Meningitis and Encephalitis Flashcards
What is the definition of meningitis?
Inflammation of the meninges
What is the definition of encephalitis?
Inflammation of the brain
What are the symptoms and signs of a case of meningococcal meningitis caused by neisseria meningitidis (Bacterial)
Symptoms 12 hour gradual onset headache Severe + generalised Feverish Photophobic Nuchal rigidity – not moving neck
Signs Temp – 38.9 HR – 110 bpm BP – 100/60 No rash
Describe the carriage and transmission of meningococcal meningitis
Throat carriage in approx. 10% population
25% of 15 to 19 year olds
Person-person spread
Inhalation of respiratory secretions
Close prolonged contact, e.g. household members
Direct contact (kissing)
Disease in minority
What can meningococcal disease cause? What are the differentiations?
Can either cause septicaemia or meningitis:
Septicaemia – non-blanching rash (starts off as pinpoint purple dots on hands/feet)
Meningitis without septicaemia – no rash
25% just septicaemia
60% both
15% just meningitis
What is the prognosis of meningococcal meningitis
Fatal in approx. 10% with disease:
Up to 50% with septicaemia
Approaching 100% if untreated
1 in 8 suffer long term morbidity e.g. headache, joint stiffness, epilepsy, hearing loss, learning difficulties
What is the treatment for meningococcal meningitis?
Early antibiotics improve prospect of recovery
IV ceftriaxone or cefotaxime – must be after blood cultures, should in theory be after lumbar puncture but normally is due to lack of funding.
Can start antibiotics before set diagnosis just in case
No evidence for corticosteroids for meningococcal meningitis
When are vaccines given for meningococcal meningitis?
Men C vaccine – given to 1-3 y.o. since 1999
Men B vaccine – given to 2-4 month olds since 2015
Men ACWY vaccine – given to teenagers since 2015
What are the symptoms and signs of a meningitis caused by streptococcus pneumoniae?
Symptoms 24 hour history of gradual onset headache Feverish Confused in last 12 hours No travel Hypertension Allergic Rhinitis
Signs Temp – 38 HR – 64 bpm BP 105/90 GCS 14/15 Photophobia Nuchal rigidity No rash No focal neurological signs
How would the CSF results and gram stain of a pneumococcal meningitis look?
CSF Results:
CSF glucose is lower than blood
Increased proteins
Cloudy
Gram stain:
Gram positive – purple colour
Streptococcus pneumoniae – paired
Which type of meningitis is corticosteroids treatment for? What is the treatment?
Dexamethasone for 4 days if streptococcus pneumoniae is confirmed
Significantly reduced mortality and neurological disability at 8 weeks if GCS< 11
What are the signs and symptoms of meningitis due to listeria monocytogenes?
Symptoms Unwell for 4 days Vomiting and diarrhoea Fever Muscle aching 2 days gradual onset severe global headache No rash
Signs Temp 38.8 HR 100bpm BP 110/70 GCS 14/15 (disoriented in time and place) Photophobia Nuchal rigidity No rash present No focal neurological signs
What are the CSF results of meningitis due to listeria
Lymphocytes not polymorphs
No organisms seen on gram stain – similar to fungal
How does listeria cause meningitis, who is at risk? What is the mortality?
Blood cultures
3rd common cause of bacterial meningitis in adults (rarer than meningococcal or pneumococcal)
Eat listeria – shouldn’t cause a problem unless immunocompromised/pregnant or neonates
If gets into blood such as with those who are immunosuppressed it causes meningitis in 55-70%
Mortality approx. 25%
How would you treat listeria meningitis?
treat with amoxicillin 2g every 4 hours aswell as normal antibiotics (ceftriaxone or cefotaxime) until know for sure the cause from lumbar puncture
What are the signs and symptoms of viral meningitis due to enterovirus
Symptoms
2 day history gradual onset severe headache
Preceding 3 days muscle aching + lethargy
Feeling hot and cold
Photophobia
Neck stiffness
Signs Temperature 38.6°C Heart rate 110 bpm BP 100/60 Alert, orientated Photophobia Nuchal rigidity No rash present
What are the csf results of a enteroviral meningitis
Protein is only a little up and not significant blood glucose to CSF glucose – suggests viral
Clear colourless – viral
What are some common causes of viral meningitis
Enteroviruses Herpes Simplex Virus (Mollaret’s) Mumps Measles Adenovirus HIV Non viral: Lyme disease, syphilis, drugs Often have other symptoms too e.g. measles has rash
What is the treatment for viral meningitis?
Self limiting
Doesn’t need specific treatment- just treat symptoms
What are the symptoms of TB meningitis?
Symptoms
Unwell for 2 months 2 stone weight loss Fever Drenching night sweats 1 month gradual onset worsening headache
What are the risk factors of TB meningitis?
HIV, alcoholism, diabetes, steroids, anti-TNF agents, immigration from area of high prevalence
What is the treatment for TB meningitis?
Start treatment without waiting for results
12 months treatment:
rifampicin, isoniazid, pyrazinamide, ethambutol
Dexamethasone (Thwaites regimen)
Acetazolamide + frusemide, or repeated LP for communicating hydrocephalus
Consider early ventriculo-peritoneal shunting for non-communicating hydrocephalus
What are the symptoms of cryptococcal menigitis due to fungal cryptococcus neoformans?
3 stone weight loss in 6 months
Gradual onset headache + fever for 2 weeks
No photophobia
No neck stiffness
No rash
Received antibiotics for chest infection 6 weeks ago
What is treatment for cryptococcal meningitis
AmBisome (liposomal amphotericin B) and flucytosine for 2 weeks (anti-fungal)
Serial lumbar punctures
8 weeks fluconazole – 400mg daily
Who is at risk of cryptococcal meningitis?
Immunocompromised, rare immunocompetant have cryptococcal meningitis
What are the symptoms of viral encephalitis?
Normally fit and well 2 days progressive headache + fever Preceding “flu-like” symptoms 24 hours acute confusion, behavioural change Insomnia No regular medications No unwell contacts
What would CSF results of viral encephalitis look
Viral – clear CSF (bacterial, fungal would be cloudy), same as viral meningitis
Not significant increase in protein
Not significant difference between blood glucose and CSF glucose
How do you distinguish between encephalitis and meningitis?
Altered mental status
Motor or sensory deficits
Altered behaviour / personality
Speech or movement disorder
What are the infectious causes of encephalitis?
Viruses
Direct invasion of the CNS:
Herpes viruses (Most common one)
Arboviruses (arthropod-borne viruses e.g. mosquitos when birds ar reservoirs and take virus to US)
Immune-mediated post infection/vaccination:
ADEM (acute disseminated encephalomyelitis)
Mumps, measles, rubella, influenza
Bacteria
Listeria, mycoplasma, Lyme, syphilis
TB
Parasites
Cerebral malaria, toxoplasmosis, Parastrongylus
Fungi
What are the types of viruses that can cause encephalitis?
Herpes viruses: Herpes simplex 1 & 2 Varicella zoster virus Epstein-Barr virus Cytomegalovirus Human herpes virus 6, Human herpes virus 7 Enteroviruses: Coxsackie, echoviruses, enteroviruses 70 & 71, parechovirus Poliovirus Paramyxoviruses Measles, mumps Others (rarer) Influenza, adenovirus, parvovirus, rubella
What is the clinical presentation of HSV encephalitis?
Acute presentation Flu-like prodrome Fever (90%) Headache Altered consciousness Disorientation (76%) Seizures in 1/3 of patients with HSV-1 encephalitis Focal neurological signs common Speech disturbance (59%) Behavioural change, e.g. hypomania, irritability (41%) Memory impairment
What is the prognosis of HSV encephalitis
Mortality 70% if untreated 2/3 survivors have significant neuropsychiatric sequelae: 69% Memory impairment 45% Personality / behavioural change 41% Dysphasia 25% Seizures
What is the treatment for enecephalitis?
Aciclovir: sooner given the better, if suspected encephalitis perform urgent LP and commence acyclovir +/- antibiotics. If LP delayed start treatment ASAP
Reduces mortality from 70% to 28%
Limits severity of postencephalitic impairment
Poor outcome if delay >2 days between hospitalisation and commencing treatment
What is the advice on when to stop acyclovir?
14-21 days in confirmed HSV encephalitis
If clinical suspicion of HSV encephalitis is high but initial CSF PCR negative, continue aciclovir and repeat LP after 48 hrs
If repeat PCR negative but clinical suspicion persists then continue IV aciclovir for at least 10 days
If clinical suspicion low or alternative diagnosis apparent then stop aciclovir after 2nd negative PCR
What was the dexenceph study investigating?
Retrospective non-randomised data – corticosteroid administration improved outcome in 22 of 45 patients with HSV encephalitis given steroids at the same time as aciclovir was initiated
Efficacy not yet proven
Optimal timing unclear
Often used if significant brain oedema or if deterioration despite appropriate antiviral treatment
How can a teratoma cause encephalitis?
Body produces antibodies against NMDAR in the teratome, they then attack other areas
Young female patients with psychiatric symptoms, amnesia, seizures, frequent dyskinesias, autonomic dysfunction and decreased GCS
All had ovarian or other teratomas
Immediate removal of teratoma lead to removal of antibody-mediated response
Rapid recovery
