CH 14--Nervous System 2/Infections Flashcards
INFECTIONS–Classified according to the tissue affected:
I. meninges = (Meningitis)
II. Cerebral parenchyma = (encephalitis or brain abscess)
KNOW
INFECTIONS–Classified according to the tissue affected:
I. Meningitis—-Inflammation of the meninges, may be either acute or chronic.
Can be classified according to the TYPE of infection into:
- Acute pyogenic meningitis
- Acute lymphocytic meningitis
- Chronic meningitis
KNOW
MENINGITIS—Can be classified according to the TYPE of infection
TYPE 1— Acute ___________ meningitis
Causative organism may be:
- Group B streptococci & E. coli (neonatal infection)
- Hemophilus influenzae (infants & children)
- Meningococcus (adolescents & young adults)
- Streptococcus pneumoniae (infants & elderly)
Routes of infection:
- Blood
- Direct spread from adjacent structures
- Penetrating trauma (skull fractures)
- Lumbar puncture or brain surgery
pyogenic
_____________ meningitis
(A) A creamy exudate opacifies the leptomeninges.
(B) the accumulation of numerous neutrophils in the subarachnoid space.
Manifestations:
———–* Symptoms: General: fever
Meningeal irritation: - headache- vomiting- neck pain
———— Signs: 1- Neck and back stiffness
2- Positive Kernig’s sign (inability to straighten the raised leg because of pain)
3- Brudzinski’s sign (flexion of patient’s neck causes flexion of patient’s hips & knees)
***These are caused by a reflex spasm in the spinal muscles due to the irritations of the nerves and meninges
Diagnosis:
(1) Examination of CSF
(2) Isolation of causative organism
Treatment = antibiotics
Purulent
MENINGITIS—Can be classified according to the TYPE of infection
- Acute _____________ meningitis (aseptic meningitis)
A. Etiology: Viruses (enteroviruses, mumps, echovirus, coxsackieviruses)
B. Manifestations:
—Similar to bacterial meningitis but less pronounced and self-limited
C. DIAGNOSIS = Viral culture: positive in 70% of cases
lymphocytic
MENINGITIS—Can be classified according to the TYPE of infection
- _____________ meningitis
A------Etiology: - T.B. - Tryponema pallidum - Brucella - Fungi: coccidiomycosis, cryptococcosis B------Pathologic lesions: 1. Chronic granulomatous inflammation → fibrosis 2. Subarachnoid space full of exudate 3. Complications: - vasculitis → ischemia microinfarcts - fibrosis → cranial nerve palsies - obstructive hydrocephalus
Chronic
________ meningitis = The meninges covering the
base of the brain are OPACIFIED.
Tuberculous
Cryptococcus neoformans meninges–Cryptococcus neoformans organisms often lack acapsule, but the nucleus stains well with GMS staining in the meninges in a case of _________ meningitis.
cryptococcal
INFECTIONS–Classified according to the tissue affected:
II. CEREBRAL PARENCHYMA—-TWO TYPES:
A. BRAIN ABSCESS
B. ENCEPHALITIS
KNOW BOTH
INFECTIONS–Classified according to the tissue affected:
II. CEREBRAL PARENCHYMA—-TYPE 1: 1 OF 2
1——–BRAIN ABSCESS
Etiology:
- Staphylococci
- Streptococci
- Pneumococci
Routes of infection: Complication of other diseases: 1. Middle ear and paranasal sinuses infection 2. \_\_\_\_\_\_\_ \_\_\_\_\_\_\_\_\_\_ → emboli to brain 3.\_\_\_\_\_\_\_\_\_ disease (e.g. abscess)
Pathologic lesions:
- Inflammatory lesion → central necrosis and liquefaction
- Fibrogliotic wall
- Surrounding brain tissue shows severe edema (vasogenic)
Treatment: → surgical and antibiotics
Bacterial endocarditis
Lung
INFECTIONS–Classified according to the tissue affected:
II. CEREBRAL PARENCHYMA—-TWO TYPES: 2 0F 2
2——–Viral Encephalitis
4 TYPES:
- Herpes simplex encephalitis
- Rabies
- Subacute sclerosing pan-encephalitis
- Acquired immunodeficiency syndrome
Pathological lesions:
- Mononuclear cell infiltrate, mainly perivascular
- Intra-cytoplasmic or intra-nuclear inclusions
- Degeneration of neurons
- Site: varies in different diseases
KNOW 4 TYPES OF VIRAL ENCEPHALITIS
ON FOUR OTHER CARDS!
4 TYPES OF VIRAL ENCEPHALITIS
- Herpes simplex encephalitis
Transmission:
Type I: Spread of______ (e.g. lesion in mouth)
Type II: During _________ (neonatal)
Site:
- The TEMPORAL lobes are preferentially involved
by a hemorrhagic, necrotizing inflammation.
*****Herpes simplex
Intranuclear inclusions are seen “__________ type A
inclusions”
blood
delivery
COWDRY
4 TYPES OF VIRAL ENCEPHALITIS
- Rabies
Transmission: Bite of infected animals
Site:
- Hippocampus
- Brain stem
- Intra-cytoplasmic inclusions,_______ ___ = (diagnostic)
Negri body (THIS WAS HIGHLIGHTED)
**Negri body = Rabies encephalitis is characterized by round, eosinophilic cytoplasmic inclusions that resemble an
erythrocyte.
4 TYPES OF VIRAL ENCEPHALITIS
- Subacute Sclerosing pan-encephalitis
Transmission:
- Several years after________ attack
- Occurs mainly in ___________
- Insidious onset
Site:
- Cerebral gray matter
- Basal ganglia = Intra-nuclear inclusions
Clinically:
-Personality changes
-Dementia
-MYOCLONUS = (sudden, involuntary jerking of a muscle or group of muscles)
_________________usually occurs within a few years
measles
children
DEATH!!
4 TYPES OF VIRAL ENCEPHALITIS
- Acquired immunodeficency syndrome—AIDS
Transmission:
- __________ contact
- Transfusion of _______ & blood products or sharing needles among drug abusers
- Maternofetal
Site:
Cerebral and cerebellar white & gray matter
with neuronal loss & demyelination → dementia
Sexual
blood
