Mainly affects communities in developing countries of Latin America, Asia, and Africa.
Presentation is variable and is dependent on size, location, and condition of the cyst. Extra-intestinal manifestations include cysticercosis (can affect any organ), hydatidosis (can affect any organ but typically the liver and lungs), and neurocysticercosis (affecting the central nervous system).
Diagnosis is made by stool examination and serology; radiology is necessary for extra-intestinal manifestations.
Intestinal infection is treated with antiparasitic therapy only, while extra-intestinal infection requires additional treatments including corticosteroids, anticonvulsants, and surgical intervention. Patients with neurocysticercosis may present with increased intracranial pressure, which is a medical emergency.
An infection by parasitic flatworms of the taxonomic class Cestoda. The worms can vary in length from a few millimetres to 25 metres, and can contain thousands of proglottids (tapeworm segments). Adult tapeworms usually possess an anterior scolex (head; plural 'scolices') that may be modified with structures or organelles that attach to the host. When mature, these parasites reside in the intestinal tract of definitive carnivorous hosts, and larval cysts are formed in the intermediate hosts.
Tapeworms cause intestinal infection in humans when the immature cysticercoid larvae attach to the intestinal mucosa using the scolices, and grow by production of proglottid segments. Certain cestodes can also cause extra-intestinal infections. Ingested eggs hatch in the intestines and larvae migrate to extra-intestinal tissues, where they encyst. Cysts due to Taenia solium within the central nervous system are referred to as neurocysticercosis, and cysts in other locations are termed cysticercosis. Cysts due to Echinococcus granulosus are referred to as cystic echinococcosis or hydatid cysts, and cysts due to E multilocularis are referred to as alveolar echinococcosis.
Taeniasis (or taeniosis) refers to infection with tapeworms of the genus Taenia (e.g., T solium, T saginata).
History and exam
Key diagnostic factors
- presence of risk factors
- worm segments in stool
- increased intracranial pressure
- allergy manifestations
Other diagnostic factors
- vague intestinal symptoms
- sleep disturbance
- visual disturbances
- living on farms
- poor hygiene
- eating or handling undercooked meat
- eating or handling undercooked fish or crustaceans
- ingestion of contaminated water
- dog owners
- outdoor pursuits
1st investigations to order
- stool examination
- full blood count
- enzyme-linked immunoelectrotransfer blot (EITB)
- Echinococcus enzyme-linked immunosorbent assay (ELISA) and Western blot serology
- computed tomography of brain
- magnetic resonance imaging of brain/spine
Investigations to consider
- screening for tuberculosis and strongyloidiasis
central nervous system disease: with elevated intracranial pressure
central nervous system disease: without elevated intracranial pressure
hepatic or thoracic disease
Jose A. Serpa, MD, MS, CTropMed
Associate Professor of Medicine
Infectious Diseases Fellowship
Baylor College of Medicine
JAS declares that he has no competing interests.
Andrew Chou, MD
Baylor College of Medicine
AC declares that he has no competing interests.
Dr Jose A. Serpa and Dr Andrew Chou would like to gratefully acknowledge Dr Christina Coyle and Dr Maheen Saeed, previous contributors to this topic.
CC is an author of several references cited in this topic. MS declares that she has no competing interests.
William A. Petri, Jr, MD, PhD, FACP
Chief and Professor of Medicine
Division of Infectious Diseases and International Health
University of Virginia Health System
WAP declares that he has no competing interests.
Linda Kalilani, MBBS, MPhil, PhD
College of Medicine
University of Malawi
LK declares that she has no competing interests.
Paul Roberts, MD
PR declares that he has no competing interests.
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