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Diarrhea
Experience expert weight loss care at GastroDoxs in Houston with Dr. Nghia Nguyen. Board-certified and patient-centered, he offers personalized plans-combining nutrition, exercise, lifestyle coaching, FDA-approved medications, and advanced non-surgical procedures-to guide you toward safe, sustainable results and lasting health improvements.
Dr. Nghia Nguyen, DO, is a board-certified gastroenterologist providing advanced digestive care in the Greater Houston area. He earned his medical degree from the Texas College of Osteopathic Medicine and completed both his Internal Medicine residency and Gastroenterology fellowship at the University of Texas at Rio Grande Valley. Dr. Nguyen specializes in treating conditions such as acid reflux, irritable bowel syndrome (IBS), inflammatory bowel disease (IBD), and liver disorders.
Common Causes and Risk Factors
Infections (viruses such as norovirus or rotavirus; bacteria like E. coli, Salmonella; parasites)
Food intolerances (lactose, fructose) and food allergies
Blood or mucus in the stool (in more severe cases)
How Dr. Nghia Nguyen Diagnoses Diarrhea, Epigastric Pain, and Weight Changes?
Dr. Nguyen uses a step-by-step approach:
Medical History and Physical Exam
She reviews your symptom timeline, dietary habits, stressors, medication use, travel history, and family history. A targeted exam assesses abdominal tenderness, signs of dehydration, nutritional status, and muscle mass.
Laboratory Tests
Blood work includes a complete blood count to detect anemia or infection, comprehensive metabolic panel for electrolytes and liver/kidney function, thyroid function tests, celiac serologies, inflammatory markers (CRP, ESR), and vitamin levels.
Stool Studies
We test for infectious pathogens (bacteria, viruses, parasites), Clostridioides difficile toxins, fecal calprotectin for inflammation, and stool elastase to evaluate pancreatic function.
Imaging Studies
Abdominal ultrasound to examine the liver, gallbladder, pancreas, and bowel loops.
CT or MRI enterography if structural issues or small-bowel pathology are suspected.
Endoscopic Evaluation
Upper endoscopy (EGD) inspects the esophagus, stomach, and duodenum for ulcers, gastritis, celiac disease, and allows for targeted biopsies.
Colonoscopy evaluates the colon and terminal ileum for colitis, IBD, microscopic colitis, or neoplasms when diarrhea is chronic or weight loss is significant.
Advanced Functional Testing (if needed)
Specialized tests such as hydrogen breath tests for small-intestinal bacterial overgrowth (SIBO) or lactose intolerance, gastric emptying study for gastroparesis, and motility testing help pinpoint functional disorders.
Treatment
Our Team offers a full range of care for safe, effective weight loss.
1. Lifestyle and Diet Modifications
Personalized meal plans built around whole foods, lean protein, fiber-rich grains, and plenty of vegetables
Exercise programs tailored to your schedule and fitness level to support steady progress
Stress-management strategies and sleep-optimization techniques to enhance metabolic health
2. Medications
FDA-approved weight loss drugs chosen based on your medical history
Appetite suppressants and GLP-1 agonists (eg, semaglutide) to help you feel full longer
Close monitoring for side effects and dose adjustments to keep you safe
3. Minimally Invasive or Advanced Procedures
Endoscopic sleeve gastroplasty to reduce stomach volume and promote early satiety
Gastric balloon therapy as a reversible, non-surgical option
Combined therapy protocols—procedures plus medication—for long-term weight management
Dr. Nghia Nguyen, DO, is a board-certified gastroenterologist providing advanced digestive care in the Greater Houston area. He earned his medical degree from the Texas College of Osteopathic Medicine and completed both his Internal Medicine residency and Gastroenterology fellowship at the University of Texas at Rio Grande Valley. Dr. Nguyen specializes in treating conditions such as acid reflux, irritable bowel syndrome (IBS), inflammatory bowel disease (IBD), and liver disorders.
Frequently Asked Questions
What causes diarrhea?
Common causes include infections, food intolerance, medications, and chronic conditions like IBS or IBD.
When should I see a doctor for diarrhea?
If it lasts more than two days, includes blood, or leads to dehydration, seek medical attention.
Can stress cause diarrhea?
Yes. Stress and anxiety can affect gut motility and trigger diarrhea in some people.
What should I eat if I have diarrhea?
Stick to bland foods like bananas, rice, applesauce, and toast (BRAT diet) and avoid greasy or spicy foods.
Is diarrhea a symptom of COVID-19?
Yes. In some cases, diarrhea can be an early symptom of COVID-19 along with fever and fatigue.
Can over-the-counter medications help?
Yes. Loperamide (Imodium) may help, but avoid it if you have a fever or blood in stool.
What tests are done to find the cause?
Depending on your case, stool tests, blood work, or a colonoscopy may be recommended.
