History and exam
Key diagnostic factors
common
worm segments in stool
Patients may present after noticing proglottids in the toilet bowl or after feeling the spontaneous movement of proglottids through the anus.
Spontaneous egress of proglottids per rectum is most frequently reported in Taenia saginata or T solium infestation.
increased intracranial pressure
Patients with neurocysticercosis may have increased intracranial pressure due to hydrocephalus or diffuse cerebral edema. It can occur in the setting of intraventricular and subarachnoid disease, and less commonly in intraparenchymal disease, and can be life threatening.
seizures
Patients with central nervous system manifestations may present with seizures.
All patients from endemic areas who present with new-onset seizures require evaluation for neurocysticercosis.[42]
hepatomegaly
Signs of cysts in the liver may include hepatomegaly.
cough
May indicate cysts in the lungs.
hemoptysis
May indicate cysts in the lungs.
uncommon
allergy manifestations
Rupture or leakage of tapeworm cysts into the peritoneum usually results in acute or intermittent allergy manifestations (urticaria or anaphylaxis).
Minimal inflammatory reaction may occur with Taenia saginata, suggesting that these tapeworms have an "irritative" effect, which may cause clinical symptoms.
anemia
Diphyllobothrium latum infections may cause anemia due to absorption of vitamin B12 by the tapeworm.
About 40% of people harboring the worm have reduced serum vitamin B12, but fewer than 2% develop anemia.[37]
Other diagnostic factors
common
asymptomatic
Many infections are asymptomatic.
Hydatid cysts are frequently only discovered as incidental findings at autopsy.
vague intestinal symptoms
Patients with intestinal disease may present with vague symptoms including abdominal pain, hunger pain, sore tongue, sore gums, loss of appetite, increased appetite, weight loss, bloating, constipation, diarrhea, sensation of "something moving inside," and/or nausea.[2]
Patients infected with Hymenolepis nana infection are often children with loose bowel movements. H nana infection can also present with diffuse persistent abdominal pain.
sleep disturbance
Many children with Hymenolepis nana have sleep and behavioral disturbances that clear after tapeworm eradication.
headaches
Central nervous system manifestations can cause headaches.
Patients from endemic areas who have migraine symptoms or chronic headaches of unclear etiology should be considered for evaluation for neurocysticercosis.
rash
Many patients with Hymenolepis nana have itchy skin eruptions.[27] Patients with a ruptured or leaking echinococcal cyst may have urticarial eruptions.
uncommon
subcutaneous nodules
pyrexia
Signs of cysts in the liver may include evidence of sepsis if biliary tree communications are present with subsequent superinfection.[41]
visual disturbances
A small number of patients have ocular involvement. Funduscopic examination is recommended to exclude intraocular cysticerci.[33]
Risk factors
strong
living on farms
Farmers and those living in endemic regions where pigs are raised and, in the case of Echinococcus species, living in regions where dogs herd sheep, are at increased risk of tapeworm infection.
poor hygiene
Tapeworm eggs can be sticky, and are often found under the fingernails of carriers.
Food prepared by carriers can lead to infection in consumers if poor hygiene techniques are employed.
eating or handling undercooked meat
Infection with Taenia species may occur whenever undercooked beef (infected with T saginata cysticerci) or pork (infected with T solium cysticerci) is ingested.
eating or handling undercooked fish or crustaceans
Infection with Diphyllobothrium latum may occur whenever undercooked fish or crustaceans are ingested.
ingestion of contaminated water
Infection with Diphyllobothrium latum may occur when water contaminated by infected fish/crustacean feces (or fruit/vegetables washed in water contaminated by infected fish/crustacean feces) is ingested.
dog owners
Infection with Echinococcus granulosus may occur from contact with contaminated dog feces.
age <12 years
Children ages <12 years seem to be at an increased risk of tapeworm infection (e.g., Hymenolepis nana), in particular when other risk factors such as rural living, close proximity to animals, poor hygiene, and lack of access to safe drinking water are present.[21][22] One cross-sectional study in rural China found antibodies for neurocysticercosis in up to 22% of the children tested in some schools, higher than the percentage found in adults in surrounding villages.[23] Children may also be more likely to accidentally ingest contaminated feces from pets, increasing the risk of Echinococcus granulosus or E multilocularis infections. Many children do not have symptoms, which increases the risk of spreading to others, especially if hand hygiene is poor.
weak
outdoor pursuits
Poor hand hygiene commonly adopted when camping and pursuing other outdoor activities increases the risk of accidentally ingesting contaminated fox, canid, and/or cat feces and developing Echinococcus multilocularis or E granulosus infections.
Accidental ingestion of infected insects can result in Hymenolepis nana infection.
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