Differential Diagnosis for 86-year-old Female with Diarrhea
The patient's presentation of diarrhea, abdominal cramping, fatigue, and dizziness with standing, in the context of her recent hospitalization and medication changes, suggests several potential diagnoses. These can be categorized as follows:
Single most likely diagnosis
- Medication-induced diarrhea (Eliquis): The patient was recently started on Eliquis (apixaban), an anticoagulant known to cause gastrointestinal side effects, including diarrhea. The temporal relationship between the initiation of Eliquis and the onset of diarrhea supports this diagnosis. The change in stool consistency and increase in frequency could be attributed to the medication's effect on the gastrointestinal system.
Other Likely diagnoses
- Infectious diarrhea: Although the patient denies fever, which is often associated with infectious causes, her age and recent hospitalization increase her risk for infections, including Clostridioides difficile (C. diff), which can present without fever.
- Bacterial overgrowth: Given her history of diabetes and the use of medications that can alter gut motility, bacterial overgrowth is a plausible cause of her chronic diarrhea.
- Irritable bowel syndrome (IBS): While less likely given the acute onset, IBS could be considered, especially if other causes are ruled out. However, the patient's age and the presence of alarm symptoms (e.g., dizziness with standing) make this less likely.
Do Not Miss (ddxs that may not be likely, but would be deadly if missed)
- Ischemic colitis: Given her history of hypertension, hyperlipidemia, and recent pulmonary embolism (PE) and deep vein thrombosis (DVT), there is a risk of vascular events. Ischemic colitis, although less common, could present with diarrhea and abdominal pain.
- C. difficile infection: This is a critical diagnosis to consider, especially given her recent hospitalization and antibiotic use (though not explicitly mentioned, it's a common practice in patients with PE and DVT). C. difficile can cause severe diarrhea and is associated with significant morbidity and mortality in elderly patients.
- Gastrointestinal bleeding: Despite denying hematochezia, the patient's anticoagulation therapy increases her risk of bleeding. A slow bleed could present with diarrhea and symptoms of anemia, such as fatigue and dizziness.
Rare diagnoses
- Thyroid storm: Although the patient's diabetes and other conditions might suggest a metabolic cause, thyroid storm is rare and typically presents with more systemic symptoms, including fever, tachycardia, and altered mental status.
- Neuroendocrine tumors: These are rare tumors that can produce substances leading to diarrhea. Given the patient's age and lack of other suggestive symptoms (e.g., flushing, wheezing), this diagnosis is less likely but could be considered if other causes are ruled out and the diarrhea persists or worsens.