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Internal Medicine

Tapeworm infestation

Parasitic disease due to infection with tapeworms belonging to the genus Taenia.

Parasitic disease due to infection with tapeworms belonging to the genus Taenia.

  • Adult form: Taeniasis
  • Larval form: Cysticercosis

Epidemiology

Life cycle:

taenia_lifecycle
Life cycle of the eucestode Taenia: Inset 5 shows the scolex, a disk with hooks on the end. Inset 6 shows the tapeworm’s whole body, in which the scolex is the tiny, round tip in the top left corner, and a mature proglottid has just detached | Centers for Disease Control and Prevention – http://www.dpd.cdc.gov/dpdx/images/ParasiteImages/S-Z/Taeniasis/Taenia_LifeCycle.gif, Public Domain, https://commons.wikimedia.org/w/index.php?curid=776600
  • Principal intermediate hosts:
    • Taenia solium (pork tapeworm)
    • Taenia saginata (beef tapeworm)
  • Man is the only definitive host for both

Aetiology

Food or drinking water contaminated by tapeworm eggs from human feces

  • Untreated water
  • Uncooked meat
  • Uncooked vegetables

Clinical features

Taeniasis

Most infections with adult worms (Taeniasis) are asymptomatic
  • If symptomatic (severe infections), nonspecific complaints:
    • Nausea
    • Pain in abdomen
    • Diarrhoea

Cysticercosis

Carriers have an increased risk of developing cysticercosis by repeated autoinfection.
  • Common target organs:
    • Brain
    • Muscle
    • Subcutaneous tissue
  • Clinical manifestations depend on the location, number and size of cysts in the brain and host inflammatory response.
    • Viable cysts generally do not elicit a strong response
    • On the other hand, degenerating cysts provoke a vigorous host response.

Neurocysticercosis

M/C parasitic infection of the CNS
  • Partial or generalized seizure (20-50% cases of all seizures)
  • ↑ Intracranial tension
  • Focal neurological deficits
  • Disturbed consciousness or behavior

Diagnosis

Stool examination:

  • Demonstration of eggs or proglottids
    • Patients may pass motile segments of worms through anus

CSF examination:

  • CSF eosinophilia

Enzyme-linked immunotransfer blot (EITB):

90% sensitivity & specificity
  • Detection of antibodies

CT and MRI (brain):

Diagnostic
neurocysticercosis
Magnetic resonance image in a person with neurocysticercosis showing many cysts within the brain | Public Domain, https://commons.wikimedia.org/w/index.php?curid=1070993

Management

  • Anti-cysticercosis medications:
    • Niclosamide
    • Praziquantel
  • Steroids (2-3 days before and during treatment)
    • During treatment, dying parasities can provoke severe life-threatening inflammatory response which can be prevented by giving steroids

Neurocysticercosis

  • Observation
  • Anticonvulsant medication
    • Children having seizures and calcified, inactive lesions on CT do not require specific therapy, apart from anticonvulsants.
  • Antiparasitic drugs
  • Surgery
  • Anti-cysticercal drugs:
    • Albendazole and praziquantel
    • Contraindicated for spinal or ocular disease as drug-induced inflammation may produce irreversible organ damage
      • These lesions, as well as those within the ventricular system, are best managed surgically.

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