CENTRAL NERVOUS SYSTEM INFECTIONS Flashcards by Iseoluwa Ojo

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.

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There are four principal routes by which microbes enter the nervous system

List them

Haematogenous spread
Direct implantation
Local extension
Along nerve

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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.

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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

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Meningitis is ________ involvement of the meninges.

inflammatory

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Meningitis may involve the dura called ___________, or the leptomeninges (pia- arachnoid) termed ____________.

pachymeningitis

leptomeningitis

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pachymeningitis , leptomeningitis

Which is more common

leptomeningitis is far more common, and unless otherwise specified, meningitis would mean leptomeningitis

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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

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Infectious meningitis is broadly classified into 3 types:

○ ________________
○ _____________________ (________)
○—————(———-)

Acute pyogenic meningitis

Acute lymphocytic (viral, aseptic)

Chronic (bacterial or fungal).

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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

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Acute pyogenic (Bacterial) Meningitis

____________ is most likely to cause epidemics and Is most prevalent in (dry or wet?) season

N.meningitidis

dry

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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

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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

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Acute bacterial meningitis is a medical emergency

T/F

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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

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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

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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

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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

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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.

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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

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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

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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

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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

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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

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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

Chronic meningitis: Clinical features Tuberculous meningitis manifests clinically as _____,_______,_____,_______. The clinical course in cryptococcal meningitis may, however, be _———- and _______ in a few weeks, or be ______ for months to years.

headache, confusion, malaise and vomiting fulminant and fatal; indolent

Chronic meningitis: Diagnosis The CSF findings in chronic meningitis are as under: Naked eye appearance of a ______ or ________ CSF which may form ________ on standing. ________ CSF pressure (above ________ water). ________ leucocytosis consisting mostly of _________ and some _______ _______ protein content.

clear or slightly turbid ; fibrin web Raised; 300 mm Mononuclear; lymphocytes; macrophages Raised

Chronic meningitis: Diagnosis _________ glucose concentration. ________ may be found on microscopy of centrifuged deposits by ____ staining in tuberculous meningitis. Pathognomonic ______ cryptococci with a _____ are appreciated in _____ preparation of CSF in cases of cryptococcal meningitis, while the capsule is better demonstrated by ________

Lowered Tubercle bacilli; ZN encapsulated; hall ; India ink ; mucicarmine stain

Chronic meningitis: Morphology (Tuberculous) The most common pattern of tuberculous involvement is a __________________ __________ that characteristically involves the ____ of the brain, ______ the cisterns and ______ cranial nerves On microscopic examination, involved areas contain mixed inflammatory infiltrates containing lymphocytes, plasma cells, and macrophages

diffuse meningoencephalitis. Fibrinous exudate; base effacing

Chronic meningitis: Morphology (Tuberculous) Florid cases show well-formed __________ with —————- and __________ Organisms can often be seen with __________ stains. CNS involvement may also take the form of one or more well-circumscribed ____________ ( ___________ ), which may be associated with meningitis

granulomas caseous necrosis and giant cells. intraparenchymal masses tuberculomas

Chronic meningitis: Morphology (Tuberculous) A tuberculoma may be as large as several centimeters in diameter, causing ____________. These lesions usually have a _____ area of _______ necrosis surrounded by ________ ________ may occur in inactive lesions.

significant mass effect central caseous; granulomas calcification

Chronic meningitis: Morphology (Cryptococcus) With cryptococcal infection, there is a chronic meningitis affecting the _________________ , which are ______ and ________ by reactive connective tissue that may obstruct the outflow of CSF from the __________________________, giving rise to __________ The meningeal infiltrates consist of chronic inflammatory cells and fibroblasts admixed with cryptococci

basal leptomeninges opaque; thickened foramina of Luschka and Magendie hydrocephalus

Chronic meningitis: Morphology (Tuberculosis) On microscopic examination, involved areas contain mixed inflammatory infiltrates containing ______,__________, and ———- (Cryptococcus) The meningeal infiltrates consist of chronic inflammatory cells and _________ admixed with ________

lymphocytes, plasma cells, and macrophages fibroblasts

Complications of meningitis ________ loss recurrent _______ ________ problems with ________ problems with ________ and _______ ________ failure

Hearing seizures hydrocephaly memory movement and coordination renal

Acute focal suppurative infections ______ abscess ________ ———- _______ abscess

Brain Subdural empyema Extradural

Acute focal suppurative infections ________ and _____ are the most common offending organisms identified in brain abscess in non- immunosuppressed patients

Streptococci and staphylococci

Brain Abscess A brain abscess is a (localized or generalized?) focus of _____ of brain tissue with accompanying ______, usually caused by a ______ infection.

localized; necrosis inflammation; bacterial

Brain Abscess Predisposing conditions include; ____________________ which may give rise to multiple brain abscesses ____________ disease (__________ ) ___________(rare) Immunosupression

Acute bacterial endocarditis Congenital heart; R to L shunting Bronchiectasis

Brain Abscess: Morphology Abscesses are discrete lesions with central ———- surrounded by brain ———. At the outer margin of the necrotic lesion there is exuberant ________ with ___________ around the necrosis

liquefactive necrosis; swelling granulation tissue; neovascularization

Brain Abscess: Morphology In well-established lesions, a __________ is produced by fibroblasts derived from the ________________. Outside the fibrous capsule is a zone of _________ containing numerous ________ __________

collagenous capsule walls of blood vessels reactive gliosis gemistocytic astrocytes

Neurosyphillis Neurosyphilis is a manifestation of the _______ stage of syphilis and occurs in only about ____% of individuals with untreated infection.

tertiary; 10

Neurosyphillis The major patterns of CNS involvement are _________ neurosyphilis _______ neurosyphilis __________________ Causative organism is ___________

meningovascular paretic tabes dorsalis. Tropenema pallidum

Neurosyphillis Symptoms include: Abnormal ____/___________ numbness in ______ limbs, poor _______ control Treatment is with ________,_______

gait/unable to walk lower; bladder penicillin, probenecid

Neuroborreliosis (Lyme disease) Lyme disease is caused by the ________ ,———- ————-, which is transmitted by various species of ______ .

spirochete Borrelia burgdorferi Ixodes tick

______________ (Lyme disease)

Neuroborreliosis

Neuroborreliosis (Lyme disease) Neurologic symptoms are highly variable and include ______ meningitis ________ palsies and other polyneuropathies, as well as ___________.

aseptic facial nerve encephalopathy

Viruses can infect the CNS and produce either _________,_________, or both ( ——————- ).

aseptic meningitis, viral encephalitis meningoencephalitis

Viral Encephalitis ○ Herpes simplex virus/Herpes zoster infects the ______ and ———- to get into the blood ○ Enteroviruses like poliovirus via the —————- ○ Arbovirus by _______ ○ CMV by __________ infection

skin and mucous membrane alimentary canal arthropod bite transplacental

Viral Encephalitis Although histologic changes vary from one viral infection of the CNS to the other but, in general, the characteristic features of viral diseases of the CNS are: Parenchymal infiltrate, chiefly in _______ location, of ______ cells consisting of _____,______, and _______ Microscopic clusters of ______ cells and presence of _________. _____________ bodies in most viral diseases and specific cytoplasmic inclusions of _______ in rabies

perivascular; mononuclear lymphocytes, plasma cells and macrophages. microglial; neuronophagia Intranuclear inclusion; Negri bodies

HIV Encephalopathy (AIDS-Dementia Complex) HIV has profound ______ but unlike tropism for _______ cells of the immune system. HIV has not been identified to infect the _________ but instead infects the cells of _______________ cell line including _______ cells. HIV infection then sets in a cascade of toxic mediators and cytokines—TNF- a, IL-1, IL-6, TGF-b, IFN-g, platelet activating factor (PAF) and endothelin, all of which cause damage to the ________

neurovirulence; CD4+ T neuronal cells; monocyte-macrophage ; microglial neuroglial tissues

HIV Encephalopathy (AIDS-Dementia Complex) (Early or Late?) in the course of AIDS, a group of signs and symptoms of CNS disease appear termed HIV encephalopathy or AIDS-dementia complex. One major clinical feature of this entity is the occurrence of ————- i.e. ___________________________ of the individual compared to previous level.

Late dementia fall in the cognitive ability

Progressive multifocal leucoencephalopathy is a (slow or rapid?) viral infection of the CNS caused by a ______virus called JC virus (not to be confused with _______ or __________)

Slow ; polyoma CJ disease or mad-cow disease

PML develops in __________ individual like CMV and Toxoplasmosis

immunocompromised

Progressive multifocal leucoencephalopathy It is an important form of encephalitis due to _______________________. PML infects _______ and causes progressive ________ at multifocal areas scattered throughout the CNS.

increasing number of cases of AIDS oligodendrocytes; demyelination

____________ Encephalopathy = Creutzfeldt-Jakob Disease = ___________

Spongiform Mad cow disease

Spongiform Encephalopathy (Creutzfeldt-Jakob Disease) though included under the group of viral encephalitis but is caused by _______________

accumulation of prion proteins

Prions are abnormal forms of a _________ that cause (gradual or rapidly?) _____________ disorders that may be sporadic, familial or transmitted

cellular protein Rapidly progressive neurodegenerative

Spongiform Encephalopathy (Creutzfeldt-Jakob Disease) Majority of cases occur sporadically though ______ predisposition with ___________ inheritance has also been reported in 5-15% cases

familial ; autosomal dominant

Clinically, CJD is characterised by rapidly progressive________ with prominent association of _________. CJD is invariably _____ with mean survival of about _______ after diagnosis.

dementia myoclonus fatal 7 months

The progression of the dementia in CJD is usually so rapid that there is little if any grossly evident brain atrophy T/F

Spongiform Encephalopathy (Creutzfeldt-Jakob Disease): Morphology The pathognomonic finding is a ______ transformation of the ________ and, often, (shallow or deep?) (white or gray?) matter structures (______,_______ ) this multifocal process results in the (even or uneven?) formation of (small or large?) , apparently _____, microscopic vacuoles of varying sizes within the ______ and sometimes in the ______ of neurons

spongiform; cerebral cortex deep ; gray caudate, putamen uneven ; small; empty neuropil ; perikaryon of neurons

Spongiform Encephalopathy (Creutzfeldt-Jakob Disease): Morphology ___________ : are extracellular deposits of aggregated abnormal protein they are ______ and _______ -positive and usually occur in the _______ but are abundant in the _______ in cases of CJD

Kuru plaques Congo red- and PAS cerebellum; cerebral cortex

Spongiform Encephalopathy (Creutzfeldt-Jakob Disease): Morphology Immunohistochemical staining demonstrates the presence of ___________- resistant _____ in tissue.

proteinase K PrPsc

most common cause of brain abscess in immunocompromised patients is ???

Cerebral toxoplasmosis

Other infectious diseases of the nervous system Cerebral _________ Cerebral ________- _________ Cerebral __________- ________ ________ infections

toxoplasmosis malaria; Plasmodium falciparum amoebiasis; Acanthamoeba Rickettsial

Cerebral amoebiasis- Acanthamoeba - Common or Rare? highly _____.

Rare lethal

Rickettsial infections are _______ borne

arthropod