Meningitis Flashcards
Define meningism?
symptom complex characterised by headache, photophobia, vomiting and muscle spasm leading to a stiff neck
Define meningitis
Infection of the meninges, leading to inflammation and signs of meningeal irritation
the 5 steps of pathogenesis of meningitis?
1- attachment to mucosal epithelial cells
2- transgression of the mucosal barrier
3- survival in the bloodstream
4-entry into CSF
5-production of overt infection in the meninges
the common bacterial causes of meningitis?
neisseria meningitidis,
streptococcus pneumoniae,
e.coli and group b streptococci (in neonates)
the common viral causes of meningitis?
enteroviruses (echovirus, parechoviruses, coxsackie A and B, polio),
mumps,
Herpes simplex virus
What bacteria is the likely cause of meningitis in a patient with a shunt?
coagulase negative staphylococci
Non-infective causes of meningitis?
tumour cells in csf, adverse drug reactions, chemicals, diseases of unknown aetiology, leptospirosis, lyme disease
What is aseptic meningitis?
syndrome when the csf shows an excessive no. of lymphocytes
differential diagnoses for meninigism?
subarrachnoid haemorrhage, migraine, flu, tonsillitis, pneumonia, sinusitis, UTI
what presentation should always make you consider meningitis?
history of URTI + 1 of: vomiting, headahce, stiff neck, lethargy, clouding of consciousness
Risk factor for meningitis?
recent skull trauma,
alcoholism,
diabetes mellitus
What is kernig’s sign?
with hip flexed, you can’t straighten the leg due to hamstring spasm in meningism
When do you see Kernig’s sign?
meningitis
Investigations for meningitis?
blood cultures, lumbar puncture, fbc, U&Es, LFT
When should you not take a lumbar puncture?
If there are signs of a space occupying lesion eg focal neurological signs
CSF tests carried out?
gram stain, differential cell count, antigen detection test, bacterial culture, mycobacterial or fungal culture, PCR for viruses, PCR for bacteria, glucose, protein
normal CSF colour and wcc?
gin colour,
5 wc/mm3
define xanthochromia?
yellowish appearance of CSF, several hours after bleeding into the subarachnoid space
Main difference between bacterial and viral meningitis?
cell number and protein increased in both, but more so in bacterial,
neutrophils predominant cell in bacterial,
lymphocytes predominant cell in viral,
glucose reduced in bacterial
Antibiotics used in bacterial meningitis?
Benzylpenicillin,
ceftriaxone
(penetrate csf when meninges inflammed)
what age groups are more commonly affected by meningococcal meningitis?
children,
young adults
What bacteria causes meningococcal meningitis?
neisseria meningitidis,
gram -ve
what is the name and characteristic of the meningitis rash?
purpuric rash,
doesn’t blanche on pressure
what is chronic meningococcaemia?
illness lasts for weeks/months,
rash, joint pains, fever, endocarditis
Treatment of meningococcal meningitis or sepsis?
early suspect- parenteral penicillin, ceftriaxone, after results- benzylpenicillin, supportive therapy, discharge- rifampicin or ciprofloxacin (only adults)
Bad clinical prognostic markers for meningitis?
antibiotic delay,
extremities of ages,
purpuric lesions,
shock with absence of signs of meningitis and hyperpyrexia
Bad lab prognostic markers for meningitis?
presence of Disseminated intravascular coagulation
metabolic acidosis,
absence of polymorph leucocytes
Who should be notified if a patient has meningococcal infection?
Local consultant of health protection,
arrange prophylaxis for all close people
what age groups are more commonly affected by pneumococcal meningitis?
any age but more commonly adults
predisposing factors to pneumococcal meningitis?
pneumonia, sinusitis, endocarditis, head trauma, alcoholism or splenetomy
bacterial cause of pneumococcal meningitis?
streptococcus pneumoniae,
gram +ve,
alpha haemolytic
treatment for pneumococcal meningitis?
if resistant/1st line- ceftriaxone
benzylpenicillin,
vaccine- for >65, or high risk groups, routine childhood vaccines
inital presentation of pneumococcal meningitis?
altered consciousness,
focal neurological signs
complications of pneumococcal meningitis
loss of hearing, cn deficts, hemiparesis, hydrocephalus, seizures
Presentation of haemophilus influenzae meningitis?
mild URTI, rapid deterioration, otitis/ pharyngitis, seizures, coma, gram-ve cocci and bacilli
haemophilus influenzae meningitis treatment?
dexamethasone,
rifampicin (prophylaxis),
conjugate Hib Vaccine
Listeria monocytogenes meningitis?
gram +ve bacillus,
neonate and adult meningitis,
>55 treatment IV ampicillin
How does tuberculous meningitis occur?
rupture od a subependymal tubercle into the subarachnoid space,
post primary event following miliary TB or pleural effusion
Investigation presentations of tuberculous meningitis?
CSF white cell increased and mixed, \+ve for acid and alcohol fast bacilli, CSF glucose reduced, gram stain -ve, culture
Clinical presentation of viral meningitis?
rapid onset of headache,
photophobia,
low grade fever,
stiff neck
Investigations for viral meningitis?
PCR of CSF,
throat swabs,
stool culture,
HIV test
treatment for viral meningitis?
enterovirus and parechoviruses- self limiting,
chronic- IV immuniglobulkin,
HSV- aciclovir
Risk factors for cryptococcal meningitis?
HIV,
diabetes,
lymphoma,
immunosuppressive drugs
Investigations for fungal meningitis?
gram stain with india ink,
csf and serum cryptococcal polysaccharide antigen
presentation of fungal meningitis?
low grade fever, nausea, headache, lethargy, confusion, abdominal pain
Treatment of fungal meningitis?
parenteral amphotericin + flucytosine OR
fluconazole
Prevention of fungal meningitis?
chemoprophylaxis with fluconazole after a cryptococcal meningitis episode
How does neonate meningitis differ from adult?
symptoms are non specific and not well localised,
bacteria commonly involved- group b strepctococci, e.coli, l.monocytogenes, enteroviruses and parechoviruses
if a pregnant women consumes contaminated pate, soft cheese and goat’s milk what are they putting their baby at risk of?
meningitis caused by listeria monocytogenes, gram +ve
treatment of listeria monocytogenes meningitis?
ampicillin + gentamicin
Group B streptococci responsible for neonate meningitis, gram +ve or -ve?
gram +ve,
commensal in female genital tract,
sensitive to benzylpenicillin and amoxycillin
What strain of e.coli is more likely responsible for neonate meningitis?
K1 strain
Describe early onset neonate meningitis?
within 3 days of birth,
associated with prematurity, difficult or prolonged birth,
resp distress,
bacteraemia,
organisma aquired from mother’s genital tract
Describe late onset neonate meningitis
more than 1 week after birth,
bacteraemia and meningitis
investigations into bacterial neonate meninigitis
neonatal csf,
blood culture,
maternal blood culutres and genital tract cultures
investigations into viral neonate meninigitis
neonatal csf,
edta blood,
faeces and nasopharyngeal secretions
Treatment or neonate meningitis?
parenteral ampicillin and gentamicin or cefotaxime
prevention of neonate meningitis?
chemoprophylaxis to prevent group b strep meningits to high risk mums- amoxicillin or co-amoxiclav
