Left lower abdominal pain and diarrhea: what conditions commonly cause this pairing?

Left lower abdominal pain and diarrhea often occur together in a variety of gastrointestinal conditions. While most causes are not life-threatening, persistent or severe symptoms warrant prompt medical attention. Below is an overview of common conditions, their typical features, and when to seek care.

Common Causes

1. Diverticular Disease
   • Pathology: Outpouchings (diverticula) form in the colon wall, most often in the sigmoid colon (left lower quadrant).
   • Clinical features:
   – Left lower abdominal pain, often constant and dull
   – Fever, chills (if diverticulitis develops)
   – Changes in bowel habits: diarrhea or constipation
   • When to suspect it: Sudden worsening of pain, fever, or blood in stool
   • Note: According to Stollman & Raskin (1999), uncomplicated diverticulosis is common after age 50 and often asymptomatic; diverticulitis causes acute pain and systemic symptoms.

2. Ulcerative Colitis (UC)
   • Pathology: Chronic inflammation of the colon lining, starting in the rectum and extending proximally.
   • Clinical features:
   – Crampy lower abdominal pain (can be left-sided)
   – Frequent, small-volume diarrhea often mixed with blood or mucus
   – Tenesmus (urgent, felt need to empty bowels)
   – Extraintestinal symptoms: joint pain, skin rashes
   • When to suspect it: Persistent diarrhea with blood, weight loss, family history of IBD
   • Reference: Ungaro et al. (2017) describe UC’s hallmark of continuous mucosal inflammation and relapsing-remitting course.

3. Infectious Colitis
   • Bacterial causes:
   – Campylobacter, Salmonella, Shigella, E. coli, C. difficile
   – Features: acute onset, high-volume diarrhea (often bloody), fever, systemic toxicity
   • Viral causes:
   – Norovirus, rotavirus
   – Features: watery diarrhea, vomiting, low-grade fever
   • Parasitic causes:
   – Giardia lamblia, Entamoeba histolytica
   – Features: diarrhea lasting weeks, weight loss, bloating
   • When to suspect it: Recent travel, antibiotic use (C. difficile), outbreak exposure, acute febrile illness

4. Irritable Bowel Syndrome (IBS)
   • Pathology: Functional disorder without inflammation
   • Clinical features:
   – Crampy abdominal pain relieved by defecation
   – Alternating diarrhea and constipation (IBS-D subtype)
   – Bloating, mucus in stool, normal labs and imaging
   • When to suspect it: Long history of recurrent symptoms, no alarming features (weight loss, blood, fever)

5. Ischemic Colitis
   • Pathology: Reduced blood flow to the colon, often during low-flow states or in patients with vascular disease
   • Clinical features:
   – Sudden abdominal pain (often left side)
   – Urgent need to defecate, bloody diarrhea
   – Older age, heart disease, dehydration
   • When to suspect it: Sudden severe pain with bloody stools in at-risk individuals

6. Medication-Related Colitis
   • Antibiotic-associated (C. difficile)
   • Nonsteroidal anti-inflammatory drugs (NSAIDs)
   • Chemotherapy agents
   • Features: Diarrhea can range from mild to life-threatening; pain may be variable
   • When to suspect it: Recent start of a new medication, especially antibiotics

7. Ovarian or Gynecologic Causes (in women)
   • Twisted ovary (ovarian torsion), ovarian cyst rupture, endometriosis
   • Often accompanied by pelvic pain, irregular bleeding, or painful periods
   • Diarrhea may occur from pelvic irritation

8. Less Common Causes
   • Crohn’s disease (can affect left colon)
   • Diverticular bleeding (often painless but can coexist with diarrhea)
   • Toxic megacolon (severe UC or infectious colitis complication)

Key Symptoms and “Red Flags”

Watch for any of these warning signs, which require urgent evaluation:

• High fever (> 101°F/38.3°C)
• Severe, unrelenting pain
• Bloody stools or melena
• Significant weight loss (> 10% of body weight)
• Signs of dehydration: dizziness, decreased urination
• New symptoms in people over 50 without prior history
• Family history of colon cancer or inflammatory bowel disease

Initial Evaluation

A healthcare provider will typically start with:

• Medical history: onset, duration, character of pain, stool patterns, travel, medications
• Physical exam: abdominal tenderness, rebound, bowel sounds
• Laboratory tests:
  • Complete blood count (CBC) for infection or anemia
  • C-reactive protein (CRP) or erythrocyte sedimentation rate (ESR) for inflammation
  • Stool studies for pathogens, leukocytes, occult blood
• Imaging:
  • Abdominal ultrasound or CT scan (especially to evaluate diverticulitis or ischemia)
• Colonoscopy or sigmoidoscopy when IBD or chronic colitis is suspected

When to Seek Care

Consider doing a free, online symptom check for left lower abdominal pain and diarrhea to help clarify your next steps. If you experience any red-flag symptoms or if your discomfort persists beyond a few days, speak to a doctor. Early evaluation can prevent complications and guide effective treatment.

General Management Principles

1. Hydration and Diet
   • Oral rehydration solutions for mild-moderate dehydration
   • Clear liquids initially (broth, tea, clear juice)
   • Gradually reintroduce low-fiber foods (bananas, rice, applesauce)
   • Avoid dairy, caffeine, alcohol, and high-fat, spicy foods until recovery

2. Medications
   • Antibiotics for bacterial infections or diverticulitis (only if prescribed)
   • Anti-diarrheal agents (loperamide) for non-bloody diarrhea without fever
   • Antispasmodics (e.g., hyoscine) for crampy pain
   • 5-aminosalicylic acid (5-ASA) drugs, steroids, or biologics for IBD under specialist care

3. Probiotics
   • May help restore healthy gut flora after infections or antibiotic use
   • Evidence varies by strain; speak to your doctor before starting

4. Surgery
   • Reserved for complications (e.g., abscess, perforation in diverticulitis; toxic megacolon)
   • UC refractory to medical therapy may require colectomy

Prevention Tips

• Eat a high-fiber diet (whole grains, fruits, vegetables) to prevent diverticulosis
• Stay hydrated and exercise regularly
• Practice good hand hygiene to reduce infectious risks
• Use antibiotics judiciously and only as prescribed
• Attend regular screenings (colon cancer screening by age 45–50, earlier if high risk)

Key Takeaway

Left lower abdominal pain and diarrhea can stem from a range of causes—from mild, self-limited infections and IBS to more serious conditions like diverticulitis or ulcerative colitis. Understanding the pattern of symptoms, associated features, and red-flag signs can help you decide when to manage at home and when to seek professional care.

If you’re unsure about the severity of your symptoms or if they worsen, please speak to a doctor. Your health and peace of mind are worth timely evaluation.