This document provides an overview of neurocysticercosis (NCC), which is an infection of the central nervous system caused by the larvae of the pork tapeworm Taenia solium. NCC is endemic in many parts of the world and is the leading cause of adult-onset epilepsy. It discusses the pathogenesis, classification, clinical presentations, diagnostic criteria and differential diagnosis, and treatment options for NCC. Key points include that NCC presents with a variety of neurological symptoms depending on the location and stage of the cysticerci, imaging such as CT and MRI are important for diagnosis, and albendazole is the drug of choice for antiparasitic treatment along with corticosteroids.

1. NEUROCYSTICERCOSIS
Payoz Pandey

2. Introduction
Pathogenesis
Classification
Clinical presentations
Investigations
Diagnostic criteria
Differential diagnosis
Treatment

3. Introduction- History
Neurocysticercosis is an ancient disease
Hippocrates recognised human tapeworms
Aristotle compared their appearance to hail stones
Kuchenmeister in 1855 confirmed larval stages
Van Beneden demonstrated cysticerci in the pig
muscles.

4. Introduction
NCC is the infection of the CNS by the larvae of Taenia solium.
Neurocysticercosis (NCC) is the most common parasitic
disease of the nervous system.
It is the leading cause of adult onset epilepsy (29% of epilepsy
in endemic regions world wide).
It is endemic in Central and South America, sub-Saharan Africa,
and in some regions of the Far East, including the Indian
subcontinent, Indonesia, and China, reaching an incidence of
3.6% in some regions.
Of note is the near absence of infection in Muslim countries,
where the consumption of pork is forbidden by Islam

5. Figure 2: Worldwide prevalence of neurocysticercosis.
Burneo J G et al. CMAJ 2009;180:639-642
©2009 by Canadian Medical Association

7. Introduction
Pathogenesis
Classification
Clinical presentations
Investigations
Diagnostic criteria
Differential diagnosis
Treatment

8. Cestodes / Tapeworms
Either
Taenia solium
Human- intermediate
host
Echinococcosis
Sparganosis
Coenurosis
Human- definitive
host
Taenia saginata
Diphyllobothrium
Hymenolepis
Dipylidium caninum

9. Taeniasis Solium
The pork tapeworm T. solium can cause
two distinct forms of infection in humans:
Adult tapeworms in the intestine or
Larval forms in the tissues (cysticercosis).
Humans are the only definitive hosts for T.
solium;
Pigs are the usual intermediate hosts,
although other animals may harbor the
larval forms.

12. Mode of infection
Hetero-inoculation
Eggs from the environment
Internal auto-inoculation
Regurgitation of the proglottids into the
stomach
External auto-inoculation
From self

13. Histologic Features
A cysticercus is a liquid-filled vesicle with a 3-layer wall and scolex , although the
scolex may not be found.
The parasite can adopt 3 different presentations
The cystic form
They are approximately 7 mm in diameter and
May be single or multiple.
Frequent locations :leptomeninges & cerebral cortex.
The racemose form (multiple cysts in the basal cisterns)
They do not have a scolex.
Because of their location, the racemose form can produce hydrocephalus
Sometimes they give the impression of an "infiltrative" aspect (Trelles
"canceriform" presentation)
Mixed form: presence of both of the cystic and racemose forms.

14. Types of cyst
Cysticercus cellulosae:
Less virulent
Small (<2cm, round, thin walled)
In the parenchyma or Subarachnoid space
Often remain silent

15. Cysticercus racemose:
The racemose (ie, appearing like a cluster of grapes)
form refers to the presence of multiple cysts without
a scolex.
May form giant vesicles up to 10 cm in diameter with
predilection for basal cisterns
Cysticercotic arachnoiditis
Presents as hydrocephalus / meningitis
Can occlude vessels  stroke
Intense inflammation and seizures

16. While in the nervous system, the T solium parasite goes
through different stages of involution, which include the
following:
Stage Parasite Host response
Cystic or
Vesicular stage
Viable parasite (scolex) Downregulation of host immunity
 mild inflammatory reaction
Colloidal stage Degenerating scolex Severe inflammatory reaction 
granuloma
Granular stage Degenerated scolex Astrocytic gliosis
Calcified stage Calcified nodule Intense gliosis around the cyst

17. Introduction
Pathogenesis
Classification
Clinical presentations
Investigations
Diagnostic criteria
Differential diagnosis
Treatment

18. Classification
Anatomical classification
Sotelo et al
Carpio et al
Chorobski

19. Anatomical classification:
(Sorvillo et al., 1992)
Parenchymal NC
Ventricular NC
Basal meningites
Mixed forms

20. Sotelo et al classification
Active forms
Arachnoiditis
Hydrocephalus secondary to meningeal inflammation
Parenchymal cysts
Brain infarction secondary to vasculitis
Mass effect due to large cyst or cyst clumps
Intraventricular cysts
Spinal cysts
Inactive forms of NC
Parenchymal calcifications
Hydrocephalus secondary to meningeal fibrosis

21. Carpio et al
Active form
Live, viable parenchymal or extraparenchymal cysts,
rarely produces symptoms apart from the rare instanceof
mass effect
Transitional form
Symptomatic seizures occur with this form.
Degenerating subarachnoid cysts produce meningitis,
arachnoiditis and hydrocephalus, ventricular cysts lead to
acute hydroephalus
Inactive form
Single or multiple parenchymal calcifications or
hydrocephalus secondary to meningeal fibrosis.

22. Introduction
Pathogenesis
Classification
Clinical presentations
Investigations
Diagnostic criteria
Differential diagnosis
Treatment

23. Clinical features
Neurocysticercosis is a pleomorphic disease
Most symptomatic patients are 15–40 years old, and
the disease has no gender?(Vasquez or race
predilection
Many are asymptomatic (80%)
Peak is estimated to occur 3-5 years after infection
The onset of symptoms is usually subacute to
chronic, with the exception of seizures, which
present in an acute fashion

24. Cysticerci can be found anywhere in the body
but are most commonly detected in the brain,
cerebrospinal fluid (CSF), skeletal muscle,
subcutaneous tissue, or eye.
Physical findings depend on where the cyst is
located in the nervous system.
Symptoms are mainly due to mass effect,
inflammatory response, or obstruction of
foramina and ventricular system of brain.

25. Parenchymal NC
Epilepsy
It is the most common presentation (70%) of
neurocysticercosis
It is the leading cause of adult-onset epilepsy.
Risk of seizures in seropositive individuals 2-3 times
higher than seronegative controls.
Headache, nausea, vomiting
Strokes
Lacunar infarcts and large cerebral infarcts dueto
occlusion or vascular damage.

26. Frontal lobe involvement
Psychosis, dementia,, intellectual
impairement
Cerebellar ataxia
Encephalitis and diffuse brain edema
Common in children and young females
Risk of developing severe neurological
sequelae

27. Intraventricular
Constitutes 5-10%
4th ventricle most common site ofobstruction
Lateral ventricular cysts less likely to cause
obstruction
Hydrocephalus without localizing signs
Bruns’ syndrome : Unattached cysts may cause
sudden positional mechanical obstruction causing
nausea, vomiting and vertigo.

28. Meningeal cyst
Meningeal Irritation signs
Raised ICT from inflammation, edema

29. Intracranial hypertension:
Obstruction of CSF flow by basal or ventricular
cysticercosis.
May also be due to large cysts displacing midline
structures, granular ependymitis, arachnoiditis, or the
so-called cysticercotic encephalitis caused by the
inflammatory response to a massive infestation of
cerebral parenchyma with cysticerci.
Patients may have seizures and deterioration of their
mental status, mainly due to the host's inflammatory
reaction.

30. Neuropsychiatric disturbances
They appear to be related more to the presence
of intracranial hypertension than to the number
or location of parasites in the brain.
Hydrocephalus(10-30%)
Communicating hydrocephalus due to
inflammation and fibrosis of the arachnoid villi or
inflammatory reaction to the meninges and
subsequent occlusion of the foramina of
Luschka and Magendie.
Noncommunicating hydrocephalus may be a
due to intraventricular cysts.

31. Presentations of other forms of neurocysticercosis
Intrasellar neurocysticercosis: ophthalmologic and
endocrinologic manifestations mimicking those of
pituitary tumors.
Spinal neurocysticercosis :
It is a rare manifestation (1-3%)
Thoracic lesions the most common.
Extramedullary form : most frequent and is responsible of
symptoms of spinal dysfunction such as radicular pain,
weakness, and paresthesias.
Intramedullary presentation may cause paraparesis,
sensory deficits with a level, and sphincter disturbances.

32. Ocular cysticercosis (1-
3%)Most commonly in the subretinal space.
Patients may present with decreased visual
acuity, visual field defects, or monocular
blindness.

33. Systemic cysticercosis
It is most common in the Asian continent.
The parasites may be located in the
subcutaneous tissue or muscle.
Peripheral nerve involvement as well as
involvement of the liver or spleen have been
reported.

34. Introduction
Pathogenesis
Classification
Clinical presentations
Investigations
Diagnostic criteria
Differential diagnosis
Treatment

35. Peripheral eosinophilia only if cyst is
leaking
Raised IgE levels

36. Immunologic Testing
ELISA :
○ Antibody detection in CSF is more reliable
than on serum
○ It is the most widely used test of CSF;
○ It is 87%sensitive 95% specific
○ Also used for serum antibodies detection.

37. Enzyme-linked immunoelectrotransfer blot (EITB)
assay
Test of choice for detecting anticysticercal antibodies
Uses affinity-purified glycoprotein antigens
The test is 95% sensitive and 100% specific
Superior to both ELISA & PCR
Serum testing is more sensitive than on CSF.
Disadvantage
False-negative in up to 50% of patients with a single cerebral cyst or in
those with calcifications alone.
May be positive in patients who are exposed to the adult parasite without
developing cysticercosis .

38. CSF Analysis
Indicated in every patient with a solitary
brain lesion.
It is insensitive and nonspecific in the
diagnosis of cysticercosis
Contraindication:
Large cysts causing severe edema and
displacement of brain structures
Obstructive hydrocephalus.

39. Results:
Normal: Brain parenchyma lesions,
Abnormal : 50-80% case of basal cisterns or
ventricular lesions.
CSF findings
Mononuclear pleocytosis, usually not exceeding
200-300 cells/mm3
Normal glucose levels,
Elevated protein levels,(50-200 mg/dL)
Eosinophilia
High immunoglobulin G (IgG) index,
Oligoclonal bands( in some).

40. Stool Examination
Taeniasis may be established by detecting T solium eggs
and proglottids in a patient's stool.
Taeniasis and neurocysticercosis coexist in 10-15% of
patients with neurocysticercosis.
Intestinal taeniasis is very common in patients with
massive infestation with cysticerci but without
cysticercotic encephalitis.
Tapeworm carriers may be identified by examining the
stool of the relatives of a patient with cysticercosis
encephalitis.

42. CT Scan
It is the preferred imaging study for detection of
parenchymal calcifications.

43. Stage Cyst wall Scolex Comment
Vesicular Non-enhancing
Well defined
membrane
Only one viable scolex
Eccentric hyperdense
hole-with-dot” appearance
Suggestive of viable
larva
Colloidal Ring Enhancing
with perilesional
edema
Degenerating scolex
Fluid becomes more
turbid
Earliest stage in the
cyst involution - larval
degeneration
Granular Focal nodular
enhancing necrotic
lesions with
perilesional edema
Degenerating scolex Eosinophilic structure
Bladder and scolex
are in various stages
of disintegration
Calcified Small hyperdense nodules without perilesional edema

44. CT- Vesicular stage

45. CT- Collodal stage:
Post contrast ring enhancement

46. CT- Granular stage

47. CT- calcified stage

48. MRI
Imaging modality of choice for :
Intraventricular and cisternal /subarachnoidal cysts
Very small cysts
Cystic degeneration and pericystic inflammatory reaction

49. Stage Cyst fluid Perilesional region Other comments
Vesicular T1WI: Isointense
T2WI: Isointense
No edema
No enhancement
Single :
•Pea-in-the-pod
•Hole-with- dot
Multiple:
•Swiss cheese
Colloidal T1WI:
Hyperintense
T2WI:
Hyperintense
Surrounding edema is
T1WI : hypointense
T2WI : hyperintense
On T2WIs, the
hypointense cyst wall
stands out between
the hyperintense cyst
fluid and edema
Granular Same as above More edema
Thicker ring enhancement
Calcified Edema with high signal surrounding low signal cyst

51. CT VS MRI
MRI preferred since it is more sensitive in detecting:
Small lesions
Brainstem, Cisternal cysts & intraventricular lesions
Perilesional edema around calcific lesions
Scolex
Degenerative changes in the parasite
CT scan preferred for
Cheaper
Small areas of calcifications.
Cysticercal infestation of extraocular muscles.
* Perform CT scan first followed by MRI in patients with
inconclusive findings or in those with negative CT scans where
strong clinical suspicion persists.

52. MRI showing a cysticercus in the lateral ventricle, with
resultant hydrocephalus

53. Computed tomography shows multiple intracranial calcifications
(starry sky appearance)

54. CT cysternography
CT cisternography is reserved for rare refractory cases in which
MRI is not diagnostic or is contraindicated.

55. MR angiography
Occlusion of
intracranial artery in
subarachnoid
neurocysticercosis

56. Introduction
Pathogenesis
Classification
Clinical presentations
Investigations
Diagnostic criteria
Differential diagnosis
Treatment

57. Classification of intra cranial space occupying lesions
Congenital Dermoid,
Epidermoid,
Teratoma
Traumatic Subdural & Extradural haematoma
Inflammatory Abscess,
Tuberculoma,
Syphilitic gumma,
Fungal Granulomas
Parasitic Cysticercosis,
Hydratid cyst,
Amebic abscess
Schistosoma japonicum
Neoplasm

58. Etiological categories Radiological categories

59. Cysticercus vs Tuberculoma
Cysticercus granuloma Tuberculoma
Round in shape Irregular shaped
Cystic Solid
20mm or less with ring
enhancement or visible scolex
Greater than 20 mm
Cerebral edema not enough to
produce midline shift or focal
neurological deficit
Associated with severe perifocal
edema and focal neurological
deficits
MRS: choline/creatine ratio less
than 1
MRS: choline/creatine ratio
greater than 1

60. Introduction
Pathogenesis
Classification
Clinical presentations
Investigations
Diagnostic criteria
Differential diagnosis
Treatment

61. Treatment options
Cysticidal therapy + steroids
Corticosteroids alone
Supportive
Anticonvulsants
Anti edema
Analgesics
Surgery

62. Antiparasites
Albendazole superior to Praziquantel
Giant cysts
Subarachnoid
Intraventricular,
Spinal
Parameter Albendazole Praziquantel
Cost Cheaper Costlier
CSF penetration Good Poor
Efficacy More (75-90%) Less (60-70%)
With anticonvulsants Does not interact Interact
With steroids Does not interact Interact

63. Praziquantel is generally considered second-line
therapy

64. Dosage
Praziquantel
Initial regimen 50 mg/kg/day 15 days
Suggested Single parenchymal
cyst
3 individual doses of 25-30
mg/kg at 2-hour intervals
6 hours
Multiple cyst 50 mg/kg/day 15 days
Albendazole
Initial regimen 15 mg/kg/day 1 month
Suggested Single parenchymal cyst 15 mg/kg/day 3 days
Multiple cyst 15 mg/kg/day 1 week
Large subarachnoid
cysts
up to 30 mg/kg/day Prolonged

65. Steroids
Antiparasites are generally given
simultaneously with steroids to control the
edema and intracranial hypertension.
Drug Dose
Dexamethasone 4.5 - 24 mg/day
Prednisone 1 mg/kg/day

66. BEFORE INITIATING
.
Consider treating with a single dose of
ivermectin before beginning
corticosteroids, as many patients have
risk factors for strongyloidiasis.
Look for conditions precluding
anticysticidal therapy.

67. Cysticidal drugs not a first line
??
Cysticercotic encephalitis with
hydrocephalus
Giant subarachnoid cysticerci
Ventricular cysts
Calcifications alone
Spinal
Ocular

68. Treatment concensus

69. Parenchymal- viable cysts
Viable cysts
Mild (1 to 5 cysts) • Antiparasitic treatment + steroids
• Antiparasitic treatment; steroids
used only if side effects related to
therapy appear
• No antiparasitic treatment;
neuroimaging follow-up
Moderate (more than 5 cysts) Antiparasitic treatment + steroids
Heavy (more than 100 cysts) • Antiparasitic treatment + high-dose
steroids
• Chronic steroid management; no
antiparasitic treatment; follow-up

70. Parenchymal
Enhancing lesions (degenerating cysts)
Mild or moderate • No antiparasitic treatment; neuroimaging follow-up
• Antiparasitic treatment + steroids
• Antiparasitic treatment; steroids only if side effects
develop
Heavy (cysticercotic
encephalitis)
No antiparasitic treatment; high-dose steroids and
osmotic diuretics
Calcified cysticerci
Any number No antiparasitic treatment

71. Extraparenchymal neurocysticercosis
Ventricular cysticercosi Neuroendoscopic removal if available.
Subarachnoid cysts, including
• Giant cysts
• Racemose cysticercosis
• Chronic meningitis
• Antiparasitic + steroids,
• Hydrocephalus  ventricular shunt
Hydrocephalus with no visible cysts on
neuroimaging
Ventricular shunt (no antiparasitics)
Extracranial
Spinal cysticercosis Primarily surgical;
(anecdotal reports of successful
use of albendazole with steroids)
Ophthalmic cysticercosis Surgical resection of cysts

72. Anticonvulsants
Recommended for patients who present with seizures
First seizures due to inflamed cysticercal lesions should be
considered acute symptomatic seizures. & should be treated
only for the duration of the acute condition. However, treatment
may be continued during the period when the inflammatory
response is active, which might last several months
Should be stopped after resolution of the acute lesion
Seizures occurring after resolution of edema or calcification of
the degenerating cyst should be considered unprovoked, and,
long-term AED administration is warranted
Should be considered in patients w/ multiple cysts who have no
history of seizure activity

73. Anti-epileptics duration ???
Duration remains undefined and depends neither on
the type of seizure at presentation nor on other risk
factors for recurrence, such as age at onset and
number of seizures before diagnosis.
Although the usual practice has been to use AEDfor
2 years seizure-free interval, shorter durations of
AED have been proposed.
It seems prudent to withdraw anticonvulsants after a
1-year seizure-free interval in cases where the lesion
has disappeared and the EEG has normalized;
longer durations are needed for those with persistent
or calcified lesions.

75. Surgical Intervention
Hydrocephalus due to an intraventricular cyst: placement of a
ventricular shunt is recommended, followed by surgical
extirpation of the cyst and subsequent medical treatment.[16]
In cases of multiple cysts in the subarachnoid space (ie, the
racemose form), surgical extirpation, on an urgent basis, is
recommended.
If the obstruction is due to arachnoiditis, placement of a
ventricular shunt should be followed by administration of
steroids and subsequent medical therapy.

76. Surgical treatment in the particular case of medically
refractory epilepsy due to a single lesion has been
reported.
Neuroendoscopy is a tool with great potential for use in
the management of ventricular cysticercosis.
Most patients with spinal lesions require surgical
management
Surgical intervention also recommended for cysts:
Attached to middle cerebral artery
Compressing the optic chiasm

78. Follow-up
Follow-up imaging study is recommended after
2-3 months following treatment, especially in
cases in which anticysticercal medications are
used as a diagnostic tool.
The use of imaging will guide the requirement
of future trials of anticysticercal medication in
cases of subarachnoid cysticercosis.

79. Prognosis
In most cases , the prognosis is good.
Seizures seem to improve after treatment with anticysticercal
drugs.
The racemose form is associated with poor prognosis and
elevated mortality rate (>20%).
22% have recurrent seizures.
Others include headaches, neurologic deficits related to
strokes, and hydrocephalus.
Patients with complications such as hydrocephalus, large cysts,
multiple lesions with edema, chronic meningitis, and vasculitis
do not respond very well to treatment.

80. PREVENTION
Human Tapeworm Infections
Inspection of pork for cysticerci
Freezing or adequately cooking meat to destroy cysticerci
Administering antiparasitic agents to pigs
Infection in Pigs
Confining animals and not allowing them to roam freely
Improved sanitary conditions
Egg Transmission to Humans
Good personal hygiene and hand washing prior to food
preparation
Identifying human carriers of tapeworms
Mass community programs to treat tapeworm carriers.
Possible Vaccine – porcine vaccine currently in the works

81. Conclusion
Neurocysticercosis, is the major cause of epileptic seizures in
developing countries.
Varied clinical presentation preclude clinical diagnosis in most
cases and demand Imaging.
Amidst controversies, treatment of neurocysticercosis is still
dubious.
Neurocysticercosis is potentially eradicable.
Early diagnosis, individual case based treatment & community
measures for prevention remain the corner stones of disease
management.

82. Thank you