CNS INFECTION

S

Done by:

Areej Al Daur Aya Ferwana Bara’a Sheek Al Eed

TO:Dr.Ayham Abu Laila

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.

Transmission1. 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 beta-hemolysis 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, non-spore-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 rashDiffuse 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

symptomsThe 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, arthropod-

borne 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 encephalitisIII. St Louis encephalitisIV. La Crosse encephalitisV. West Nile encephalitis.

Eastern Equine Encephalitis

• This infection is caused by an arthropod-borne alphavirus of the Togaviridae family

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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.

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• 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

cytomegalovirusThe 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

H I V

• 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 inflammationlarva 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

• CNS manifestations–Mass lesion (most common)–Meningoencephalitis–Encephalopathy

Toxoplasmosis

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

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