CNS infections Flashcards
congenital infections of the fetal and neonatal brain are commonly referred to as the group of ____. they often result in significant brain injury, and congenital brain malformations are more frequently seen with earlier onset of infections in utero due to disruption of the normal CNS development during fetal gestation
TORCH
TORCH infection includes
toxoplasmosis, other infections (syphilis, varicella zoster, lymphocytic choriomeningitis), rubella, cytomegalovirus, herpes simplex
another important virus now recognized prenatal CNS infection aside from TORCH
Zika virus
member of the herpes family of viruses andis the most common congenital CNS infection. In utero transmission occurs hematogeneously during viral reactivation in seropositive pregnant women or primary infection during pregnancy
Cytomegalovirus
30 to 50% of CMV infection is from
transplacental transmission
symptomatic neonates with this viral infection may have hepatosplenomegaly, jaundice, cerebral involvement (psychomotor retardation), chorioretinitis and deafness. virus also preferentially multiplies along the ependyma and germinal matrix resulting in a periventricular pattern of injury and development of dystrophic calcifications
CMV
calcifications of the basal ganglia or cortex are not seen in CMV but are noted in
congenital toxoplasmosis
this viral infection cause loss of periventricular white matter which then forms custs, ventriculomegaly and microcephaly. infection during the first trimester can result in neuronal migration anomalies such as heterotopia and lissencephaly and disorders of cortical organization including schizencephaly, polymicrogyria and cortical dysplasia. delayed myelination and cerebellar hypoplasia are also common findings
CMV
caused by parasite protozoan, results from hematogeneous spread after pregnant woman eats undercooked meat or is exposed to cat feces, both of which can harbor viable oocysts
toxoplasmosis
toxoplasmosis causes
necrotizing encephalitis of fetal brain, during first 2 trimester of gestation, but typically no developmental malformations. microcephaly, chorioretinitis and mental retardation
imaging findings of toxoplasmosis
atrophy, dilated ventricles, dystrophic calcifications scattered in the white matter, basal ganglia and cortex
a rodent-borne arena virus which can closely mimic toxoplasmosis and CMV on neonatal neuroimaging. onset of infection in first trimester often leads to spontaneous abortion. presents with chorioretinitis, either hydrocephalus or microcephaly but with results of accompanying microbiologic and serologic studies being negative for more common congenital pathogens. cerebral calcifications can be periventricular in location and/or distributed between white matter, deep gray nuclei and cortex
lymphocytic choriomeningitis virus (LCMV)
encephalitis in neonates often results from infection during descent through the birth canal when the mother has genital infection with _____
herpes virus type 2
if patient survives with neonatal HSV 2, the following manifestations may be seen
varying degrees of microcephaly, mental retardation, microphthalamia, enlarged ventricles, intracranial calcifications and multicystic encephalomalacia
early in the course of HSV encephalitis, US will show
increased parenchymal echogenicity
CT findings in HSV encephalitis
diffuse brain swelling or bilateral patchy areas of hypodensity in the cerebral white matter and cortex, with relative sparing of the basal ganglia, thalami and posterior fossa structures. these hypodense lesions correspond to areas of T2 hyperintensity on MRI and progress to areas of necrosis and cystic encephalomalacia
true or false: opportunistic infections and neoplasms seen in adults with AIDS are not usually seen in young children
true
affected infants of this viral infection are more susceptible to respiratory infections and diarrhea that can present with encephalopathy, developmental delay and failure to thrive. it primarily affects white matter and basal ganglia, especially globi pallidi, best seen with CT, while MRI alows better demonstration of T2 hyperintense white matter abnormalities. in some cases, there is associated vasculopathy with fusiform dilatation and ectasia of the intracranial arteries
congenital HIV
viral infection that cause diffuse meningoencephalitis, brain infarction and necrosis. infants who survive severe infection present with microcephaly, ocular abnormalities and deafness. CT reveals dystropic calcifications in the deep gray nuclei and cortex, whereas MRI better demonstrates infarcts, white matter loss and occassionally delayed myelination
rubella
is a flavivirus which originated in Africa and southeast asia and is transmitted by several species of mosquitoes, especially Aedes aegypti. presents with congenital microcephaly and CNS malformations. unlike CMV, it does not have predilection for the germinal matrix
Zika virus
this virus impairs cell proliferation and promotes apoptosis and cell death. CT best demonstrates both punctate or linear calcifications which localize predominantly to the gray-white junction in the frontal and parietal lobes, and to a lesser extend along the deep gray nuclei and periventricular zone. MRI may show brain volume loss, ventriculomegaly, abnormal myelination, callosal dysgenesis, heterotopia, lissencephaly and polymicrogyria
Zika virus
these extra-axial collections are generally confined by dural attachments which prevent rapid expansion of abscesses and account for their lentiform shape and convex inner margins
epidural
these extra-axial collections can spread more easily thoough the subdural space and be more acutely life threatening, thus requiring rapid neurosurgical intervention
subdural empyemas
frontal sinusitis in children can be complicated by osteomyelitis, with subperiosteal, epidural or subdural abscesses. this is referred to as
pott puffy tumor
how to differentiate subdural empyemas from subdural effusions in MRI
subdural empyemas can be hyperintense on DWI allowing them to be distinguished from subdural efusions which can also enhance mildly
Mild, smooth dural or meningeal enhancement may be seen after craniotomies and in patients with ventriculostomy catheters, especially with MRI. this enhancement can persist for years and should be considered benign in this clinical setting. it is most likely reflects a _____ from perioperative hemorrhage and/or dural scarring
chemical meningitis
bacterial meningitis is caused by ___ in children, ____ in teens and young adults, _____ in older adults, _____ in neonates, _____ in premature newborns
Haemophilus influenzae- children
Neisseria meningitidis- teens and young adults
Streptococcus pneumonia- older adults
Group B streptococcus and E.coli meningitis -neonates
Citrobacter meningitis -premature newborns
inflammatory exudate caused by meningitis appears ___ on CT and FLAIR
hyperdense on CT and hyperintense on FLAIR
most common form of CNS tuberculosis
tuberculous meningitis
true or false: in TB meningitis, chest radiograph may be normal in 40 to 75% of cases
true
CSF findings in TB meningitis
pleocytosis, elevated protein, markedly reduced glucose levels
this type of meningitis will show thickened and enhancing meninges, especially along the basal cisterns, corresponding to a thick gelatinous inflammatory exudate
TB meningitis
meningeal enhancement in this type of meningitis is usually more peripherally distributed and less thick when compared to TB and other granulomatous meningitides
bacterial meningitis
most common complication of TB meningitis
infarct due to extension of inflammatory exudates in the basal cisterns, along the perivascular spaces causing an arteritis with irregular narrowing or occlusion of vessels, most commonly along the distribution of lenticuolstriates and thalamoperforating arteries in the deep gray nuclei
this type of meningitis also cause thick meningeal enhancement of the basal cisterns just like in TB, but with varying degrees of enhancement, based on the immunocompetence of the patient. extension of this type of meningitis to the brain also occurs less often than with TB or pyogenic meningitis
Fungal meningitis; except in aspergillosis and mucormycosis wherein brain extension is also common
occurs when the larvae of the pork tapeworm Taenia solium infest the subarachnoid space, especially the basal cisterns. the larval cysts may grow in grape-like clusters or conform to the shape of the involved cisterns
Meningobasal or racemose cysticercosis
common complications of meningobasal or racemose cysticercosis
cysts may obstruct the foramen of Monro, sylvian aqueduct, third and fourth ventricles, resulting in hydrocephalus. death may result from acute hydrocephalus and ventriculitis
viral meningitis are more commonly caused by what agents
enteroviruses, mumps, Epstein-Barr virus, togavirus, lymphocytic choriomeningitis virus, HIV
true or false: in viral meningitis, patients do not require tx and neurologic deficits are uncommon unless infection progresses to encephalitis. neuroimaging are typically normal but mild meningeal enhancement may occur
true
subdural effusion are common with what type of viral meningitis
H. influenzae
noninfectious granulomatous disease of unclear etiology which involves the CNS in up to 14% of patients at autopsy. helpful for diagnosis involve increased seruma and CSF levels of angiotensin-converting enzyme
sarcoidosis
this type of meningitis primarily affects the leptomeninges, and abnormal leptomeningeal and dural enhancement can be seen with both CT and MRI. thickening and enhancement of the cranial nerves and the hypothalamic-pituitary axis are not uncommon. calcifications are not typical
sarcoidosis
most common organisms that cayse pyogenic cerebritis and abscess
anaerobic
infection with this bacteria is common after surgery or trauma
Staphylococcys aureus
with pyogenic cerebritis or abscess resulting from hematogeneous spread, this lobes are most commonly involved, with the abscess centered at the gray-white junction
frontal and parietal lobes (MCA distribution)
this lobe is most commonly affected with spread of sinus infection
frontal lobes
usually involved in patients with spread from otomastoiditis
temporal lobes or cerebellum
true or false: in pyogenic cerebritis or abscess, fever is absent more than 50% if the time. Meningeal signs are present in only 30% of patients
true
Solitary abscess is usually treated with
stereotactic needle aspiration followed by antibiotic therapy, in an eloquent area of the brain. if there is significant mass effect or the lesion is in a relatively “safe” area, a formal drainage or resection is performed
four pathologically described stages of cerebritis and brain abscess
early cerebritis, late cerebritis, early capsule and late capsule
in this stage or cerebritis and abscess, the infected portion of the brain is swollen and edematous. Areas of early necrosis are filled with inflammatory polymorphonuclear leukocytes, lymphocytes and plasma cells. organisms are present in both the center and the periphery of the lesion which has ill-defined margins. CT scan may be normal or show an area of low density. On MRI, lesion is hypointense or isointense on T1 and hyperintense on T2 and FLAIR images. There may be mild mass effect and patchy areas of enhancement within the lesion on both CT and MRI. a ring of enhancement is not present on this stage
early cerebritis
stage of cerebritis and abscess that occurs within 1 or 2 weeks of infection. central necrosis progresses and begins to coalesce, with fewer organisms detected pathologically. there is vascular proliferation at the periphery of the lesion, with more inflammatory cells and early granulation tissue, which represent the brain’s effort to contain the infection. centrally, there is increased hypodensity on CT, hypointensity on T1 and hyperintensity on T2 and FLAIR sequences. DWI may show some increased signal intensity within the center of the lesion. there is worsening vasogenic edema present outside the enhancing rim and overall increased mass effect. No discrete capsule is evident
Late cerebritis
stage of cerebritis and abscess that occurs within 2 weeks, the infection is wall off as capsule of collagena dn reticulin forms along the inflammatory vascular margin of the infection. Macrophages, phagocytes and neutrophils are also present in the capsule. CT and MR shows a well-defined, usually smooth and thin, rim of enhancement
Early capsule stage
stage of cerebritis or abscess wherein the rim of enhancement becomes even better defined and thicken, reflecting more complete collagen in the abscess wall. Multiloculation is common. CT or MR scans reveal enhancement of the ependymal lining of the ventricles and altered density and signal intensity of the intraventricular CSF
Late capsule stage
this clinical features of prominent central hyperintensity on DWI, smooth complete enhancing rim, significant surrounding vasogenic edema, and T2 hypointensity of the capsule should strongly suggest a
brain abscess
an incomplete ring of enhancement and accompanying characteristic white matter lesions favor this diagnosis rather than abscess
demyelinating lesions
MRS findings in confirming cerebral abscess
elevated lactate and amino acids in the center of the lesion
presents with a thicker, more irregular ring of enhancement that persists within an area of infarction should suggest the diagnosis of
septic embolus
septic emboli may lead to _____, which can result in intraparenchymal or subarachnoid hemorrhage
mycotic aneurysm formation
focal mycobacterial infection of the brain occurs in 2 forms, namely
tuberculoma and abscess
it is a granuloma with central caseous necrosis
tuberculoma
it has characteristic similar to those of a pyogenic abscess but usually develops in patients with impaired T-cell immunity
tuberculous abscess
true or false: most tuberculomas are not associated with TB meningitis
true
true or false: in tuberculomas, up to 50% of patients have abnormal chest radiograph
true
most tuberculomas in adults are located
supratentorially, involving the frontal or parietal lobes
60% of tuberculomas in children are in the
posterior fossa, usually the cerebellum
in tuberculoma, surrounding edema is usually ____, and the center of tuberculoma is usually _____ than the center of bacterial abscess due to caseous necrosis
relatively mild edema, with denser core
this is a rare complication of TB seen primarily in immunocompromised patients. Impaired T-cell function prevents the normal host response required for tuberculoma formation with caseous necrosis. lesions are often large and multiloculated, in distinction to tuberculomas
tuberculous abscess
true or false: fungal CNS involvement is a manifestation of disseminated infection, with hematogeneous spread, usually from pulmonary disease
true
most frequent presentation of blastomycosis
meningitis
frequent manifestation of coccidioidomycosis
parenchymal abscesses and granuloma
true or false: most fungal granulomas are small and show solid or thick rim enhancement
true
most common opportunistic fungal CNS infections are
cryptococcosis, aspergillosis and mucormycosis and candidiasis
CNS aspergillosis may arise from
infected paranasal sinuses, leading to meningitis or meningoencephalitis
almost all patients with CNS mucormycosis are
diabetic or immunocompromised
most frequently reported CNS fungal infection. it preferentially involves immunosuppresed patients, and especially those with AIDS, but cases also seen in immunocompetent individuals
Cryptococcosis
specific cryptococcus that preferentially involves the immunosuppresed patients, usually from bird excreta
Cryptococcus neoformans
specific cryptococcus that is found in patients with normal immune function, usually from tropical and subtropical trees
Cryptococcus gattii
usual manifestation of cryptococcal CNS infection
meningitis
these are small, usually multiple, solid-enhancing peripherally located parenchymal nodules with vasogenic edema in CNS cryptococcosis
Cryptococcomas
these are cysts found in immunocompromised, especially AIDS patients afflicted by cryptococcus. brieflym they cause dilatation of the perivascular spaces filled with the organism and mucinous material. they appear as rounded, smoothly marginated lesions in the basal ganglia that are nearly isodense and isointense to CSF. there is minimal, if any, peripheral edema or enhancement
cryptococcal gelatinous pseudocysts
most common parasitis CNS infections
cysticercosis, echinococcosis, toxoplasmosis and amoebiasis
most common causes of mortality from parasitic infetions
malaria and amoebiasis
caused by the larvae of the pork tapeworm Taenia solium. Transmission occurs via fecal-oral route. it is the most common cause of seizures in Latin america
Neurocysticercosis
imaging findings in the earliest stage of infestation of cysticercosis
minimal, if any, edema, and/or nodular enhancement
in this stage of neurocysticercosis, viable parasitic cysts appear as small (usually 1 cm or less) solitary or multiple rounded lesions that are hypodense on CT and isointense to CSF on MRI. lesions are usually distributed peripherally near the gray-white junction or in the gray matter. a small marginal nodule representing the scolex is sometimes seen. there is usually no enhancement or edema
vesicular stage
this stage of neurocysticercosis ensues when the cyst dies and its fluid leaks into the surrounding brain inciting inflammation. this produce clinical symptoms of acute encephalitis, which may be severe depending on the number of lesions. imaging studies show ring-enhancing lesions with surrounding vasogenic edema
colloid stage
in this stage or neurocysticercosis, the dead cyst further degenerates in the nodular granula stage, becomes smaller and causes less edema, but shows increasing nodular or irregular peripheral enhancement
nodular granular stage
this is the last stage of neurocysticercosis wherein a dense residual calcification is left with no remaining edema or enhancement. Plain CT scan excels at detecting these small, peripherally distributed calcifications. With MRI, calcifications are best seen on T2* weighted GRE sequence
Nodular calcified stage
spinal cysticercosis is usually
intradural but can either be intra- or extramedullary
also known as hydatid disease, occurs in South America, Africa, Central Europe, Middle East and rarely in the southwestern US. etiologic agent is the dog tapeworm
Echnococcosis
CNS echinococcosis presents as cysts that are usually solitary, unilocular or multilocular, large, round and smoothly marginted, often located in the ____ and may rarely have mural calcifications. There is usually no surrounding edema or abnormal contrast enhancment, unless the cyst has ruptured, leading to an inflammatory reaction and more acute presentation
supratentorial
most often implicated organisms in Amebic meningoencephalitis
Entamoeba histolytica, Acanthamoeba, Naegleria fowleri
this pathogen can enter the nasal cavity of patients swimming in infested freshwater ponds and extend through the olfactory apparatus and cribriform plate into the brain. Severe meningoencephalitis results and is usually fatal
N. fowleri
early infection findings in amebic meningoencephalitis
there may be meningeal and/or gray matter enhancement. associated vasculitis and cerebral infartion can occassionally be observed
later findings in amebic meningoencephalitis
diffuse cerebral edema and hemorrhage may occur
true or false: amebic abscesses are more common in debilitated or immunosuppresed patients
true
caused by sexually transmitted spirochete treponema pallidum. develops in 5% of patients who are not treated for the primary infection. involvement of the CNS usually occurs in the secondary or tertially stages
Neurosyphilis
true or false: patients with neurosyphillis are commonly asymptomatic. neuroimaging can therefore be normal or demonstrate cerebral volume loss and nonspecific T2-hyperintense white matter lesions on MRI
true
small enhancing nodules at the surface of the brain with adjacent meningeal enhancement, related to neurosyphilis
gummas or syphilitic granulomas
this form of neurosyphilis presents as an acute stroke syndrome or subacute illness with a variety of symptoms. pathologically, there is thickening of the meninges and a medium-to-large vessel arteritis. May show multiple segmental constrictions and/or occlusions of large and medium arteries including the distal internal carotid, anterior cerebral, middle cerebral, posterior cerebral and distal basilar arteries in MRA or CTA
meningovascular syphilis
a multisystem spirochete infection, which is most commonly caused by Borrelia burgdorferi in North America. Spreads to humans worldwide via ticks from deer, mice, raccoons and birds. Neurologic abnormalities are found in 10 to 15% of patients, presenting with peripheral and cranial neuropathies, radiculopathies, myelopathies, encephalitis, meningitis, pain syndromes and cognitive and movement disorders
Lyme disease
Commonly affected cranial nerves in lyme disease
CN III to VIII, more commonly in CNS VII
cranial neuritis in Lyme disease presents as
thick, enhancing cranial nerves
parenchymal CNS Lyme disease presents as
multiple, small white matter lesions, similar to that seen with MS, often enhance with nodular or ring-like pattern
occurs in immunocompetent patients of all ages and is the most common cause of sporadic encephalitis
Herpes simplex virus type 1
herpes infection may cause what manifestations in CNS involvement
encephalitis or cranial neuritis. it is commonly secondary to reactivation of latent HSV1, especially within the trigeminal ganglion
these CNS viral infection may show normal or poorly defined hypodense regions in one or both temporal lobes in CT. symmetric or asymmetric gyral pattern of hyperintensity on T2 and FLAIR sequences. Frontal lobes and cingulate gyrus in particular may also be involved
Herpes simplex
True or false: Varicella zoster rarely cause encephalitis that can be similar to the caused by herpes simplex
true
Unlike HSV, VZV has less predilection for temporal lobe, it is distributed
more multifocal distribution
it is the usual cause of herpes zoster ophthalmicus which can be complicated by ipsilateral cerebral angiitis causing cerebral infarction and contralateral hemiparesis
VZV
VZV may infect any of the cranial nerves, but these CNs are most commonly involved and result in herpes zoster oticus (Ramsay Hunt syndrome)
CNs VII and VIII
In this syndrome caused by VZV, there is ear pain and facial paralysis accompanied by a vesicular eruption about the ear. CT scans are usually normal but MRI of the internal auditory canals should reveal abnormal enhancement of one or both of these cranial nerves
Herpes zoster oticus or Ramsay Hunt Syndrome
unusual cause of encephalitis except when encountered in congenital form or in immunosuppressed adult patients, especially those with AIDS
cytomegalovirus
very rare condition caused by chronic infection by a variant of the measles virus. it typically presents in children and young adults with prior measles infection before the age of 2 years and after an intervening asymptomatic period of up to years. disease causes progressive dementia, seizures, myoclonus and paralysis and virtually always leads to death
Subacute sclerosing panencephalitis (SSPE)
Initial findings in SSPE
can often be normal but can reveal early asymmetric patchy or diffuse swelling with hypodensity and T2 hyperintensity of cerebral white matter. enhancement is usually absent
equine encephalitides are caused by
arbovirus (insect borne)
arbovirus preferentially affect the
deep gray nuclei and brainstem
a mosquito-borne arbovirus increasingly seen in the US which incites a meningoencephalitis of widely variable clinical severity
West Nile virus
mosquito-borne arbovirus causing meningoencephalitis of widely variable clinical severity endemic in Asia
Japanese encephalitis
these mosquito-borne arboviruses can demonstrate symmetric swelling , hypodensity and T2 hyperintensity of the thalami, basal ganglia, and brainstem. Associated enhancement and reduced diffusion may also be observed
West nile and japanese encephalitides
same imaging pattern of west nile and japanese encephalitides but with additional superimposed hemorrhage is seen in acute necrotizing encephalitis in children and has been associated with what virus
influenza A and B virus
it is a devastating disease of childhood and of unknown etiology. Viral and/or autoimmune encephalitis are implicated. clinical course is characterized by intractable seizures, progressive neurologic deficits, and frequently, coma
Rasmussen encephalitis
in this encephalitis, it typically affects one cerebral hemisphere. MR study show focal cortical swelling and T2 hyperintensity with minimal, if any, enhancement in the involved hemisphere early on, but these progress to dramatic asymmetric atrophy later. the affected hemisphere has been shown to be hypometabolic by SPECT and PET nuclear scans
Rasmussen encephalitis
these pathogens have a notable predilection for the brainstem and cerebellum, causing rhomboencephalitis
Listeria and Mycoplasma
an acute demyelinating disease that occurs most commonly after a recent viral illness or vaccination but sometimes spontaneously. autoimmune demyelination is the currently accepted mechanism, and infectious pathogens have not been isolated
Acute disseminated encephalomyelitis (ADEM)
rare, severe variant of ADEM that is often fatal. Major imaging feature is rapid progresion of white matter lesions over the course of several days. pathologically there is perivascular hemorrhagic necrosis, primarily in the centrum semiovale
Acute hemorrhagic leukoencephalitis
transmissible spongiform encephalopathy caused by an infectious proteinaceous particle or “prion”. It is rare, uniformly fatal and rapidly progressive neurodegenerative disorder
Creutzfeldt-Jakob disease
protease-resistant particles resulting from altered conformation of a normal host cellular protein encoden by the PrP gene. they accumulate in the neural tissue and result in cell death. Patients initially present with variable neurologic signs but ultimately develop a rapidly progressive dementia with myoclonic jerks and akinetic mutism
Prions
In this condition causing neurodegenerative disorders, CT is not helpful and is usually normal or shows generalized cerebral volume loss. DWI and FLAIR sequences are most if these patients undergo MRI. Both sequences can demonstrate hyperintensity in the striatum (caudate and putaminal nuclei) symmetrically and/or subtle ribbon-like hyperintensity in scattered areas of the cerebral cortex in early cases
Creutzfeldt-Jakob disease
Iatrogenic Creutzfeldt-Jakob disease can be contacted from
neurosurgical tools, corneal transplants, use of cadaveric dura mater or pituitary extracts
this variant of Creutzfeldt-Jakob disease is linked to bovine spongiform encephalopathy whereby prions are transmitted to humans who eat the meat of infected cow. MRI shows different findings of symmetric T2 hyperintensity in the posterior and dorsomedial aspects of the thalamic nucle (pulvinar and “hockey-stick” sign)
New variant CJD
common site of involvement in patients with AIDS
CNS
most common CNS infections include
HIV encephalopathy, toxoplasmosis, cryptococcosis, and other fungal infections; CMV and herpes encephalitis; mycobacterial infection, PML, meningovascular syphilis
most common CNS neoplasm associated with AIDS
Primary CNS lymphoma
Most severely involved in HIV encephalopathy
centrum semiovale, but all white matter tracts, including brainstem and cerebellum may be affected. the cortical gray matter is usually spared
Known as the AIDS dementia complex
subcortical dementia with cognitive, behavioral and motor deterioration
used to descibe infants and children wih HIV encephalitis who exhibit loss of developmental milestones, apathy, failure of brain growth and myelination, spastic paraparesis
HIV-associated progressive encephalopathy
most common manifestation of HIV infection of the brain on neuroimaging
Diffuse atrophy, largely central atrophy, reflecting predominant white matter involvement
presents as diffuse, symmetric, ill-defined often hazy pattern of T2 hyperintensity in the deep and periventricular white matter or multiple small T2-hyperintense white matter lesions are the most common findings in patients afflicted with HIV
HIV encephalopathy
most common observations in young children with HIV encephalitis
generalized atrophy and symmetric calcifications in the basal ganglia
most common opportunistic CNS infection and brain mass in AIDS patients, occuring in about 13% to 33% of these patients with CNS complications. Occurs in patients with CD4 lymphocyte counts <200 cells/mm3
toxoplasmosis
CNS toxoplasmosis in HIV usually have imaging findings of
necrotizing encephalitis, results with formation of thin-walled abscesses
true or false: fungal, mycobacterial and amebic abscesses do occur but bacterial abscesses are rare in AIDS patients
true
most common fungal infection in HIV patients
CNS cryptococcosis
diagnosis of cryptococcosis is made by
detection of cryptococcal antigen in serum or CSF
infection of the immunosuppresed patient caued by reactivation of the latent JC polyomavirus.
Progressive multifocal leukoencephalopthy
Most common CNS infection in AIDS patients pathologically, but does not usually result in frank tissue necrosis and is usually subclinical
CMV
True or false: Intracranial mycobacterial infections occur in relatively small percentage of AIDS patients. Most of these patients are IV drug abusers with pulmonary TB
true
