From the Guidelines
The best initial diagnostic test for a 38-year-old female with postprandial abdominal cramping and diarrhea for 3 weeks is an initial screening blood test, including a full blood count, ferritin, tissue transglutaminase/EMA, and thyroid function test, as well as stool tests for inflammation, such as faecal calprotectin, as recommended by the British Society of Gastroenterology 1. This approach helps to establish a baseline, rule out common infectious causes of diarrhea, and differentiate between inflammatory bowel disease and irritable bowel syndrome. The duration of symptoms suggests a subacute process that could be infectious, inflammatory, or functional in nature. Key considerations in the diagnostic workup include:
- Screening for coeliac disease using serological tests, which have high sensitivity and specificity for the disease 1
- Testing for Clostridium difficile infection using a combination of glutamate dehydrogenase enzyme immunoassay or PCR and toxin EIA 1
- Evaluating for other potential causes of diarrhea, such as inflammatory bowel disease, microscopic colitis, or colorectal neoplasia, which may require colonoscopy and biopsies 1
- Considering conditions like bile acid malabsorption or carbohydrate malabsorption, which might require specific breath tests if initial evaluation is unremarkable. Given the postprandial nature of symptoms, it is essential to consider a broad differential diagnosis and tailor the diagnostic approach accordingly. The most recent and highest quality study, published in 2021, emphasizes the importance of considering inflammatory bowel disease in older patients presenting with diarrhea, rectal bleeding, urgency, abdominal pain, or weight loss 1. However, in this case, the patient is 38 years old, and the diagnostic approach should be tailored to her specific presentation and risk factors. Overall, a comprehensive and stepwise approach to diagnosis, prioritizing the most likely causes and using a combination of laboratory tests and clinical evaluation, is essential for determining the underlying cause of this patient's symptoms.
From the Research
Diagnostic Approach
To determine the best initial diagnostic test for a 38-year-old female with postprandial abdominal cramping and diarrhea for 3 weeks, consider the following:
- The patient's symptoms could be indicative of various conditions, including infectious gastroenteritis, inflammatory bowel disease (IBD), or other gastrointestinal disorders.
- A study published in 2015 2 discusses the use of biomarkers for the diagnosis of infectious gastroenteritis, including systemic biomarkers (such as C-reactive protein) and fecal biomarkers (such as lactoferrin and calprotectin).
- Another study from 2009 3 highlights the importance of biomarkers in IBD, including acute-phase proteins, fecal markers, and serologic markers, which can help differentiate between IBD and functional disorders.
Initial Diagnostic Tests
Consider the following initial diagnostic tests:
- Serum C-reactive protein (CRP) levels: A study from 2013 4 found that CRP levels can be used to discriminate between inflammatory and non-inflammatory diarrhea, with a cut-off level of 3.08 mg/dL having a sensitivity of 82% and a specificity of 85%.
- Simple routine blood tests: A study from 1995 5 suggests that routine blood tests, including full blood count, platelet count, erythrocyte sedimentation rate, C reactive protein, and serum albumin, may help select patients who require endoscopic assessment.
- Fecal biomarkers: The 2015 study 2 mentions the use of fecal biomarkers, such as lactoferrin and calprotectin, which may be helpful in diagnosing infectious gastroenteritis.
Less Likely Diagnoses
Consider the following less likely diagnoses:
- Fabry disease: A 2022 review 6 discusses the gastrointestinal manifestations of Fabry disease, which may include postprandial cramping pain and diarrhea, but notes that the disease is rare and often misdiagnosed.