Meningitis and Encephalitis Flashcards
What is the definition of meningitis?
Inflammation of the protective membranes covering the brain and spinal cord
What is the protective covering of the brain called?
Meninges
Which on an LP would indicate meningitis?
Elevated CSF, WCC and protein
At what age is the highest incidence of bacterial meningitis?
45-65 years
What is the mortality rate of bacterial meningitis?
20%
What type of bacterial meningitis has a higher mortality rate?
Pneumococcal meningitis
What type of meningitis are older adults and immunocompromised individuals more likely to get?
Listeria monocytogenes
What % of meningitis is viral?
50-80%
What is Kernig’s sign?
Flex hip at 90 degrees and extend knee.
Patient resists full knee extension when hip flexed.
Sign of meningeal irritation
What is Brudzinki sign?
Passive flexion of neck causes flexion of both legs and thighs.
Sign of meningeal irritation.
How is suspected meningitis managed (no signs of brain shift)?
A-E
Blood cultures
Lumbar puncture
Ceftriaxone or Cefotaxime 2g immediately after LP
Dexamethasone 10mg IV
When can cause papilloedema and what is it?
Swelling of the optic disc due to elevated intracranial pressure
If LP is not done within first hour of suspecting meningitis, when are abx given?
straight after blood cultures
Is a CT head indicated in suspected meningitis?
Not usually as it’s a clinical diagnosis.
Not indicated if no shock, sepsis or signs of brain shift.
How is suspected meningitis managed (with signs of brain shift)?
Brain shift = raises ICP
A-E
High flow O2
Bloods - FBC, U+E’s, Clotting, cultures
Dexamethasone 10mg IV
Ceftriaxone or Cefotaxime 2g immediately after blood cultures
Delay LP
Arrange neuroimaging
What is the difference between the management of meningitis with and without signs of brain shift?
With brain shift - delay LP and get neuro imaging. Abx (Ceftriaxone/Cefotaxime 2g) after blood cultures.
Without brain shift - Urgent LP with abx (Ceftriaxone/Cefotaxime 2g) after LP. Neuro-imaging not usually indicated.
How is severe sepsis or a rapidly evolving rash managed (with or without signs of meningitis)?
ITU support
A-E
Sepsis 6
Delay LP
Ceftriaxone or Cefotaxime 2g IV after blood cultures
What type of rash do you see in meningococcal septicaemia?
Petechial rash
Can progress to purpura and ecchymoses and clotting system fails
What type of rash is this?
What type of rash is this?
Which alternative abx would be given in suspected meningitis if pen/Cephalosporin allergic?
Chloramphenical 25mg/kg
Which abx would you give in someone over 60 or immunocompromised with meningitis?
Cefttriaxone/Cefotaxime + Amoxicillin 2g IV
If allergic to amoxicillin - give Chloramphenicol and Co-trimoxazole 10-20mg/kg
Which abx would you give in someone with suspected meningitis who has had recent travel to somewhere with a risk of penicillin resistant pneumococci?
Ceftriaxone/Cefotaxime + Vancomycin 15-20mg/kg IV or Rifampacin 600mg IV/PO dependent on trust.
At which vertebral level is a LP done?
L3/4 or L4/5
What is CSF fluid in a LP sent off for?
Measure opening pressure
MCS
Protein
Glucose (with concurrent blood glucose)
Meningococcal and pneumococcal PCR
Enteroviral, Herpes Simplex + Varicella
Consider TB investigations
What are the common organisms in bacterial meningitis?
Neisseria Meningitidis
Streptococcus pneumoniae
What type of bacteria is neisseria meningitidis?
Gram negative rod
What type of bacteria is streptococcus pneumoniae?
Gram positive cocci
When should you delay a LP?
What are the signs of brain shift?
How long does it take to develop symptoms of TB meningitis?
Weeks
Other types are more sudden
Where is there a high incidence of TB meningitis?
Africa
Indian sub-continent
How is TB meningitis treated?
Rifampicin, Isoniazid and Pyrazinamide for 9 months
+/- steroids
What are the complications of TB meningitis?
Hydrocephalus
Tuberculomas (mass)
Seizures
What is the mortality of TB meningitis?
60%
What would you see in histology of TB meningitis?
Acid-fast bacilli on Ziehl-Neilson staining
How long is TB meningitis samples kept for before they can be said to be negative?
6 weeks
If all four ventricles of the brain are dilated, where would the site of obstruction be?
Either the foramina of Luschka or Magendie or in the subarachnoid space
What type of fungus can be seen in meningitis?
Cryptococcus.
Treated with amphoteracin.
How does viral meningitis present?
Neck stiffness, headache, photophobia.
Not usually reduced consciousness.
How is viral meningitis treated?
Treated as if bacteria until proved otherwise.
CSF PCR - Enterovirus, herpes simplex, varicella roster.
No evidence for aciclovir
Treat with IVI and analgesia
What is the definition of encephalitis?
Inflammation of the brain
What is the difference between meningitis and encephalitis?
Meningitis - inflammation of meninges.
Encephalitis - inflammation of brain
What is a combination of encephalitis and meningitis called?
Meningioencephalitis
Is encephalitis a clinical or pathological diagnosis?
Pathological
What markers can suggest encephalitis?
abnormal CSF or neuroimaging
What causes encephalitis?
What is ADEM?
Acute Disseminated Encephalitic Myelitis
Patient has had a vaccine or infection several weeks earlier (2-3), produce antibodies to fight infection that attacks brain instead.
Which is the most common type of viral encephalitis?
Herpes simplex
Majority is HSV-1, 10% if HSV-2 (in immunocompromised)
Varicella zoster also common
Cytomegalovirus in immunocompromised.
What age does viral encephalitis peak?
Young and elderly
Which type of virus can cause an aseptic meningitis which can then cause encephalitis?
Enterovirus
How does herpes simplex cause encephalitis?
The CNS infection is secondary to active infection elsewhere in the body, or more commonly reactivation of dormant infection.
What are the neuropathological features of herpes simplex encephalitis?
What is the clinical presentation of encephalitis?
How is encephalitis managed?
Where does herpes simplex encephalitis typically go in the brain?
Right temporal lobe
Which abnormalities do you see on an EEG in encephalitis?
Periodic lateralising epileptiform discharges
How is viral encephalitis treated?
What is auto-immune encephalitis?
Body’s immune system attacking brain causing inflammation
Which antibodies can cause autoimmune encephalitis?
NMDAR
LGI1
CASPR2
How can autoimmune encephalitis present?
Altered cognition
Altered psychiatric state
Seizures
What paraneoplastic conditions can cause auto-immune encephalitis
NMDA receptor encephalitis caused by teratomas
How is auto-immune encephalitis managed?
