History
The clinical presentation of cysticercosis depends on the number, location, and stage of the lesions present, as well as the host immune response.
In general, the diagnosis of neurocysticercosis should be considered in any individual who is from or has traveled to an area where Taenia solium is endemic and who has new-onset partial seizures (with or without secondary generalization), behavioral disturbances, confusion, stupor, cognitive impairment, or signs of increased intracranial pressure (ICP).
Seizures are the presenting symptom in more than 70% of cases. The seizures frequently begin as simple or complex partial seizures but become generalized in 80% of cases. [5]
Parenchymal disease causes seizures and focal neurologic deficits.
Headache, vertigo, vomiting, papilledema, an altered level of consciousness, and gait disturbances may be present in patients with meningeal cysticercosis.
Neurocysticercosis can present with nearly any type of focal neurologic deficit. Persons with arachnoiditis can present with stroke syndromes due to occlusion of small and medium size intracranial arteries. Arachnoiditis can produce entrapment of cranial nerves resulting in extraocular muscle palsies, hearing loss, facial nerve palsy. Spinal neurocysticercosis can cause spinal cord compression, nerve root pain, focal extremity weakness and sensory deficits, transverse myelitis, or meningitis. [6]
Intraventricular neurocysticercosis (5-10% of all cases) is associated with hydrocephalus and acute, subacute, or intermittent signs of increased ICP without localizing signs. The lateral ventricles are less likely to become obstructed, whereas the fourth ventricle most commonly becomes obstructed. Hydrocephalus develops from the intense and widespread immune response in the subarachnoid space.
Neurocysticercosis-associated inflammation is more severe in children and women than in adult men. Children are more likely to have single, enhancing nodules.
Cysticercoid encephalitis is seen in children and presents with altered mental status associated with seizures and raised intracranial pressure. These patients usually have hundreds of small, viable, or degenerating cysts, with a diffuse inflammatory reaction.
Ocular cysticercosis may decrease visual acuity because of retinal detachment, iridocyclitis, or floating cysticerci in the vitreous. [7]
Heavy infections in skeletal or heart muscle may result in myositis or carditis, respectively.
Rarely, cysticerci may obstruct small terminal arteries or cause a vasculitis, leading to a cerebral infarction.
Children with an acute infection that is massive may present with signs and symptoms of fulminant encephalitis.
Intellectual deterioration due to extensive frontal lobe disease may simulate dementia or parkinsonism.
Chronic basilar meningitis is associated with many forms of neurocysticercosis. In addition to signs of meningeal irritation, increased ICP due to inflammation, edema, or an obstructing cyst may be present.
A study that evaluated 81 cases of neurocysticercosis from 1980-2013 in five centers in Italy and Spain found that when comparing pediatric cases to adult cases, pediatric cases were more likely to have eosinophilia, to have other parasitic infections, and to be asymptomatic. [8]
Physical Examination
Findings vary depending on the number, location, and local effects of cysticerci, as well as on the host response. In general, neurologic deficits, seizures, and subcutaneous or ocular cysts may be present. Cysts may be palpable under the skin. The features of the history assist in focusing the physical examination.
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Cysticercosis life cycle. Image courtesy of the Centers for Disease Control and Prevention.
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MRI of 6-year-old boy from Peru with single right frontal cyst (coronal image). Image courtesy of Eric H. Kossoff, MD.
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Axial image MRI of same patient as in Media file 2. Image courtesy of Eric H. Kossoff, MD.
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CT scan of intraparenchymal cysticercosis with lesions in different stages. Lesions that are breaking down demonstrate peripheral enhancement after intravenous contrast injection, whereas lesions without peripheral enhancement are intact. Typical residual calcification from an old focus of infection is observed in the left occipital lobe. Image courtesy of Fred Greensite, MD.
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Racemose (extraparenchymal) cysticercosis (T1-weighted MRI). Note the cyst in the fourth ventricle, causing obstructive hydrocephalus. Image courtesy of Fred Greensite, MD.
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Racemose cysticercosis (T1-weighted MRI). Note cluster of cysts anterior to the pons and inferior to the hypothalamus in a different patient. Image courtesy of Fred Greensite, MD.
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Racemose cysticercosis (same patient as in Media file 6). Note the enhancing margin of the cysts in the suprasellar cistern and in the left sylvian fissure after gadolinium injection (T1-weighted MRI). Image courtesy of Fred Greensite, MD.
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Racemose cysticercosis (same patient as in Media files 6-7). Coronal image (postgadolinium T1-weighted MRI) posterior to the slice in Media file 7. Cysts in this slice (below the hypothalamus) do not have enhancing margins. Also, unlike intraparenchymal lesions, scolexes are typically not identified in the cysts of racemose cysticercosis. Image courtesy of Fred Greensite, MD.
