Differential Diagnosis for 16-year-old with Nausea, Diarrhea, and Abdominal Discomfort
- Single most likely diagnosis:
- Viral Gastroenteritis: This is the most likely diagnosis given the acute onset of symptoms, including nausea, diarrhea, and abdominal discomfort, without fever or vomiting. The fact that the father has similar symptoms supports a contagious cause, and the absence of recent travel, antibiotic use, or changes in diet points away from other common causes of gastrointestinal upset.
- Other Likely diagnoses:
- Food Poisoning: Although the patient denies any change in diet, food poisoning remains a possibility, especially if the food was contaminated with a pathogen. The symptoms of food poisoning can be similar to viral gastroenteritis, including nausea, diarrhea, and abdominal discomfort.
- Irritable Bowel Syndrome (IBS): While IBS is a chronic condition, an acute exacerbation could present with similar symptoms. However, the acute onset and the fact that the father has similar symptoms make this less likely.
- Do Not Miss diagnoses:
- Appendicitis: Although the patient's symptoms have improved, and she is afebrile, appendicitis can present with a variety of symptoms, including abdominal discomfort and diarrhea. It is crucial to consider this diagnosis due to the potential for severe consequences if missed.
- Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease or ulcerative colitis can present with diarrhea, abdominal pain, and nausea. While less likely given the acute onset, these conditions require prompt diagnosis and treatment to prevent complications.
- Intussusception: This is a condition where a part of the intestine telescopes into another part, which can cause abdominal pain, nausea, and diarrhea. It is more common in younger children but can occur in adolescents.
- Rare diagnoses:
- Giardiasis: This is an intestinal infection caused by the parasite Giardia lamblia. It can cause diarrhea, abdominal cramps, and nausea, but it is less common and typically associated with travel or exposure to contaminated water.
- Clostridioides difficile (C. diff) Infection: Although the patient denies recent antibiotic use, C. diff infection can occur without this risk factor, especially in outbreaks. It causes diarrhea, abdominal pain, and can be severe if not treated promptly.