CNS Flashcards
Bacterial causes of meningitis
Infants (2-4 mnths)
S. agalactiae,
E. coli,
L. monocytogenes,
S. pneumoniae,
N. meningitides,
H. influenzae
Pressing a PIN on a baby will give a MEAN cry
Pneumonae, INfluenza
Monocytogenes,Ecoli, aglactia, Nisseria meningitis
Viral meningitis also reffered to as
Aspectic meningitis
Venezuelan Equine Encephalitis Virus- type
Alphavirus
Non-polio Enteroviruses common types
Enterovirus 71, Echovirus 18, Coxsackieviruses
Infants (2-4 mnths) Bacterial meningitis
S. agalactiae, E. coli, L. monocytogenes, S. pneumoniae, N. meningitides, H. influenzae*
Post splenectomy, complement deficiency
N. meningitides
This bacterial meningitis seen in
Infants -
– Adults >60y, alcoholics, cancer patients, renal transplant.
Listeria monocytogenes
Encephalitis CSF findings
Rabies virus dx
– Skin biopsy: Immunohistochemical staining - Rabies Ag
– Negri bodies: Intracytoplamsic inclusions in neurons
– Corneal smears – Rabies Ag
– Rabies virus neutralizing Ab – CSF or serum (unimmunized) Direct Ab Test
African Sleeping Sickness
Protazoa
African Trypanosomes
Vectors st. Louise vs. eastern equine
Schistosomiasis
Schistosoma species
Liver or bladder
brain or spinal cord vasculature
Haemophilus influenzae
• Clinical features
Slower onset (meningococcal meningitis), 3-4d – Follows: nasopharyngitis, sinusitis or otitis media – 1/3 survivors – neurologic sequelae
Predominant Demyelination imaging defect
JC virus
Most common cause (Chronic meningitis)
Mycobacterium tuberculosis
CSF findings in Western Equine Encephalitis Virus
CSF: pleocytosis (lymphocytic), normal-↑ protein, normal glucose
Primary amebic memeningoencephalitis (PAM)
Ameoba implicated
Naegleria fowleri
Underlying conditions related to Staphylococci
Diabetes mellitus
– Alcoholism
– Chronic renal failure (hemodialysis)
Dx of California Encephalitis Group
– IgM antibodies in CSF or serum
Listeria monocytogenes serotypes
Serotypes: 1/2b & 4b (80% cases)
St. Louis Encephalitis Virus distribution
Canada, US, Central & Southern America
GAE; skin or lung lesions
Amoeba implicated
Balamuthia mandrillaris
Eosinophilic Meningitis
Angiostrongylus cantonensis (rat lung worm)
Gnathostoma spinigerum
Clinical features of Streptococcus pneumoniae
Rapid 1-2 days (or gradual)
– Impaired consciousness common
Subependymal enhancement imaging defect
CMV ventriculitis
Meningitis
inflammation of meninges
Vector-borne viruses
Togaviridae
– Flaviviridae
– Bunyaviridae
– Reoviridae
Multifocal haemorrhagic infarctions & demyelinating lesions imaging defect
Varicella zoster virus vasculopathy
Basilar skull fracture + CSF leak
Puts you at risk for this bacterial meningitis
Streptococcus pneumoniae
Diagnosis neoforms
india ink (capsule)
CM1 defects (Hodgkin’s disease, steroid therapy), elderly
L. monocytogenes
Distribution of Venezuelan Equine Encephalitis Virus
Southern US, Central & S. America
Herpes simplex 1 & 2 connection to meningitis
Post neonatal
• Important: differentiate encephalitis from meningitis
– Most common: HSV 2 • primary to genital infection
• 36% women, 13% men
Bacterial meningitis Neonates (0-2 mnths)
Group B Streptococci (S. agalactiae), E. coli (other Gram –ve enterics), L. monocytogenes
Spirocheteal meningitis… whats the bacterial cause
Treponema pallidum
Slow onset (period of weeks) – ↓ Fever, lethargy – TB, Fungi & (Protozoa)
Chronic (RARE)
Brudzinski’s sign
Look up pic Flex knees and neck
Sx of California Encephalitis Group
Focalneurologicdisease
– Hemiparesis, aphasia, dysarthria, chorea
Biology behind prions
– Normal cellular glycoprotein: PrPc (↑ a helix, ↓ b helix)
– Infectious glycoprotein form: PrPsc (↓a helix, ↑ b helix)
Adults (Adolescents- >55y) Bacterial meningitis
N. meningitides, S. pneumoniae
Fontal, Temporal, Parietal, abscess
Predisposing/ bacteria
Trauma, Penetrating wound
S. aureus, Clostridia
Bacterial etiology of CSF shunts
– Staphylococci (epidermidis & aureus)
– Gram negative bacteria (E. coli, Klebsiella, Proteus & Pseudomonas)
– Streptococci
– Diphtheroids (Propionibacterium acnes)
– Anaerobes
– Mixed culture
Temporal lobe abcess what predisposes you, what bacteria
Otitis media, Mastoiditis
Streptococci, Bacteroides, Enterobacteriacea
HA-CNS infection: MRSA
- CSF shunts: S. epidermidis
- Mortality 14-77%
Staphylococci
Mycobacterium tuberculosis adult vs children
– Children (haematogenous disseminated tuberculosis) • Rapid
– Adults
• Indolent
Eastern Equine Encephalitis Virus distribution
US, Southern America, Caribbean
FOCAL CNS SYNDROMES
Brain Abscess
Subdural empyema
Epidural abscess
CSF findings in Colorado Tick Fever Virus
CSF: pleocytosis (mildly lymphocytic), normal-mildly↑ protein, normal glucose
Enterovirus Seasonality
Late Summer, fall
Yellow csf
Blood breakdown products Hyperbilirubinemia CSF protein ≥150mg/dL (1.5g/L), >100,000 RBC/mm3
St. Louis Encephalitis Virus- type
Flavivirus
Listeria monocytogenes
• Biology:
Gram +ve rod – Virulence:
• Internalin A & B • Listeriolysin O
PRIONS
Infectious proteins
– No Nucleic acid genome
– Resistant: formaldehyde (3.7%), dry heat, boiling, ethanol (50%) & ionizing radiation
– Sensitive: phenol (90%), household bleach, ether, NaOH (2 N), strong detergents (10% sodium dodecyl sulfate) & autoclaving (1 hour, 121oC)
Alcoholism, skull fractures, myeloma, splenectomy
S. pneumoniae
Clinical feature of Mycobacterium tuberculosis
Rupture in subarachnoid space
Distribution of Japanese Encephalitis Virus
Asia, Western Pacific, Australia
Dx of fungal brain abscess
CT scan
– Hypodense centre
– Peripheral uniform ring – Brain oedema
Fungal Meningitis lab values
Opening pressure Variable WBC count Variable Cell differential lymphocytes Protein 50-100mg/dL Glucose
Comparing meningitis lab values by organism
Japanese Encephalitis Virus type
Flaviviridae
>50 years Bacterial meningitis
S. pneumoniae, N. meningitides, L. monocytogenes, Aerobic Gram –ves
Eastern Equine Encephalitis Virus- type
Alphavirus
Granulomatous Amebic Encephalitis (GAE); skin or lung lesions; amebic keratitis
Ameoba implicated
Acanthamoeba species
Western Equine Encephalitis Virus- type
Alphavirus
Pathogenesis of CNS shunts
– Retrograde infection
– Skin
– Haematogenous seeding
– Colonization at surgery
Neisseria meningitidis
• Clinical features
Distinguishing feature
Quick onset
– Acute photophobia
– Skin petechiae → ecchymoses/diffuse petechial rash -
DIC
Neisseria meningitidis
• Prevention
2005, Quadrivalent: A, C, Y & W135
– Protection: ~3y
– No protection from carriage (MPSV4-menomune)
meningococcal conjugate vaccine seen as better
CSF findings in Measles
CSF: usually normal (↑Ig level)
Exposure to bats, other wild animals, dog bites, developing countries
Rabies
Brown CSF
Meningeal melanomatosis (Metastatic Melanoma)
characteristics of Enteroviruses
Picornaviridae
– Naked, icosahedral, small (25-30nm), ss +ve RNA
Echoviruses 30, 18, 16, 11, 9, 6 & 7
• Coxsackieviruses B1, B2, B3, B4 & A9 • Enteroviruses 71 & 70
Meningoencephalomyelitis
infection of meninges+ brain parenchyma+spinal cord
Colorado Tick Fever Virus dx
IgM by ELISA
Histoplasma capsulatum
• Geographic location
Ohio & Mississippi river valley, Central America
Distribution of Colorado Tick Fever Virus
WesternUS&Canada(Mountains)
NORMAL CSF VALUES
• WBC count: children & adults 0-5/mm3 (70% lymphocytes, 30% monocytes) neonates 32/mm3 • RBC count: None • [Glucose]: ratio to serum glucose ≥60% 40-70mg/dL not >300mg/dL • [Protein]: adults 18-58mg/dL (by 6-12 mnths old) newborn 150mg/dL
Brain abscess in the frontal lobe- what predisposes, and what organisms
Sinusitis, Dental abscess
Streptococci, Bacteroides, S. aureus, Haemophilus spp.
Abscess
localised infection in spinal cord or brain – Acute/Chronic Brain Abscess – Empyema – epidural or subepidural abscess