What is the first-line treatment for a patient presenting with body aches, stomach aches, diarrhea, fatigue, and decreased appetite?

First-Line Treatment for Acute Gastroenteritis

For a patient presenting with body aches, stomach aches, diarrhea, fatigue, and decreased appetite—symptoms consistent with acute gastroenteritis—the first-line treatment is oral rehydration with fluids and electrolytes, combined with symptomatic management using loperamide for diarrhea control if no warning signs are present. 1

Initial Assessment and Red Flags

Before initiating treatment, rapidly assess for warning signs that would contraindicate self-management:

• High fever (>38.5°C) or frank blood in stools (dysentery) requires medical supervision 1
• Severe dehydration (dizziness on standing, decreased urine output) necessitates urgent rehydration 1
• Age >75 years or significant comorbidities should prompt physician evaluation 1
• Recent antibiotic use warrants testing for Clostridioides difficile 2

If none of these warning signs are present, proceed with first-line self-management.

Rehydration: The Foundation of Treatment

Oral rehydration is the cornerstone of therapy for all patients with acute diarrhea. 1, 3

• Maintain fluid intake with glucose-containing fluids and electrolyte-rich soups 1
• Oral rehydration solutions are ideal but not mandatory for otherwise healthy adults 1
• Continue fluid intake throughout the illness to prevent dehydration 1

Symptomatic Management with Loperamide

Loperamide is the first-line antidiarrheal agent for non-dysenteric diarrhea in adults. 1

Dosing regimen:

• Initial dose: 4 mg orally
• Followed by: 2 mg after every unformed stool or every 4 hours
• Maximum: 16 mg per day 1

Important caveats:

• Do not use if fever >38.5°C or bloody stools are present 1
• Discontinue after 12-hour diarrhea-free interval 1
• Common side effects include abdominal pain, bloating, nausea, and constipation; careful dose titration minimizes these 1

Dietary Modifications

No evidence supports fasting in adults with acute diarrhea. 1

• Eliminate lactose-containing products temporarily 1
• Avoid high-osmolar dietary supplements 1
• Gradually reintroduce solid foods as symptoms improve 1
• Maintain adequate fluid intake throughout 1

When to Escalate Care

If symptoms persist beyond 24-48 hours on loperamide or worsen at any point:

• Persistent mild-moderate diarrhea >24 hours: Consider increasing loperamide to 2 mg every 2 hours and adding oral antibiotics as prophylaxis 1
• Persistent diarrhea >48 hours: Discontinue loperamide and seek medical evaluation for stool studies and possible second-line agents (octreotide 100-150 mcg subcutaneously three times daily) 1
• Development of warning signs: Immediate medical attention required 1

Body Aches and Fatigue Management

The systemic symptoms (body aches, fatigue, decreased appetite) are typically viral in origin and self-limited:

• These symptoms generally resolve as the gastrointestinal illness improves 4, 3
• Supportive care with rest and hydration is appropriate 3
• Acetaminophen or NSAIDs can be used for body aches if needed (general medical knowledge)

Duration and Expected Course

Most cases of acute infectious gastroenteritis are self-limited, resolving within one week. 2 Microbial studies are not needed for mild symptoms that resolve within this timeframe. 2 However, approximately 9% of patients may develop post-infectious irritable bowel syndrome, which can persist beyond the acute illness. 2