Neurocysticercosis

1. DR. AJAY KUMAR SINGH
DNB NEUROSURGERY
VPIMS

2. Parasitic infection may involve the CNS
 Neurocysticercosis
 Echhinococcus
 Toxoplasmosis
 Amoebiasis
 Schistosomiasis
 Malaria

3. NEUROCYSTICERCOSIS
 A zoonosis caused by larval stage of Taenia solium
(cysticercus)
 M/C helminthic infection of CNS, and a leading
cause of acquired epilepsy worldwide
 Cysticercus usually involves subcutaneous tissue,
muscle, brain, eye and heart.

4. Historical perspective
 The earliest in 2000 BC in works of ancient Egyptians.
 Aristotle (384–322 BC) reveals that the infection of pork with
tapeworm was known to ancient Greeks.
 Forbidden by Jewish and Islamic dietary laws
 Rumler (1555) described cysticercosis.
 In 1850, Küchenmeister fed pork containing cysticerci to
prisoners awaiting execution and later recovered the developing
and adult tapeworms from their intestines during autopsy.
 By 19th century-----eggs of T. solium.

6. EPIDEMIOLOGY
 Endemic in Latin America, China, Southeast Asia, India, and
sub-Saharan Africa.
 In India, Kashmir, largely populated by Muslims, and from
Kerala, as education and hygienic standards are good in the state.
 The NIMHANS, Bangalore reported a diagnosis of NCC in 2%
of unselected series of epilepsy patients.
 In a study from New Delhi, NCC accounted for 2.5% of all
intracranial space occupying lesions.

7.  The solitary form of the disease (solitary cysticercus granuloma,
SCG) is the commonest presentation, reported in nearly 2/3rd of
all patients with NCC.
 25-50% of patients presenting with partial seizures are diagnosed
with a SCG on the CT scan.
 Pork eaters: <1-2% and more than 95% of Indian patients
with NCC are vegetarians.

8.  Cysticercosis is highly prevalent in the northern States of
 Bihar, Orissa, UP and Punjab. In a rural pig farming community
of Mohanlalganj block, Lucknow district, UP, the prevalence of
taeniasis was found to be 18.6%.
 In the same community, active epilepsy was confirmed in 5.8%
of the populations and 48.3% of people with epilepsy fulfilled
either definitive or probable diagnostic criteria for NCC.

10. TAENIA SOLIUM

11. Patient with
Taeniasis
Egg or
Proglottid
s
Susceptible
population
Internal autoinfection: migration of
the egg from the intestine into the
stomach
External autoinfection: Ingest food contamiated
by egg
Heteroinfection: Ingest food contaminated
by egg
Route of transmission

12. LIFE CYCLE OF T. SOLIUM
3 stages to the life cycle:
 Adult, embryo and larva.
Infection with the adult worm: Undercooked infested pork.
 The encysted larva released in the intestine into an adult over about 2
months.
Infection with the larva
 Food or contaminated water, Feco-oral autoinoculation ,
Autoinfection
 In duodenum of man and pig the shell of ova dissolve and hatched
embryo burrow through the small bowel wall to enter circulation….
Brain, eye, muscle, heart.

13. http://www.dpd.cdc.gov/dpdx/

15. Disease States
 Taeniasis = adult tapeworm in small intestine
 Usually asymptomatic (eggs or proglottids in feces)
 Vague abdominal symptoms occasionally report
 Cysticercosis = T. solium larvae in human tissues (eg,
muscle)
 Usually asymptomatic
 Painless subcutaneous nodules in arms and chest
 Neurocysticercosis (NCC) = cysts in the central
nervous system
 Most severe manifestation

16.  In the intermediary host, embryos develops a cyst wall in
= 2 months (immature cyst) which matures in = 4 months
to a larva.
 Usualy rapidly eliminated by the immune system.
 Many dies naturally within 5-7 years or with cysticidal
therapy producing an inflammatory reaction with the
collapse of cyst (granular nodular stage) and sometimes
calcify (nodular calcified stage).

17. PATHOGENSIS
The cysticerci are fluid-filled vesicles consisting of two main
parts:
 (1) the vesicular wall
 (2) the scolex.
The vesicular wall is a membranous structure composed of
three layers:
 (1) an outer or cuticular layer.
 (2) a middle or cellular layer with pseudoepithelial structure.
 (3) an inner or reticular layer.
The invaginated scolex has a head or rostellum armed with
suckers and hooks and a rudimentary body or strobila that
includes the spiral canal.

19.  Cysticerci in the brain parenchyma are usually small and tend
to lodge in the cerebral cortex or the basal ganglia.
 Size, 10 mm because of pressure in parenchyma.
 M/c location of subarachnoid cysticerci are the Sylvian
fissure and the basal cisterns.
 Ventricular cysticerci are usually single.
 They may be attached to the choroid plexus or may be freely
floating in the ventricular cavities.
 M/c location IV ventricle.
 Intraventricular cysts tend to acquire large size.

20.  Cysticerci located in the basal cisterns may undergo a
disproportionate growth of their membrane, with extension
processes attached to each other, which tend to gather in
clusters resembling a bunch of grapes (racemose
cysticercosis).
 In these cases, the scolex is frequently absent and cannot be
identified even after microscopic examination. It is believed
that their scolex regresses as the result of a hydropic
degenerative process resulting from the availability of space
or the continuous entrance of CSF into the vesicles.

21.  It is a common practise to refer to cysts that have a scolex as
Cysticercus cellulosae, and those without a scolex as
Cysticercus racemosus; however, such terminology may
create confusion because they are both forms of the same
parasite—T. solium—and commonly coexist in the same
patient.

22. Neurocysticercosis: the clinical disorder
Morphologically, by Escobar, four stages of development and
regression of the cysticercous in the CNS are recognized:
i. Cystic or vesicular stage is viable and comprises of
well-defined, fluid-filled membrane containing scolex.
ii. Degenerating, colloid stage; It appears as eosinophilic
structure in which components of the bladder and scolex
are in various stages of disintegration and tissue around
have multinuclear giant cells, foamy macrophages, and
neutrophils.
iii. Nodular stage.
iv. The fibrous nodule undergoes mineralization and
calcification.

23. Classification of neurocysticercosis into active
and the inactive forms
 Active forms of NC
Arachnoiditis
Hydrocephalus
Parenchymal cysts
Brain infarct secondary to vasculitis
Mass effect due to large cyst or the cyst lumps
Intraventricular cysts
Spinal cyst
 Inactive forms of NC
Parenchymal calcifications
Hydrocephalus secondary to meningeal fibrosis

24. Anatomical classification of
neurocysticercosis
 1. Parenchymal NC
 2. Extraparenchymal NC
a. Ventricular
b. Subarachnoid
 3. Mixed

25. Clinical Features
A. Solitary Cerebral Cysticercus Granuloma
Two important types - parenchymal NCC and extraparenchymal
Initially ---“immature tuberculoma” or “microscopic
tuberculoma” and these patients were treated with ATT.
 In late 1980---Vellore, India.
 Seizures, m/c manifestation of SCG.
 Partial seizure or Genralised.
 Status epilepticus occurs in > 1% of patients with single
lesions.
 Lack of progressive neurological deficit and increased ICP
 Following resolution of SCG. The majority of SCGs resolve
by 1 year.

26. B. Meningeal Cysticercosis
 It elicit an intense inflammatory reaction in the SAS, with formation
of a dense exudate, causes abnormal thickening of the leptomeninges
at the base of the skull, from the optochiasmatic region
(optochiasmatic arachnoditis) to the foramen magnum.
 Arachnoiditis caused by cysticercus can cause entrapment of nerves
exiting from the brainstem.
 Visual field defects, decreased visual acuity and third nerve
entrapment manifesting as diplopia.
 Symptoms or signs of ICP pressure d/t blocakage of Foramen of
luschka’s and foramen of Magendie’s.

27. D. Intraventricular neurocysticercosis
 15-55% in NCC.
 The intraventricular cysts become symptomatic at the time of
implantation due to obstruction of the CSF flow, 38% with
rapid clinical deterioration.
 Inflammation around dead or dying cysts produces
ependymitis, scarring, obstruction and ventriculitis.
 M/c in IV ventricle.

28. Spinal
 1.6−13% in NCC.
Leptomeningeal (Extramedullary) form: It is 6−8 times more
common than the intramedullary form. By downward migration of
larva from the cerebral to the spinal SAS.
Intramedullary form: Uncommon. Haematogenous spread.
 The parasite commonly lodges in the thoracic spinal cord.
 Subarachnoid cysticerci of spinal canal cause non-specific clinical
picture of radicular pains and motor deficit of subacute onset and
progressive course

29. Diagnosis
A. Serological diagnosis
 Complement fixation tests (CFT) and indirect haemagglutination
tests IHA.
 IHA test are more sensitive and specific than the CFT.
 The IHA technique was found to be specific for the detection of
antibodies in CSF samples while cross reactions were observed with
ELISA.
 The gold standard in serodiagnosis is the Electroimmunotransfer blot
asssay (EITB).

30. Radiological investigation
 Plain X-rays of muscles and skull may show rice grain or
cigar-shaped calcification.
 In the CT scan, single or multiple, variable sized, low density
rounded cystic lesions with a small hyperdense eccentric
mural nodule (spot) representing the scolex giving a “starry
night” effect in the parenchyma, are suggestive of NCC.
 Ring enhancement occurs either due to inflammatory reaction
or granuloma formation.

32.  Plain and contrast CT may not delineate an intraventricular
cyst. It demonstrates hydrocephalus and a round
enlargement of the IV ventricle.
 Ventricular or periventicular enhancement suggests
ependymitis. In cases of hydrocephalus, contrast CT
ventriculography is required for localisation of CSF
obstruction and to confirm the actual presence of the
parasite.
 A regular rounded filling defect similar to an inverted cup
suggests the presence of a cyst.

33. 1. Vesicular stage (active, live or developing cyst form):
 This presents as a fine, brittle, translucent membrane of
uniform thickness with a small denser area corresponding to the
scolex and containing colourless transparent fluid similar to
CSF intensity on MRI.
 The scolex appears as a mural nodule of high-signal intensity
on T1 and low-signal intensity on T2 sequences like a hole or
pea-in-a-pod.
 Cysticercosis cellulosae
 Cysticercus racemosus.

34.  2. Colloid stage (degenerating cyst): The membrane becomes
thick and opaque and clear fluid is replaced by whitish gel
appearing as high-signal intensity on T1 weighted images.
 3. Granular stage: The gel undergoes calcium deposition.
 Ring enhancement occurs after gadolinium injection
 and there is variable degree of perilesional oedema.
 4. Calcified stage: This appears as hypo-intensities on
 both T1 and T2 sequences.

35.  A pig brain showing a viable cyst in the external side of the
brain.
 A viable intraparenchymal cyst (MRI, FLAIR),
 A viable cyst with signs of inflammation (MRI, T1 with
contrast),
 A degenerating cyst or enhancing lesion (Solitary Cysticercal
Granuloma, MRI, T1 with contrast),
 A calcified cyst (non-contrasted CT)

36. Diagnostic criteria for
neurocysticercosis (NCC)
Absolute criteria
 • Histological demonstration of the parasite from biopsy
of a brain or spinal cord lesion
 • Evidence of cystic lesions showing the scolex on
neuroimaging studies
 • Direct visualization of subretinal parasites by
fundoscopic examination

37. Major criteria
 Evidence of lesions highly suggestive of NCC on
neuroimaging
 Positive serum immunoblot for the detection of
anticysticercal antibodies
 Resolution of intracranial cystic lesions after therapy with
albendazole or praziquantel
 Spontaneous resolution of small single enhancing lesions

38. Minor
 1. Lesions compatible with neurocysticercosis on neuroimaging
 studies
 2. Clinical manifestations suggestive of neurocysticercosis‖
 3. Positive CSF ELISA for detection of anticysticercal antibodies
or cysticercal antigens
 4. Cysticercosis outside the CNS ¶
Epidemiologic
 1. Evidence of a household contact with T. solium infection
 2. Individuals coming from or living in an area where
cysticercosis is endemic
 3. History of frequent travel to disease endemic areas

39. Prevention and treatment
 Improved animal husbandry
 Enhanced personal hygiene
 Thorough cooking/ freezing of pork to kill cysticerci
 Enhanced environmental sanitation
 proper disposal of human feces
Vaccination
 Till date no vaccine has been developed against the
T. solium .

41. Treatment
Role of antihelminthic drugs
 Albendazole :15 mg/kg/day for 8−21 days
 Praziquantel : 50−100 mg/kg/day for 1-30 days.
Recently, ultrashort single day therapy with praziquantel 75
mg/kg/day divided in three 25 mg/kg/doses each, given at 2
hourly intervals (7−9−11 AM)
Four hours later (3 PM), 10 mg dexamethasone I/M or 80 mg oral
prednisolone is given followed by the same doses of steroids for
the next three mornings.
Role of corticosteroids
 Steroids prevent secondary inflammatory reactions triggered by
acute destruction of the parasite

42. Role of antiepileptic drugs
 Prevent seizure recurrence, until lesion is actively degenerating
 The AED may be withdrawn once complete resolution of the
granuloma is demonstrated on follow-up imaging studies.
 However, the risk of seizure recurrence remains high if the
granuloma resolves leaving behind a calcific residue.
 In the case of resolution with calcification, longer duration of
AED should be considered. It is unclear how long AEDs should
be administered to individuals with SCG that resolve with
calcification

43. Surgery
 In general, surgery is required when:
 • The diagnosis is uncertain.
 • Cysts exhibit tumour-like effect (oedema and/or mass
effect) which are refractory to medical treatment.
 • Hydrocephalus.
 • Intraventricular cysticerosis is diagnosed.
 • Presence of acute or sub-acute rise of ICP.
For parenchymatous type of cysticercosis, the following
surgical approaches are recommended

44.  Stereotactic excisional biopsy/open craniotomy and cyst
removal is recommended in cases of a single giant
cortical cyst or large clumps exhibiting tumour like
behaviour.
 Supratentorial decompressive craniectomy/craniotomy/
lobectomy is undertaken when the pseudotumour type of
oedema is refractory to medical treatment.

45.  For Intraventricular and subarachnoid forms of NCC, the
surgical procedure usually used which includes a shunting
procedure for managing hydrocephalus, cyst removal or
excision through a posterior fossa craniotomy for fourth
ventricle/subarachnoid cysts and supratentorial open or
stereotactic craniotomy for subarachnoid third or lateral
ventricle cysts
 Endoscopic Excision in case of intraventricular cyst.

46. Hydatid disease
 Hydatid disease is caused by the parasite tapeworm Taenia)
Echinococcus.
 Recognised since the times of Hippocrates (410−379 BC) and
Galen (131−210 AD).
 Guesnard reported the first case of cerebral hydatid cyst, while
vertebral hydatidosis was first described by Chaussier in 1807.
 In 1808, Rudolph coined the term Echinococcus to describe the
vesicular worms.

47. EPIDEMIOLOGY
 Uruguay, Argentina, Australia, New Zealand and South Africa.
Europe and Central Asia.
 In India, the disease has been reported from different parts of the
country, but is more common in the Kurnool district of Andhra
 Pradesh, in Punjab and in the Madurai district of TamilNadu.

49. LIFE CYCLE
There are two main varieties of Echinococcus:
 (i) Echinococcus granulosus, (cystic) causing the hydatid disease
 (ii) Echinococcus multilocularilar (alveolar hydatid) disease
(caused by Echinococcus multilocularis).
 Echinococcus granulosus produces hydatid cysts in man.
 Its larval form is called the hydatid cyst.
 The definitive hosts dog.
 The mature tapeworms live in the small intestines of the dog. The
intermediate host includes all mammals, especially sheep. Man --
by accidental contamination.

50.  The embryo can successfully pass through the capillary
filters of the liver and lungs and get entry into the systemic
circulation and thus reach the CNS, the cranium and the
vertebrae.
 The liver is affected in about 65% of cases,
 The lungs in about 15−20%
 The brain in about 2−5%.

51. Structure of the Hydatid Cyst
 The hydatid cyst has three layers:
 A) The outer pericyst, composed of modified host cells. This
layer is a dense fibrous zone in the liver and other organs.
 B) The middle laminated membrane which is acellular and
allows the passage of nutrients.
 C) the inner germinal layer where the scolices (the larval stage of
the parasite) and the laminated membrane are produced.

52.  The middle laminated and inner germinal layer made true wall
of the cyst, endocyst.
 Daughter cysts are small spheres containing the protoscolices.
The inner-most layer which is the germinative or fertile
membrane performs two major functions
 1) production of the laminated membrane outward
 2) germination of the later generation scolices inward.

53. CEREBRAL ECHINOCOCCOSIS
Pathology
 The fluid in the cyst is watery and colourless, but, occasionally,
may be whitish or yellow.
 It contains scolices, brood capsules (referred to as hydatid sand)
and, occasionally, daughter cysts.
 The cyst is well delineated from the surrounding brain. Cerebral
cysts are nearly always single, large and confined to the white
matter.

54.  Multiple hydatid cysts represent a secondary form of the
disease, resulting from either rupture of a cyst in the left side of
the heart, or traumatic, spontaneous or surgical rupture of the
primary cerebral hydatid cyst.
 Secondary cysts lack a brood capsule and are infertile.
 Cerebral hydatid cysts are more common in children and young
adults

55.  .
 Mostly supratent and tend to occur in the distribution of MCA
 As the hydatid cyst grows in size, it compresses and distorts
the surrounding brain tissue and displaces blood vessels.
 There is no neural tissue reaction, unless the cyst is disturbed.
 Daughter cysts are more frequent in the brain than elsewhere.

56.  The cyst may cause raised ICP by its size and/or interference
with CSF pathways.
 The cyst, as it grows, may produce asymmetry of the cranium,
and localised thinning, erosion and bulging of the calvarium
overlying the cyst.
 The cyst does not infiltrate the bone. ?
 The average growth of a hydatid cyst has been estimated at
about 1.5 cm/ year to 10 cm/year.

57. Clinical feature
 Cerebral hydatid cysts are most commonly seen in children
and in young adults.
 While in adults, focal neurological signs, mental changes.
Children, Seizures, features of raised ICP.
 Crackedpot resonance (McEwen’s sign) is common in
children.
 Macrocrania, Papilloedema.
 The cyst is located most commonly in the posterior part of the
cerebral hemisphere and hemianopia is an important sign.
 Contralateral hemiparesis may be present.

58.  Arana-Iniguez has described what is known in
 Uruguay as the tetrad of Schroeder:
 (a) A patient who is a country dweller
 (b) In good general condition
 (c) With the picture of raised intracranial pressure
 (d) Without marked focal findings.
 This tetrad was seen in 86% of his cases. This is, however, not
specific for hydatidosis.

59. Diagnosis
 A raised eosinophil count in the blood,
 A positive Casoni’s intradermal skin test and CFT.
 Indirect haemagglutination,
 Immunoelectrophoresis and indirect immunofluorescence.

60.  X ray skull, raised intracranial
pressure. The skull vault
overlying the cyst may show
localised thinning, erosion and
bulging.
 Angiograms show marked
displacement of the vessels
which curve around the
periphery of a circular
avascular area.

61.  The CT scan reveals an intraparenchymal hypodense lesion
with a clearly defined margin. The cyst =CSF, but hydatid
sand, if present, may increase the attenuation values.
 Usually significant ventricular shift and HCP seen.
Perilesional oedema and
mural nodules are significantly
absent, d/d lesion from a brain abscess
and other cystic tumours.
 Rarely calcification.

62.  On the MR, the unilocular cysts are large and spherical with
thin walls which partially reach the brain surface.
 In MRI scan, these lesions have high signal intensity on T2
and low signal intensity on T1, and are slightly hyperintense
with respect to CSF on balanced images.
 Calcification, infection, rupture of entodermic membrane or
perifocal oedema.
 D/d, arachnoid cyst and epidermoid tumuor.
 Epidermoids usually have a slightly hyperintense signal
intensity on proton density weighted.
 MR images and they usually engulf nerves and vessels,
whereas arachnoid and hydatid cysts displace adjacent
structures.
 Racemose cysticercosis.

64.  Treatment
 Surgical  total removal of the cyst without rupturing it so
as to prevent contamination of the operative field with living
scolices.
 The craniotomy should be large and that the cyst wall be
exposed by a series of radiating cortical incisions, termed
Dowling’s episiotomies.
 It is advisable to cover the surrounding exposed brain with
cetrimide soaked in normal saline to prevent contamination
of the surrounding brain by accidental rupture of the cyst.

65.  The head is then lowered so that the cyst is dependent,
facilitating its expulsion which is helped by gently irrigating
the cleavage plane between the cyst and the brain with saline.
 A thin cyst wall, periventricular location and micro-adhesions
to the surrounding brain tissue leads to rupture in about 12%
of cases resulting in distal deposit of secondary cysts
elsewhere on follow-up.

66.  If accidental rupture of the cyst occurs, irrigation with
hypertonic saline, destroying the scolices through osmotic
desiccation.
 Intracystic injection of 10% formalin, 0.5% silver nitrate,
hydrogen peroxide or 1.0% acqueous iodine hypertonic saline
has been used to destroy residual larvae.

67.  Saline injection into the opposite lateral ventricle has also been
performed to facilitate the removal of cysts without spillage.
 Aspiration or opening of the cyst should be avoided.
 In deep-seated cysts located in eloquent and vital areas such as
the brainstem, management by internal decompression by
aspiration followed by complete reoval of the cyst wall,
protecting the surrounding cisterns and CSF spaces may be
done without anaphylaxis or dissemination.

68.  After primary infestation, the host develops an immunologic
response that is protective against re-infection but not effective
against the lodged parasite. The absence of anaphylaxis has
been explained by evasion of the host immune attack against
the parasite by the suppression of T-lymphocyte function and
inhibition of macrophage-lymphocyte interaction.
 Rapid decompression caused by evacuation of a large cyst
may result in disturbances in autoregulatory mechanisms,
which need to be watched for in the postoperative period.

69.  Praziquantel does not pass through the hydatid cyst wall, but
high levels are seen in the CSF.
 As it has a powerful lethal action on free scolices, it may be
used in the event of spillage of the cyst fluid.
 Although protoscolicidal agents do not penetrate large
hydatid cysts in sufficient quantity, highly soluble
albendazole can be used over a prolonged period for the
treatment of small multiple cysts in inaccessible sites.

70. Alveolar Hydatid Disease
Echinococcus multilocularis
Clinical Manifestations
 FCD, seizures, and intracranial hypertension.
 Spinal cord involvement, associated with root pain and
motor or sensory deficits below the level of the lesion, is
more common in cystic hydatid disease than in alveolar
hydatid disease, but it may be observed in both.

71. Diagnosis
 On neuroimaging studies, alveolar hydatid disease is
characterized
 by multiple lesions surrounded by edema, with ring-like
enhancement mimicking other infectious or neoplastic
diseases of the CNS.
 CT is better than MRI for demonstrating lytic lesions in
vertebral bodies.
 Immunologic diagnosis is better with alveolar echinococcosis
than with cystic hydatid disease.
 ELISA using purified and recombinant antigens (Em2 and
II/3-lO ELISA) is the test of choice.

72. Pathology
 E. multilocularis cysts are small, group in clusters, elicit a
severe inflammatory reaction from the host, and tend to
metastasize both locally and distantly.
 They are usually located within the brain parenchyma.8!
Primary hydatid disease of the heart may be the source of an
embolic cerebral infarction that is generally located in the
territory of the middle cerebral artery.

73. Treatment
 Invasive, total surgical removal usually requires resection
of adjacent tissue.
 Albendazole, before surgery or in inoperable alveolar
hydatid disease.
 With a combination of surgery and cysticidal therapy, 50%
of lesions regress, 40% remain static, and 10% continue to
grow.

74.  Ramamurthi and tandon 3rd edition.
 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2912527/
 Youman’s 6th ediction
 NCC indian sscenario Med update 2012 vol 12.

75. THANK YOU