Flashcards in Viral Meningitis and Encephalitis Deck (43):
What type of viruses have no lipid membranes
What is the classification of aseptic meningitis, with regards to the white cell count and the bacterial culture?
White cell count- >5x106/L in CSF
-ve bacterial culture of the CSF
What are the most common causes of aseptic meningitis?
Viruses, listeria, TB, syphilis, malignancy, autoimmune conditions, drugs
Which age group is viral meningitis common in?
2 peaks of hospital admissions; neonates and 5 yr olds
How does enterovirus enter your body?
Via the GI tract- faecal oral transmission
Causative organisms of viral meningitis
Via what paths do viruses invade the CNS?
Via cerebral microvascular endothelial cells
via choroid plexus epithelium
spread along olfactory nerve
What are the 3 symptoms of meningism?
Headache, neck stiffness, photophobia
Apart from meningism, what other symptoms do you get in meningitis?
Is it easy to distinguish cliniclaly between viral and bacterial meningitis?
In infants, meningeal signs may be absent. What should you look for instead?
nuchal rigidity (neck stiffness)
bulging anterior frontalle (only if severe intracranial pressure)
Examination sign for meningitis; flex hip and knee to 90, the knee cannot be extended due to hamstring stiffness
Examination for meningitis- flexing the neck causes the hips and knees to flex
What should you look for in a CSF specimen, with suspected meningitis?
Microscopy, culture and sensitivity (MCS)
Glucose (check blood glucose at the same time)
Viral PCR; enteroviruses, HSV, VZV
What is the opening pressure for bacterial meningitis?
Above normal (200-500)
Is the WBC count higher in viral or bacterial meningitis?
What is the WBC differential in viral meningitis?
What is the WBC differential in bacterial meningitis?
High neutrophil count
What is the protein conc. for bacterial meningitis?
What is the glucose ratio (CSF:blood) for bacterial meningitis?
What other specific bacterial test in the CSF is positive for bacterial meningitis?
Gram stain positive
Treatment for bacterial meningitis
Treatment for viral meningitis
Some argument suggest aciclovir
Is meningitis a notifiable disease?
Commonest cause of viral meningitis in the UK?
Cause of meningitis; late summer/autumn epidemics. Fever, vomiting, anorexia, rash, upper respiratory tract symptoms. No specific treatment and full recovery normal.
How does HSV1 manifest?
cold sores and encephalitis
How does HSV2 manifest?
genital herpes and meningitis
What is mollaret's meningitis?
Recurrent aseptic meningitis. Recurrent cause- HSV2
In what proportion of mumps cases do you get meningitis?
What is the cause of meningitis, 5 days after onset of parotiditis, abdo pain and orchitis (inflammation of 1 or more testicles) Preventable with vaccine.
At what point in the HIV infection does meningitis occur?
Occurs as part of primary infection
What are the associated features of HIV meningitis?
Like glandular fever; fever, lympadenopathy, pharyngitis, rash
What is the major viral cause of encephalitis
What are the common causes of viral encephalitis?
What additional features do you find in viral encephalitis, compared with viral meningitis?
Altered mental state (confusion, bizarre behaviour)
Focal neurology, seizures, weakness, cranial nerve palsy, ataxia
Treatment for viral encephalitis
High dose IV aciclovir
What form of viral encephalitis is a medical emergecy- rare but high morbidity associated with it?
Herpes simplex encephalitis
What age range is typical for Herpes simplex encephalitis?
Bimodal distribution (50yrs)
What are the 2 stages of herpes simplex encephalitis?
Primary infection: direct transmission of virus along the neural/olfactory pathways
Reactivation: in the trigeminal ganglia
What is a complication of herpes simplex encephalitis, that causes inflammation/swelling of the brain tissue?
Acute focal necrotising encephalitis
Auto-immune mediated CNS demyelination, can follow viral illness or vaccination. Clinical features are the same as encephalitis.
Acute disseminated encephalomyelopathay (ADEM)