CNS Infections- Predisposing, Transmission, & Age groups Flashcards
Meningeal inflammation resulting from an infection within the
subarachnoid space
Causes of meningitis
- viruses are the most common cause.
- bacteria are 2nd most common cause – 7 major agents.
- fungus are less common – Cryptococcus neoformans var. grubii
- protozoa are less common – Toxoplasma ghondii, Naegleria fowleri.
Tetanus mimics some S & S of ______ but tetanus is a ________
meningitis but tetanus is a neurotoxemia, like botulism
Encephalitis
Inflammation of the brain parenchyma
Encephalitis: Focal/Localized/Specifc areas of the brain affected, not all areas – caused primarily by __________
HSV-1
HSV-1 disease is treatable by antiviral therapy.
Encephalitis: Diffuse/affects all areas of the brain – caused primarily by _______
arbovirus – supportive therapy only
Encephalomyelitis – encephalitis with myelitis (spinal chord inflammation) – caused by ________
poliovirus and West Nile virus – supportive therapy only
Slow virus encephalitis diseases may be caused by ___________
HIV - HIV-1-associated cognitive/motor complex (AKA AIDS Dementia Complex).
Another type of slow viral encephalitis is Progressive multifocal leukoencephalopathy (PML) and is caused by ________
polyomaviruses – papovavirus: JC virus in severe T-cell suppression/AIDS or transplant patient or MS patient on immunosuppresive therapy.
Another type of slow viral encephalitis is Subacute, sclerosing panencephalopathy (SSPE) and is caused by ________
Measles virus
Lesion is macroscopic in size and of sufficient mass/volume to press against the normal brain tissue → increased intracranial pressure → _____________
focal seizures
Mass lesions/abscess of CNS; CT will show
CT scan showing ring-enhancing (mass) lesion supports the diagnosis
Etiologic agents of mass lesion or abscess of CNS are (3 listed)
- Abscess – S. aureus, anaerobes.
- Neurocysticercosis (cysts) – Taenia solium.
- Toxoplasmosis –(pseudocyts) - Toxoplasma gondii
Neurotoxic diseases - Pathology is due to a neurotoxin/exotoxin which affects either _________ or _________
- CNS – tetanus – Clostridium tetani (mimics some S & S of meningitis but tetanus is a neurotoxemia)
- PNS – botulism – Clostridium botulinum
PNS disease- Leprosy
Leprosy – Infection of sensory nerves – Mycobacterium leprae.
PNS Disease- Guillain-Barre’ Syndrome
Guillain-Barre’ Syndrome – demyelination of PNS - autoimmune disease –Campylobacter jejuni.
PNS disease- Botulism
Botulism – toxin inhibits nerves at the neuromuscular junction –Clostridium botulinum.
Prion diseases (2 types)
- New Variant Creutzfeldt-Jacob Disease: Prion of bovine spongiform encephalitis.
- Creutzfeldt-Jacob Disease (CJD). Human Prions.
Common BACTERIAL cause of purulent/pyogenic meningitis and more frequently result in severe disease. Age-dependent etiology is common. 7 major agents are ______
- Neisseria meningitidis, (young & old)
- Streptococcus pneumoniae (y & o)
- Haemophilus influenzae, type b (y & o)
- Streptococcus agalactiae (neonate)
- Escherichia coli K1 (neonate)
- Klebsiella pneumoniae (neonate)
- Listeria monocytogenes (elderly)
4 Agents causing bacterial encephalitis &/or mass lesions
- Mycoplasma pneumoniae.
- Listeria monocytogenes
- S. aureus
- anaerobic [mixed] infections.
2 Agents causing Neutrotoxic disease
- Clostridium botulinum
2. Clostridium tetani
Viruses. A given virus may cause aseptic meningitis or encephalitis but ________
one site predominates over another
Aseptic (viral) meningitis, (most common agents of meningitis) often runs a benign course and rarely cause neurological sequelae Age-dependent etiology is often seen (8 of them):
- *Human herpes virus-6 and -7 (in infants & young children
- Non polio enteroviruses (Echo virus, coxsackie, entero 68-71)
- Arbovirus
- *HSV 2
- *LCMV
- HIV
- *Mumps
- Polio
* different from list of viruses that cause high mortality and neuro problems
Viral Encephalitis (unlike viral meningitis) cases have high mortality and high incidence of significant/severe neurological sequelae. 9 Causes are:
- herpes simplex virus-1
- arboviruses
- rabies
- polio
- non-polio enteroviruses (Echovirus, Coxsackie viruses, enteroviruses 68→71)
- HIV.
- JC virus.
- Measles virus (rare only due to vaccination of humans: measles infectious encephalitis, SSPE)
- VZV & CMV.
Viral Encephalitis: Diffuse Encephalitis caused by Arbovirus (a Zoonosis) primary cause of epidemic diffuse encephalitis in summer/fall months, 8 causes are:
- Eastern equine encephalitis (EEE) – EEEV.
- Western equine encephalitis (WEE) – WEEV.
- St. Louis encephalitis (SLE) – SLEV.
- California encephalitis serogroup: Jamestown canyon, La Cross viruses.
- West Nile encephalitis (WNE Africa, Europe, US) – WNEV.
- Powassan encephalitis (POW) is caused by POWV via the tick.
- Coltiviruses: Colorado tick fever
- Others: HSV-1 and the non-polio enteroviruses
Viral Encephalitis: Focal encephalitis, 7 causes are
- **HSV-1 usually, sporadic, focal encephalitis all year round.
- Arboviruses and the non-polio enteroviruses.
- **Rabies virus – Rabies (rare due to vaccination of dogs and cats)
- **Encephalomyelitis – encephalitis with myelitis (spinal chord inflammation): poliovirus (rare due to vaccination of humans) & West Nile virus (an arbovirus)
- CMV in the patient with severe T cell immunosuppression/AIDS or transplant pt.
- VZV (rare only due to vaccination of humans).
- C virus and PML.
Viral Encephalitis: Slow virus encephalitis diseases, 3 causes are
- HIV - HIV-1-associated cognitive/motor complex (AKA AIDS Dementia Complex).
- Progressive multifocal leukoencephalopathy (PML): polyoma – papovavirus: JC virus severe T-cell suppression/AIDS or transplant pt.
- Subacute, sclerosing panencephalopathy (SSPE): Measles (Rubeola virus).
Fungal causes of meningitis
3 most common agents are:
- Cryptococcus – a meningoencehalitis
- Candida. – meningitis
- Coccidioides immitis – a meningoencehalitis.
Prions in CNS, causes of meningitis are
- Bovine spongiform encephalopathy prion
2. Creutzfeldt-Jacob Disease
Parasites usually cause a meningoencephalitis; 6 of them are
- **Toxoplasma gondii (protozoan- Toxoplasmosis).
- **Taenia solium, agent of neurocysticercosis (NCC; helminth).
- Echinococcus granulosus or multilocularis (Cystic Echinococcosis-hydatid cyst)
- Baylisascaris procyonis (Raccoon Round Worm Encephalitis/Baylisascariasis)
- Toxocaria cannis or cati (Toxocaria)
- **Naegleria fowleri predominate agent (Amoeba –Amoebic meningoencephalitis)
Others are Acanthamoeba spp., Balamuthia mandrillaris, Vahlkampfia spp., Hartmanella spp.
7 Encapsulated agents that cause meningitis are
- S. pneumoniae
- S. agalactiae
- H. influenzae, type b (Hib)
- N. meningitidis
- E. coli K1
- K. pneumoniae
- Cryptococcus neoformans var. neoformans
Predisposing factors to contract meningitis are
Immunodeficiency:
- T cell.
- B cell.
- Terminal complement deficiency and N. meningitidis.
- Long-term corticosteroid therapy.
- Immunosuppression of solid organ transplant (SOT) patient.
- Cancer due to chemotherapy or to form of cancer, e.g., lymphoma
- AIDS
Humoral immunity (B cell-mediated immunity) is required to prevent disease caused by the following extracellular bacteria whose primary virulence factor is an antiphagocytic capsule:
- S. pneumoniae.
2. S. agalactiae.
3. H. influenzae, type b (Hib)
4. N. meningitidis.
5. E. coli K1.
6. K. pneumoniae.
Cell-mediated-immunity (T cell-mediated) is required to prevent disease caused by the following agents with are either facultative or obligate intracellular agents:
- Listeria monocytogenes.
2. Toxoplasma gondii.
3. Cryptococcus neoformans
4. cytomegalovirus (CMV)
5. Mycobacterium tuberculosis
6. JC virus and PML
7. HIV
8. LCMV.
9. E. coli K1??
Chronic or debilitating disease that predispose you are
- Advanced HIV/AIDS.
2. Sickle cell disease.
3. Lymphoma/cancer.
The physician must have high index of suspicion with the elderly because of all of the following:
- often hypothermic so don’t manifest with fever.
- neck arthritis so already manifest with nuchal rigidity.
- dementia masks lethargy and irritability.
Newborns with fever should be ______
routinely tapped because so few S & S in this age group.
Nosocomial causes predisposing someone
- Intraventricular catheters (IVC)
2. choclear implant:
Bacterial Reservoirs
Carriage is in nasopharynx and humans are only host for these bacteria:
- S. pneumoniae;
- H. influenzae, type b (Hib)
- N. meningitidis,
- S. agalactiae (also in vagina, GIT, skin).
* Humans are only host Mycobacterium tuberculosis**
Bacterial Reservoirs
Carriage is in nares for
Staphylococcus aureus
Bacterial Reservoirs
Carriage in humans is primarily on mucosal surfaces for
endogenous anaerobic flora
Bacterial Reservoirs
Carriage in humans is primarily in the colon for
- Streptococcus agalactiae,
- E. coli
- K. pneumoniae
- Listeria monocytogenes.
- with migration to the vagina and vaginal colonization and migration to urethra → cystitis:
Streptococcus agalactiae, E. coli, K. pneumoniae
Bacterial Reservoirs
Animals and/or humans are reservoir for:
- E. coli K1.
- K. pneumonia.
- L. monocytogenes.
- M. leprae.
- Streptococcus agalactiae,
- Animals and/or humans are reservoir for Staphylococcus aureus but humans are the primary source of infections.
Bacterial Reservoirs
Soil is the reservoir for
- C. tetani, (soil reservoirs),
- C. botulinum. (soil, water, animal reservoirs),
- L. monocytogenes (ubiquitous).
Viral Agents- Zoonosis reservoir
- Arboviruses – animals (mammals &/or birds) and arthropods (mosquito or tick).
- Rabies virus– mammals.
- LCMV – mammals, especially rodents.
Viral Agents- Humans are sole reservoir for:
- enteroviruses
- measles virus
- herpes viruses, HSV-1, HSV-2, HHV-6, HHV-7, CMV
- HIV.
- JC & BK viruses.
- mumps virus
Reservoir for Cryptococcus neoformans
(soil and animal [bird] reservoirs) – fungus
Reservoir for Toxoplasma gondii
(animal reservoir) – protozoan
Reservoir for Taenia solium
(pig and humans reservoir) – tape worm.
Reservoir for Echinococcus granulosus or multilocularis
(Cystic Echinococcosis-hydatid cyst)
Reservoir for Baylisascaris procyonis
(Raccoon Round Worm Encephalitis/Baylisascariasis)
Reservoir for Toxocaria cannis or cati
(Toxocaria) in cat or dog round worm
Reservoir for Amoebic meningoencephalitis:
mainly Naegleria fowleri – warm water reservoir.
Mode of transmission for Arboviruses
animals (mammals &/or birds) and arthropods (mosquito or tick).
Mode of transmission for Rabies virus
Bat mostly, raccon-East Coast, skunk-mid-West in US – Dog, WW
Mode of transmission for LCMV
- from rodent
- exposure to rodents, droppings, seretions, fluids
General zoonosis is the mode of transmission for: (7 of them)
- Listeria monocytogenes
- Mycobacterium leprae
- Toxocaria cannis or cati (Toxocaria)
- Toxoplasma gondii (cysts bearing larvae)
- Echinococcus granulosus or multilocularis (Cystic Echinococcosis-hydatid cyst)
- Bovine spongiform encephalopathy prion (AKA new variant Creutzfeldt-Jacob Ds)
- C. botulinum
Mode of transmission for Baylisascaris procyonis
(Raccoon Round Worm; Encephalitis/Baylisascariasis)
Mode of transmission for Cryptococcus neoformans
(animal-bird mechanical vector)
Consumption of tainted food may transmit:
3 of them
- Bovine spongiform encephalopathy prion.
- Taenia solium (cysts bearing larvae) – not directly to CNS, indirectly.
- Toxoplasma gondii (cysts bearing trophs or bradyozoites)
Fecal-oral route / food is contaminated with feces (leads to CNS disease):
(8 of them)
- Taenia solium (ova) neurocysticercosis from human,
- Toxoplasma gondii (ova) Toxoplasmosis from cat litter, soil.
- enteroviruses (polio, ECHO & Coxsackie viruses, enteroviruses 68→71).
- Listeria monocytogenes from many sources.
- LCMV from rodent.
- Echinococcus granulosus or multilocularis (Cystic Echinococcosis-hydatid cyst)
- Baylisascaris procyonis (Raccoon Round Worm Encephalitis/Baylisascariasis)
- Toxocaria cannis or cati (Toxocaria)
CNS Infections transmitted in utero (vertical)
8 of them
- Streptococcus agalactiae (less common than during parturition)
- Listeria monocytogenes (more common than during parturition)
- Non-polio enterovirus (Coxsackie & Echoviruses, enteroviruses 68→71).
- LCMV.
- Toxoplasma - Toxoplasma gondii.
- Rubella
- CMV
- Herpes simplex virus
CNS infections transmitted during parturition
5 of them
- Streptococcus agalactiae (more common than In utero transmission)
- Listeria monocytogenes
- E. coli
- K. pneumoniae
- Herpes virus and CMV (more common In utero transmission)
CNS infections from inhalation of infectious dust (2 of them)
- Cryptococcus neoformans
2. LCMV
Agents of CNS disease associated with familial/close –contact outbreaks include:
- hib.
- meningococcus.
- Non-polio enterovirues.
- T. solium – if someone is shedding ova.
- Very rare, very, very uncommon agents that can cause outbreaks in USA are: M. leprae (lepromatous form), mumps virus, measles virus, rabies virus, polio virus
Predisposing factors for Neisseria meningitis
human exposure, terminal complement deficiency
Associated factor for non polio enteroviruses, polio enteroviruses, and Taenia solium ova
human feces
Predisposing factor for Naegleria fowleri
Exposure to fresh water with algae
Predisposing factors for Streptococcus. agalactiae
low birth weight infant, rupture of membranes >24h before delivery, colonized vaginal canal
Predisposing factor for Streptococcus pneumoniae
congenital CSF leak
Associated factor for Toxoplasma gondii ova
cat feces
Associated factor for Toxoplasma gondii pseudocyst
under cooked or uncooked meat
Bacterial meningitis accounts for _____ of all cases of meningitis while Viral meningitis (aseptic meningitis) accounts for _____
However, most cases of viral meningitis are ________
less than ½
viral- the majority
not definitively diagnosed
Most common agents of viral meningitis in children→ adults are the ___________
Problem for physician is differentiating between bacterial pyogenic/purulent meningitis, which is _______ and benign viral meningitis.
ECHO and Coxsackie viruses, then the arbovirues, HSV-2, etc.
a medical emergency
Most common agents of viral meningitis are
- Non-polio enteroviruses (ECHO viruses and Coxsackie viruses).
- HHV-6, HHV-7
Seasonality for Arbovirus
late summer→early fall seasonality
cause meningitis & diffuse encephalitis.
HSV-1 causes
focal encephalitis
no seasonality
HSV-2 causes
if manifesting with primary symptomatic infection (genital herpes) – meningitis.
Seasonality and cause of LCMV
if winter seasonality and history of rodent exposure – meningitis
Seasonality of Polio
Polio (late summer and early fall seasonality, meningitis primarily young children → adults) and Mumps (rare due to vaccination).
Meningococcal disease is the most frequent cause of bacterial meningitis in __________ in the United States (approximately 2800 cases of meningococcal disease in the United States each year)
infants, children, adolescents, and young adults
Of the 3000 cases> 60% are in individuals over 11 years old (this age group has the highest mortality rate; 25% versus 10-14% overall)
Of the 3000 cases, 11%-19% of survivors are left with long-term disabilities: hearing loss, cognitive impairment, renal failure, limb amputations.
__________ has the highest case mortality rate for any bacterial agent of meningitis.
S. pneumoniae
its the most common infectious agent associated with patients with recurrent meningeal infections.
About 1/2 of all cases of meningitis in the US are _________
nosocomial-acquired meningitis
hospital acquired
Bacteria with year round seasonality
- S. agalactiae.
- E. coli K1
- K. pneumoniae
Bacteria with summer seasonality
L. monocytogenes
Bacteria with late winter-early spring seasonality
- H. influenzae type b (Hib)
- N. meningitidis
- S. pneumoniae
Viruses with year round seasonality
- HHV-1
- HHV-2
- HHV-6 & -7
- CMV
- HIV
- Rabies
Viruses with late summer and early fall seasonality
- ECHO viruses and Coxsackie viruses
- Polio virus
- Arboviruses
Viruses with winter seasonality
LCMV
ALL major agents with seasonality in late summer/early fall
- ECHO viruses and Coxsackie viruses
- Polio virus
- Arboviruses
- Listeria monocytogenes,
- Neglaria fowleri
ALL major agents with winter seasonality
- LCMV
- H. influenzae type b
- S. pneumoniae
ALL major agents with year round seasonality
- HHV-1, HHV-2, HHV-6 & -7
- CMV
- HIV
- Rabies
- Streptococcus agalactiae (more common than In utero transmission)
- E. coli
- K. pneumoniae
Age dependent infections- transmitted in utero
- S. agalactiae.
- L. monocytogenes.
- Non-polio enterovirus (Coxsackie & Echoviruses).
- LCMV
- Toxoplasma
- Rubella
- CMV
- herpes simplex virus
Age dependent infections- transmitted during parturition
- Streptococcus agalactiae (more common than In utero transmission)
- Listeria monocytogenes,
- E. coli
- K. pneumoniae
- Herpes virus and CMV (more common In utero transmission)
Congenital infections – The unborn child’ s infection is acquired in-utero and results in a diseased child at birth. The common agents of congenital infections are ________
“TORCH” agents
- Toxoplasma → TO
- Rubella →R
- Cytomegalovirus [CMV] →C
- Herpes simplex virus [HSV]) -2 or -1 →H
Describe TORCH test
a test to detect a congential (AKA intrauterine infection) infection in a neonate via presence of specific IgM in chord blood.
_______ is leading cause (by far) of infection and morbidity in the neonate. It is estimated that 40,000 neonates born in the US each year are infected with this and 8,000 of these will have serious neurological sequelae.
CMV infection
Common causes of CNS disease in neonates
- S. agalactiae - Highest incidence of infection & morbidity among procaryotes.
- E. coli K1.
- K. pneumoniae.
- L. monocytogenes.
- ***Cytomegalovirus (CMV) - Highest incidence of infection & morbidity of all agents.
- ***Herpes simplex virus (HSV) 1 or 2
- ***Non-polio enterovirus (Coxsackie & Echoviruses)
- Human herpes virus-6 and –7 (HHV-6 and HHV-7)
***=MOST common in neonates
Common causes of CNS disease in infants and young children
- HH-6, HH-7
- **HSV 1 & 2
- **non-polio enterovirus (Coxsackie & Echoviruses).
- N. meningitides
- S. pneumoniae
- Mycobacterium tuberculosis.
- **Arboviruses
- **LCMV
- Mumps
ALL of these are the same for adolescents and elderly except #1 & 2
**= most common over the age of 2
Common causes of CNS disease in adolescents and elderly
- non-polio enterovirus (Coxsackie & Echoviruses).
- Arboviruses.
- N. meningitides,
- S. pneumoniae
- *L. monocytogenes – those over 50-y-o-age.
- Mycobacterium tuberculosis.
- Mumps (Adolescents)
Most common viral cause in 6 mo to 2 years
HHV-6 & HHV-7
Common BACTERIAL agents by age: Neonate
a. S. agalactiae,
b. E. coli K1,
c. L. monocytogenes
d. K. pneumoniae K1, K2
a= most common, d=least common
Common BACTERIAL agents by age: Infant to adult
a. N. meningitides
b. S. pneumoniae
a is most common, b is second most common
Common BACTERIAL agents by age: Elderly
a. N. meningitides
b. S. pneumoniae
c. L. monocytogenes