WEEK 4: NEUROLOGY CNS INFECTIONS Flashcards
Etiology of CNS infections in neonates
E Coli, Group B Strep, Listeria, Strep agalactiae
Etiology if CNS infections in Children
N. meningitidis, H. influenza if unvaccinated, Strep pneumoniae
Etiology if CNS infections in young adult
N. Meningitidis, Strep pneumoniae
Etiology if CNS infections in older people
S. pneumoniae, Listeria monocytogenes
Etiology if CNS infections in immunosuppressed
M. Tuberculosis, Cryptococcus
Etiology if CNS infections if there is a shunt?
Staphylococcus
CSF Findings in Bacterial Meningitis?
Glucose Low, Protein Raised, Polymorphs raised
Route for brain abcess?
Hematogenous
local spread
Foreign body
Organisms for brain abcess? (4)
Anaerobic strep
Bacteroides
Staphylococci
Gram Negatives
Viral encephalitis agents?
Herpes Simplex, Arboviruses, Mumps, Measles
Viral meningitis agents?
enterovirus, mumps, herpes simplex, arboviruses
CSF findings in viral meningitis?
Glucose normal, protein raised, lymphocytes raised
most cases of meningitis result from what route?>
hematogenous dissemination
sources of infections in the CNS?
Contiguous spread: sinusitis, otitis media, birth defects
Hematogenous:
Direct inoculation: Trauma, neurosurgical complications
Reactivation of latent disease: TB, HSV
The clinical factors noted to be associated with adverse outcomes in bacterial meningitis included
Streptococcal pneumonia as the etiology, focal neurological deficits, and hyponatremia (serum sodium concentration <130mmol/L)
the most common acute neurological complications observed in bacterial meningitis
Subdural effusion, seizures and hydrocephalus
Distinction between the gray matter and white matter is gone. This means to say
Cerebral edema
Finger-like appearance of white matter
perilesional edema
most common agents of bacterial meningitis
most common are H.
influenzae, N. meningitidis, and S. pneumoniae,
associated condition in patients who had meningitis with HIB
hearing loss, seizures most often here too
Hib reamain sensitive to what drug?
third gen cephalosporins (
In neonatal period, GBS infection is
associated usually in
vaginally born child or in the birth canal.
Infection with Neisseria meningitidis most commonly
manifests as
asymptomatic colonization in the
nasopharynx of healthy adolescents and adults
is a gram-negative aerobic intracellular diplococcus that
colonizes humans only and that causes disease after
transmission to a susceptible individual
N. meningitidis
N meningitidis incubation period
Incubation period of 2-7 days
When the onset is attended by a
petechial or purpuric rash or by large
ecchymoses and lividity of the skin of
the lower parts of the body. what agent?
N. Meningitidis
Along the spectrum of presentations of meningococcal disease, the most common clinical syndromes are
meningitis and meningococcal septicemia
Tuberculous Meningitis and Tuberculoma TB of the central nervous system is seen most often in
young children but also develops in adults, especially those infected with HIV.
Tuberculous meningitis results from the hematogenous spread of
primary or post primary pulmonary TB or from the rupture of a sub-ependymal tubercle into the subarachnoid space.
evidence of old pulmonary lesions or a miliary pattern is found on chest radiography
Tuberculous Meningitis
Acute Bacterial meningitis vs TB meningitis in terms of exudation
In Acute Bacterial meningitis, exudates can be found in the subarachnoid space, specifically, in the convexity, causing subdural effusion, and communicating hydrocephalus due to obstruction on the absorption of the CSF in the subarachnoid space.
In TB meningitis, suppuration can be found in the base of the brain and cisterns, and it’s called Basal meningitis – has a ‘star-shaped’ appearance (
Gold standard in the dx of TB meningitis?
Culture of CSF is diagnostic in up to 80% of cases and remains the gold standard.
This is a preferred INITIAL diagnostic, but this is NOT the GOLD STANDARD in TB meningitis
Realtime automated nucleic acid amplification (the Xpert MTB/RIF assay)
pathognomonic of patients with chronic meningitis or TB meningitis in imaging?
Imaging studies (CT and MRI) may show hydrocephalus and abnormal enhancement of basal cisterns or ependyma.
3 pathognomonic findings in the enhance CT or CT with contrast of patients with TB meningitis, and these are:
Presence of basal enhancement
Hydrocephalus
Presence of infarct
There is rapid killing of TB bacilli. what phase in the the TB regimen?
Initial phase
Fewer drugs are necessary (usually 2), but longer time
• These drugs eliminate the remaining bacilli. what phase in the TB regimen?
Continuation phase
Symptoms of Bacterial Meningitis?
Fever, Headache, Neck Stiffness, changes in mental funciton
Rashes typical of patients with meningococcemia?
Violaceous Purpurous Rashes
Causative agent that presents with General paresis and tabes dorsalis
Neurosyphilis (Treponema pallidum)
Neurosyphilis is more frequently symptomatic in patients who are co-infected with HIV, particularly in the setting of a low CD4+ T lymphocyte count T or F?
T
Major clinical categories of symptomatic neurosyphilis include
meningeal, meningovascular, and parenchymatous syphilis
Meaning to say, it can be presenting with meningitis, infarction, or encephalitis
These symptoms reflect widespread late parenchymal damage
“PARESIS”
> Personality
o Affect
o Reflexes (Hyperactive)
o Eye (ex: Argyll Robertson pupils)
o Sensorium (illusion, delusion, hallucinations)
o Intellect (a decrease in recent memory and in the capacity for orientation, calculations, judgment and insight)
o Speech
presents as symptoms and signs of demyelination of the posterior columns, dorsal roots and dorsal root ganglia
Tabes Dorsalis
Tabes Dorsalis Symptoms?
Symptoms include: o Ataxic Wide-based gait and foot drop o Paresthesia o Bladder Disturbances o Impotence o Areflexia o Loss of positional, deep-pain and temperature sensations
Botulinum toxin is produced by 4 recognized species of clostridia:
o Clostridium Botulinum
o Clostridium Argentinense
o Clostridium Baratii
o Clostridium Butyricum
T or F. All species of clostirdia are anaerobic gram-positive organisms that form subterminal spores; C. Botulinum and C. Argentinense spores have been recovered from the environment. The spores survive environmental conditions and ordinary cooking procedures
T
Toxin production however requires a rare confluence of product storage conditions:
o An aerobic environment
o pH of > 4.6
o Low salt and sugar concentration
o Temp of > 4o C
The distinctive clinical syndrome of botulism consists of
symmetrical cranial-nerve palsies, followed by Bilateral descending flaccid paralysis that may progress to Respiratory failure and death.
Incubation period from ingestion of contaminated food to onset of symptoms in food-borne botulism is
usually 8-36hrs but can be as long as 10 days and is dose dependent.
Incubation periods of _____ days have been documented in wound botulism associated with accidental injury.
4 - 17 days
It is most commonly caused by mumps virus, polio virus and the non-polio enterovirus. Acute encephalitis is much less common, with very limited available data on long-term prognosis.
Herpes Simplex Encephalitis
drug for Herpes Simplex Encephalitis?
Acyclovir
Dengue viruses 1–4 (DENV 1–4) principal reservoir?
Non Human Primates and Mosquitos ( Aedes Aegypti, A. albopictus
Japanese Encephalitis Virus reservoir?
Principal reservoir: Ardeid wading birds (in particular herons), horses, pigs o Mosquitoes (Culex spp., in particular C. tritaeniorhynchus)
Zika Virus carrier?
Ae. Aegypti & Ae. Albopictus (also carries Dengue Virus)
transfusion, and in utero.
If a pregnant woman is infected with Zika virus, the baby may have congenital malformation, the most common of which is
Microcephaly
What does the zika virus infects that impairs mitosis and survival?
NES (neuroepithelial stem cells) and radial glial cells
Poliomyelitis is acquired via what route?
oral fecal route usually from contaminated food or water.
what is AFP surveillance in Polio
o A-cute
o F-laccid
o P-aralysis
All children < 15 years of age presenting with ACUTE, FLACCID PARALYSIS of any cause should be reported to the DOH, and stool is collected. This is AFP Surveillance so that we can always stop the transmission of polio virus.
is polio an anterior or posterior horn cell disease?
anterior horn cell
a small RNA virus that is a member of the enterovirus group of the picornavirus family.
poliomyelitis agent (polio virus)
The main reservoir of infection of polio is the
human intestinal tract
normal opening pressure in CSF?
<180 mm H20
WBC count in CSF normal?
0-5;
increased in Bacterial Meningitis, Fungal and TB Meningitis.
Sa Viral Normal to Slight elev
WBC differential predominance in bacterial, viral etc?
Bacterial - PMN
Viral, Fungal and TB: Lymphocytes
normal protein in CSF? bacterial? viral?>
15 to 50
Bacterial - INCCC
Viral Fungal
TB - slightly increased
Glucose in CSF normally?
45 - 100 (2/3 of serum)
decreased in bacterial and TB
normal in fungal and viral
Rabies virus is a member of the family
Rhabdoviridae
2 genera in family Rhabdoviridae?
Lyssavirus and Vesiculovirus
a lyssavirus that infects a broad range of
animals and causes serious neurologic disease when
transmitted to humans.
Rabies
Rabies incubation period
20-90 days
Clinical Stages of Rabies?
Incubation Period Prodrome Encephalitic Paralytic Coma, Death
member of the Togaviridae family and the
only member of the genus Rubivirus. This single-stranded
RNA enveloped virus measures 50–70 nm in diameter.
Rubella Virus
Its core protein is surrounded by a single-layer lipoprotein
envelope with spike-like projections containing two
glycoproteins:
E1 and E2
only known reservoir of rubella virus?
Human
The most serious consequence of rubella virus infection can
develop when
a woman becomes infected during pregnancy,
particularly during the first trimester.
Congenital rubella syndrome
Microcephaly,
cataract, and cardiac anomalies
caused by persistent measles virus infection that would lead to complications
MIBE (measles inclusion body encephalitis)
SSPE (subacute sclerosing panencephalitis)
a slowly progressive disease characterized by seizures and progressive deterioration of cognitive and motor functions, with death occurring 5–15 years after measles virus infection.
SSPE
is often transmitted sexually, and asymptomatic carriage in semen or cervical secretions is common.
CMV
HSV 1/ HSV 2 causes focal encephalitis common in older population;
HSV 1/ HSV 2 is more common in the neonatal period
HSV 1
HSV 2
The clinical hallmark of HSV encephalitis has been
the acute onset of fever and focal neurologic symptoms and signs, especially in the temporal lobe.
Coma is a characteristic and ominous feature of
falciparum malaria
manifests as diffuse symmetric encephalopathy; focal neurologic signs are unusual. Although some passive resistance to head flexion may be detected, signs of meningeal irritation are absent
Cerebral Malaria
Species of the genus plasmodium
P. falciparum
o P. vivax
o 2 morphologically identical sympatric species of P. ovale
(as suggested by recent evidence)
o P. malariae
o P. knowlesi – Southeast Asia, monkey amalria
All deaths from malaria are coming from what speci?
P. Falciparum
Schistosomiasis is caused by?
S. Mansoni; S. haematobium, S. Japonicum
If shcistosomiasis is caught early, what drug is adequate?
praziquantel
what is the parasitological diagnosis of S. mansoni and japonicum?
Stool Kato Katz
what is the parasitological diagnosis of S. haematobium?
Urine Filtration
Concern is heightened by history of headache and neurologic symptoms in a patient with underlying immunosuppressive disorders such as advanced HIV infection or solid organ transplantation
Cryptococcal infections
dimorphic, existing in the asexual yeast form characterized by oval to spherical cells with a polysaccharide capsule, and in the sexual or prefect state characterized by the presence of basidiospores
Cryptococcus neoformans
Colonies of Cryptococcus
white to cream in color, but characteristic dark brown colonies are formed when grown on birdseed agar
Meningeal cryptococcosis can lead to sudden catastrophic
Vision Loss
Prion category of infections includes a quartet of human diseases
Creutzfeldt-Jakob disease (and a variant that infects cows and may be rarely transmitted to humans), the Gerstmann-Sträussler-Scheinker syndrome, kuru, and fatal familial insomnia.
Transmissible pathogen is a proteinaceous infectious particle that is devoid of nucleic acid, resists the action of enzymes that destroy RNA and DNA, fails to produce an immune response, and electron microscopically does not have the structure of a virus.
Prion
Meningeal Triad
o Fever
o Headache
o Vomiting
Gold standard in diagnosing CNS infection
CSF analysis
Lumbar puncture is contraindicated in the following situations:
o Presence of signs of increased ICP
o Presence of infection at the site for puncture
o Presence of focal neurologic findings* ( with caution for signs of inc. ICP)
Site of lumbar puncture in adults
L3 to L4
When to do CT scan with contrast?
Hydrocephalus and pleural effusion
