CNS Infxns II Flashcards
(33 cards)
Acute bacterial meningitis- most common cause in
(a) neonates
(b) teenagers
(c) adults
8-10% death rate, so this is some serious shiz
Most common cause in
(a) neonates = influenzae type b
(b) teenagers = neisseria meningitidis
(c) adults = streptococcus pneumoniae
Describe the difference btwn an early and late stage brain abscess
Early stage: cerebritis (inflammation) w/ neurotrophilic infiltration, edema, and vascular congestion
Late stage: capsule!!! firm capsule of granulation tissue w/ lympocytes and plasma cells covering the pus/bacteria filled region
-outside the capsule is the edema and reactive atrocytes
Typical presentation of Whipple’s disease
-caused by gram (+) bacterium
Mostly causes GI symptoms w/ CNS involvement: personality changes and dementia
How can syphilis cause a stroke?
Syphilis gets into CNS w/in the first 2 years of infection
-can invade BVs (meningovascular syphilis) then cause
Heubner’s endarteritis = severe intimal proliferation occluding a vessel = stroke
Aspergillus spp
Fungal meningitis w/ propensity to invade blood vesses => can induce multifocal hemorrhage
Mucormycosis
Cause of fungal meningitis seen in diabetic pts
Most common cause of meningitis + CN palsy
TB
-when have meningitis + CN palsies you can localize the lesion to the base of the brain (basal meningitis), and TB is the most common acute bacterial meningitis affecting the base of the brain
Describe the 3 progressive stages of acute bacterial meningitis
1st = meningitis- just the meninges infected
2nd = meningovasculitis- secondary vasculitis where the infection infiltrates the BVs
3rd = meningoencephalitis- infection of actual brain parenchyma due to spread thru BVs
What stage is a CNS infection at if it presents w/ seizures?
Seizures indicating involvement of actual brain tissue (not just the meninges)
-so encephalitis or meningoencephalitis
Describe how cerebral edema can occur secondary to meningitis
Organism invades the BVs and destroys them. BVs become leaky => cerebral edema
What is a petechial rash indicative of?
Meningococcal Septicemia
-rapid progression to shock, mortality up to 40%
What is the most severe form of meningococcal septicemia?
Waterhouse-Friderichsen Syndrome
= adrenal gland failure due to bleeding in the adrenal glands
Most common cause of Waterhouse-Friderichsen Syndrome
Meningococcus- neisseria meningitides
How can subacute bacterial endocarditis cause a brain abscess?
Infected embolus travels up from the heart to the brain
What type of organisms caused neonatal meningitis?
Gram negative
- neonatal meningitis from maternal genital flora
- very very destructive, best thing here is prevention
Treatment of brain abscess refractory to IV abx
Brain surgery to drain abscess or locally inject abx after breaking thru the capsule
-failing IV abx possibly b/c abx can’t get thru the thick capsule into the necrotic center
Which CNS infection can also primarily impact the spinal cord?
TB
-Pott’s disease = TB affecting the vertebral body which then compresses the spinal cord
What histological stain is used to test for TB?
AFB (acid fast stain)
What is a tuberculoma?
(a) Histological features of a tuberculoma
Tuberculoma = firm lump as a manifestation of TB
-can be in the brain and the problem is that they can rupture and spread the disease
(a) Histologically = multinucleated giant cells and caseating necrotic granulomas
When you see plasma cells on a histological slice of the brain what do you think of?
Syphilis
What is general paresis?
Neuropsychiatric disorder of the brain caused by chronic meningoencephalitis due to syphilis
- 10-20 years after initial infection w/ syphilis
- pts present w/ intellectual decline, irritability, seizures, psychotic symptoms
possible mechanism: cerebral atrophy (due to chronic meningoencephalitis) of the frontal and temporal lobes => psychotic symptoms
What is tabes dorsalis?
= syphilitic myelopathy
-slow degeneration of dorsal column and spinal cord nerves => loss of proprioception, vibration, and fine touch
What is the most common cause of fungal meningitis?
including in immunocompromised pts
Cyptococcus neoformans
-characteristic basal ganglion lesion
Most likely bug:
HIV+ pt w/ diplopia and hyperreflexia
-LP: WBC = 250
Mycobacterium tuberculosis
WBC 250 => infectious
- meningitis + CN involvement = TB
- account for hyperreflexia (UMN) w/ spinal cord TB lesion
