Y4 - Meningitis Flashcards
What are the most common causes of meningitis in new borns?
GBS
E. coli
Listeria monocytogenes
What are the most common causes of meningitis in infants and children?
Strep pneumoniae
Neisseria meningitidis
Hib
What are the most common causes of meningitis in adolescents and young adults?
Neisseria meningitidis
Strep pneumoniae
What are the most common causes of meningitis in older adults?
Strep pneumoniae
Neisseria meningitidis
Listeria monocytogenes
Define meningism
Irritation of the meninges leading to the classic triad of fever, headache, photophobia
Define meningitis
Inflammation of the meninges
Define encephalitis
Brain parenchymal inflammation
LEADS to focal neurological signs
Define myelitis
Inflammation of the spinal cord
LEADS to referred symptoms along dermatomes
Define bacteraemia
Organism in the bloodstream
Leads to minimal symptoms
Define septicaemia
Bacteraemia with a high sepsis score (fever, tachycardia, shock, coagulopathy, organ failure)
Define pyaemia
Metastatic foci
What are the clinical findings of meningitis?
Meningism (headache, fever, photophobia)
Fits, consciousness affected
Contacts, travel, immunisation status?
Rash
Kernig’s and brudzinski’s sign
Focal signs
Septic signs (e.g. hypotension, tachycardia)
What is kernig’s sign?
Extension of knee painful
Or limited knee extension
What is brudzinski’s sign?
Passive flexion of neck leads to hip and knee flexion
What is a non-blanching rash in meningitis indicative of?
A viral infection
What is a blanching rash in meningitis indicative of?
A bacterial infection
What investigations should you order in suspected meningitis?
Bloods - culture, WBC, U&Es
Radiology - CT before LP (to check for collections/cerebral oedema)
LP
What tests do you want to do on the CSF collected from LP in suspected meningitis?
Red cells, polymorphs, lymphocytes, glucose, protein, Ig, culture, immunoassay, PCR
When must you do an LP?
When know its safe - i.e. after scan and BEFORE antibiotics
What would be the basic CSF findings in someone with a bacterial meningitis?
Polymorphs most common cell, raised protein count, low glucose
What would be the basic CSF findings in someone with a viral meningitis?
Lymphocytes most common cell, raised protein count, normal glucose
What would be the basic CSF findings in someone with a tuberculous meningitis?
Lymphocytes most common cell, raised protein count, low glucose
What bacteria is screened for in pregnancy and if not treated may lead to neonatal meningitis?
GBS
Also the most common cause of neonatal meningitis
What is the most common cause of meningitis in those with a VP shunt?
Staph. epidermis and staph aureus (remember these are skin flora)
Coliforms (VP ends in peritoneum)
What is the most common cause of meningitis in those post-head injury?
Strep pneumonia most common if CSF leak
Others: pseudomonas, staph aureus
What is the most common cause of meningitis?
Strep pneumoniae
What other feature (apart from meningitis) can pneumococcal meningitis cause?
Cerebral oedema
What are the risk factors for pneumococcal meningitis?
Alcoholic
Rough living
Immunosupressed
How does pneumococcus protect against phagocytosis?
It has a polysaccharide capsule
In which group is meningococcal meningitis most common?
Children
What are the most common serotypes of meningococcus?
A most common
C next most common
How do you manage meningococcal meningitis?
Preadmission penicillin
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!11
What is the pathogenesis of meningococcal meningitis?
Contact between bacteria and patient –> nasopharyngeal colonisation
Protease/viral infection leads to cellular penetration
Delete as appropriate:
Meningococcal rashes are blanching/non-blanching
Non-blanching
Who should get prophylaxis for meningitis?
Close contacts of meningococcal meningitis patients (family, flatmates, kissing contacts)
What prophylaxis do close contacts of meningococcal infection get?
Single dose ciprofloxacin
48h Rifampicin
Single dose ceftriaxone
Vaccine if serotype C
How can meningococcal disease present?
Sepsis (endotoxins trigger sepsis syndrome) or meningitis or both
Also assoc with DIC
How is the mortality of meningococcal disease significantly reduced?
Early recognition and administration of IM penicillin
How do we prevent bacterial meningitis?
Vaccination (Men A, B, C, H. influenzae, pneumococcal vaccine)
Perinatal screening (group B strep & antepartum penicillin)
Chemoprophylaxis for close contacts of those with meningococcus/H. influenzae
What encephalopathic features may be present in H. influenzae meningitis?
Cerebral oedema
Subdural effusions
How do you manage meningitis?
ABCD
Antibiotics - penicillin/cefotaxime
nb - haemophilus meningitis not responsive to penicillin
Steroids (dexamethasone for cerebral oedema if seen on CT/focal neurological signs)
Screen for sepsis
Analgesia
What does antibiotic choice for meningitis depend on?
Causative parhogen
Resistance of local pathogens
Penetration of CSF
If listeria possible cause (e.g. neonate, immunosuppressed, elderly) add amoxicillin
What are the possible complications of meningitis?
Circulatory collapse Focal neurological abnormalities Hydrocephalus Brain abscess Seizures
What is the mortality of bacterial meningitis?
Less than 10%
What is the morbidity of bacterial meningitis?
15% Hearing Seizures Learning problems Lower IQ when compared with sibs
What can cause lymphocytic meningitis?
Viruses (eneteroviruses, e.g. coxsackie, ECHO, mumps, measles)
Bacterial - partially treated, TB, Lyme disease, syphilis, encephalitis, SLE
What is the most common cause of meningitis?
Viral then pneumococcal
What are the two main causes of encephalitis?
HSV
Everything else
What are the clinical features of encephalitis?
Seizures, impaired consciousness behavioural changes, cognitive impairment, hallucinations, focal signs
What underlying diseases may present with encephalitis?
Measles, mumps, HIV, cancer, autoimmune dx
What are the CSF changes in encephalitis?
Numerous lymphocytes, raised protein (IgG), organisms (culture, PCR (Herpes), immunoassay)
What changes will you see on T2 CT scan of someone with HSV encephalitis?
Hyperintensity of the temporal lobes
Virus has affinity for the temporal lobes
How do you treat encephalitis?
HSV - acyclovir high dose parenterally
Bacterial - Rx as appropriate
