Differential Diagnosis for Patient Reporting a Worm in Vomit
Single Most Likely Diagnosis
- Anisakiasis: This is a parasitic infection caused by the ingestion of raw or undercooked fish containing Anisakis larvae. The patient's symptom of seeing a worm in her vomit is highly suggestive of this diagnosis, as the larvae can attach to the stomach lining and cause gastrointestinal symptoms.
Other Likely Diagnoses
- Ascaris lumbricoides (Roundworm) infection: While less common in adults, if the patient has ingested contaminated food or water, they could have an intestinal infection with roundworms, which could potentially be vomited up.
- Taenia saginata (Beef Tapeworm) or Taenia solium (Pork Tapeworm) infection: These tapeworms can infect humans through the ingestion of undercooked meat. Although less likely to be vomited, segments of the tapeworm (proglottids) could potentially be seen in the vomit.
Do Not Miss Diagnoses
- Intestinal obstruction or perforation due to a large worm burden: Although rare, a significant number of worms could potentially cause a mechanical obstruction or perforation of the intestine, which would be a medical emergency.
- Gastrointestinal bleeding: Certain parasites, if present in large numbers or if they attach to the intestinal wall, could potentially cause bleeding, which might not be immediately apparent but could lead to severe anemia or hypovolemic shock.
Rare Diagnoses
- Diphyllobothriasis (Fish Tapeworm): This infection is caused by consuming undercooked or raw fish infected with the Diphyllobothrium latum tapeworm. It's less likely to present with worms in the vomit but could be considered if other symptoms like weight loss, abdominal discomfort, and vitamin B12 deficiency are present.
- Echinococcosis (Hydatid Disease): Although primarily known for causing cystic lesions in organs like the liver or lungs, in rare cases, it could potentially involve the gastrointestinal tract, but seeing a worm in the vomit would be an extremely unusual presentation.