Pathology 2.1 Flashcards
(43 cards)
Where do bacteria usually localize in an infectious disease of the CNS?
- leptomeninges (arachnoid and pia) –> meningitis
- parenchyma –> cerebritis then progresses to abscess formation
Where do viruses and fungi usually localize in an infectious disease of the CNS?
- preferred intracranial and intraspinal sites
- ex: polio virus at motor neurons of the spinal cord and bulbar area
- ex: HSV in temporal lobes
- ex: cryptococcus in leptomeninges
- aspergillus induces cerebral parenchymal abscesses
Which type of infection is caused by bacteria?
meningitis (most severe)
Which type of infection is caused by virus?
encephalitis
How does the brain repair itself?
astrogleosis
How does syphilis infect the CNS?
- Treponema gains access to the CNS through the bloodstream
- prolonged residency in neural tissues, causing:
- infection
- sensory abnormalities
- dementia
How does RMSF (Rocky Mountain Spotted Fever) infect the CNS?
targets endothelial cells
What is leptomeningitis?
An inflammatory process that is localized to the interfacing surfaces of the pia and arachnoid, where CSF flows
What is pachymeningitis?
- Inflammation of the dura, usually a consequence of contiguous infection, such as chronic sinusitis or mastoiditis.
- The dura is a barrier to infection, and inflammation is restricted to its outer surface.
Which bacterial meningitis is most common in neonates?
E. coli (Gr - rod)
Group B Strep (Gr + cocci)
(normal microbiota of urethra)
Which bacterial meningitis is most common in infants (3mo to yrs)?
H. influenzae
**Gr - rod
Which bacterial meningitis is most common in adults?
Strep pneumococcus (Gr +) **purple diplococci
Which bacterial meningitis is most common in military barracks?
N. meningitidis (Gr -)
**pink doplococci
What is characteristic in the CSF of bacterial meningitis?
neutrophils int eh CSF
What is the hallmark of meningitis caused by TB, viral meningitis, and chronic fungal infections?
lymphocytes
What does the brain look like grossly in bacterial meningitis?
- exudate of PMNs and fibrin
- opacified arachnoid
- creamy gray or white appearance
How does bacterial meningitis present clinically?
- vomitting
- fever
- convulsions (children)
- untreated = coma, death
What are Kernig and Brudzinski signs?
Kernig:
-cervical rigidity, head retraction, pain in the knee when the hip is flexed
Brudinski:
-spontaneous flexion of the knees and hips when the neck is flexed
What is characteristic of TB meningitis?
- TB granulomas in meninges
- strong predilection of meninges at base of brain around chiasm
- result in meningeal fibrosis which leads to communicating hydrocephalus
- also lead to arteritis (responsible for parenchymal infarcts)
What is tuberculmoa?
- parenchymal involvement by TB
- solitary spherical mass with a central area of caseous necrosis
- TB get to brain through blood
What is Pott’s Disease?
- TB of spine
- epidermal granulomatous mass causes spinal destruction and spinal cord compression
Which stain is only used for TB?
AFB (acid-fast bacillus) stain
What is the most common viral disease of the CNS?
viral meningitis
What is the clinical presentation of viral meningitis?
- sudden febrile illness
- headache
