What is the appropriate diagnosis and treatment for a 23-year-old patient presenting with hematochezia and mucus in the stool?

Blood and Mucus in Stool in a 23-Year-Old Patient

In a 23-year-old presenting with blood and mucus in stool, inflammatory bowel disease (particularly ulcerative colitis) is the primary concern and requires urgent colonoscopy with biopsy for definitive diagnosis, followed by initiation of aminosalicylate therapy if confirmed. 1, 2

Initial Clinical Assessment

Key History and Physical Examination Elements

• Characterize the bleeding pattern: Blood mixed throughout stool versus on the surface only, presence of mucus, frequency of bowel movements, and stool consistency 1
• Identify inflammatory symptoms: Watery diarrhea, cramping, urgency, abdominal pain, fever, or nocturnal bowel movements strongly suggest inflammatory disease rather than benign anorectal pathology 1, 2
• Perform digital rectal examination: Essential to identify hemorrhoids, fissures, masses, or other anorectal pathology, but never attribute symptoms to hemorrhoids without endoscopic evaluation 1
• Check for red flag symptoms: Weight loss, anemia, fever, or systemic symptoms warrant immediate gastroenterology referral 3

Essential Laboratory Testing

• Complete blood count: Assess for anemia and leukocytosis 4, 1
• Inflammatory markers: C-reactive protein, procalcitonin if severe symptoms present 4
• Stool studies: Test for infectious causes including bacterial pathogens (Salmonella, Shigella, Campylobacter), Clostridioides difficile, and parasites if fever or acute onset 4, 3

Differential Diagnosis Priority

Most Likely: Inflammatory Bowel Disease

Ulcerative colitis classically presents with bloody diarrhea with mucus, rectal urgency, tenesmus, and abdominal pain relieved by defecation in young adults. 2 The combination of blood and mucus is particularly characteristic of UC and Crohn's disease. 1

Alternative Diagnoses to Consider

• Infectious colitis: Acute bloody diarrhea (dysentery) with frequent scant stools containing blood and mucus, typically with fever and lasting <7 days 4
• Internal hemorrhoids: Can cause bright red blood on stool surface, but mucus is not typical and symptoms should not be attributed to hemorrhoids without colonoscopy 5, 1
• Ischemic colitis: Less likely in a 23-year-old without vascular disease risk factors 1

Diagnostic Workup Algorithm

Step 1: Rule Out Upper GI Source (If Severe Bleeding)

• Nasogastric lavage or upper endoscopy: Only if severe hematochezia with hemodynamic instability, as 10-15% of severe hematochezia originates from upper GI tract 4

Step 2: Mandatory Lower Endoscopy

All patients with blood and mucus in stool require colonoscopy, not just sigmoidoscopy, regardless of age or presence of hemorrhoids. 1 This is critical because:

• Sigmoidoscopy alone is inadequate: Only diagnostic if actively bleeding lesion is visualized 4
• Colonoscopy with biopsy is definitive: Required to diagnose UC, assess disease extent and severity, and rule out malignancy 2
• Never skip endoscopy: Even when hemorrhoids are visible, as hemorrhoids are common and may coexist with serious pathology including inflammatory bowel disease 1

Step 3: Endoscopic Findings Guide Diagnosis

For ulcerative colitis: Continuous colonic inflammation with erythema, loss of vascular pattern, granularity, friability, bleeding, and ulcerations with distinct demarcation between inflamed and non-inflamed bowel 2

Histopathology confirms diagnosis: Decreased crypt density, crypt architectural distortion, irregular mucosal surface, heavy diffuse transmucosal inflammation without granulomas 2

Treatment Based on Diagnosis

If Ulcerative Colitis Confirmed

For mild to moderate disease in a 23-year-old:

• Induction therapy: Mesalamine 2.4-4.8 g once daily (oral) combined with topical 5-ASA for more extensive disease 6, 2
• Maintenance therapy: Mesalamine 2.4 g once daily after remission achieved 6
• Monitor renal function: Evaluate before initiation and periodically during therapy due to risk of renal impairment 6

If Infectious Colitis

• Most cases are self-limiting: Supportive care with oral rehydration and early refeeding 4, 3
• Antibiotics only if indicated: Severe illness, immunocompromised state, or specific pathogens identified 4

Critical Pitfalls to Avoid

1. Never attribute blood and mucus to hemorrhoids without colonoscopy: This is the most dangerous error, as serious pathology including IBD and malignancy may be missed 5, 1

2. Do not delay endoscopy in young patients: Age <50 does not exclude need for complete colonic evaluation when blood and mucus are present together 1

3. Do not rely on sigmoidoscopy alone: UC can affect the entire colon, and extent of disease determines treatment 2

4. Recognize acute intolerance syndrome: If patient worsens on mesalamine with cramping, abdominal pain, bloody diarrhea, fever, or rash, discontinue immediately as this may represent drug intolerance rather than disease progression 6