CNS infection Flashcards
what micro- organism is the leading cause of bacterial meningitis
- Neisseria meningitidis.
what is meningitis
Meningitis is inflammation of the layers of tissue that cover the brain and spinal cord (meninges) and of the fluid-filled space between the meninges (subarachnoid space)
What are the Meninges 3 layers of membranes which protect the brain Leptomeninges
- Dura mater
- Arachnoid mater
- Pia mater
Inflammation of the meninges - Arachnoid and pia mater layers
Which symptoms might led to a suspicion of bacterial meningitis?
- Bulging fontelle
- stiff neck or back
- altered mental state,
- photophobia,
-kerning’s and Brudzinks’s signs,
-focal neurological deficit, - petechial/purpuric rash,
-limb pain, - cold hands and feet,
-unusual skin colour,
-capillary refill time >2s,
-shock and hypotension
How would this diagnosis be confirmed in secondary care
- A Physical examination
- Monitoring of vital signs:
In all people with suspected bacterial meningitis or meningococcal disease perform a risk stratification and assess
- Conscious level (for example using the Glasgow Coma Scale [GCS], or the Alert, Voice, Pain, Unresponsive [AVPU] scale)
- HR and BP
- RR, O2 sats (if a pulse oximeter is available)
- Temperature
- Capillary refill time
- Blood tests for CRP and WBC
- Lumbar puncture with examination of CS
(c) Describe how bacterial meningitis is usually treated?
- Urgent antibiotic treatment
- Adjunctive therapy
- Supportive therapy
- Urgent antibiotic treatment
- Based on clinical situation and most probable bacterial aetiology
- Further treatment depends on bacteria identified in CSF
- Antibiotic drug properties needed to achieve therapeutic concentration of antibiotic in CSF
- Lipid solubility, ionic dissociation at blood pH, low molecular weight
Empiric therapy of suspected meningococcal disease - Single dose of benzylpenicillin sodium (cefotaxime in penicillin allergy) before urgent transfer to hospital
- Adjunctive therapy
- e.g. Corticosteroids
Regulates inflammatory response and ↓ CSF hydrostatic pressure - Dexamethasone initiated before/with first dose of antibiotics and continued for 4 days
- Associated with improved outcomes
Should not be given to: - Immunocompromised patients
- Those who have already received antimicrobial therapy
- Patients aged <1 month
- Supportive therapy
- Restore and maintain respiratory, cardiac, neurological function
- Fluid management
- Over- or under-hydration associated with adverse outcomes
- E.g. brain swelling, shock - Regular monitoring of clinical signs of hydration state needed
- Repeated every 6-12 hours for first 48 hours
Outline who chemoprophylaxis is indicated and not indicated for, as well as the commonly used pharmacological agents.
- Aims to ↓ risk of invasive disease by eradicating carriage in those at highest risk
- Prophylaxis indicated, irrespective of vaccination status:
- Prolonged close contact with the case in household type setting during the 7 days before onset of illness
- Transient close contact with a case only if directly exposed to large particle droplets/secretions from respiratory tract of a case
- Prophylaxis not indicated:
- Pupils in same school, work colleagues, friends, kissing on cheek or mouth, sharing food or drink, traveling in next seat on plane/train/bus/car, post-mortem contact.
Ciprofloxacin - chemoprophylaxis
- Can be given as single dose
- Does not interact with oral contraceptives
- More readily available in community pharmacies
- Recommended in all age groups, pregnancy and breastfeeding
- Should be given as soon as possible (within 24 hours)
- May have unpredictable effects in patients with epilepsy
Rifampicin - chemoprophylaxis
- Preferred second-line antibiotic
- Must be given twice daily for two days
- Number of C/Is, interactions, S/Es
