Term
| meningitis organism prevalence change from 1970s to 1990s |
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Definition
Streptococcus pneumoniae ̄ 26%
Neisseria meningitidis ̄ 58%
Group B Streptococcus ̄ 4%
Haemophilus influenzae ̄ 35%
Listeria monocytogenes ̄ 46% |
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Term
| Acute vs Chronic Meningitis |
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Definition
-Defined by duration of signs and symptoms
-Acute <4 weeks
-Chronic >4 weeks |
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Term
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Definition
- Bacteria
• Community-acquired - S. pneumoniae, N. meningitidis,
Group B Streptococcus
• Post-op or hospital acquired – MRSA, Pseudomonas aeruginosa
• Infants/Elderly Listeria monocytogenes
- Viruses
• Enterovirus, Coxsackie virus, Echovirus, HSV-2, Arbovirus, Adenovirus, Measles virus, Influenzae virus
- Fungi
• Coccidioides, Cryptococcus
- TB |
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Term
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Definition
So what's going on here? Well, this is the pathophysiology. You can read through this. Basically, you get seeded. And usually you get seeded with these organisms through the nasopharyngeal area. They then penetrate. They get in. They get into the sinuses. They work their way across the blood-brain barrier. And they get into the brain.
One of the most interesting cases of meningitis I ever saw was a person that had surgery. They'd been intubated. The intubation led to bacterial flora from the mouth getting into the sinuses. They developed a sinus infection which then infected the sinus bones, so they developed an osteomyelitis in their sinuses. And then it eroded through and got into their brain.
So that doesn't happen that often. But that's kind of the seeding mechanism. Usually, it gets into the nasopharyngeal area and then crosses into the blood-brain barrier.
With bacteria, you get a huge inflammatory response in all the spaces and the spinal fluid. And this is all-- see all this white stuff kind of coating this autopsy brain? All that white, that's all pus. That's all inflammatory process. That's all white cells. That's all bacteria. |
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Term
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Definition
| • Inflammatory response to bacterial infection of the pia- arachnoid and CSF of the subarachnoid space. |
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Term
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Definition
- Age
• Infants are at higher risk for bacterial meningitis than people in other age groups.
- Community setting
• Larger groups of people gather together. College students living in dormitories and military personnel.
- Certain medical conditions
• There are certain diseases, medications, and surgical procedures that may weaken the immune system or increase risk of meningitis in other ways.
- Travel
• Travelers to the meningitis belt in sub-Saharan Africa may be at risk for meningococcal meningitis. |
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Term
Clincal Presentation
• Acute meningitis |
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Definition
• Abrupt or rapid onset
• “flu-like” prodrome – myalgias • Fever
• Headache
• Nuchal stiffness
• Altered sensorium
• Rash |
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Term
| meningitis Physical Exam- What’s Important? |
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Definition
• Nuchal rigidity (30%)
- Brudzinski and Kernig sign
• Rash
- Noted in 66% of patients with meningococcal, but may also beseen with Haemophilus and Streptococcus
• Focal neurologic signs (33%)
- More common with pneumococcal
• Altered consciousness (69%)
• Papilledema (3%) |
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Term
| meningitis Systemic infection clinical findings |
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Definition
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Term
| meningitis Meningeal inflammation clinical findings |
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Definition
| Neck stiffness Kernig/Brudzinski Cranial nerve palsies |
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Term
| meningitis Cerebral vasculitis clinical findings |
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Definition
| Focal neurologic abnormalities Seizures |
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Term
| meningitis Elevated intracranial pressure clinical findings |
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Definition
Change in mental status Headache
Cranial nerve palsies Seizures |
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Term
| meningitis Special Groups- Presentation |
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Definition
• Neonates- no meningismus, but temperature instability, listlessness, refusal to eat, jaundice, diarrhea
• Adults co-morbid conditions- lethargy, obtundation, confusion, no fever
• Neutropenic patients- very subtle presentation, change in mental status
- Secondary to inability to mount an inflammatory response |
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Term
meningitis CT Indications
• Guidelines for performing CT scan before LP |
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Definition
• Recent seizures (<1 week)
• Immunocompromised
• History of CNS disease
• Altered mental status
• Abnormal gaze or facial palsy
• Abnormal language or inability to answer 2 questions or follow 2 commands
• Visual field abnormalities
• Arm or leg drift |
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Term
meningitis CSF Studies
• CSF Cell count |
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Definition
• Non-specific
• WBC count > 2,000/mm3 was predictive of bacterial meningitis • Neutrophil count >100 was also predictive
• WBC count < 1,000/mm3 noted in 20% of patients
• Listerial infection presents with low WBC and a mononuclear cell predominance |
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Term
meningitis CSF Studies
• CSF Culture |
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Definition
• The Gold Standard
• Positive in 85% of cases with a CSF WBC >1000/mm3
• Varies with organism
- H. influenzae 96%
- S. pneumoniae 87%
- N. meningitidis 80%
• Positive cultures lower in patients on antibiotics prior to LP
• 24 hours of pretreatment drops rate to 59% |
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Term
meningitis CSF Studies
• CSF Gram stain |
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Definition
• Cheap and well-validated
• Study of just under 4000 patients with bacterial meningitis 45% of CSF culture negative patients had a positive Gram stain (Bryan, 1990)
- 44% of the patients in this study had been pre-treated with antibiotics
• Sensitivity of Gram stain varies by organism |
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Term
meningitis CSF Studies
• Latex agglutination tests |
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Definition
• Provides results in less than 15 minutes
• Detect antibodies against the capsular polysaccharides og the pathogen
• Recommended for patients with suspected bacterial meningitis with negative Gram stain and culture
• Have a high sensitivity
- Sensitivity drops with pre-treatment with antibiotics • Sensitivity decreased from 60% to 9% for meningococcal meningitis (Bronska, 2006)
• Overall use is limited |
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Term
meningitis CSF Studies
• Polymerase chain reaction (PCR) |
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Definition
• Nucleic acid amplification tests
• Use limited by testing availability and time to perform
• High diagnostic accuracy (88-100%)
• Test for H. influenzae, S. pneumoniae, and N. meningitidis
• Meningococcal testing being used widely in suspected meningococcal meningitis with negative cultures
• Studies being done on L. monocytogenes • Results unclear at this time
• Also used in viral meningitis |
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Term
meningitis CSF Studies
• CRP |
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Definition
• An acute phase reactant
• Synthesized by the liver
- In response to interleukin 6 which is produced during infection and
inflammation
• Activates classical complement pathway
• Secretion starts in 6 hours, peaks in 36 hours
• Elevated levels suggestive of bacterial infection, but do not establish the diagnosis |
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Term
| meningitis Treatment- Empirical |
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Definition
• Ceftriaxone 4 g IV daily or 2 gm IV Q 12, or Cefotaxime 2 gm IV Q 4, plus
• Vancomycin 1.5 gm IV Q 12
• In newborn or over age 50 add Ampicillin 2 gm IV Q 4 or
penicillin 2.4 gm IV Q 4
• If PCN allergic, ask for details:
- Rash : use cephalosporin
- Anaphylactic : use Aztreonam 2 gm IV Q 8 |
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Term
meningits Treatment
• Corticosteroids |
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Definition
• Reduce the inflammation caused by infection
• Dexamethasone leads to a reduction in hearing loss and other neurological sequelae
• No reduction in overall mortality
• Improves outcomes in adults and reduces mortality in patients with S.
pneumoniae meningitis
• Inhibits synthesis of cytokines causing inflammation
• Decreases CSF outflow resistance
• Stabilizes blood-brain barrier
• Give before or with 1st dose of antibiotics for 4 days |
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Term
| meningistis treatment duration of therapy in days by organism |
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Definition
Neisseria meningitidis
7
Haemophilus influenzae
7
Streptococcus pneumoniae
10-14
Streptococcus agalactiae
14-21
Aerobic gram-negative bacilli
21
Listeria monocytogenes
≥ 21 |
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Term
| meningitis management algorithm |
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Definition
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Term
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Definition
- Vaccines
• H. influenzae type B vaccine
• Pneumovax
• Meningococcal vaccine
• All should be administered to any asplenic patient
- Exposure to meningococcus
• Rifampin 600 mg PO BID x 4 doses or Ciprofloxacin 500 mg single dose (adults) or ceftriaxone 125 mg IM single dose
• Only for intimate contacts: spouse, boyfriend/girlfriend, household contacts
• Not needed for: classmates, co-workers, HCWs (ER personnel, EMTs, etc) |
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Term
| Acute Bacterial Meningitis: DDx |
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Definition
• Bacterial, viral, fungal, TB meningitis
• Drug-induced hypersensitivity meningitis
• Carcinomatous or lymphomatous meningitis • Viral encephalitis
• Tick-borne bacterial infections
• Brain abscess
• Subdural empyema
• Venous sinus thrombosis
• Autoimmune (e.g., Sarcoid, SLE) |
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Term
| Acute Bacterial Meningitis: Complications |
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Definition
• Decreased intellectual function • Memory impairment
• Cerebral edema
• Hydrocephalus
• Septic shock, multisystem organ dysfunction • Septic venous sinus thrombosis
• Arteritis
• Cranial nerve palsies (hearing)
• Seizure |
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Term
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Definition
- Enteroviruses cause 85-95% of cases
• Include Enterovirus, Coxsackie virus, and Echo virus • Cause 30,000 to 75,000 cases per year
• Typically noted summer/fall
• Fecal-oral spread
- Other viruses
• Mumps (viral meningitis and encephalitis)
• Herpesviruses (HSV-1, HSV-2, Varicella-zoster, CMV, EBV)
• HIV
• Lymphocytic choriomeningitis virus
- Cannot distinguish initially from bacterial meningitis
- Severe HA, photophobia, nuchal rigidity, fever
- May be preceded by a few weeks by viral gastroenteritis
• Ask patient if he/she had the “stomach flu” some time in the past couple weeks
- Almost never involves brain (meningoencephalitis) • Pt never obtunded, no history of seizure
- Disease is self-limited, resolves after 7 to 10 days without treatment
- No serious sequelae |
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Term
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Definition
• Low numbers of WBCs : 10 to 500
- PMNs predominate early, Monos or Lymphocytes later
• CSF to serum glucose ratio usually = 50%
• Protein may be high
• Gram stain, culture and bacterial antigens negative • Enteroviral PCR positive about 70% of time |
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Term
| Approach to Viral Meningitis |
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Definition
• Treat like bacterial meningitis until the 72 hr culture comes back negative, or...
• Enteroviral PCR comes back positive
• Consider acyclovir if CSF HSV PCR positive
- HSV meningitis is self-limited |
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Term
| How do we distinguish viral from bacterial based on labs? |
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Definition
- Gram stain
• Positive in bacterial meningitis 50-90% of time • Decrease to 7-41% if on oral antibiotics
- CSF results that suggest bacterial
• Glucose <40 mg/dl
• Protein >200 mg/dl
• WBC count >1000/μL with >80% neutrophils • Opening pressure > 300 mm
- Classic findings not always noted
• 12% of bacterial meningitis patients do not have any of the classic findings
• Half of viral meningitis cases may have elevated neutrophils |
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Term
| Chronic Meningitis: Causes |
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Definition
lBacterial
-Partially treated acute meningitis/parameningeal infection
-Mycobacterium tuberculosis
-Lyme Disease
-Syphilis
lFungal
-Cryptococcus neoformans
lProtozoal
-Toxoplasma gondii
lHelminthic
- Cysticercosis
lMeningeal/parameningeal infections
lMalignancy
lNoninfectious inflammatory d/o
lChemical meningitis |
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Term
| Chronic Meningitis: Pathophysiology |
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Definition
lInflammation causes obstruction of CSF-hydrocephalus, increased ICP
lCognitive changes, cranial nerve deficits, seizures, myelopathy, stroke
lRadiculopathies/Myelopathies |
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Term
| Chronic Meningitis: Signs and Symptoms |
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Definition
lHA
lNeck pain
lChange in mental status lWeakness
lVisual changes lNumbness |
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Term
| Chronic Meningitis: Evaluation |
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Definition
lH&P (including recent travel/search for systemic disease) lLP
lPredominance of mononuclear cells
lCT/MRI-brain/spinal cord
lBlood Work lCXR
lUA etc. |
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Term
Brain Abscess: Epidemiology and Risk
Factors |
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Definition
• Focal, suppurative infection within brain parenchyma
• 1/100,000
• Risk factors
- Otitis media/mastoiditis/paranasal sinusitis
- Chest infections
- Penetrating head trauma/neurosurgery
- Dental infections |
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Term
| Brain Abscess: Pathophysiology |
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Definition
- Days 1-3 early cerebritis
• Perivascular infiltration of inflammatory cells • Central core necrosis
• Edema
- Days 4-9 late cerebritis
• Pus, macrophages/fibroblasts
- Days 10-13 early capsule formation • Ring-enhancing
- Days 14+ late capsule formation • Necrotic center with capsule |
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Term
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Definition
- Otitis media/mastoiditis
• Streptococci
• Bacteroides spp.
• P. aeruginosa
Enterobacteriaceae
- Paranasal Sinusitis
• Streptococci
• Haemophilus spp. • Bacteroides spp.
• Pseudomonas spp. • S. aureus
- Endocarditis
• Viridans Streptococci or
S. aureus
- Lung
• Streptococci
• Staphylococci
• Bacteroides
• Fusobacterium spp.
- Urine
• Enterobacteriaceae or P. aeruginosa |
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Term
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Definition
- Head Trauma/Neurosurgery
• Staphylococci
• Enterobacteriaceae
• Pseudomonas spp. |
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Term
| Brain Abscess: Signs and Symptoms |
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Definition
• Headache-constant, dull, aching • Fever
• Seizure
• Focal neuro deficit
- Hemiparesis
- Aphasia
- Visual field defects
• Increased ICP
• Deficits depend on part of brain affected • No meningismus |
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Term
| Brain Abscess: Evaluation |
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Definition
• MRI, CT
• Needle aspiration-gram stain/cx results
• Blood cx
• Blood work |
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Term
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Definition
• Treatment-drainage
- Antibiotics 6-8 weeks and serial MRI/CT
• Community Acquired
- 3rd generation cephalosporin
- Metronidazole
• Head trauma/neurosurgery
- Ceftazidime-Pseudomonas spp.
- Vanco-staphylococci
• AEDs |
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Term
| Brain Abscess: Complications |
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Definition
• Seizures
• Persistent weakness • Aphasia
• Mental impairment
• Mortality <15% |
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Term
| SUBDURAL EMPYEMA Epidemiology, Risk Factors, Causes |
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Definition
• Rare-15-20% of focal suppurative CNS infections
• Sinusitis
• Head trauma/
neurosurgery
• Males>females 3:1
• 20s-30s
• Etiology
• Streptococci
• Staphlococci
• Enterobacteriaceae • Anaerobic bacteria |
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Term
| SUBDURAL EMPYEMA Pathophysiology |
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Definition
• Thrombophlebitis of veins draining sinuses
• Osteomyelitis
• Neurosurgery |
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Term
| SUBDURAL EMPYEMA Signs and Symptoms |
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Definition
• Fever
•HA
• Sinusitis
• Neuro deficits-weakness
• Seizures
• Nuchal rigidity
• Increased ICP
• Decreased level of consciousness |
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Term
| SUBDURAL EMPYEMA Evolution and Treatment |
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Definition
• DX-MRI/CT
• Treatment- a medical emergency!
- Requires drainage-burr holes vs craniotomy
- Empiric therapy-min 4w
• 3rd generation
cephalosporin
• Vancomycin
• Metronidazole
• Narrow coverage with gram stain/cx results |
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Term
| SUBDURAL EMPYEMA complications/prognosis |
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Definition
• Seizures/hemiparesis
• Prognosis depends upon-
- PE at time of presentation
- Size of collection
- Time elapsed until drainage |
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Term
EPIDURAL ABSCESS
Epidemiology |
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Definition
• Between skull and dura
• Average age >50 years old
• Account for <2% of focal suppurative CNS infections
• Prognosis
- Mortality <5%
- Likely full recovery |
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Term
| EPIDURAL ABSCESS risk factors |
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Definition
• Diabetes mellitus
• Spinal trauma/surgery
• IV drug abuse
• Alcoholism
• Renal insufficiency
• Immunosuppression
- Chronic steroids, cirrhosis, cancer, infection
• Pregnancy |
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Term
| EPIDURAL ABSCESS pathophys |
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Definition
• Direct extension (10-30%)
- Osteomyelitis, soft tissue
• Hematogenous spread (50%)
• Instrumentation (15-20%)
- Surgery, epidural injection
• Unknown (~30%) |
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Term
|
Definition
- Sources
• Surgery-
osteomyelitis
• Fracture
• Sinusitis, mastoiditis, otitis media
• Venous transmission |
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Term
| EPIDURAL ABSCESS Signs and Symptoms |
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Definition
• Fever
• HA
• Nuchal rigidity
• Seizures
• Focal neuro deficits
• Change in mental status
• Wound infection-post-op
• Early presentation maybe non-specific
• Stage 1
• Severe back pain and
fever
• Stage 2
• Spinal irritation and
radicular pain
• Stage 3
• Fecal and urinary
incontinence
• Stage 4
• Paralysis |
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Term
| EPIDURAL ABSCESS Evaluation and Treatment |
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Definition
- Physical exam
• Spinal- tenderness
• Neurologic exam- complete
• Rectal exam
- Evaluation
• CBC
• Sed rate/CRP
• Blood cultures
• MRI/CT • MRI best
• Drainage
• Empiric therapy
- 3rd gen. cephalosporin, nafcillin, or vancomycin and metronidazole
- 3 week treatment minimum after drainage
- Narrow antibiotic treatment after culture results obtained |
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