C. diff and Meningitis

Question 1

Name the likely pathogen of bacterial meningitis, according to age group:

Answer 1

neonates (<1 month old): Group B streptococcus, Listeria monocytogenes, E.coli

infants (< 2 years old): S. pneumoniae, Neisseria meningitidis, Group B streptococcus, E.coli

children and adults (2-50 years old): S. pneumoniae, Neisseria meningitidis

elderly (>50 years old): S. pneumoniae, Neisseria meningitidis, Listeria monocytogenes, aerobic gram negative bacilli (e.g. E.coli, Kelbsiella species)

Question 2

Name the empiric therapy for bacterial meningitis, according to age group:

Answer 2

neonates (<1 month old): ceftriaxone + ampicillin (ampicillin covers Listeria monocytogenes)

infants (<2 years old): ceftriaxone + vancomycin
(vancomycin covers ceftriaxone resistant S. pneumoniae)

children and adults (2-50 years old): ceftriaxone + vancomycin

elderly (>50 years old): ceftriaxone + vancomycin + ampicillin

Question 3

Name the culture directed therapy for S. pneumoniae caused bacterial meningitis:

Answer 3

penicillin susceptible: penicillin G or ampicillin

penicillin resistant, cephalosporin susceptible: ceftriaxone

cephalosporin resistant: IV vancomycin + rifampcin

for 10-14 days

Question 4

Name the culture directed therapy for Neisseria meningitidis caused bacterial meningitis

Answer 4

penicillin susceptible: penicillin G or ampicillin

penicillin resistant or mild penicillin allergy: ceftriaxone

for 5-7 days

Question 5

Name the culture directed therapy for Listeria monocytogenes caused bacterial meningitis

Answer 5

penicillin G or ampicillin

mild penicillin allergy: co-trimoxazole or meropenem

for at least 21 days

Question 6

Name the culture directed therapy for Group B streptococcus caused meningitis:

Answer 6

penicillin G or ampicillin

mild penicillin allergy: ceftriaxone

for 14-21 days

Question 7

Name the doses for treatment of bacterial meningitis for penicillin G, rifampicin, vancomycin and linezolid

Answer 7

penicillin G: IV 4MU q4h
rifampicin: IV 300mg q12h
vancomycin: IV 25-30mg/kg q8h-12h with LD of 15mg/kg
linezolid: PO/IV 600mg q12h

Question 8

Name the regimes for the chemoprophylaxis of Neisseria meningitidis for close contacts (household/daycare) of patients with menigococcal disease / exposed to nasopharynx oral secretions

Answer 8

rifampicin:
adult - PO 600mg q12h x 4 doses
children - PO 10mg/kg q12h x 4 doses
neonates - PO 5mg/kg q12h x 4 doses

ciprofloxacin:
adult ONLY - PO 500mg x 1 dose

ceftriaxone:
IM 125-250mg x 1 dose

Question 9

Name the criteria for diagnosis of bacterial meningitis (subjective and objective)

Answer 9

subjective signs and symptoms: fever, chills, classic triad (headache, backache, neck rigidity), mental status changes (irritability), photophobia, N/V/anorexia, poor feeding habits (infants), Petechiae / purpura (specific for N. meningitis), Kernig’s sign, Brudzinski’s sign, Buldging fontae (for babies)

objective results from CSF fluid (obtained via lumbar puncture): turbid CSF fluid, elevated opening pressure, low CSF glucose (CSF: blood ratio of < 0.4), raised CSF protein of >1.5g/L, raised WBC of >100 cells/mm^3 (mostly neutrophils)

general laboratory findings suggestive of systemic infections but non-specific for bacterial meningitis: WBC < 4 x 10^9/L or > 10 x 10^9/L, neutrophil > 75%, CRP>40mg/L, procalcitonin >= 0.5ug/L

Question 10

Name the risk factors for bacterial meningitis

Answer 10

head trauma, CNS shunts, neurological procedures, CSF fistula or leak, local infections (otitis media, sinusitis, pharyngitis), immunosuppresion, splenectomized patients, congenital defects

Question 11

Name the risk factors for C. difficile infections

Answer 11

use of nasogastric feeding tube, hx of antibiotics use (number, dose, duration, overall exposure; clindamycin, 3rd generation cephalosporins and fluoroquinolones pose the greatest risk), history of CDI, history of GI surgery, gastric-acid suppressive therapy, previous hospitalisation within the past 1 year, duration of hospitalisation, residence in nursing home / long term care facilities, immunosuppression, elderly > 65 years, multiple or severe co-morbidities

Question 12

Name the 4 ways to control and prevent CDI

Answer 12

Isolation of CDI patients in private room with separated toilet, Hand hygiene with handwashing with soap, Environmental cleaning with sporicidal agents, Antimicrobial stewardship to minimize the frequency and duration of high-risk antibiotic therapy and the number of antibiotics provided

Question 13

Name the criteria for diagnosis of CDI (subjective and objective)

Answer 13

Subjective: watery diarrhoea >= 3x/day, abdominal cramps and distension, nausea, anorexia, malaise, fever, leukocytosis, hypovolemia, fulminant (hypotension/shock, ileus, toxic megacolon - radiological evidence), pseudomembranous colitis- colonscopic evidence

*do not test and treat asymptomatic patients

Objective: positive stool test result for Clostridiodes difficile or its toxins (toxin A/B), SCr >= 133 umol/L (or 1.5 mg/dL) OR WBC >= 15 x 10^9/L - criteria for severe CDI

Question 14

Name the antibiotic regime for non-severe CDI (SCr< 133 umol/L AND WBC < 15 x 10^9/L)

Answer 14

PO vancomycin 125mg QDS
PO fidaxomicin 200mg BD
PO metronidazole 400mg TDS

treat for 10 days, may extend to 14 days if symptoms are not completely resolved

Question 15

Name the antibiotic regime for severe CDI (SCr >= 133umol/L OR WBC >= 15 x 10^9/L)

Answer 15

PO vancomycin 125mg QDS
PO fidaxomicin 200mg BD

treat for 10 days, extend to 14 days if symptoms are not completely resolved

Question 16

Name the antibiotic regime for fulminant CDI (hypotension, ileus, toxic megacolon)

Answer 16

IV metronidazole 500mg q8h
+/- PO vancomycin 500mg QDS
+/- PR vancomycin 500mg QDS

treat for 10 days, extend to 14 days if symptoms are not completely resolved

Question 17

Name the antibiotic regime for first recurrent CDI

Answer 17

if previous treatment was vancomycin/fidaxomicin:
PO fidaxomicin 200mg BD x 10 days
PO fidaxomicin 200mg BD x 5 days, 5mg EOD x 20 days
PO vancomycin 125mg QDS x 10-14 days, 125mg BD x 7 days, 125mg OD x 7 days, 125mg every 2-3 days x 2-8 weeks

If previous treatment was metronidazole:
PO vancomycin 125mg QDS x 10 days