CNS Infections Flashcards
Myelitis
inflammation of the spinal cord
meningitis
inflammation of the meninges
How much time one has to send the CSF for analysis?
1 hr
WHat is the most common cause of meningitis?
Viral
Aseptic Meningitis means there is no pathogenic cause T/F
F, just that nothing grew on culture. could be due to viruses or the patient being given Antibiotics
Main cause of bacterial meningitis in children and adults?
Neisseria meningitides (AUs B-C, World A)
Streptococcus pneumonia
Haemophylus influenza B (<5yo)
Main cause of bacterial meningitis in neonates?
Neisseria meningitides (AUs B-C, World A) Streptococcus pneumonia Haemophylus influenza B E coli Neisseria monocytogenes Group B streptococci
Main symptoms and signs of meningitis?
stiff neck photophobia fever vomiting headache
What does bacterial sources of meningitis in adults share in common?
Capsulated and can inhabit nose
What is the gold standard for the diagnosis of bacterial meningitis?
grow bacteria from the CSF: Culture, Gram Stain, PCR
Is symptoms of meningitis are present but CSF is normal what is the diagnosis?
Suspected Meningitis
if patient has meningococcal meningitis what must have he had beforehand?
meningococcaemia (purpuric rash: non blanching)
Characteristics of CSF
Glucose 60% of blood
protein <5x10^6 u/l
Blood -
Characteristics of viral meningitis
high glucose
low protein
100s lymphocytes
Characteristics of bacterial meningitis
1000s lymphocytes
low glucose
high protein
gram +
Treatment of meningitis
1 Resuscitation/life support
2 fluids
3 antibiotics
4 contact prophylaxis
What causes the symptoms in bacterial meningitis?
the immune response
What is the antibiotic treatment for bacterial meningitis?
3Rd gen cephalosporins
If neonates
+ penicillin and gentomycin
Define encephalitis
inflammation of the brain parenchyma mainly due to viral infection
Most common cause of viral encephalitis
Herpes Simplex Virus
Neurotropism
Neuroinvasiveness
Neurovirulence
1 replicates in nerve cells
2 enters and infects the CNS
3 capable of causing disease within nervous system
Most common pathogen in meningitis
Enteroviruses
What is one of the most serious viral diseases? cause
Viral encephalitis, herpes simplex virus and rabies virus
What is post-infectious encephalitis?
inflammation and demyelination of the brain without any pathogen present (measles, chickenpox, rubella, mumps)
Guillan Barre syndrome?
acute inflammatory demyelinating disease following viral infection (EBV, cytomegalovirus and HIV) causes debilitating paralysis
Reye’s Syndrome
Cerebral oedema w/out inflammation post infection of influenza or chickenpox in children (25% mortality rate) related with aspirin use for fever
Viruses that are obligated neurotropics?
Herpes simplex virus and Rabies virus
What virus can only reach the brain by blood infection?
polio
What is the form of the genome for herpes virus?
linear dsDNA
herpes virus has low —-1– but high —2—
neuroinvasiveness
neurovirulence
What is the most common cause of severe sporadic encephalitis?
herpes simplex virus
is herpes simplex virus enveloped?
yes, icosahedral
Neuronal route is the most common way of infecting the brain by HSV?
true, rarely by blood
What is the main way varicella zooster might reach the brain?
by blood after replication in the airway mucosa
when does the rash appears in varicella zooster infection?
in the secondary viraemia after replicating in the spleen and the liver
latent reactivation of varicella zooster virus shows as
Shingles
Which viral infection produces LATs and ehat are they?
Latency Activated mRNA, because the DNA remains in the ganglia as episomes
Herpes Simplex virus
WHat type of genome does rabies virus has? is it enveloped?
-RNA and yes
helical
Rabies is both very —1— and —-2—-
neuroinvasive and neurovirulent
where does rabies replicates before reaching the nerves?
muscle tissue at place of bite
Rabies virus is perfect in hiding from the inmmune system T/F
F, its replication causes glycoproteins to show in the host cells membrane
What part of the rabies virus is transported by the nerves?
nucleocapside
Nerves show MCH 1
No they do not
WHat is the characteristics of polio virus?
+RNA
no envelope
icosahedral capsule
belongs to enterovirus
polio virus has low —-1– but high —2—-
Neuroinvasiveness
neurovirulence
polio virus is neurotropic
False
what is one of the complications of polio virus infection?
acute IRREVERSIBLE flaccid paralysis (<1%)
why does poliovirus causes acute IRREVERSIBLE flaccid paralysis
because it is able to kill the cells of the ventral horn of the spine (also able to cross bbb)
