Differential Diagnosis
- Single most likely diagnosis
- Giardiasis: The patient's symptoms of diarrhea, fever, and body aches after consuming possible spoiled food, along with the description of yellow/white, loose stools, are consistent with giardiasis. The prolonged duration of symptoms and the presence of orthostatic hypotension (dizziness upon standing, low BP, and low PR) also support this diagnosis.
- Other Likely diagnoses
- Viral gastroenteritis: The patient's initial symptoms of fever, body aches, and diarrhea after possible exposure to spoiled food could be indicative of a viral gastroenteritis. However, the prolonged duration and severity of symptoms make this less likely.
- Bacterial gastroenteritis: Similar to viral gastroenteritis, the patient's symptoms could be consistent with a bacterial infection, especially given the possible exposure to spoiled food. However, the lack of recent antibiotic use and the specific characteristics of the diarrhea make this less likely than giardiasis.
- Inflammatory bowel disease (IBD): Although less likely given the acute onset and specific symptoms, IBD (e.g., Crohn's disease or ulcerative colitis) could present with chronic diarrhea and systemic symptoms. Further evaluation would be necessary to consider this diagnosis.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Clostridioides difficile (C. diff) infection: Although the patient denies recent antibiotic use, it is essential to consider C. diff infection due to its potential severity and the fact that it can occasionally occur without recent antibiotic exposure.
- Intestinal obstruction or ischemia: The patient's severe diarrhea and orthostatic hypotension could be indicative of a more severe condition such as intestinal obstruction or ischemia, which would require immediate medical attention.
- Rare diagnoses
- Whipple's disease: A rare, systemic bacterial infection that can cause chronic diarrhea, weight loss, and systemic symptoms. The patient's symptoms could be consistent with Whipple's disease, but it is much less likely than other diagnoses.
- Microscopic colitis: A condition characterized by chronic, watery diarrhea, which could be considered in the differential diagnosis, especially if other causes are ruled out. However, it is less likely given the acute onset and specific symptoms in this case.