eMedicine Specialties > Infectious Diseases > CNS Infections

Cysticercosis: Follow-up

Author: Mossammat M Mansur, MD, Infectious Disease Fellow, Louisiana State University
Coauthor(s): Martin Montes, MD, Fellow, Department of Medicine, Section of Infectious Disease, Baylor College of Medicine; Research Associate, Instituto de Medicina Tropical ‘Alexander von Humboldt', Universidad Peruana Cayetano Heredia, Perú; Linda S Yancey, MD, Consulting Staff, West Houston Infectious Diseases
Contributor Information and Disclosures

Updated: Jul 25, 2008

Follow-up

Further Inpatient Care

• ICU monitoring is necessary in patients with uncontrolled seizures, elevated ICP, or severe extraparenchymal disease.
• If antiparasitic therapy is provided, patients should be hospitalized and monitored during the initial phase.
  • As cysticerci die, neurologic symptoms may worsen because of an increased inflammatory response.
  • Most symptoms associated with antiparasitic therapy develop within 3-5 days of beginning therapy.
  • Antiparasitic therapy may then be completed in an outpatient setting.
• Prior initiation of therapy with antiparasitic medications or corticosteroids, the following steps should be taken:
  • Apply a purified protein derivative (PPD) skin test. Patients in whom the PPD result is positive should be treated with isoniazid along with pyridoxine (vitamin B6) for the duration of their steroid treatment.
  • Because many patients with cysticercosis also have risk factors for strongyloidiasis, these patients should be treated with ivermectin (200 μg/kg administered in two single doses two weeks apart before steroids are initiated.
  • An ophthalmologist should perform an eye examination to exclude ocular cysticercosis.

Further Outpatient Care

• The initial brain reimaging should be performed two months after therapy completion.
• Parasite antigen levels typically fall by 3 months after successful treatment. 
• For patient monitoring, the imaging should be performed on a biannual basis to monitor the cysts.
• If the cysts are growing in the absence of therapy, antiparasitic therapy should be considered.
• In patients with seizures due to neurocysticercosis without calcification, perform imaging studies every 3-6 months. If calcification develops, lifelong anticonvulsant therapy is indicated, and further imaging studies can be performed as needed.
• If results of imaging studies show normalization and seizures are under control after 2 years of therapy, anticonvulsants may be tapered, and further imaging can be performed as needed.
• Patients with calcified lesions and a seizure disorder should be maintained on anticonvulsants indefinitely, and they should undergo imaging studies only as needed.
• Monitor anticonvulsant serum levels to prevent toxicity.

Inpatient & Outpatient Medications

• Discharge medications may include steroids, anticonvulsants, antiparasitics, and cimetidine.
• The anticonvulsants carbamazepine and phenytoin are first-choice treatments.
• Antihelminthic agents: Antihelminthic medications are controversial. Reserve such treatment for select cases. When antihelminthics are used, albendazole is preferable to praziquantel.

Transfer

• Patients with extraparenchymal neurocysticercosis should be treated at hospitals with active neurosurgical and neurological services because emergency procedures such as shunt placement or ventriculostomy may be required in patients with worsening hydrocephalus.
• Arrange transfer if the facility is unable to provide neurologic or neurosurgical care.

Deterrence/Prevention

• Educate patients regarding routes of transmission of cysticerci ova.
• Meat inspection has been effective at preventing transmission of tapeworms in developed countries but has been uniformly unsuccessful in developing countries.
• In areas of endemic cysticercosis, avoid undercooked pork to reduce the risk of intestinal infection.
• Be vigilant about avoiding potential fecal-oral transmission to reduce the risk of neurocysticercosis while in endemic areas. Individuals traveling to such areas should observe the following guidelines:
  • Eat only fruits and vegetables that you have peeled yourself.
  • Thoroughly wash (with water from a clean source) all food prior to ingestion.
  • Maintain good personal hygiene and wash hands prior to food preparation.
• Mass chemotherapy has been used to interrupt transmission in some areas of endemic infection, but disease usually returns within a few years.
• Mass anthelminthic therapy yields only limited success and may cause adverse neurologic events in individuals with undiagnosed neurocysticercosis who receive these drugs. 
• Consider identifying human carriers of tapeworms, possibly based on a history of proglottid passage, and instituting targeted treatment.
• Serologic screening of the contacts of patients should also be considered in the management of cysticercosis, particularly in nonendemic countries when transmission may have occurred within a household (eg, via food prepared by a household worker from an endemic country). 
• Vaccines for prevention of cysticercosis have proven effective for other Taenia species and are in development for T solium.
• Transmission of cysticercal infections to pigs can be prevented with the following measures:
• Changing pig-raising practices in endemic areas by confining the animals and preventing them from roaming freely to avoid contact with infectious ova excreted in human feces
• Improving sanitary conditions and proper disposal of human stool
• Possibly vaccinating pigs (Preliminary studies suggest this may be feasible.)

Complications

• Parenchymal disease causes seizures but few long-term complications. However, studies suggest that childhood infection may be associated with learning disabilities and cognitive dysfunction.
• Extraparenchymal disease may cause elevated ICP, resulting in herniation and death.
• Vasculitis associated with cisternal neurocysticercosis may cause strokes, communicating hydrocephalus, and death.

Prognosis

• Most patients with parenchymal cysticercosis either remain asymptomatic or develop a self-limited seizure disorder.
• Among patients who develop intracerebral calcifications, most have recurrent seizures unless treated with anticonvulsants. If treated with anticonvulsants, the seizures are generally easily controlled.
• Ventricular neurocysticercosis usually requires shunting.
  • Neurosurgery may be complicated by focal neurologic damage.
  • Shunt revisions are often needed unless patients are treated with corticosteroids or antiparasitic drugs. However, even with treatment, some still require subsequent revision.
  • Prior to the use of corticosteroids and antiparasitic drugs, subarachnoid disease was associated with a 90% 10-year fatality rate, even with shunting. With current management, fatalities appear to be rare.
• Good evidence indicates that, once infected, patients are immune to reinfection.

Patient Education

• Patients and their family members should be educated on how to decrease the source of egg carriers by emphasizing improvement in sanitation, separation of pigs from humans, and food-preparation hygiene in endemic areas.
• Family members should be queried about symptoms suggestive of tapeworm infection, such as passing proglottids. They should be treated if symptoms are present.
• Family members should also be screened.
• Patients with seizures and their families should know proper seizure first-aid.
• Patients who have had seizures should know about possible driving restrictions, which, in the United States, vary from state to state.
• Patients who have received a VP shunt should be educated about the signs and symptoms of elevated ICP (possible shunt failure) and meningitis (secondary infection of indwelling hardware).
• For excellent patient education resources, please see eMedicine's Infections Center and Parasites and Worms Center.

Miscellaneous

Medicolegal Pitfalls

• Failure to consider the diagnosis and to perform appropriate testing (primarily neuroimaging studies)
  • The symptoms of neurocysticercosis are nonspecific, but imaging studies usually confirm the diagnosis.
  • The key to diagnosis is careful evaluation of patients who are at risk.
  • Diagnostic testing in patients with seizures who have not undergone previous studies should include neuroimaging studies (either CT scanning or MRI).
  • If patients have suggestive lesions, obtaining further history of exposure, serologic analyses, or imaging studies that show soft-tissue calcifications can confirm the diagnosis.
• Failure to promptly initiate therapy for elevated ICP
  • As with other conditions, symptomatic increased ICP in neurocysticercosis is an emergency.
  • Patients usually present with headaches, but the headaches may not be significantly different from those due to a wide range of other causes.
  • Patients with headaches who also have symptoms of increased ICP or mass lesion require more emergent evaluation. These symptoms include nausea and vomiting, dizziness, visual changes, or abnormal neurologic examination findings.
  • Obstructive hydrocephalus often requires surgical intervention.

Special Concerns

• Identification of the source of infection and prevention of further exposure is paramount in the care of neurocysticercosis.
• Cases of cysticercosis do not need to be reported to the CDC unless local transmission is suspected. In this case, the Division of Parasitic Diseases at the CDC can be contacted through state and local health departments. More information is available at the CDC Web site.
• In 1997, a study by Del Brutto et al found an association between neurocysticercosis and cerebral gliomas in adults, possibly due to astrocytic gliosis that surrounds the cyst. Further study and evaluation are needed.¹²

The authors and editors would like to acknowledge Dr. Martin Montes, Dr. Clinton White Jr., and Dr. Thomas P. Giordano, who were the original authors of this article. They would also like to acknowledge the prior contributions of Dr. John W King to the development and writing of this article.

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