Download Imaging in Neurocysticercosis

September
2004
Imaging in
Neurocysticercosis
Sarun Charumilind,
Harvard Medical School, Year III
Gillian Lieberman, MD
Index Patient
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Index Patient: Mr. CP
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Mr. CP is a previously healthy 25 y.o. man who
immigrated from Cape Verde in 1995 and who
presents to an outside hospital with:
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5-day history of progressively severe headaches and h/o
chronic HA x4 yrs, relieved with change in position
2 days of “forgetfulness”
Appearance of agitation and nervousness
No significant PMH, allergies, meds.
No c/o of N/V, incontinence, visual, speech,
personality changes.
Given Demerol and Phenergan.
CT and MRI with gadolinium are ordered.
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Index Pt.: Imaging at Outside Hospital
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Hydrocephalus
Third ventricular
lesion - ?cyst
Transferred to
BIDMC
Opening
pressure > 30
L. frontal
ventriculostomy
and drain
placement
Repeat CT/MRI
Hydrocephalus of lateral ventricles
Third ventricular cyst: coronal cut
Third ventricular cyst: transverse cut
Third ventricular cyst: sagittal cut
Images from PACS, BIDMC
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Index Pt: BIDMC Imaging:
CT & MRI w/ Gad
Hydrocephalus of lateral ventricles (CT)
Calcification in right pons (CT)
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3rd ventricular cyst (MR, post-gad) Calcification in right parietal lobe (CT)
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Mild, diffusely
enlarged ventricles
esp. at third ventricule
and temporal horns
Effaced sulci
Scattered
calcifications along
sulci ( R pons, R post.
frontal lobe)
Third ventricular cyst
with enhancement
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Images from PACS, BIDMC
Differential Diagnosis
Obstructive
Hydrocephalu
s
„ Tumor: benign
or malignant
„ Cyst (colloid,
arachnoid,
PARASITIC)
„ Abscess
„ Congenital
„ Multiple
sclerosis
„ Tuberous
sclerosis
Cyst With Mural Multiple
Nodule
Intracranial
Calcifications
„ Tumor: benign or
malignant
„ Atherosclerosis
(ganglioglioma,
„ Idiopathic
GBM,
„ Physiologic
astrocytoma)
(dura, choroid
„ Metastasis
plexi, pineal
gland)
„ PARASITIC cyst
(cysticercus,
„ PARASITIC
paragonimus)
(cysticercosis,
paragonimus)
Reeder MM and B Felson, Gamuts in Radiology, 2003.
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Hospital Course & Follow-up
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SURG: Right transcallosal cyst
resection – brown, tan colored cyst
removed
IMAGING: resolved hydrocephalus
W/U:
„ ID consult: PPD neg., no growth
in serum or CSF, no AFB, positive
Index Pt: Resolution of hydrocephalus (CT)
for CC Abs
Optho consult: no intraocular Sx
„ Pathology: confirmed NCC
TX: Treated with albendazole x 7d +
decadron
DISCHARGE DX:
Neurocysticercosis
F/U: headaches resolved, discuss PPX
if return to Cape Verde
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Images from PACS, BIDMC
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Taenia Solium: Parasite of the Poor
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Most common helminthic
infection of CNS
Based on lifecycle, is facilitated
only in poor living conditions
Endemic to many regions:
Mexico, Central and South
America, sub-Saharan Africa,
Asia
Higher prevalence in rural
areas (10-25%)
High prevalence in high-porkconsuming/-raising countries
50,000 deaths/yr, 20 million
infected
Most common cause of
acquired epilepsy
worldwide
United States: ~1000 cases
per year
Global prevalence of Taenia solium
ftp://ftp.cdc.gov/pub/infectious_diseases/iceid/2002/pdf/schantz.pdf
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Taenia Solium: Lifecycle
http://www.ucm.es/inf
o/parasito/Taenia%20
escolex.jpg
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http://www.dpd.cdc.gov/dpdx/HTML/Cysticercosis.htm
Cysticercosis: Clinical Manifestations
Symptomatic Cysticercosis
Neurocysticercosis
Extraneural Cysticercosis
•Eye
•Muscle
Extraparenchymal
Parenchymal
•Subcutaneous
Pt. #2: Muscular (tongue)*
•Intraventricular
•Subarachnoid
•Spinal
Pt. #3: Parenchymal**
Pt. #4: Subcutaneous**
Pt. #5: Intraocular*
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Images from *http://www.facmed.unam.mx/grid/photos.htm and **http://faculty.uaeu.ac.ae/~youssefa/homepage/taenia.htm
NCC: Pathophysiology
Neurocysticercosis
20% Symptomatic
80% Asymptomatic
Life Stages of T. Solium
Cysticerci
•Mass effects
•Inflammatory response
•Foraminal obstruction
•Ventricular obstruction
•Asymptomatic
•Host immune tolerance
•Duration: 3-5 yrs
Degree of Sx depends on:
•Inflammatory response
•Cyst loses ability to moderate
immune response
•Active NCC
•Lifecycle stage
•Site
•Number of cysts
Tx depends on Sx
1. Meds: antiparasitic, antiinflammatory,
anticonvulsant
2. Surgery
3. Nothing!
Degenerating
Inactive
•Calcified
•Asymptomatic
•Potential epileptic/obstructive
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focus
Stage 1: Vesicular Cysts
CT: Small, rounded,
well-demarcated,
low-density w/o
edema.
Pt. #6: Head CT w/ contrast
MRI: signal similar to CSF
in T1 and T2; scolex seen
in cyst: “hole-with-dot” or
“swiss cheese” if severe.
Pt. #7: MRI w/o contrast
Pt. #8: MRI w/o contrast
122003.
Images from Garica HH and Del OH Bruto,
Stage 2: Colloidal Cysts
Pt. #9: Colloidal cyst on MRI
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CT: ill-defined with edema,
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MRI: thick hypointense
wall + perilesional
hyperintense edema
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ring pattern with contrast =
acute encephalitic phase
Pt. #10: Cysticercotic Encephalitis
Cysticercotic Encephalitis:
diffuse edema + collapsed
ventricles + multiple lesions =
young cysts attacked by host
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Images from Garica HH and Del OH Bruto, 2003.
Stage 3: Granular Cysts & Stage 4:
Calcified Cysts
Granular
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CT: granulomatous
Calcified
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Pt. #11: “Single enhancing lesion” on CT
CT: small, hyperdense
nodules w/o edema unless
relapse
Pt. #12: MRI: Signal void w/ surrounding edema
Images from Garica HH and Del OH Bruto, 2003.
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MRI: signal void +
hyper- intense edematous
rim
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MRI: edema with high
signal surrounding low
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signal cyst
Other Cyst Locations
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Subarachnoid: large,
multi-lobulated
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Ventricular: best on
MRI, isodense on CT
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Spinal: nonspecific
enlargement, filling
defects on myelogram
Pt. #13:
Giant cyst in
Sylvian fissure
Pt. #14:
Ventricular cysts
on MRI FLAIR
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Images from Garica HH and Del OH Bruto, 2003.
Comparing Modalities
•Plain film: Rarely used (incidental
subQ and muscle Ca++)
•CT v. MRI: Depends on stage
•CT: Cheaper, better at Ca++
•MRI:
•Better sensitivity (esp. active cysts,
cysts in post. fossa)
•Better scolex visualization
•Not widely available globally
•Approach: CT first, then MRI if
inconclusive, strong suspicion, or
follow-up.
Index Pt: Close-up views of mural nodule
cyst: cysticercus with scolex inside (MRI)
Images from PACS, BIDMC
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Other Diagnostic Workup
Pt: #15: Taenia solium egg
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Serology
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Targets: AntiCC antibodies or
cysticercal antigens
Substrates: CSF, saliva, or blood
Methods: ELISA, complement
fixation, immunoblot, etc.
Standard: Enzyme-linked
immunoblot, detect antiCC Abs
http://www.biosci.ohio-state.edu/~parasite/taenia.html
Pt. #16: Electron microscopy of an egg
Pathology
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White fluid-filled bladder 5-10 mm
diamter w/ solid 2 mm larval
tapeworm
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http://www.facmed.unam.mx/grid/photos.htm
Diagnostic Criteria
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3.
Absolute:
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Histologic
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Scolex on imaging
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Ocular signs
Major:
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Lesions “suggestive” on
imaging
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Positive serology for Abs
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Improvement after
treatment
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Spontaneous resolution of
single lesion
Minor:
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Lesions “compatible” on
imaging
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Clinical signs “suggestive”
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Positive serology for Abs or
Ags
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CC outside CNS
4. Epidemiologic:
„ Household contact
„ Geographic correlation
„ Travel correlation
Diagnosis:
„ Definitive:
„ 1 absolute + 1 epi
„ 2 major + 1 minor +
1 epi
„ Probably:
„ 1 major + 2 minor
„ 1 major + 1 minor +
1 epidemiologic
„ 3 minor + 1
epidemiologic
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The International Debate over Criteria
In the setting of many countries with endemic NCC…
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Biopsy: not possible to perform in all suspected pts.
Ocular: direct visualization rare, hardly reported
Scolex: uncommon on CT/MRI
Epi: majority of Indians have single enhancing, yet this is only a “major” criteria
Different DDX: CNS tuberculosis, with also single/multiple tuberculoma that
show as multiple enhancing CT/MRI lesions, similar to NCC; also multiple
tuberculoma, fungal granuloma, primary or secondary malignancies, and
multiple pyogenic abscesses
Serology: EITB (Ab immunoblot) not available, not sensitive
Tx: albendazole/praziquantel may not be effective, and tx role is unclear
“Minor” and “Epi” Criteria: not specific enough?
Current criteria more suitable for the patients in regions where
both NCC and other CNS infections are uncommon, as opposed
to India or other developing countries, which have high
prevalence of these.
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A Patient with MVA 2° to Seizure
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Mr. EM: previously
Pt.#17: Calcification near cranial vertex (CT)
healthy 33 yo man from
Cape Verde, struck
another vehicle at 80
mph.
Seized at scene of MVA
and outside the ER.
Imaging: Trauma,
Pt.#17: MR, susceptibility, of same lesion
Spine, Head series: No
fractures
NCHCT: 8 small
calcifications without
edema
TX: Seizure control. No
surgery.
Pt.#17: T2 MR of same lesion
Pt.#17: Cacification in posterior fossa (CT)
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Images from PACS, BIDMC
A Patient with MVA 2° to
Seizure (cont.)
Remember!
In developing regions of the world, seizure is a
common first presentation of NCC. NCC is the most
common cause of adult-onset acquired epilepsy
worldwide.
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A Patient with Incidental NCC?
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Mr. RB: 38 yo Nepali man with seizure and head trauma
NCHCT: Ventricular and parenchymal calcifications
DDX: EtOH withdrawal v. NCC
Pt.#18: Multiple parenchymal and ventricular calcifications (noncontrast CT)
Images from PACS, BIDMC
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A Patient with Incidental NCC?
(cont.)
Remember!
Though calcifications may cause obstruction or serve
as seizure foci, more often than not, they cause no
pathology. 80% of persons with NCC are
asymptomatic.
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A Patient with Arachnoiditis 2°
to NCC
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Mr. MB: 52 yo Cape
Verdean man with
previous Dx of NCC
with 4th ventricular
cyst removal
Presents: severe HA,
fever, and LLE
radicular pain, neck
stiffness, blurry vision
Imaging: Obstructive
hydrocephalus +
spinal cord
inflammation
TX: Anti-TB for
meningitis without
success (misdiagnosis
of TB)
Pt.#19: Cervicomedullary enhancement
(T1 MR)
Pt.#19: T1-T2 enhancement (T1 MR)
Images from PACS, BIDMC
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Arachnoiditis 2° to NCC (cont.)
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Arachnoiditis: spinal cord inflammation evidenced by
nerve root clumping and adhesions to thecal sac
DX: Hydrocephalus 2° to impaired CSF absorption from
CSF inflammatory process Æ Neurocysticercosis
Pt.#19: Lumbosacral involvement: clumping and adhesions (T1 MR, post gad)
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Images from PACS, BIDMC
Arachnoiditis 2° to NCC (cont.)
Remember!
NCC may have spinal manifestations. Despite this
patient’s h/o cyst removal, other cysts may have
been present in various life stages. Albendazole is
only 75-90% effective.* Up to 41% of patients posttreatment may exhibit noninflamed but viable cysts.**
*Takayanagui 1992, *Sotelo 1998, **Garcia 2004
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A Patient with Toxoplasmosis
v. NCC
Pt.#20: Noncontrast Head CT showing lesions with edema
Mr. HD: 33 yo Haitian
man who on his 1-year
anniversary of being
diagnosed with
HIV/AIDS presents with
severe headaches,
photophobia, blurred
vision, dizziness, NVx1,
neck pain on movement,
fevers, chills, sweats
„ Imaging: Multiple
enhancing lesions with
surrounding edema
„ DX: DISSEMINATED
CEREBRAL
TOXOPLASMOSIS
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Images from PACS, BIDMC
A Patient with Toxoplasmosis v.
NCC (cont.)
Remember!
The differential for multiple intracranial calcifications
is wide. In addition, settings where NCC is highly
prevalent are also settings for other infectious
pathologies of the brain: toxoplasmosis, lymphoma in
HIV patients, TB granulomas, etc.
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Conclusion
„ Imaging
findings depend on modality,
cysticercus stage, and location.
„ Both CT and MRI have a role, but CT is
the best screening tool.
„ Debatable whether diagnostic criteria work
for all global settings (differences in
prevalence and technology).
„ Diagnosis often requires serologic, clinical,
pathologic, and epidemiologic correlation.
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References
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Dunsworth, GA. “Neurocysticercosis: A Review.” Pediatric Nursing. 1999 May 1; 25(3), 301-304.
Felson. Gamuts in Radiology. City: Publisher, Year of Publication. A-45 – A118.
Garcia HH and OH Del Bruto. “Imaging Findings in Neurocysticercosis.” Acta Tropica. 2003; 87(1), 71-78.
Garcia HH et al. A trial of antiparasitic treatment to reduce the rate of seizures due to cerebral
cysticercosis. N Engl J Med 2004 Jan 15;350(3):249-58.
Jain V, et al. “Disseminated Cysticercosis.” The Journal of the Association of Physicians of India. 2000;
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Nash TE, J Pretell, and HH Garcia. “Calcified Cysticerci Provoke Perilesional Edema and Seizures.” Clinical
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Ong S, et al. “Neurocysticercosis in Radiographically Imaged Seizure Patients in U.S. Emergency
Departments.” Emerging Infectious Diseases. 2002 Jun; 8(6), 608-613.
Sotelo J, et al. Short course of albendazole therapy for neurocysticercosis. Arch Neurol 1988
Oct;45(10):1130-3.
Takayanagui OM and Jardim E. Therapy for neurocysticercosis. Comparison between albendazole and
praziquantel. Arch Neurol 1992 Mar;49(3):290-4.
Zimmermann AT and WS Jeffries. “Taenia Solium and Neurocysticercosis.” Medical Journal of Australia.
2001; 175, 670-671.
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Acknowledgements
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Joe Barry, MD
Steve Reddy, MD
Barbara Appignani, MD
Andrew Tarulli, MD
David Hackney, MD
Gillian Lieberman, MD
Pamela Lepkowski
Larry Barbaras, Webmaster
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