CNS
INFECTIONS
Done by:
Areej Al Daur
Aya Ferwana
TO:
Dr.Ayham Abu Laila
Bara’a Sheek Al Eed
Let’s begin with Bara’a
Infections
of CNS
Bacterial
Viral
Fungal
Protozoal
Bacterial
infection
Bacterial infection in CNS may cause:
• meningitis,
• brain abscess,
• subdural and epidural abscesses
• empyema
The diagnosis for the bacterial infection
Basic observation:
:
• fever
• severe headaches
• stiff neck
Blood test….
MRI scan…
Spinal tap…..
Examination of the CSF typically reveals:
• elevated protein concentration,
• a depressed glucose concentration,
• a moderate leukocytosis composed mainly of
lymphocytes.
• The exception is the cerebellar syndrome, in
which the protein concentration is elevated
but there is no leukocytosis.
• Cultures of CNS tissue and fluid are frequently
sterile; however, bacteria are occasionally
recovered from the CSF and from the brain
granuloma.
Transmission
1. Through contaminated food
• (e.g., L. monocytogenes, Salmonella, and
Brucella spp.),
L. monocytogenes
• a gram-positive, nonsporulating bacillus that is
facultatively anaerobic and produces weak betahemolysis on blood agar.
• Most human infection by L. monocytogenes is
acquired by consumption of contaminated food.
• L. monocytogenes, is able to enter the brain via a non
hematogenous route by retrograde transport within
cranial nerves.
Brucella Species
• Brucellae are small, nonmotile, and
non spore-forming gram-negative
coccobacilli.
• human disease is caused
predominantly by B. abortus, B.
melitensis, and B. suis
• Human infection typically is acquired by ingestion of
unpasteurized milk or cheese.
• occupational exposure to infected animals, in
particular sheep, goats, swine, camels, and cattle.
• Brucella attacks the CNS and neurobrucellosis is
found much less commonly in children than in
adults.
• permanent neurological deficits, particularly
deafness, are common.
Salmonella Species
• Salmonella spp. are gram-negative, facultative
anaerobic, motile, non-lactose-fermenting, nonspore-forming bacilli.
• In addition to headache,
• CNS manifestations of enteric fever in the form of
neuropsychiatric manifestations from encephalitis,
including confusion and psychosis, occur in 5 to 10%
of patients.
2. Through inhalation
(M. tuberculosis and C. burnetii).
M. tuberculosis
• CNS infection by M. tuberculosis occurs in individuals of any
age.
• Most cases in children occurred between the ages of 6
months and 4 years, whereas adult cases clustered in patients
aged 20 to 50 years.
3. Through the bite of infected arthropods
•
(R. rickettsii, R. prowazekii, and E. chaffeensis),
What is meningitis? What is
encephalitis?
• Infection of the meninges, the membranes that surround the
brain and spinal cord, is called meningitis.
• inflammation of the brain itself is called encephalitis.
• Myelitis is an infection of the spinal cord.
• When both the brain and the spinal cord become inflamed,
the condition is called encephalomyelitis
Meningococcemia
Prominent rash
Diffuse purpuric lesions
principally involving the
extremities.
Who is at risk for encephalitis and
meningitis?
 People with weakened immune systems,
including
• HIV patients:
• Cancer,
• diabetes,
• alcoholism
• substance abuse disorder
• prolonged use of steroid
Bacterial meningitis
• upper respiratory tract infection.
• bacteria invade the meninges directly.
• penetrating wound (surgical procedure)
Streptococcus pneumoniae
• Pneumococcal meningitis is the
most common form of meningitis.
• At particular risk are children under
age 2 and adults with a weakened
or depressed immune system.
streptococcus
pneumoniae
meningitis
Neisseria meningitidis
• Meningococcal
meningitis, is common
in children ages 2-18.
• Between 10 and 15
percent of cases are
fatal.
• with another 10-15
percent causing brain
damage and other
serious side effects.
Haemophilus influenzae
• Haemophilus meningitis was at one time
the most common form of bacterial
meningitis.
• Fortunately, the Haemophilus influenzae
b vaccine has greatly reduced the
number of cases.
Other forms…..
• Listeria monocytogenes meningitis, which can cross
the placental barrier and cause a baby to be stillborn
or die shortly after birth.
• Mycobacterium tuberculosis meningitis
• Escherichia coli
meningitis, which is
most common in elderly
adults and newborns
and may be transmitted
to a baby through the
birth canal,
How are these disorders
transmitted?
saliva,
•
• nasal discharge,
• feces,
• respiratory and throat secretions
(often spread through kissing,
coughing, or sharing drinking
glasses or cigarettes).
Brain abscess
• inflammation and collection of infected
material, within the Brain.
• Brain abscess is relatively rare, accounting for 1
in 10,000 hospital admissions.
• Single abscess occurs in 75% of cases, and the
remainder of cases involve multiple abscesses.
Causes:
spread of bacteria from a nearby infection.
• Otitis media.
• sinusitis
• an abscessed tooth.
Other sources of bacteria include:
• abdominal infection .
• Endocarditis.
• penetrating head wounds.
Empyema…………
 Collection of purulent material confined within
epidural or subdural space
Subdural empyema usually occurs in association
with:
• sinusitis.
• a severe ear infection,
• a head injury, or a blood infection.
Jaya suffers from
cerebral empyema, a
brain infection. She
has already undergone
a number of
operations and
continues to be
treated
symptoms
The most common symptoms are:
• headache
• altered mental status
• seizures
• Fever and stiff neck.
• vomiting, eye tremor, and uncoordinated movements.
 bacteria that cause brain abscesses can cause subdural
empyemas.
• streptococci,
• staphylococci,
• pseudomonas,
• bacteroides,
• enterobacter,
• klebsiella,
• H. influenzae, and E. coli.
Go with Areej…
Viral
infections of
the CNS
Viral Encephalitis
• Infection of brain parenchyma
• Presents of neurological abnormalities
distinguish it from meningitis
California encephalitis
• California encephalitis is an arbovirus-induced, arthropodborne encephalitis or encephalomeningitis.
• The virus is transmitted to humans through a mosquito bite.
arborviral encephalitis
• Five types of arborviral encephalitis are found in the
United States, including:
I. eastern equine encephalitis (EEE)
II. western equine encephalitis
III. St Louis encephalitis
IV. La Crosse encephalitis
V. West Nile encephalitis.
Eastern Equine Encephalitis
• This infection is caused by an arthropod-borne
alphavirus of the Togaviridae family
Herpes Simplex Encephalitis
• HSV remains dormant in the nervous system; rarely,
it presents as encephalitis.
• This encephalitis is a neurologic emergency and the
most important neurologic sequela of HSV.
•
•
•
•
The infection of neonates may occur:
intrauterine
during parturition
breast- feeding
• Prognosis is poor as
hydranencephaly
porencephalic cysts
• HSE in other age groups
causes
• necrotizing encephalitis in
the temporal and
orbitofrontal lobes of the
brain
Japanese encephalitis
• Japanese encephalitis is a neurologic infection closely related
to St. Louis encephalitis and West Nile encephalitis.
Viral meningitis
•
more than 85% of viral meningitis cases are caused by
nonpolio enteroviruses.
• Mumps, polio, and lymphocytic choriomeningitis viruses
(LCMVs) are now rare offenders in developed countries.
• However, polio remains a major cause of debilitating myelitis
in some regions of the world.
Enteroviruses
• Enteroviruses account for more than 85% of all
cases of viral meningitis
• include echoviruses, coxsackieviruses A and B,
polioviruses, and the numbered enteroviruses.
• majority of meningitis cases are caused by
serotypes of coxsackievirus and echovirus
Arboviruses
• 5% of cases
• Some of the important arboviruses include
the eastern and western equine encephalitis
viruses, from the Togavirus family; St. Louis
encephalitis’ West Nile, Japanese B, and
Murray Valley viruses, from the Flavivirus
family; and California group and Jamestown
Canyon viruses, from the Bunyaviridae
family.
• The most common clinical manifestation is
meningoencephalitis rather than pure meningitis
• Seizures are more common with arboviral meningitis
than with any other group of viruses.
Mumps
• A member of the Paramyxovirus family, mumps
virus was one of the first known causative
agents of meningitis and meningoencephalitis
Prion-Related Diseases
Kuru
Creutzfeldt-Jacob Diease.
KURU
• spongiform degeneration and
astrocytosis but no inflammatory
reaction
random laughing
headaches
trembling
joint pains
• The victims present with cerebellar ataxia
CREUTZFELDT - JACOB DISEASE
(CJD)
• The clinical manifestations include:
spasticity
ataxia
visual loss
CREUTZFELDT - JACOB DISEASE
(CJD)
•
•
•
•
involuntary movements
mental changes
speech problems
personality changes
cytomegalovirus
The congenital infection with this virus is
associated with:
• microcephaly
• hydrocephalus
• seizures
• optic atrophy
• deafness
Acquired infections have been associated
with:
• transverse myelitis
• brachial plexitis
• Guillain-Barré syndrome
• adult encephalitis
HIV
• several neurological manifestations
• At the stage of seroconversion
• the patient may experience, general signs and
symptoms of any viral illness
• mild meningitis
• Encephalitis
• myelitis
Go with Aya…
Fungal
infections of
the CNS
Fungal Meningitis
• Cryptococcosis - most common fungal
infection in CNS diagnosed in live
patients
– Cryptococcoma (mucinous pseudocyst) occurs almost entirely in the HIV population
– 3-10mm, most commonly in the basal
ganglia
Cryptococcosis
Fungal Meningitis
• Candidiasis - most common fungal
infection in CNS diagnosed in dead
patients
– rare in healthy individuals
• Aspergillosis
• Coccidiomycosis - normally causes
meningitis
• Aspergillosis – Abscess in the centrum ovale.
Note many satellite lesions common among
fungal infections.
Mucor – aggressive and locally
destructive infection.
Fungal Meningitis
• Insidious onset with progressive headache,
fever, lethargy, mild neck stiffness
• Complications: abcess, neuro deficits, ocular
nerve damage (especially cryptococcus)
• Usually pulmonary source, usually
immunocompromised
• Presents similar to TB meningitis
Protozoal
infections of
the CNS
Cysticercosis
• Most common parasitic infection in CNS
–Caused by larval stage of Taenia
solium- pork tapeworm
–Incubation period from months to
decades
• 83% of cases show symptoms within 7
years of exposure
Cysticercosis
• Common routes of infection
–Food (usually vegetables) or water
containing eggs from human feces
–Fecal - Oral autoinfection (poor
sanitation habits)
–Autoinfection from reverse peristalsis
Cysticercosis
• Location:
– meningeal 27-56%
– parenchymal 30-63%
– ventricular 12-18% (may cause hydrocephalus)
– mixed - 23%
• Clinical
– symptoms of increased intracranial pressure
Cysticercosis
• serology
–antibody titers significant if 1:64
in the serum and 1:8 in the CSF
• CT scan
–ring enhancing / calcified lesions,
multiple
Cystercercus cellulosae - (3-20 mm)
regular round thin walled cyst,
produces only mild inflammation
larva in cyst
Echinococcosis
• “Hydatid Cyst” - caused by ingestion of the
dog tapeworm
• Treatment - Surgical excision without cyst
rupture
– Cyst is full of worms
• Adjunctive treatment
– Albendazole
Echinococcus Cyst –
intraoperative
Toxoplasmosis
• CNS manifestations
–Mass lesion (most common)
–Meningoencephalitis
–Encephalopathy
Toxoplasmosis
• CT findings
– Mass lesion - comprises 70-80% of cerebral masses
in AIDS patients
– large low density area with mild to moderate
edema
– most commonly in the basal ganglia
– Often multiple
– Most patients with CT diagnosed toxoplasmosis
also have evidence of cerebral atrophy
Toxoplasmosis
Toxoplasmosis
Amoeba
• Naegleria fowleri "the brain-eating
amoeba")
• Invade the central nervous system via
the nose
• Cause primary amoebic
meningoencephalitis (PAM)
Amoeba
• PAM usually occurs in healthy children
or young adults with no prior history of
immune compromise who have
recently been exposed to bodies of
fresh water.
Symptoms
• Onset 1 to 14 days after exposure.
• The initial symptoms include:
– changes in taste and smell
– headache, fever, nausea, vomiting, and stiff neck.
• Secondary symptoms include:
– confusion, hallucinations, lack of attention, ataxia,
and seizures.
• The disease progresses rapidly 3 to 7 days, with death
occurring from 7 to 14 days