meningitis Flashcards
What is meningitis?
inflammation of the membranes covering the brain and spinal cord (meninges)
causes of meningitis
– Viruses
– Bacteria
– Fungi
Inc risk of meningitis after what?
head trauma
in presence of ventriculo-peritoneal shunts (brian surgery, putting in shunts)
layers of meninges
dura matter (out)
arachniod (middle)
pia matter (inner)
most common cause of bacterial meningitis
Neisseria meningitidis
(gram negative diplococci)
Neisseria meningitidis
- 13 types (serogroups)
- characterised by surface structures in the capsule and outer cell membrane
- 5 responsible for most cases of invasive disease
- A, B, C, Y and W-135
other bacterial causes
- S. Pneumoniae
(G+ve cocci) - H. influenzae type B
(G-ve rods)
What does causastive agent depend on?
age of pt
viral causes of meningitis
- less severe than bacterial meningitis
- usually resolves without Tx
- caused by viruses that live in the intestines
- Enteroviruses (most common)
- mumps and measles viruses and herpes viruses
- poor hygiene may increase the risk of transmission
- not all people exposed to the virus will develop meningitis
fungal causes of meningitis
- life threatening
- rare disease
- usually in pts with compromised immune fxn
- slow progression
- difficult to diagnose and treat
- Cryptococcus, Candida
non-infective causes of meningitis
- complication of head injury, brain surgery, some cancers
- sometimes drugs
greatest age risk for meningitis
< 5 years
common bacterial pathogens in newborns
- Group B streptococci
- E coli
- Listeria monocytogenes
common bacterial pathogens in infants
- Neisseria meningitidis
- Haemophilus influenzae
- Streptococcus pneumoniae
common bacterial pathogens in children
- N meningitidis
- S pneumoniae
common bacterial pathogens in adults
- S pneumoniae
- N meningitidis
- Mycobacteria
most common cause in Africa
Group A meningococcus
vaccine for what casue of meningitis
Meningitis A
(Group A meningococcus)
Neisseria meningitidis - spread
- normally in nasopharynx
- transmitted by droplets/ secretions from the URTI
- spread by close contact (not highly transmissible)
- epidemics in crowded environments
RF
- infants & young children
- community settings - inc close contact
- asplenia
- immunocompromised
- exposure to active/passive tobacco smoke
- elderly
- pregnancy and working with animals inc risk of meningitis with Listeria bacteria
presentation of Neisseria Meningitidis
- Bacterial meningitis (15%)
- Meningococcal septicaemia (25%)
- Combination of both (60%)
classic signs & Sx
- Fever
- Headache
- Photophobia
- Neck stiffness
- Petechial rash
signs and Sx in young children
- fever
- N&V
- poor feeding
- irritability
- drowsiness
- confusion
- sudden fever & rigors
- muscle & joint aches
- cold extremeties
- Sx of raised ICP (bulging fontanelle, irregular breathing, abnormal tone)
- petechial rash (usually N meningitidis)
Petechial rash
- usually in septicaemia but may be absent in meningitis
- blanching and macropapular in early disease, develops into petechial, non-blanching rash
- rapidly evolving rash = severe disease
- non-blanching = MED EMERGENCY
(glass test not in NICE guidance)
Kernig’s and Brudzinski’s sign in meningitis
- severe stiffness of the HAMSTRINGS causes an inability to straighten leg when hip is flexed to 90 degrees
- severe neck stiffness causes hips and knees to flex when the neck is flexed
diff between meningitis and sepsis
PRODROME SAME
- fever
- N&V
- malaise
- lethargy
MENINGITIS
- severe headache
- neck stiffness
- photophobia
- drowsiness/confusion
** death from inc ICP
SEPSIS
- limb/joint pain
- cold hands/feet
- pale/mottled skin
- oliguria/thirst
- rash
- tachycardia
- rigors
- abdo pain
** death from CV failure
diagnosis
- Hx and examination
- blood tests
- nasopharyngeal swab through mouth
blood tests for diagnosis
- FBC
- blood films
- CRP
- blood culture
- serology & PCR
- testing of CSF sample = GOLD STANDARD diagnostic test
When to start Tx?
empirical Tx initiated on strong clinical suspicion & should not be witheld until cultures taken
CSF sample
- Lumbar puncture drains CSF from back below end spinal cord
- NOT performed if pts:
– features of raised (ICP)
– haemodynamic instability
– clotting abnormalities or thrombocytopenia - if meningitis, CSF sample appears turbid
- causative organism cultured from CSF sample
- bacteria may not be cultured if ABX have already been administered
general Tx for meningitis
- broad spec IV ABX
- ABX choice depends on most likely causative organism
- determined by age
- good CSF penetration essential
- ABX changes if necessary once causative organism ID
- guidelines reflect local patterns of resistance
empirical Tx - early Tx before hospital if practical
benzylpenicillin (NICE)
benzylpenicillin & cefotaxime
(parenteral)
When is benzylpenicillin witheld?
only in allergy only due to anaphylaxis
empirical Tx - hospital
ceftriaxone (3rd gen cephalosporin)
1st line over 3 months
Tx in under 3 months
- need ABX active against listeria
- cefotaxime + ampicillin/amoxicillin
- Listeria most likely in U3mths
supportive therapies
- Corticosteroids
- Intravenous fluids
- Enteral nutrition
- Anticonvulsant therapy if app (convulsions from inc ICP, pressure on brain)
- Management of complications of septicaemia and shock
– Respiratory support
– Correction of metabolic disturbances
– IV fluids
– Vasoactive therapies
– Renal replacement therapies if required
LT complications
- Hearing loss
- Orthopaedic complications
- Skin complications
- Psychosocial problems
- Neurological and developmental problems
- Renal failure
When is chemoprophylaxis indicated?
- prolonged close contacts - same household during the 7 days before presentation
- transient close contacts - directly exposed to large particle droplets/secretions from the RT of pt around time of admin to hospital
- patient - given as soon as able to take oral meds, unless treated with ceftriaxone
When is chemoprophylaxis NOT indicated?
– Staff and children attending same nursery/school
– Residents of nursing/residential homes
– Food/drink sharing or similar low level of salivary contact
– Travelling in next seat on same plane/train/bus
Chemoprophylaxis options
- given asap after diagnosis
- choice of ABX includes:
- Ciprofloxacin
- rec for all age groups and pregnancy
- single dose admin - Rifampicin
- suitable for all pt groups (without c/i)
- BD for 2 days
- interactions - Ceftriaxone
- injection so only used when other Txs unsuitable
vaccination
Hib / Men C vaccine
* routine immunisation at 1 year
Quadrivalent Vaccines
* meningococcal polysaccharides A, C, W135 and Y vaccine (ACWY Vax®)
* quadrivalent meningococcal diphtheria-conjugate vaccine (MCV-4)
* suitable for individuals at risk & meningitis patients & close contacts
Men B vaccine
* NHS for babies born after Sept 2015
* Routine immunisation at 2, 4, 12mths
Other vaccines
* 5-in-1 vaccine
- DTaP/IPV/Hib vaccine
- routine imm at 8, 12, 16 weeks
- Pneumococcal vaccine
- routine imm at 8, 16 weeks, 1yr
reporting meningitis
if diagnosis of meningitis suspected, dr legally obliged to report to local health protection unit of the health porteciton agenct
