CNS Infections Flashcards by Claire O'Regan

List 7 types of CNS infections

Encephalitis, 
Meningitis, 
Meningoencephalitis, 
Encephalomyelitis, 
Epidural abscess, 
Neuritis, 
Sepsis syndrome due to infection elsewhere (indirect)

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What is the difference between meningitis and encephalitis?

Encephalitis involves inflammation of brain parenchyma

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How is meningitis classified? (5)

Acute pyogenic (pus forming) meningitis, 
Acute aseptic meningitis, 
Acute focal suppurative infection, 
Chronic bacterial infection, 
Acute encephalitis

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What is the most common microbial cause of acute pyogenic meningitis?

Bacterial

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What is most common microbial cause of acute aseptic meningitis?

Viral

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Give 3 examples of acute focal suppurative infections

Brain abscess,
Subdural empyema,
Extradural empyema

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Give an example of a chronic bacterial infection of meningitis

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How does pyogenic meningitis present in pathology?

Thick layer of suppurative exudate covering the leptomeninges (arachnoid and pia mater) of surface of brain

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How does pyogenic meningitis present microscopically in histology?

Neutrophils in the subarachnoid space

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What are the 4 bugs found in bacterial meningitis? Which is very rare?

Strep pneumoniae,
Neisseria meningitidis,
Listeria monocytogenes,
Haemophilus influenzae - very rare

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What type of bacteria is strep pneumoniae?

Gram +ve diplococci

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What type of bacteria is neisseria meningitidis?

Gram -ve diplococci

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What type of bacteria is listeria monocytogenes?

Gram +ve bacilli

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What type of bacteria is haemophilus influenzae?

curvilinear gram -ve bacillis

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Immunosuppressed patients of very young or people >60 tend to get which type of bacterial meningitis?

Listeria monocytogenes

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Which bacterial meningitis used to mostly be in children but has been mostly eradicated by vaccines?

Haemophilus influenzae

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Secondary attack

Neisseria meningitidis

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What is treatment for patients with strep pneumoniae, neisseria, haemophilus influenzae?

Ceftriazone IV 2g bd and dexamethasone IV 10mg qds

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What is treatment for patients with listeria bacterial meningitidis?

Ceftiaxone IV 2g bd + dexamethasone IV 10g qds + amoxicillin IV 2g 4ourly

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If needing to add listeria cover and patient has penicillin allergy, what is treatment?

Co-trimoxazole IV

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How long continue antibiotics for each bacteria: strep, neisseria, haem, listeria?

Strep: 5 days ceftriaxone
Neisseria: 10 days ceftriaxone
Haem: 10 days ceftriaxone
Listeria: 21 days amox

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If patient has travelled to country with high rates of penicillin resistant pneumococci (e.g. Canada, China, Poland, Spain, USA, Mexico, Italy, Greece, Turkey, Croatia, Pakistan), what is treatment?

Ceftriaxone IV + dexamethasone IV + vancomycin IV or rifampicin IV/PO

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Which patients should steroids be given to, how much?

ALL patients suspected of bacterial meningitis - 10mg IV 15-20mins before or with first dose of antibiotic

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Giving what drug reduces unfavourable outcome from 25% to 15% and mortality from 15% to 7%?

Study These Flashcards

Steroids

When should you NOT give steroids meningitis? (4)

Post-surgical meningitis, severe immunocompromise, meningococcal septic/septic shock, hypersensitivity to steroids

Which bacteria has most striking benefit from steroids in menigitis?

Strep pneumonia (pneumococcal meningitis) so if not that can stop steroids

Viral meningitis is common and usually occurs in late summer/autumn. What type of viruses tend to cause viral meningitis?

Enteroviruses

What is important to ask about in history of someone with viral meningitis?

Travel history

List 3 diagnostic tests for viral meningitis and which is best?

Viral stool culture, Throat swab PCR, CSF PCR - best one

What is treatment for viral meningitis?

Supportive as self limiting e.g. fluids, paracetamol

What is difference between encephalitis and meningo-encephalitis in terms of presenting symptoms?

Meningo-encephalitis displays normal meningitis symptoms of headache, fever and neck stiffness PLUS features of encephalitis

Outline symptoms of encephalitis (6)

Cerebral cortex is diffusely involved so INSIDIOUS onset of mental status changes, reduced consciousness/coma, Confusion, psychosis, Seizures, behavioural and speech disturbances, focal/diffuse neurologic signs e.g. partial paralysis

List 3 investigations for encephalitis

Lumbar puncture, EEG, MRI

What virus would you think about if patient presents with insidious onset of overall brain dysfunction symptoms i.e. everything dimmed?

Herpes simplex virus

If delay in diagnosis but you are suspicious patient has viral encephalitis what treatment should be started pre-emptively?

Aciclovir

How does HIV CNS infection normally present?

Meningitis

What is ADEM and when can it occur? (2)

Acute disseminated encephalomyelitis - post flu/vaccine

List 8 common symptoms of CNS infection

``` Headache, Vomiting, Pyrexia, Neck stiffness, Photophobia, Lethargy, Confusion, Rash ```

Bacterial meningitis caused by which bacteria is very common with a cribiform plate fracture?

Strep pneumoniae

Bacterial meningitis caused by which bacteria is can occur with neurosurgery/head trauma?

Staphyloccous, | Gram negative bacilli

Strep pneumoniae and neisseria are common causes of bacterial meningitis in all age groups but strep is more common in young and neisseria more common in older. True/false?

False - is common in all age groups but neisseria more common in young and strep more common in older

What percentage of people who survive an initial diagnosis of meningitis with sepsis will live with after-effects e.g. limb loss, deafness, blindness, cerebral palsy, quadriplegia and severe mental impairment?

25%

What causes the complications of meningitis? (5)

``` Purulence - pus clusters at base of brain and around nerves (especially CN III, VI), Invasion - abscesses, Cerebral oedema, Ventriculitis, hydrocephalus ```

List 3 types of pathogenesis of bacterial meningitis

Nasopharyngeal colonisation, Direct extension of bacteria e.g. sinusitis, mastoidis and goes into brain, From remote infection e.g. endocarditis (rare)

Who should undergo CT prior to lumbar puncture? I.e. who should not get lumbar puncture straight away - warning signs (8)

``` Immunosuppressed people, History of CNS disease, New onset seizure, (within 1 week) Papilloedema, Abnormal levels of consciousness, Shock, Bradycardia/hypertension, Focal neurologic deficit ```

CSF results are 99% predictive of bacterial meningitis if:

CSF WBC count is very very high (>2000) and is mostly neutrophils (>1180), high protein and glucose in CSF a lot lower than serum because has been consumed

Where is meningitis belt? (Meningococcus)

Across middle of west africa piece to east side

Outline differences in CSF results between viral and bacterial in terms of cell type, cell number, gram stain, protein, glucose

Cell type: bacterial polymorphs and viral lymphocytes Cell number: bacterial loads and viral less Gram stain: bacterial positive and viral negative Protein: bacterial high and viral normal/slightly high Glucose: very low compared to BG, usually normal

If no clear diagnosis from LP, stool and throat swabs, opening pressure, culture what additional tests can be done?

165 rRNA PCRs on CSF if bacterial seems likely, | CSF PCR for HSV1 and 2, zoster, enterovirus, stool and throat enterovirus PCR if viral seems likely

How could you tell TB from viral/bacterial from CSF sample?

Cell count and type is same as viral (so lower)and is also lymphocytes but protein levels high and glucose levels low compared to blood glucose

Symptoms of meningococcal meningitis are due to what from the bacteria?

Endotoxin

What form of meningococcal infection presents with big deep purple purpuric rash that won’t blanch when pressed on?

Fulminant septicaemia.

Meningococcal bacteria colonises the nasopharynx and around 10-25% of people carry it with no symptoms. True/false?

True

Which are the more common capsular groups of meningococcus in UK?

B, C, W and Y

TB meningitis is subacute illness. True/false?

True

What is aseptic meningitis?

Meningitis where no bacteria found

Contact prophylaxis treatment?

500mg single dose oral ciprofloxacin

In management of bacterial meningitis with low GCS (<12) or fluctuating conscious level (fall >2) what is management?

``` Admit, Airway and high flow O2, IV ceftriaxone +/- amoxicillin, IV steroids, Do not wait for CT scan/LP!! ```

CNS Infections Flashcards

(58 cards)