From the Guidelines
The appropriate workup for an 86-year-old female with diarrhea for two weeks should prioritize maintaining hydration and electrolyte balance, and begin with a thorough history and physical examination, followed by basic laboratory tests and stool studies. The initial management should focus on rehydration, with solutions that contain water, salt, and sugar, as recommended by the Annals of Oncology study 1.
Key Components of the Workup
- A thorough history and physical examination to identify potential causes of diarrhea
- Basic laboratory tests, including complete blood count, comprehensive metabolic panel, thyroid function tests, and C-reactive protein
- Stool studies, including stool culture, ova and parasite examination, Clostridioides difficile toxin testing, and fecal occult blood test
- Assessment of recent antibiotic use, as it's a common cause of C. difficile infection in elderly patients
- Medication review, as many medications can cause diarrhea in older adults
- Dietary history to identify potential lactose intolerance or other food intolerances
Additional Testing
If diarrhea persists despite initial evaluation, additional testing may include:
- Abdominal imaging (CT scan or ultrasound) to rule out structural abnormalities
- Consideration of colonoscopy to evaluate for inflammatory bowel disease, microscopic colitis, or malignancy, particularly if there are alarm symptoms such as weight loss, blood in stool, or nocturnal symptoms
Management of Diarrhea
The management of diarrhea should follow the guidelines outlined in the Journal of the National Comprehensive Cancer Network study 1, which recommends:
- Oral hydration and electrolyte replacement
- Antidiarrheal agents, such as loperamide
- Bland diet, including bananas, rice, applesauce, and toast
- Consideration of anticholinergic agents, such as hyoscyamine, in certain cases The Journal of Clinical Oncology study 1 also provides recommendations for the management of cancer treatment-induced diarrhea, including dietary modifications and the use of loperamide. However, the most recent and highest quality study, 1, should be prioritized in guiding the management of diarrhea in this patient.
From the Research
Workup for Diarrhea
The workup for an 86-year-old female with diarrhea for two weeks should include:
- A patient history and physical examination to evaluate for pathologies such as celiac disease or inflammatory bowel disease 2
- Laboratory tests such as:
- Complete blood count
- C-reactive protein
- Anti-tissue transglutaminase immunoglobulin A (IgA)
- Total IgA
- Basic metabolic panel 2
- Stool studies to categorize diarrhea as watery, fatty, or inflammatory 2
Differential Diagnosis
The differential diagnosis for chronic diarrhea is broad and includes:
- Functional disorders such as irritable bowel syndrome and functional diarrhea
- Secretory diarrhea caused by bile acid malabsorption, microscopic colitis, endocrine disorders, and some postsurgical states
- Osmotic diarrhea caused by carbohydrate malabsorption syndromes and laxative abuse
- Fatty diarrhea caused by malabsorption or maldigestion, including disorders such as celiac disease, giardiasis, and pancreatic exocrine insufficiency 2
Inpatient vs Outpatient Evaluation
For patients with diarrhea who are hospitalized, testing with stool cultures and stool ova and parasites (O&P) is not recommended if the diarrhea develops after 72 hours of hospitalization, as it is likely to have a nosocomial or iatrogenic etiology 3 In outpatient settings, the approach to the patient with acute infectious diarrhea is strictly a clinical one, with a careful and thoughtful ordering of diagnostic tests in cases in which the information is likely to change management and outcome for the patient 4
Testing Yield
The diagnostic yield of routine testing of stool for ova and parasites in patients with acute or chronic diarrhea is low, and most clinically significant positive results are likely to be responsive to treatment with metronidazole 5