CENTRAL NERVOUS SYSTEM INFECTIONS Flashcards
Infection may damage the nervous system directly or indirectly
Directly through injury of neurons or glia by ___________
Indirectly through the ____________ and __________
the infectious agent
cytokines released by infectious agents and inflammatory response.
There are four principal routes by which microbes enter the nervous system
List them
Haematogenous spread
Direct implantation
Local extension
Along nerve
There are four principal routes by which microbes enter the nervous system
- Haematogenous spread
- Direct implantation of microorganisms is most often _______ or is sometimes associated with _______________ that provide ____________________
traumatic
congenital malformations
ready access for microorganisms.
There are four principal routes by which microbes enter the nervous system
3, Local extension can originate from __________, such as air sinuses, teeth, skull, or vertebrae.
4, Along nerve. Certain viruses such as ________,_________,_________ spread along cranial and peripheral nerves and ascend to CNS
infected adjacent structures
herpes simplex, herpes zoster and rabies
Meningitis is ________ involvement of the meninges.
inflammatory
Meningitis may involve the dura called ___________, or the leptomeninges (pia- arachnoid) termed ____________.
pachymeningitis
leptomeningitis
pachymeningitis , leptomeningitis
Which is more common
leptomeningitis is far more common, and unless otherwise specified, meningitis would mean leptomeningitis
Leptomeningitis, commonly called ________, is usually the result of _______ but infrequently _______ meningitis and _________ meningitis by infiltration of the ___________ by cancer cells may occur
meningitis; infection
chemical; carcinomatous
subarachnoid space
Infectious meningitis is broadly classified into 3 types:
○ ________________
○ _____________________ (________)
○—————(———-)
Acute pyogenic meningitis
Acute lymphocytic (viral, aseptic)
Chronic (bacterial or fungal).
Acute pyogenic (Bacterial) Meningitis
Distinctive microorganisms cause acute pyogenic meningitis in various age groups:
Neonates: ______________ and the ________
Infants and children: __________________
Adolescent and young adults: ___________
Extremes of life: _______________ and ____________
Escherichia coli and the group B streptococci
Haemophilus influenzae
Neisseria meningitidis
Streptococcus pneumoniae and Listeria monocytogenes
Acute pyogenic (Bacterial) Meningitis
____________ is most likely to cause epidemics and Is most prevalent in (dry or wet?) season
N.meningitidis
dry
Acute pyogenic meningitis: Routes of infection
•Most commonly by the __________
•From an adjacent ____________.
•By iatrogenic infection such as introduction of microorganisms at _________ or during _________
blood stream.
focus of infection
surgery ; lumbar puncture
Acute pyogenic meningitis : clinical features
The immediate clinical manifestations are fever, severe headache, vomiting, drowsiness,______,______ and occasionally, ________.
Neck _______, positive ______ and _______sign
stupor, coma
convulsions
stiffness
kernig and brudinsky
Acute bacterial meningitis is a medical emergency
T/F
T
Acute bacterial meningitis : Diagnosis
Naked eye appearance of ______ or _________ CSF.
_______ CSF pressure (above _____ of water).
__________ leucocytosis in CSF
________ CSF protein level (higher than ——- mg/dl).
____eased CSF sugar concentration (lower than ____ mg/dl).
Bacteriologic examination by Gram’s stain or by CSF culture reveals causative organism.
cloudy or frankly purulent
Elevated; 180 mm
Neutrophilic
Raised; 50
Decr; 40
Acute pyogenic meningitis: Morphology (macroscopy)
________ is evident within the leptomeninges over the surface of the brain.
The meningeal vessels are _______ and stand out prominently.
An exudate
engorged
Acute pyogenic meningitis: Morphology (macroscopy)
Anatomic distribution of the exudate varies;
it is usually ——— in H. influenzae meningitis
it is densest over the _________ near the _________ in pneumococcal meningitis
basal
cerebral convexities
sagittal sinus
Acute pyogenic meningitis: Morphology (macroscopy)
When the meningitis is fulminant, the inflammation may extend to the _______, producing _______
The Waterhouse-Friderichsen syndrome results from meningitis-associated _______ (commonly ____________) with ——————- of the ________ and _____________
ventricles; ventriculitis
septicemia; N.menigitidis
hemorrhagic infarction
adrenal glands ; cutaneous petechiae
Acute pyogenic meningitis: Morphology (microscopy)
There is presence of numerous —————— in the ————— as well as in the meninges, particularly around the ____________
Gram-staining reveals varying number of causative bacteria
polymorphonuclear neutrophils
subarachnoid space
blood vessels.
Acute lymphocytic (viral, aseptic) meningitis
Acute lymphocytic meningitis is a viral or aseptic meningitis, especially common in ———- and __________
The aetiologic agents includes _______,______,_______,______,______,________,_______ and __________
However, evidence of viral infection may not be demonstrable in about ——— of cases.
children and young adults.
enteroviruses, mumps, ECHO viruses, coxsackie virus, Epstein Barr virus, herpes simplex virus-2, arthropod-borne viruses and HIV.
a third
Acute lymphocytic (viral, aseptic) meningitis
The clinical manifestations of viral meningitis are much the same as in bacterial meningitis with features of acute onset meningeal symptoms and fever
T/F
T
Viral meningitis has a (benign or malignant ?) and __________ clinical course of (short or long?) duration and is invariably followed by ________ without the life threatening complications of bacterial meningitis
benign and self-limiting
Short
complete recovery
Acute lymphocytic (viral, aseptic) meningitis: Diagnosis
The CSF findings in viral meningitis are:
○Naked eye appearance of _________ or ________ CSF.
○CSF pressure ____eased (above ———- water).
○Lymphocytosis in CSF (10-100 cells/μl).
○CSF protein usually ———————
○CSF sugar concentration usually ______.
○CSF is bacteriologically _______.
Clear or slightly turbid
incr; 250 mm
normal; sterile
Chronic meningitis
There are two principal types of chronic meningitis
_________ (__________ meningitis)
_________ (__________ meningitis).
Both types cause _________________ reaction and may produce parenchymal lesions.
bacterial; tuberculous
fungal ; cryptococcal
chronic granulomatous
Chronic meningitis: Tuberculous meningitis
Occurs in children and adults through _____________ spread of infection from tuberculosis
It may simply be a manifestation of —————-
Less commonly, the spread may occur directly from tuberculosis of a ____________
haematogenous spread
miliary tuberculosis.
vertebral body.
Chronic meningitis: Cryptococcal meningitis
Develops particularly in _________ or ————— persons, usually as a result of ————- dissemination from a ————
debilitated or immunocompromised
haematogenous; pulmonary lesion.
Cryptococcal meningitis is especially an important cause of meningitis in patients with _______.
AIDS