Aseptic on CSF Serum and CSF cryptococcal antigen

Question 48

Which antibiotics should be given for cryptococcal meningitis?

Answer 48

IV amphotericin B/ Flucytosine Fluconazole

Question 49

What should be measured when taking a CSF sample?

Answer 49

Opening pressure Microscopy, culture +sensitivity Meningococcal and pneumococcal PCR Protein Glucose Lactate

Question 50

What further tests should be performed in suspected meningitis?

Answer 50

Bacterial- PCR on CSF Viral- PCR on CSF for: HSV1/2, VSZ, enterovirus Stool Throat swab

Question 51

What is the algorithm for meningitis?

Answer 51