CONTRIBUTION OF MRI IN SERIOUS FORMS OF ACUTE DISSEMINATED ENCEPHALOMYELITIS AND POST INFECTIOUS HERPES ENCEPHALITIS - PowerPoint PPT Presentation

About This Presentation
Title:

CONTRIBUTION OF MRI IN SERIOUS FORMS OF ACUTE DISSEMINATED ENCEPHALOMYELITIS AND POST INFECTIOUS HERPES ENCEPHALITIS

Description:

contribution of mri in serious forms of acute disseminated encephalomyelitis and post infectious herpes encephalitis m.omri, w.hizem-harzallah, z.abouzarifa, r.salem ... – PowerPoint PPT presentation

Number of Views:65
Avg rating:3.0/5.0
Slides: 21
Provided by: Insp173
Learn more at: http://strtn.org
Category:

less

Transcript and Presenter's Notes

Title: CONTRIBUTION OF MRI IN SERIOUS FORMS OF ACUTE DISSEMINATED ENCEPHALOMYELITIS AND POST INFECTIOUS HERPES ENCEPHALITIS


1
CONTRIBUTION OF MRI IN SERIOUS FORMS OF ACUTE
DISSEMINATED ENCEPHALOMYELITIS AND POST
INFECTIOUS HERPES ENCEPHALITIS
  • M.OMRI, W.HIZEM-HARZALLAH, Z.ABOUZARIFA, R.SALEM,
    M.A.JELLALI, A.ZRIG, W.MNARI, M.MAATOUK,
    M.GOLLIRadiology service, Fattouma Bourguibas
    Hospital, Rue 1er juin, 5004 Monastir, Tunisia

NR29
2
INTRODUCTION
  • Post-infectious and inflammatory
    encephalomyelitis are broadly represented by the
    syndrome acute disseminated encephalomyelitis
    (ADEM).
  • ADEM is an inflammatory demyelinating disorder of
    the central nervous system that is usually
    monophasic,which principally affects brain and
    spinal cord .
  • ADEM is predominantly, though by no means
    exclusively, a disease of children and in
    particular infants. Historically it includes post
    infectious encephalomyelitis and post-vaccination
  • encephalomyelitis.
  • It usually follows an infection or vaccination.
    The disease is characterised by multifocal white
    matter lesions on neuroimaging.

3
  • It typically follows a minor infection with a
    latency period of 230 days and is thought to be
    immune-mediated.
  • ADEM is clinically characterized by the acute
    onset of focal neurological signs and
    encephalopathy. Patients can require intensive
    care unit admission because of encephalopathy,
    coma, seizures or tetraplegia.
  • Cerebrospinal fluid analysis usually shows
    lymphocytic pleocytosis but, unlike viral or
    bacterial encephalitis, no evidence of direct
    CNSinfection is found.
  • There are no biologic markers of the disease and
    cerebral magnetic resonance imaging is essential
    to ADEM diagnosis, detecting diffuse or
    multifocal asymmetrical lesions throughout the
    white matter on T2- and FLAIR-weighted sequences.

4
OBJECTIVS
  • Show the contribution of MRI in the positive
    diagnosis in acute disseminated encephalomyelitis
    (ADEM) in its severe form and post infectious
    herpes encephalitis and also specify his interest
    prognosis and clinical correlation radio.

5
Materials and Methods
  • Retrospective analysis of 9 clinical cases( 6
    girls and 3 boys) of ADEM (5 cases) and post
    infectious herpes encephalitis (4 cases) explored
    by conventional MRI and diffusion mapping with
    CDA.
  • Average age 9 months and 12 years
  • Recent infection (n 6).
  • recent vaccination (n 3 ).
  • Reason for hospitalization - fever
    (n 7) - seizures (n 5)
    -behavioral disorders (n 4)

6
  • Physical signs -impaired consciousness (n
    8) -meningeal syndrome (n 5) -motor
    deficit (n 3) -gait disturbance (n 2)
    -achievement of cranial nerves (n 4)
  • PL (n 8) - normal formula (n 1) - and
    lymphocytic meningitis (n 7)
  • Initial brain imaging - CT (n 4) - MRI
    (n 9).
  • Additional spinal MRI (n 3).
  • Imaging control in 5 patients -MRI (n 5)

7
Results
  • Objectified anomalies in all cases were
  • Hyperintensity T2 of white matter brain
  • -bilateral and asymmetric (3 cases).
  • -diffuse (2 cases).
  • -unilateral (3cases).
  • Hyperintensity T2 of profound gray matter (1
    case).
  • Infectious vasculitis associated with vasoplegia
    blood was found in one case.
  • Diffusion was restricted with decreased ADC in 4
    cases.
  • The restriction of diffusion was associated with
    a severe clinical picture.

8
  • ADEM lesions are large, multiple, and asymmetric
    (5cas).
  • Severe and extensive T2 lesions (2cas) contrast
    with a relatively small mass effect. The
    distribution of lesions involves the subcortical
    and central white matter and cortical graye white
    junction of both cerebral hemispheres and
    infratentorial areas.
  • A pattern of diffuse demyelination is seen in one
    severe case with large demyelinating lesions of
    the white matter extending to the contralateral
    hemisphere.

9
A two-years-old previously healthy girl who
developed postinfectious focal encephalitis. MRI
findings
  • ?uid-attenuated inversion recovery (FLAIR)
    sequences show extensive area of increased signal
    in left hemisphere and right basal ganglia.

10
  • HSE. T2 weighted MRI showing extensive area of
    increased signal in left hemisphere and right
    basal ganglia

11
  • Diffusion-weighted MRI (DWI) show a restrection
    of diffusion.

12
  • T1 with G shows cortical enhancement.

13
A seven-years-old previously healthy girl who
developed post infectious focal encephalitis .
control MRI findings.
  • HSE. T2 weighted MRI showing an increased signal
    in basal ganglia

14
  • ?uid-attenuated inversion recovery (FLAIR)
    sequences show an increased signal in basal
    ganglia.
  • Diffusion est discreetly restrected.

15
Discussion
  • Acute disseminated encephalomyelitis
  • Post-infectious encephalomyelitis is associated
    with an antecedent or concomitant infection,
    usually viral. Most notoriously, measles virus
    infection is followed by ADEM in approximately 1
    in 1000 cases.
  • It is greatly reduced in incidence following the
    introduction of widespread measles vaccination,
    but still occurs. Non-specific or unidentified
    viral illnesses can also antecede ADEM, and this
    lack of a specific infectious agent should not
    preclude the diagnosis.
  • There are some variations in the ADEM phenotype
    dependent upon the antecedent illness. Measles
    associated ADEM tends to produce a more
    clinically severe phenotype while cerebellar
    ataxia .

16
  • ADEM can be distinguished from acute viral
    encephalitis because the disease is not the
    result of primary tissue invasion by an
    infectious organism. It is thought to be
    immune-mediated and is characterized
    neuropathologically by perivenular in?ammation
    and demyelination.
  • Neuroimaging
  • Cerebral computed tomography scans performed at
    admission show abnormalities only in 30 of
    patients, essentially supratentorial readily
    visible diffuse or large focal hypodensities of
    the cerebral white matter.
  • Demyelinating lesions of ADEM are better
    visualised by MRI. These demyelinating lesions of
    ADEM usually exhibit no mass effect and can be
    seen scattered throughout the white matter of the
    posterior fossa and cerebral hemispheres

17
  • Involvement of the cerebellum and brainstem is
    more common in children. Characteristic lesions
    seen on MRI appear as patchy areas of increased
    signal intensity on conventional T2-weighted
    images and on fluid attenuated inversion recovery
    sequence (FLAIR).
  • Few MRI lesions may enhance after gadolinium
    administration. Extensive perifocal oedema may be
    seen.
  • Though white matter involvement predominates grey
    matter can alsobe affected, particularly basal
    ganglion, thalami, and brainstem. Tumour-like
    lesions have also been reported in a few cases.
  • MRI lesions are identi?ed on morphological
    T2-weighted and ?uid-attenuated inversion
    recovery (FLAIR) sequences.
  • Although no speci?c MRI criteria have been
    identi?ed. MRI lesion patterns are generally
    recognized, but in all cases lesions are
    multifocal and involve mainly the supratentorial
    white matter

18
  • -multifocal lesions of less than 5 cm.
  • -con?uent multifocal lesions of more
    than 5 cm.
  • - multifocal lesions involving basal
    ganglia.
  • Although patchy areas of increased signal
    intensity are stated to involve 50 or more of
    total white matter in children.
  • In order to qualify as ADEM, lesions on MRI
    should be of the same age and no new lesion
    should appear on central nervous system imaging
    studies after the initial clinical attack.
  • The corpus callosum is usually not involved in
    ADEM infrequently its involvement has been
    reported, suggesting extensive lesion load.
    Corpus callosum involvement is more
    characteristic of multiple sclerosis.

19
  • Thalamic involvement may be seen in 40 patients
    of ADEM, making this finding a potentially useful
    discriminator.
  • MRI changes usually appear early in the course of
    the disease.
  • Although ADEM is typically a disseminated process
    in the central nervous system, often with
    impaired sensorium, a few cases are dominated by
    spinal pathology .
  • DIFFERENTIAL DIAGNOSIS
  • Distinction between infectious and
    post-infectious encephalitis can be dif?cult and
    all frequent causes of infectious encephalitis
    must be excluded before concluding to an acute
    form of post-infectious in?ammatory CNS disorder.
  • The diagnosis is considered straightforward when
    ADEM occurs after an exanthem or immunisation. A
    clear cut latent period between systemic symptoms
    and neurological illness favours ADEM along with
    the typical pattern of diffuse and multifocal
    involvement of both the central nervous system
    and peripheral nervous system and the
    characteristic MRI appearance.
  • The most important issue associated with the
    diagnosis of ADEM is can this disorder be
    diagnosed with certainty and differentiated from
    the initial manifestation of multiple sclerosis.

20
CONCLUSION
  • ADEM is a monophasic inflammatory disease
    affecting the central nervous system, which
    usually follows an infection or vaccination.
  • Distinction between infectious and
    post-infectious enceph-
  • alitis can be dif?cult and all frequent
    causes of infectious encephalitis must be
    excluded before concluding to an
  • acute form of post-infectious in?ammatory
    CNS disorder.
  • Diffuse and focal CNS signs and peripheral
    nervous system involvement may be present
    simultaneously at physical examination. Brain and
    spinal cord MRI should be systematically
    performed at the initial phase of the disease to
    look for evidence of multifocal acute in?ammation
    and demyelination.
Write a Comment
User Comments (0)
About PowerShow.com