Abdominal cramps and diarrhea: what combinations suggest colitis vs infection?

Abdominal cramps and diarrhea: distinguishing colitis from an infection

Experiencing abdominal cramps and diarrhea can be unsettling. While many cases are due to a straightforward infection, certain patterns suggest colitis—an inflammatory condition of the colon—rather than a simple bug. Knowing which combinations of symptoms point toward colitis versus infection can help you seek the right care.

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Key differences: colitis vs. infectious diarrhea

Feature	Colitis (inflammatory bowel disease)	Infection (gastroenteritis)
Duration	Chronic (weeks to years)	Acute (days to 2 weeks)
Onset	Gradual	Sudden
Stool characteristics	Blood, mucus, small volume	Watery, larger volume
Abdominal cramps	Persistent, often lower left side	Generalized, may be crampy spasms
Frequency of bowel movements	Frequent, with tenesmus (urgency)	Variable; often 3–10/day
Nocturnal symptoms	Common	Less common
Systemic signs	Low-grade fever, weight loss	High fever, chills, nausea/vomiting
Extraintestinal manifestations	Joint pain, skin rash, mouth ulcers	Rare
Fecal markers	↑ Lactoferrin, ↑ Calprotectin	May be elevated in bacterial cases

Data adapted from Tibble & Sigthorsson (2001) on fecal lactoferrin and other clinical sources.

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When to suspect colitis

If your cramps and diarrhea have any of the following patterns, colitis is more likely:

• Chronic course
  Symptoms lasting more than four weeks or recurring over months to years.
• Bloody or mucous stools
  Even small amounts of visible blood or mucus suggest inflammation of the colon lining.
• Tenesmus and urgency
  Feeling an urgent need to pass stool, often with little result.
• Nighttime symptoms
  Waking up one or more times per night to use the bathroom.
• Extraintestinal signs
  Joint aches, skin rashes (erythema nodosum, pyoderma gangrenosum), eye inflammation, or mouth ulcers.
• Weight loss and fatigue
  Unintentional weight loss, decreased appetite, or general tiredness.
• Lab/biomarker clues
  Elevated fecal lactoferrin or calprotectin—markers that flag white blood cells in the gut—found via stool testing (Tibble & Sigthorsson, 2001).

Common types of colitis include ulcerative colitis and Crohn’s disease (colonic involvement). Both can cause abdominal cramps, diarrhea, and bleeding.

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When to suspect an infection

Most people with cramps and diarrhea have an infection—viral, bacterial, or parasitic. Look for:

• Rapid onset
  Symptoms beginning abruptly, often within hours to a couple of days after exposure.
• High fever and chills
  Especially suggestive of bacterial pathogens like Salmonella, Shigella, or Campylobacter.
• Watery diarrhea
  May be profuse but usually not bloody (exceptions: EHEC, C. difficile).
• History of exposures
  Recent travel, dining out, camping, contact with sick individuals, or antibiotic use (risk for C. difficile).
• Nausea and vomiting
  More prominent with viral gastroenteritis (norovirus, rotavirus) or certain bacteria.
• Self-limited course
  Symptoms often improve within 3–7 days without specific treatment.
• Stool studies
  Positive cultures, antigen tests, or PCR identifying pathogens; leukocytes or lactoferrin can be elevated, but usually return to normal as infection resolves.

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Overlap and “red flag” situations

In some cases, infections can mimic colitis and vice versa. For example:

• Clostridioides difficile
  Prolonged antibiotic use can trigger C. difficile colitis with severe cramps, watery diarrhea, fever, and elevated fecal lactoferrin.
• Infectious colitis
  Shigella, Salmonella, and Campylobacter often cause bloody diarrhea and may require colonoscopy if severe.
• IBD flare-ups
  Can present with fevers and mimic an acute infection.

Red flags requiring immediate medical attention:

• Signs of dehydration (dizziness, dark urine, dry mouth)
• High, persistent fever (>38.5 °C or 101.5 °F)
• Severe abdominal pain or distension
• Bloody stools passed more than six times a day
• Rapid heart rate, low blood pressure
• Confusion or altered consciousness

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Diagnostic approach

1. Clinical history
   Detailed timeline, dietary/exposure history, travel, medication use, family history of IBD.
2. Physical exam
   Check for abdominal tenderness, signs of dehydration, extraintestinal findings.
3. Laboratory tests
   • CBC, CRP/ESR for inflammation
   • Electrolytes to assess dehydration
   • Stool studies: culture, ova/parasites, C. difficile toxin, leukocytes
4. Fecal markers
   • Lactoferrin and calprotectin help distinguish inflammatory from non-inflammatory diarrhea (Tibble & Sigthorsson, 2001).
5. Endoscopy
   Colonoscopy with biopsy to confirm colitis and gauge severity.
6. Imaging
   CT scan or MRI if complications (abscess, toxic megacolon) are suspected.

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Management strategies

Colitis (IBD)

• Medications
  5-aminosalicylic acid agents (mesalamine), corticosteroids, immunomodulators (azathioprine), biologics (anti-TNF).
• Diet and lifestyle
  Low-residue diet during flares, stress management, smoking cessation (Crohn’s).
• Monitoring
  Regular colonoscopy and blood tests to track disease activity.

Infectious diarrhea

• Rehydration
  Oral rehydration solutions or IV fluids for severe dehydration.
• Symptomatic relief
  Antispasmodics for cramps, antiemetics for nausea.
• Antibiotics
  Only for specific bacterial causes (e.g., Shigella, severe Campylobacter, C. difficile).
• Probiotics
  May help restore normal gut flora.

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Next steps and when to seek help

If you’re unsure whether your abdominal cramps and diarrhea point to colitis or an infection—or if you have any “red flag” signs—consider doing a free, online symptom check to help guide your next steps. Ultimately, only a medical professional can diagnose serious or life-threatening conditions.

Speak to a doctor right away if you experience:

• Severe or worsening pain
• High fever or persistent vomiting
• Signs of dehydration
• Blood in your stool
• Significant weight loss

Early evaluation and treatment can improve outcomes, whether your symptoms stem from colitis or an infection.