Flashcards in Neuro- Infection Deck (18):
How is neurological infection classified?
2 basic types
1. Within the Brain tissue
2. Within the meninges and Spinal Cord
Also classified by:
- Viral or Bacterial
Describe 4 primary ports of entry for microbes?
1) microbe entry by compromised Blood Brain Barrier
2) fracture in the skull
3) direct spread from adjoining area eg/middle ear, buckle cavity
4) along an axon that goes into the brain
What bacteria can cause Bacterial Meningitis?
Any bacterium able to enter and infect meningies Some bacteria are more likely to cause:
1) streptoccus pneumonia usually cause in Adults
2) neisseria meningitides causes meningococcal meningitis is Youth
3) Haemophilus Influenzae (under 5)
What might predispose you to Bacterial meningitis?
o Head trauma
o Neuro Sx
o Congruent Infect (eg sinusitis)
o Lowered in Immunity
Pathology of Bacterial Meningitis?
Bacteria get in, microbial proliferation and lysis in the CSF
- inflm →purulent exudate into CSF
- pus accumulates around: meningies, subarachnoid
space, ventricles and blood vessels all affected
- exudate needs space, pus on brain surface and CSF
MNFTS of BM?
- inc pressure in cranium can be life threatening
- bacterial infection: develop fever, nausea, headache,
vomiting, back pain
- nuchal rigidity nape/back of neck stiff/rigid
Meningeal irritation test
(flex of neck leading to flexion of knee)
Meningeal irritation test
(pain and resistance to extension of knee at hip)
Dx of BM?
• Hx and Px (physical)
• C & S (CSF)
o Analyze CSF
• INC proteins and neutrophils, pus, Dec Glucose (why?)
TX of BM?
• Steroids (Serious INFLM)
Describe Viral Meningitis and how it compares to BM?
• Less severe then bacterial (intracranial pressure is serious however)
• Aseptic meningitis
• Usually self limiting
• d/t several virus (just require a portal of entry)
• similar MNFTS (but less severe)
o serous exudate not purulent
What might you find in CSF during Viral Meningitis?
o Lymphocytes (to fight viral infct)
o Moderate increase in protein content
o ***Elevated immunoglobulins***
o Glucose normal (viruses don’t utilize glucose)
TX for VM
o Symptomatic Tx
• No need for anti virals if it is self limiting
What is Encephalitis?
(encephalon is brain)
• Inflm of Parenchyma (pararhyme is functional tissue of any organ – neurons of brain or spinal cord in this case)
• Usually viral
Why would encephalitis normal be viral and not bacterial?
NOT SURE, something to do with
o Mode of action of bacteria and virus very different
o Virus hijack host cell and replicate DNA inside cell then cause lysis
o Bacteria does not need to get inside the cell
What are the two virus commonly associated with encephalitis?
• Herpes simplex Type 1 = cause cold sores
o Other types (Herpes simplex Type 2 = genital herpes)
• Arbovirus (carried by arthropods …like a tick)
Patho of Encephalitis
• Localized necrosis & hemorrhage -> becomes generalized -> edema
• Cell body degeneration
• Unpredictable course (progression is not uniform)