Most patients with diphyllobothriasis, unless they have severe symptoms, can be safely treated as outpatients. Inpatient care is not generally required but may have to be considered in advanced, resistant, or complicated cases.
Diphyllobothriasis is treated by pharmacologic means; surgical treatment is not required unless otherwise indicated (eg, in a patient presenting with intestinal obstruction). Even in the face of decreased vitamin B-12 levels, less than 2% of patients with diphyllobothriasis develop anemia. Vitamin supplementation may be required in severe cases. As a rule, no activity limitations or restrictions are necessary.
Treatment of diphyllobothriasis is pharmacologic. Because the parasite’s biochemical pathways are different from those of the human host, drug toxicity is directed toward the parasite, the egg, or the larvae. Mechanisms of action vary within a drug class. Antiparasitic actions may include the following:
Inhibition of microtubules, causing irreversible block of glucose uptake
Tubulin polymerization inhibition
Depolarizing neuromuscular blockade
Increased cell membrane permeability, resulting in intracellular calcium loss
Vacuolization of the schistosome tegument
Increased cell membrane permeability to chloride ions via chloride channels alteration
Praziquantel is considered the drug of choice for D latum infection, with niclosamide as an alternative. 
The neurologic and hematologic manifestations of vitamin B-12 deficiency respond well to supplementation. In the case of vitamin B-12 deficiency secondary to diphyllobothriasis, the signs and symptoms may resolve with antiparasitic therapy alone.
Resistant or advanced cases of diphyllobothriasis may require consultation with a gastroenterologist and an infectious disease specialist. Consultation with a hematologist may be considered, depending on the severity of anemia. In the case of suspected obstruction, consultation with a surgeon is indicated.
The patient’s stool should be reexamined on day 7 after therapy to test for cure. The presence of any Diphyllobothrium segments or ova in the stool on posttherapy day 7 constitutes a treatment failure. If the first course of treatment fails, a second identical course of therapy may be administered.
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