History

Most persons with diphyllobothriasis are asymptomatic. The vast majority of patients who are diagnosed present with passage of proglottids.

Among persons with diphyllobothriasis who are symptomatic, the following are the most common symptoms^[30]:

Passage of proglottids
Indigestion or dyspepsia
Abdominal discomfort

Other, less common, symptoms include the following:

Fatigue
Diarrhea
Dizziness
Weakness (rare)
Numbness of extremities
Sensation of hunger
Pruritus ani

Gastrointestinal (GI) obstruction is rare, but when it does occur, it manifests as acute abdominal pain associated with vomiting, distention, or both.^[19]

Megaloblastic anemia is also rare. Studies note that about 40% of patients have decreased serum vitamin B12 levels, but fewer than 2% of patients are anemic.^{[31, 1]}Patients with an underlying problem (eg, celiac disease or congenital malabsorption) are at higher risk of developing a symptomatic infection. Anemic patients can present with pallor, breathlessness, and neurologic symptoms such as weakness, numbness, and disturbances in coordination. The symptoms depend on the severity.

Physical Examination

D latum has an unusual affinity for vitamin B12, and the presentation of diphyllobothriasis may resemble that of megaloblastic anemia. No typical examination findings are noted, except for those seen in severe cases of anemia. Because significant anemia affects less than 2% of persons infected with D latum, most patients with diphyllobothriasis have no signs of illness.

The following physical findings associated with diphyllobothriasis are rare and are most likely related to underlying nutritional anemia:

Pallor
Glossitis
Dyspnea
Tachycardia
Weakness
Hypoesthesia
Paresthesias
Disturbances of movement and coordination, loss of vibratory sense and proprioception (related to degeneration of the posterior columns of the spinal cord)

If the patient presents with obstruction, the following physical findings may be noted:

Abdominal tenderness
Abdominal distention
Peritoneal signs

Complications

Rarely, patients with diphyllobothriasis may need surgical relief for obstruction or replacement of vitamin B12 or iron.

Differential Diagnoses

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Media Gallery

Life cycle of diphyllobothrium.
Egg of Diphyllobothrium latum with arrow pointing to operculum.
Proglottids of Diphyllobothrium latum.
Diphyllobothrium life cycle. This illustration depicts the life cycle of different species of Diphyllobothrium parasitic cestodes, the causal agents of the disease diphyllobothriasis. Courtesy of the Centers for Disease Control and Prevention (CDC) (https://www.cdc.gov/dpdx/diphyllobothriasis/).

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Author

Shireen R Chacko, MBBS Resident Physician, Department of Internal Medicine, Albert Einstein Medical Center

Disclosure: Nothing to disclose.

Coauthor(s)

Antonette B Climaco, MD Attending Physician, Division of Infectious Diseases, Department of Medicine, Einstein Healthcare Network

Antonette B Climaco, MD is a member of the following medical societies: American Academy of HIV Medicine, HIV Medicine Association, Infectious Diseases Society of America, Philippine Medical Association

Disclosure: Nothing to disclose.

Chief Editor

Pranatharthi Haran Chandrasekar, MBBS, MD Professor, Chief of Infectious Disease, Department of Internal Medicine, Wayne State University School of Medicine

Pranatharthi Haran Chandrasekar, MBBS, MD is a member of the following medical societies: American College of Physicians, American Society for Microbiology, International Immunocompromised Host Society, Infectious Diseases Society of America

Disclosure: Nothing to disclose.

Additional Contributors

David R Haburchak, MD, FACP Key Faculty, Wellstar Kennestone Internal Medicine Residency Program, Wellstar Health System

David R Haburchak, MD, FACP is a member of the following medical societies: American College of Physicians, American Osler Society, American Society for Microbiology, Christian Medical and Dental Associations, Infectious Diseases Society of America

Disclosure: Nothing to disclose.

Derek Ryan Linklater, MD Assistant Professor of Military and Emergency Medicine, F Edward Hebert School Of Medicine; Assistant Clinical Professor of Emergency Medicine, Texas A&M Health Science Center College of Medicine; Clinical Instructor of Pediatrics, Baylor College of Medicine

Derek Ryan Linklater, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Emergency Medicine, Society for Academic Emergency Medicine, American College of Emergency Physicians

Disclosure: Nothing to disclose.

Coburn H Allen, MD Assistant Professor of Pediatrics, Dell Children's Hospital

Coburn H Allen, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Pediatrics, Infectious Diseases Society of America, Pediatric Infectious Diseases Society

Disclosure: Nothing to disclose.

Acknowledgements

Thomas M Kerkering, MD Chief of Infectious Diseases, Virginia Tech Carilion School of Medicine

Thomas M Kerkering, MD is a member of the following medical societies: Alpha Omega Alpha, American College of Physicians, American Public Health Association, American Society for Microbiology, American Society of Tropical Medicine and Hygiene, Infectious Diseases Society of America, Medical Society of Virginia, and Wilderness Medical Society