What is the management and diagnosis for a young adult with chronic diarrhea, vomiting, and elevated liver enzymes?

Management of Chronic Diarrhea with Vomiting and Elevated Liver Enzymes in a Young Adult

This 23-year-old with 1-month diarrhea, vomiting, and mildly elevated SGPT (73 U/L) requires systematic evaluation starting with basic blood tests (CBC, thyroid function, celiac serology, comprehensive metabolic panel) and stool studies (fecal calprotectin, stool culture, ova and parasites), followed by targeted investigation based on initial findings. 1, 2

Initial Clinical Assessment

Key History Elements to Obtain

• Medication review is mandatory - up to 4% of chronic diarrhea cases are medication-induced, particularly from magnesium products, NSAIDs, antibiotics, ACE inhibitors, and antiarrhythmics 3, 2
• Dietary factors including excessive caffeine intake, lactose consumption (if lactase deficient), sugar-free sweeteners containing sorbitol, and high FODMAP foods 1, 2
• Alcohol consumption - heavy alcohol use causes 60-70% of chronic pancreatitis cases and can directly damage intestinal epithelium, causing diarrhea 4, 1
• Recent antibiotic use - raises suspicion for Clostridium difficile infection 2
• Travel history - persistent diarrhea occurs in approximately 3% of travelers to developing countries 5

Alarm Features Requiring Urgent Investigation

• Unintentional weight loss 1
• Nocturnal diarrhea (suggests organic rather than functional disease) 1
• Blood in stool 1
• Duration <3 months with progressive symptoms 1

First-Line Laboratory Investigations

Blood Tests

Order the following screening panel immediately: 1, 2

• Complete blood count (to assess for anemia, infection)
• Comprehensive metabolic panel (electrolytes, liver function, kidney function)
• Thyroid function tests (hyperthyroidism causes diarrhea through effects on gut motility) 2
• Tissue transglutaminase antibodies or antiendomysium antibodies (celiac disease has 0.5-1% prevalence and commonly presents with chronic diarrhea) 1, 2
• ESR and CRP (markers of inflammation)
• Ferritin, vitamin B12, folate, calcium levels 2

Stool Studies

Obtain stool specimens for: 1

• Fecal calprotectin (to exclude colonic inflammation - particularly important in patients under age 40 to differentiate from IBS) 1
• Stool culture for Salmonella, Shigella, Campylobacter, Yersinia 1
• Ova and parasites examination (particularly Giardia, Cryptosporidium) 1, 5
• C. difficile testing if recent antibiotic exposure 1, 3
• Fecal elastase if fat malabsorption suspected (values <100 mg/g indicate exocrine pancreatic insufficiency) 1, 4

Interpretation of Mildly Elevated SGPT (73 U/L)

The mildly elevated transaminase (SGPT/ALT = 73 U/L, approximately 1.5-2x upper limit of normal) in the context of chronic diarrhea and vomiting suggests several possibilities: 6, 7

• Medication-induced hepatotoxicity - review all medications and supplements
• Celiac disease - commonly causes mild transaminase elevation
• Chronic pancreatitis - can present with both GI symptoms and liver enzyme abnormalities
• Malnutrition/dehydration - from chronic diarrhea and vomiting
• Viral hepatitis - though typically causes higher elevations

Diagnostic Algorithm Based on Initial Results

If Fecal Calprotectin is Elevated

Proceed to colonoscopy with biopsies from right and left colon (not rectum) to exclude: 1

• Inflammatory bowel disease (Crohn's disease, ulcerative colitis)
• Microscopic colitis (requires histologic diagnosis)
• Colorectal cancer (though less likely at age 23)

If Celiac Serology is Positive

Refer for upper endoscopy with duodenal biopsies to confirm diagnosis, then initiate strict lifelong gluten-free diet 3

If Initial Tests are Normal

Consider bile acid diarrhea testing - this is frequently missed and responds well to treatment: 1, 3

• SeHCAT testing (if available) or
• Serum 7α-hydroxy-4-cholesten-3-one levels
• Do not use empirical bile acid sequestrant trials without making a positive diagnosis first 1

If Parasitic Infection Suspected

Multiplex PCR panels can simultaneously detect multiple enteric pathogens, though clinical correlation is essential as these detect DNA rather than viable organisms 1

Management Approach

Rehydration is Priority

• Oral rehydration solution for mild-moderate dehydration 1
• Intravenous fluids if severe dehydration or persistent vomiting 3

Symptomatic Treatment

Loperamide can be initiated for symptomatic relief in immunocompetent adults with watery diarrhea: 1, 3

• Initial dose: 4 mg, then 2 mg after each unformed stool
• Maximum: 16 mg daily
• Avoid if fever, bloody diarrhea, or suspected inflammatory/infectious colitis (risk of toxic megacolon) 1

Ondansetron for persistent vomiting (facilitates oral rehydration): 1

• May be used in adults and children >4 years
• Note: may increase stool volume as side effect 1

Nutritional Support

• Early refeeding decreases intestinal permeability and reduces illness duration 1
• Avoid prolonged fasting (the traditional 24-hour food restriction is not beneficial) 1
• Consider lactose-free diet if lactose maldigestion suspected 1

When to Refer for Further Investigation

Refer to gastroenterology if: 1

• Symptoms persist despite normal first-line investigations and empirical treatment
• Alarm features present
• Quality of life significantly impaired
• Fecal calprotectin elevated (requires colonoscopy)
• Positive celiac serology (requires endoscopy with biopsy)
• Suspected malabsorption requiring advanced testing (MR enterography, video capsule endoscopy)

Common Pitfalls to Avoid

• Do not diagnose IBS without excluding organic disease - Rome IV criteria have only 52-74% specificity and cannot reliably exclude IBD, microscopic colitis, or bile acid diarrhea 1, 3
• Do not rely on multiplex PCR results alone - detection of pathogen DNA does not necessarily indicate active infection or clinical significance 1
• Do not use empirical antibiotics without clear indication - increases antimicrobial resistance and may worsen outcomes 3
• Do not overlook medication review - this simple step identifies the cause in 4% of cases 3, 2
• Do not forget to check for C. difficile if any antibiotic exposure in preceding 8-12 weeks 1, 3