Bacterial Meningitis Flashcards
FYI : Meningococcal = Pneumococcal = Streptococcal =
Meningococcal = N. meningitidis Pneumococcal = S. pneumoniae Streptococcal† = Group A/B Streptococcus
Listeria risk factor
Alcoholism Immunocompromised state Age < 1 month Age > 50 years
FYI: Risk factors for bacterial menigitis (BM)
Head trauma Otitis media Sinusitis or mastoiditis Neurosurgery Dermal sinus tracts Systemic sepsis Immunosuppression High-dose (long-term) steroids Immunoglobulin deficiency Chemotherapy Splenectomy Sickle Cell disease Exposure to cigarette smoke - Meningococcal Cochlear implants - Pneumococcal
Systematic complication for BM
Sepsis (FYI) Disseminated intravascular coagulation Acute respiratory distress syndrome Septic/reactive arthritis Typically a result of bacteremia that often accompanies meningitis
Neurologic complication for BM
Altered mental status Confusion, lethargy, coma Increased intracranial pressure and cerebral edema Mild to Moderate: HA, confusion, irritability, N/V Severe: Coma, vision loss, cerebellar herniation Seizures Focal neurologic deficits Cranial nerve palsy, hemiparesis, aphasia, ataxia Cerebrovascular abnormalities Thrombosis, vasculitis, aneurysm, hemorrhage Sensorineural hearing loss Intellectual impairment
Likely etiology by age groups
Newborn - 1 months and > 50 years old: Group B Streptococcus, E. coli, Klebsiella, Enterobacter, Listeria monocytogenes 1 month - 50 years old: S. pneumoniae, N. meningitidis, H. influenzae
Clinical Presentation of BM
Varies with age Classic Tetrad (≥ 2 of 4 sxs in > 90% of adults w/ ABM) -Fever -Nuchal rigidity -Altered mental status -Headache Signs Kernig sign Brudzinski sign Dermatological Manifestations Purpuric and petechial skin lesions Other symptoms Chills, vomiting, and photophobia Bulging fontanelle, irritability, refusal to eat, apnea, purpuric rash, and convulsions in young children
FYI: Nuchal rigidity
Impaired neck flexion resulting from muscle spasm (not actual rigidity) of the extensor muscles of the neck; usually attributed to meningeal irritation.
Kernig sign
The thigh is flexed at the hip and knee at 90 degree angles, and subsequent extension in the knee is painful (leading to resistance). This may indicate subarachnoid hemorrhage or meningitis.
Brudzinski sign
Severe neck stiffness causes a patient’s hips and knees to flex when the neck is flexed
Goal of therapy
Relieve signs/symptoms of infection Eradicate infection Avoid/resolve additional infectious problems E.g., CNS deterioration Prevent complications associated with antimicrobial therapy
Lumbar Puncture and complications
Puncture into subarachnoid space of lumbar region to obtain spinal fluid for diagnostic or therapeutic purposes (aka LP or spinal tap) Complications: - Headache - Back discomfort or pain - Bleeding - Brainstem herniation
Lumbar Puncture: CSF Evaluation
FYI: Delayed Lumbar Puncture
•LP after CT scan to identify possible CNS mass lesion
oAltered mentation
oFocal neurologic signs
oPapilledema
oSeizure within the previous week
oImpaired cellular immunity
•Possible Contraindications to LP (populations above)*
oPossible raised intracranial pressure
oThrombocytopenia or other bleeding predisposition (including ongoing anticoagulant therapy)
oSuspected spinal epidural abscess
What is the suspected organism for GPCs in pairs and chains?
Streptococcus pneumoniae
What is the suspected organism for Gram (-) diplococcus?
Neisseria meningitidis
What is the suspected organism for Gram (+) bacilli (rods)?
Listeria monocytogenes
What is the suspected organism for Gram (-) coccobacillus?
Haemophilus influenzae
What is the recommended and alternative (FYI) for Streptococcus Pneumoniae?
Recommended: Vanco + 3rd gen Ceph
Alternative: Moxifoxacin
What is the recommended and alternative (FYI) for Neissria Meningitidis?
Recommended: 3rd gen Cephalosporin
Alternative: Fluoroquinolone and Aztreonam
What is the recommended and alternative (FYI) for Listeria Monocytogenes?
Recommended: Amp +/- AG OR PCN +/- AG
Alternative: Bactrim
What is the recommended and alternative (FYI) for Haemophilus influenza?
Recommended: 3rd gen ceph
Alternative: Cefepime, Meropenem, Fluoroquinolone
Duration of therapy
ABx dosing for BM
Dexamethasone MOA and pt population benefit
•Inhibit production of proinflammatory cytokines
oTNF and IL-1
•Benefit in infants and children with H. influenzae and in adults with S. pneumoniae meningitis
Dexamethasone advantage and disadvantage
•Advantage: may decrease neurologic sequelae, unfavorable outcome, and death
oE.g., cerebral edema, ↑ ICP, altered cerebral blood flow, neuronal injury
•Disadvantage: might reduce CSF concentrations of antibiotics due to decreased inflammation
Adjunctive Dexomethasone for infants and children ( >6 wks old)
oDexamethasone 0.15 mg/kg IV q6h x 2- 4 days
oMust be given 10-20 minutes prior to or with first dose of antibiotics for benefit
Adjunctive Dexamethasone for adults suspected/proven pneumococcal infxn:
oDexamethasone 10 mg IV q6h x 2- 4 days
oMust be given 10-20 minutes prior to or with first dose of antibiotics for benefit
•Daily Monitoring (short-term therapy) for Dexamethsone
oHemoglobin
oOccult blood loss
oSerum potassium
oBlood glucose
Monitoring for BM
•Symptom-based
oResolution of s/sxs over time (neurologic fxn, fever, pain, etc.)
•Microbiologic eradication
oCheck blood cultures q24h until negative
oRepeat LP not routinely recommended, but consider if no improvement within 48h on appropriate therapy
•Laboratory
oCBC, SCr
oSerum drug concentration monitoring (vancomycin, AGs)
•Safety
oADRs to pharmacologic therapy
FYI: Antibiotics may be prescribed for close contacts of patients with meningococcal meningitis
oProphylaxis: Ciprofloxacin 500 mg po x 1
oAlternate: Ceftriaxone 250 mg IM x 1
FYI: Prophylaxis for H. Influenzae Meningitis
•Antibiotics may be prescribed for close contacts in the entire household of a patient with severe H. influenzae meningitis – IF there is a high-risk person within the household
oProphylaxis: rifampin 600 mg/d x 4 days
oAlternate: ciprofloxacin 500 mg x 1
•Prophylaxis not recommended for adults who are vaccinated
FYI: List 2 MenB vaccine
•Limited Guidance
Trumenba® (Approved 10/14): 3 doses
Bexsero® (Approved 1/15): 2 doses
FYI: List 3 Meningococcal vaccines quadrivalent (Serogroups A, C, W-135, and Y)
two conjugate vaccines (MCV-4), Menactra and Menveo, and
one polysaccharide vaccine (MPSV-4), Menomune, produced by Sanofi Pasteur.
FYI: Limitation of MPSV-4 vaccine
The duration of immunity mediated by Menomune (MPSV-4) is three years or less in children aged under 5 because it does not generate memory T cells. Attempting to overcome this problem by repeated immunization results in a diminished, not increased, antibodyresponse, so boosters are not recommended with this vaccine.
As with all polysaccharide vaccines, Menomune does not produce mucosal immunity, so people can still become colonised with virulent strains of meningococcus, and no herd immunity can develop.For this reason, Menomune is suitable for travelers requiring short-term protection, but not for national public health prevention programs.
Menveo and Menactra contain the same antigens as Menomune, but the antigens are conjugated to a diphtheria toxoid polysaccharide–protein complex, resulting in anticipated enhanced duration of protection, increased immunity with booster vaccinations, and effective herd immunity.
FYI: N. meningitidis Vaccines pt age and population
•VACCINATION OPTIONAL: Patients 16-23 y/o
oPreferably 16-18 y/o
•VACCINATION RECOMMENDED:
oPersons w/ persistent complement component deficiencies
oPersons with anatomic or functional asplenia
oMicrobiologists routinely exposed to isolates of N. meningitidis
oPersons identified as at increased risk because of a serogroup B meningococcal disease outbreak
