Infections of the CNS (Bacterial, fungal, spirochetal, parasitic) and Sarcoidosis Flashcards
ways by which infections reach intracranial structures
hematogenous or by extension from cranial structures adjacent to the brain
Most common pathogenic organisms in adult
pneumococcus (Strep penumo) meningococcus (Neisseria meningitides) haemophilus influenza
Most common pathogenic organisms in neonate
E. coli Group B strep
Most common pathogenic organisms in infants and unvaccinated child
H. influenzae
organism after neurosurgery or insertion of a cranial appliance
staphylococcal
Most common bacteria acocunting for 75% of cases
H. influenzae N. meningitidis S. penumoniae 4th most common L. monocytogenes
implicated organisms after lumbar puncture, spinal anesthesia, shunting procs
Pseudomonas Enterobacteriaceae - Klebsiella, Proteus
Pneumococcal meningitis is usually suspected in
alcoholics
splenectomized patients
very elderly
recurrent Bact Men
Dermal sinus tracts
sickle cell anemia
basilar skull fracture
seizures are most often encountered in
H. influenza meningitis
Most significant factor in the pathogenesis of meningitis in newborns
maternal infection UTI, puerperal fever
T/F Children in whom meningitis is complicated by subdural effusions are no more likely to have residual neurologic signs and seizures than are those without effusions
True
T/F Bacteremia is a contraindication to lumbar puncture.
False
criteria that classifies patient at high risk of bact men
positive CSF gram stain CSF absolute neutrophil count at least 1000cells/mL CSf protein at least 80mg/dL. peripheral absolute neutrophil count of at least 10,000 cells/mL history of seizure or after the time of presentation
T/F In children, fever subsided more rapidly and the incidence of sensorineural deafness and other nemologic sequelae was reduced, particularly in those children with H. influenzae meningitis
True dexamethasonegiven as 0.15mg/kg qid for 4 days
prophylaxis for household members of patients with meningococcal meningitis
ciprofloxacin single dose rifampin 600mg q12 in adults and 10mg/kg q12 in children for 2 days
Osler Triad
pneumococcal meningitis
pneumonia
endocarditis
Deafness in meningitis is due to
suppurative cochlear destruction or aminoglycoside ototoxicity
Usually affects immunocompromised individuals and takes the form of brainstem encephalitis treatment
Listeria monocytogenes tx: ampicillin 2g IV q4 + gentamicin 5mg per kg IV in 3 divided doses
conditions with low CSF glucose
sarcoidosis of CNS fungal or TB Meningitis some cases of SAH meningeal carcinomatosis chemically induced inflammation from craniopharyngioma or teratoma meningeal gliomatosis
blood cultures are positive in ___% of cases with H.influenzae, meningococcal and pneumococcal meningitis
40-60%
two ways of differentiating CSF rhinorrhea from nasal secretions
nasal secretions have low glucose, CSffrhinorrhea approximates the one obtained via LP protein content high protein - which makes handkerchief stiff - nasal
Most specific and sensitive test for CSF otorrhea and rhinorrhea
finding of Beta2-transferrin (tau)
Recurrent oropharyngeal ulceration, uveitis, orchitis, meningitis
Behcet disease
recurrent episodes of fever and headache in addition to signs of meningeal irritation
Mollaret meningitis
recurrent meningitis associated with iridocyclitis and depigmentation of the hair and skin
Vogt-Koyanagi-Harada syndrome
Empiric Therapy for Bact Men 0-4 wk
cefotaxime plus ampicillin
Empiric therapy for Bact Men 4-12 wk
3rd gen cephalosphorin plus ampicillin plus dexa
Empiric Therapy for Bact Men 3mo - 18y
3rd gen cephalopshorin plus vancomycin (+/-ampicillin)
Empiric Therapy for Bact Men 18-50 y
3rd gen cephalopshorin plus vancomycin (+/- ampicillin)
Empiric Therapy for Bact Men Immunocompromised state
Vanco plus ampicillin and ceftazidime
Intravenous drug abusers have high rates of meningitis due to S. aureus and should receive cefepime or ceftazidime with vancomycin
Empiric Therapy for Bact Men Basilar skull fracture
3rd gen cephalosphorin + vanco
Empiric Therapy for Bact Men head trauma, neurosurgery CSF shunt
Vanco plus ceftazidime
If pseudomonas is considered after neurosurgery
antipseudomonal ceftazidime or cefapim may be revised once with sensitivity of organisms
Duration of therapy for most cases of Bact Meningitis
10-14 days
T/F The CSF glucose may remain low for many days after other signs of infection have subsided and should occasion concern only if bacteria are present in the fluid and the patient remains febrile and ill,
True
Recommended doses for Bact Men with normal renal and hepatic function amikacin ampicillin cefepime ceftazidime ceftriaxone meropenem oxacillin Pen G Vancomycin
Total daily dose/ dosing interval Amikacin 15mg/kg / 8 ampicillin 12 g / 4 cefepime 4-6g / 8 -12 ceftaz 6g / 8 ceftri 4g / 12-24 merop 3-6g / 8 oxacillin 9-12g / 4 pen G 24 million units / 4 vanco 2-4g / 6-12
The essential lesion in __________ consists of focal collections of epithelioid cells surrounded by a rim of lymphocytes; frequently there are giant cells, but caseation is lacking
sarcoidosis
Syphilis is caused by
Treponema pallidum
The treponeme usually invades the CNS within ___to ____months of inoculation with the organism
3 to 18
Neurosyphilis If the nervous system is not involved by the end of the second year, as shown by completely negative CSF, there is _________ chance that the patient will develop neurosyphilis as a result of the original infection; if the CSF is negative at the end of 5 years, the likelihood of developing neurosyphilis falls to ___ percent.
1 in 20 or 5percent after 2nd year 1 percent after 5 years
The initial event in the neurosyphilitic infection is ________ , which occurs in approximately ____ percent of all cases of syphilis.
meningitis 25%
True or False
All forms of neurosyphilis begin as meningitis and meningeal inflammation are the invariable accompaniment of all forms of neurosyphilis
True
The early clinical syndromes are _____________ and ___________; the late (secondary) ones are ___________ syphilis (1 to 12 years), followed even later by tertiary syphilis, general paresis, __________ , optic atrophy, or subacute myelitis.
aseptic meningitis and meningovascular syphilis
vascular
tabes dorsalis
True or False
Because asymptomatic neurosyphilis can be recognized only by the changes in the CSF, it is advisable that all patients with syphilis should have a spinal fluid examination.
True
The CSF has been a sensitive indicator of the presence of active neurosyphilitic infection. Enumerate CSF abnormalities
The CSF abnormalities consist of
(1) a pleocytosis of up to 100 cells/mm3, sometimes higher, mostly lymphocytes and a few plasma cells and other mononuclear cells (the counts may be lower in patients with AIDS and those with leukopenia);
(2) elevation of the total protein, from 40 to 200 mg/dL
(3) an increase in gamma globulin (IgG), usually with oligoclonal banding; and
(4) positive serologic tests.
True or False In neurosyphilis, The positive serologic tests are the last to revert to normal.
True
Most common form of neurosyphilis
Meningovascular syphilis common occurrence after 6-7 years but may occur as early as 9 months up to 10-12 yrs main manifestation of secondary syphilis
pathologic changes in meningovascular syphils
The pathologic changes in this disorder consist not only of meningeal infiltrates but also of inflammation and fibrosis of small arteries (Heubner arteritis), which lead to narrowing and, finally, occlusion
duration prior to occurrence of paretic neurosyphilis (general paresis, dementia paralytica)
15 to 20 yrs from original infection middle years (35 to 50) are the usual time of onset of paretic symptoms
clinical picture in the fully developed form of paretic neurosyphilis
progressive dementia, dysarthria, myoclonic jerks, action tremor, seizures, hyperreflexia, Babinski, Argyll Robertson pupils
Pathologic changes in Paretic Neurosyphilis
meningeal thickening
brain atrophy
ventricular enlargement granular ependymitis
special stains: spirochetes are visible in the cortex changes are more pronounced in the frontal and temporal lobes
ependymal surfaces of the ventricles are studded with granular elevations protruding between ependymal cells (granular ependymitis)
chief signs in Tabes Dorsalis
absent reflexes at knee and ankle
impaired vibratory and position sense
Romberg sign
major symptoms lightning pains ataxia urinary incontinence
T/F There is some ptosis and some degree of ophthalmoplegia in Tabes Dorsalis
True
Pathologic findings in Tabes Dorsalis
striking thinness and grayness of posterior roots, principally, lumbosacral
thinning of spinal cord
peripheral nerves E/N
T/F In Tabes Dorsalis, if the CSF is positive the patient should be treated with penicillin
True
T/F Tabes Dorsalis If there is no pleocytosis, the CSF protein content is normal,and there is no evidence of cardiovascular or other typesof syphilis, antisyphilitic treatment is STILL necessary.
False
Prognosis in Syphilitic Optic Atrophy
The prognosis is poor if vision in both eyes is greatly reduced. If only one eye is badly affected, sight in the other eye can usually be saved. In exceptional cases, visual impairment may progress, even after the CSF becomes negative.
Pathologic Changes in Syphilitic Optic Atrophy
perioptic meningitis with subpial gliosis and fibrosis replacing degenerated optic nerve fibers vascular lesions with infarction of central parts of the nerve
other types of Spinal Syphilis other than Tabes
Syphilitic Meningomyelitis (Erb spastic paraplegia)
Spinal meningovascular syphilis (form of anterior spinal artery syndrome) Syphilitic amyotrophy
Syphilitic amyotrophy with spastic-ataxic paraparesis
Treatment of Neurosyphilis
Pen G given IV 18-24 million units daily (3-4 million units q4) for 10-14 days alternative procaine penicillin probenecid ceftriaxone
Followup for neurosyphilis
reexamined every 3 - 6 months after tc CSF should retested after 6-mo interval If after 6 months, free of symptoms and CSF abnormalities have been reversed, no further treatment clinical exam at 12mo and another lumbar puncture If pleocytosis remains, another procedure should be repeated after 6 months At the end of 6 months, if there are still an increased number of cells and elevated protein, another full course of penicillin should be given
True/False Neurosyphilis A persistent weakly positive serologic (VDRL) test after the cells and protein levels have returned to normal is an indication for additional treatment
False
causative spirochete in Lyme Disease
Borrelia burgdorferi
Bannwarth syndrome
painful lymphocytic meningoradiculitis
striking feature of nearly all types of subacute and chronic infection of the meninges but most notably of tuberculous and syphilitic meningitis
Heubener arteritis subintimal fibrosis
The isolation of ______________ from the CSF should suggest the possibility of a brain abscess with an associated meningitis
anaerobic streptococci, Bacteroides, Actinomyces, or a mixture of organisms
True or False H. influenza meningitis usually follows upper respiratory and ear infections.
Trure
Meningitis in the presence of furunculosis or following a neurosurgical procedure directs attention to the possibility of a ______________
coagulase-positive staphylococcal infection
Ventricular shunts or drains inserted for the relief of hydrocephalus are particularly prone to infection with
coagulase-negative staphylococci and Propionibacterium acnes and diphteroids
conditions with substantial red cells in CSF
anthrax meningitis viral infections: Hantavirus, dengue virus, ebola virus some cases of amebic meningoencephalitis
bacteria reach the cochlea via the __________, which connects the subarachnoid space to the scala tympani
cochlear aqueduct
causative organism in Catscratch fever
Bartonella henselae
gram-negative bacillus
formerly Rochalimaea henselae
treatment for Catscratch Fever
firts line azithromycin or doxycycline
rifampicin in recalcitrant cases
causative organism in Whipple Disease
Tropheryma whipplei
diagnosis in Whipple Disease
PAS staining of an intestinal (jejunal) biopsy
supplemented by PCR testing of teh bowel tissue or biopsy material from brain or lymph node
treatment in Whipple Disease
course of induction by penicillin or ceftriaone for 2 weeks followed by TMP-SMX or doxycylcine continued for 1 year
treatment in subdural empyema
3rd gen cephalosphorin and metronidazole
accounts for the largest number of brain abscess in the modern era
purulent pulmonary infections and bacterial endocarditis
imaging findings in brain abscess
T1 - capsule nehances and the interior of abscess is hypotintense
T2 - surrounding edema is apparent, capsule is hypointense,
varaible diffusion reaction within the lesion
abscess capsule tends to be thinner on the side directed to the lateral ventricle
single most effective anti-Koch’s
isoniazid
adults 5mg/kg
children 10mg/kg
should be given with pyridoxine 50 mg daily
most common SE: neuropathy, hepatitis
treatment for TB Meningitis
Isoniazid 5mg/kg/day adults; 10mg/kg in children
Rifampicin 10mg/kg/d in adults; 15mg/kg in children
Ethambutol 15mg/kg/d
Pyrazinamide 20-35mg/kg
Ethionamide (added for resistant cases) 15-25 mg/kg
True or False
The essential lesion in sarcoidosis consists of focal collections of epithelioid cells surrounded by a rim of lymphocytes; frequently there are giant cells and there is caseation.
False
caseation is lacking
Main therapy for neurosarcoidosis
Corticosteroids
most common time of occurrence of meningovascular syphilis is
6-7 years after the original infection
early as 9 months or as late as 12 years
Termed secondary syphilis
Most common pathogenic organisms in unvaccinated children
Listeria monocytogenes
staphylococcus
Most common pathogenic organism in an infant and unvaccinated child
H. influenzae
From the earliest stages of meningitis, changes are also found in the small and medium-sized subarachnoid arteries. The endothelial cells swell, multiply, and crowd into the lumen.
This reaction appears within _____ to ____ hrs
48 to 72 hrs and increases in the days that follow
T/F
Bacterial Meningitis
The unusual prominence of the vascular changes may be related to their anatomic peculiarities. Thrombosis in infectious vasculitis is more frequently seen in the arteries.
False
p698
The adventitia of the subarachnoid vessels, both of arterioles and venules, is actually formed by an investment of the arachnoid membrane, which is invariably involved by the infectious process. Thus, in a sense, the outer vessel wall is affected from the beginning by the inflammatory process-an infectious vasculitis.
The much more frequentoccurrence of thrombosis in veins than in arteries is probably accounted for by the thinner walls and the slower current of blood flow in the former.
When macrophages are exposed to endotoxins, they synthesize and released cytokines, among which are
Interleukin-1
Tumor necrosis factor
Bacterial meningtis
the presence of _____ was the only independent predictor of later seizures
persistent neurologic deficit
______________ meningitis should be suspected when the evolution is extremely rapid (delirium and stupor may supervene in a matter of hours), 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, when there is circulatory shock, and especially during local outbreaks of meningitis.
Meningococcal
T/F
Meningococcal meningitis
Because a petechial rash accompanies approximately 50 percent of meningococcal infections, its presence dictates immediate institution of antibiotic therapy, even though a similar rash may be observed with certain viral (echovirus serotype 9 and some other enteroviruses), as well as S. aureus infections, and, rarely, with other bacterial meningitides.
True
p700
______ meningitis is ususally preceded by an infection in the lungs, ears, sinuses or heart valves.
Pneumococcal
_______ meningitis usually follows upper respiratory and ear infections in uninoculated child.
H. influenzae meningitis
Cultures of the spinal fluid, which prove to be positive ______ percent of cases of bacterial meningitis
70 to 90 %
Cranial nerve abnormalities are particularly frequent in ______ meningitis
pneumococcal
begins as unilateral or cervicla adenopathy occurring after a seemingly innocuous scratch from an infected cat
high fever, encephalopathy, seizures, status epilepticus
Catscratch Fever
pathogenesis of menigitis
the infection in both mother and infant is most often caused by
gram negative enterobacterua - E. coli
Group B strep
less often pseudomonas, listerua, S. aureus or epidermidis,
group A strep
middle-aged woman
fever, weight loss, anemia, steatorrhea, abdominal pain, distention, athralgia, lymphadenopathy, hyperpigmentation
neuro: slowly progressive memory loss/dementia, supranuclear opthalmoplegia, ataxia, seizures, myoclonus, nystagmus, highly characteristic oculomasticatory movement described as myorhythmia
diagnosis: PAS-staining of jejunal biopsy
Whipple Disease
source of infection cannot be ascertained in how many percent of brain abscess cases
20%
T/F Brain Abscess
Endocarditis from the implantation in the brain of streptococci of low virulence (alpha and gamma streptococci) or similar organisms on valves previously damaged by rheumatic fever seldom gives rise to a brain abscess.
True
p714
In contrast, organisms such as S. aureus and gram-negative bacteria have a propensity to cause abscesse
How many percent of patients with congenital heart disease are complicated by brain abscess?
5%
p715
T/F
The capsule of an abscess is uniform in thickness.
False
NOT uniform in thickness, frequently being thinner on its medial (paraventricular) aspect
-earlier restrricted diffusion on MRI
Brain Abscess
type of organisms tends to vary with source
accidental or surgical trauma
drug addicts who inject themselves
endocarditis
otitic infections
lung and paransal sinuses
accidental or surgical trauma - staphylococcal
drug addicts who inject themselves - staphylococcal
endocarditis - staphylococcla
otitic infections - enteric
lung and paransal sinuses - anaerobic streptococci
Cryptococcous is a common soil fungus found in
roosting sites of brids, especially pigeons
portal of entry for cryptococcus
respiratory,
less often skin and mucous membranes
T/F
Crypto CFS studies
The gluose is reduced in 3/4 of cases and may reach high levels.
Treu
p732
rate of positive tests for India ink CSF
75%
p732
CALAS - if negative, excludes cryptococcal meningitis in ____
90% reliability in AIDS patients and slightly less in others
p732
culture medium crypto
Saboraud’s agar
Treatment for Crypto Men in pts without AIDS
Amphotericin B 0.7-1.0mg/kg/d
addition of Flucytosine 100mg/kg/d results in fewer failures or relapses, more rapid sterilization of CSF ad less nephrotoxicity, permits reduction of Ampro dose 0.3-0.5mg/kg/f
success rate 75-85% in immunocompetentq
frequent complication for Ampho B
renal tubular acidosis
Toxoplasmosis which is caused by Toxoplasma gondii is an obligate intracellular parasite readily recognized in ____
Wright- or Giemsa-stained preparations
treatment for toxoplasmosis
Oral sulfadiazine 4g initially then 4-6 g daily and pyrimethamine 200mg intitialy then 50-100mg daily
leucovorin 15-20 mg daily to countreact antifolate effect of pyrimethamine
treatment for 6 weeks
fatal disease characterized by headache, seizures, coma, with diffuse cerebral edema, and only rarely, focal features such as aphasia, hemiplegia, ataxia, hemianopia
retinopathy of macular whitening, orang or white discoloration of vessel, intraretinal blot type hemorrhages
neurologic symptoms appear 2nd-3rd week
Malaria
treatment for Malaria
quinine
artesunate
once coma and convulsions supervene, 20-30% mortality
- begins with a chancre at the site of inoculation
- localized lymphadenopathy, posterior cervical
- parasitemia
- 2nd year of infection: meningoencephalitis
- chronic progressive syndrome consisting of reversal or disruption of circadian rhythm, vacant facial expression, ptosis, ophthalmoplegia, dysarthria, muteness, seizures, apathy, stupor, coma
Trypanosomiasis
Tx: melarsoprol
- infection from ingestion of uncooked infected pork
- early symptoms: gastroenteritis
- end of 1st week up to 4-6 weeks: fever, pain and tenderness of muscles, edema of conjunctivae, eyelids, fatigue
- headache, stiff neck, mild confusional state, delirium, coma, hemiplegia, aphasia
- heart is often involved
- seldom fatal
Trichinosis, Trichinellosis
tx: albendazole and steroids
- infection with pork tapeworm Taenia solium
- most often presents with seizures, although many are asymptomatic
- only when the cyst degenerates many months or years after that an inflammatory and granunlomatous reaction is elicited
- some, large subarachnoid or intraventricular cysts may obstruct CSF flow
- tx: albendazole
Cysticercosis
which of the ffg organisms has the tendency to localize to the ffg:
a. cerebral hemisphere
b. spinal cord
schistosoma hematobium, mansoni
a. cerebral hemisphere - japonicum
b. spinal cord - mansoni
T/F
lesions of Schistosoma in the brain calcify
False
lesions DO NOT cakcify
p739
- seen in travelers who have bathed in lakes or rivers where the snail hosts of the parasite are plentiful
- initial manifestation: local skin irritation at teh site of entry of the parasite (swimmer’s itch)
- large serpiginous urticarial rash on the trunk
- katayama fever
- headaches, convulsions, papilledema, simulates brain tumor
Schistosomiasis
Schistosoma infections mainly mansoni tend to localize in the spinal cord causing an acute or subacute myelitis that is concentrated in
conus medullaris
tx for schistosomiasis
praziquantel 20mg/kg tid
clinical features of nervous system involvement
biosy evidence of granulomas in other tissues: lymph nodes, lung, bones, uvea, skin, muscle
imaging: meningeal involvement, periventricular and white matter lesions, nodular or streak-like perivenular enhancement
Neurosarcoidosis
Most certain indication for steroid therapy in neurosarcoidosis
recent onset of neurologic symptoms indicating an active phase
or a disabling syndrome such as myelopathy
